{"data":[{"code":"21NPWX4-018","name":"21NPW","slug":"21npwx4-018","description":"Sub-Woofer\/21inch\/Neo\/Paper\/1800W\/4ohm","url":"https:\/\/redcatt.net\/products\/21npwx4-018","category":"LF","type":"Sub-woofer","size_inches":21,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1800","continuous_watts":"3600","peak_watts":"7200"},"voice_coil":{"diameter":"134.6","wire":"Copper","former":"Glass Fiber","winding_height":"33"},"thiele_small_parameters":{"fs_hz":35,"re_ohm":3,"qes":0.33,"qms":11.12,"qts":0.32,"vas_liters":149,"sd_cm2":1662,"sensitivity_db":96.32,"mms_grams":514,"rms":10.16,"cms":0.04,"bl_tm":32.9,"le_mh":1.14},"physical":{"overall_diameter_mm":546,"bolt_circle_diameter_mm":520,"baffle_cutout_diameter_mm":496,"mounting_holes":"8","depth_mm":245,"net_weight_kg":14.85,"xmax_mm":"9","xmech_mm":"24"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["5.3\u201d diameter voice coil","3600 watts program power handling","Triple silicone spider, heavy duty fiber reinforced cone with large surround"],"design_notes":"The 21NPW is a high efficiency, (96 dB 1watt \/ 1 meter) 21-inch woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts. The 21NPW uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 31mm. \n\nPower Handling\nAt the core of the 21NPW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 350C, well beyond the thermal requirements of modern professional audio systems. The 21NPW delivers incredible performance. \n \nREDCATT has implemented a triple layer\/silicone spider design to ensure long term Fs memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 21NPWX4-018 is a 21-inch professional sub-woofer driver rated at 1800 W AES (3600 W continuous) into a nominal 4-ohm impedance, designed for touring, large-venue installation, and high-SPL bass reinforcement systems requiring maximum output in the sub-bass frequency range. The driver delivers 96.32 dB sensitivity (1W\/1m), among the highest in its class for a 21-inch frame, and is built around a neodymium motor generating a Bl of 32.9 T\u00b7m \u2014 providing exceptionally tight cone control at high drive levels with reduced thermal compression over sustained operation.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 100 to 220 liters, tuned between 30 and 40 Hz, delivering an estimated -3 dB frequency of approximately 30 to 40 Hz. Slot ports (250 mm \u00d7 80 mm) for fixed installation and dual 125 mm round ports for touring are both practical across all three alignments, with port velocities between 11.5 and 18.8 m\/s. The 160-liter balanced alignment tuned to 35 Hz represents the general-purpose professional recommendation, providing strong output from 35 Hz upward with dual round ports operating at 13.4 m\/s.\n\nThe driver is rated for use with amplification of approx. 1800 W AES (3600 W continuous) into 4 ohms, with a high-pass filter recommended in the 24\u201335 Hz range depending on alignment. DSP processing with excursion limiting is essential at sustained high-power levels; below the tuning frequency, cone excursion increases rapidly and approaches the 9 mm Xmax before thermal limits are reached. Two drivers wired in parallel present a 2-ohm load; series wiring presents 8 ohms.\n\nThe 21NPWX4-018 is intended for professional touring sub arrays, stadium and large-venue ground stacks, club and nightclub subwoofer installations, concert infrastructure subwoofer systems, and fixed-install bass reinforcement in venues where the combination of high sensitivity, extreme power handling (Polyimide former rated to 350\u00b0C), and maximum cone displacement define the required performance envelope.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 21NPWX4-018\nDriver: 21NPWX4-018 (21NPW) \u2014 21\" pro sub-woofer, 4 ohm\nKey T\/S: Fs=35.0Hz, Qts=0.32, Qes=0.33, Qms=11.12, Vas=149L, Sens=96.32dB\nPower: AES 1800W \/ Cont 3600W \/ Peak 7200W\nXmax=9.0mm, Xmech=24.0mm, Sd=1662.0cm\u00b2, Bl=32.9T\u00b7m\nLe=1.14mH | Neodymium | 5.3\" Polyimide former | Triple silicone spider\n\nDESIGN HIGHLIGHTS:\n - Bl=32.9 T\u00b7m \u2014 the highest motor force index in the REDCATT pro\n lineup; exceptionally tight cone control, low Qts, and high\n sensitivity at maximum drive levels\n - 96.32 dB sensitivity (1W\/1m) \u2014 excellent for a 21\" sub, allows\n less amplifier power for a given SPL vs lower-sensitivity designs\n - 5.3\" (134.6mm) voice coil on Polyimide composite former, rated to\n peak temperatures in excess of 350\u00b0C \u2014 the primary enabler of\n sustained 3600W continuous operation\n - Triple layer\/silicone spider \u2014 engineered for long-term Fs memory\n and consistent mechanical behavior under touring conditions; resists\n creep and spider fatigue during high-power sustained operation\n - Triple roll constant-geometry fabric surround \u2014 maintains controlled\n cone motion throughout the 9mm Xmax linear range; 31mm P-P design\n excursion travel\n - CF paper cone \u2014 carbon fiber reinforced for rigidity and controlled\n modal behavior in the upper bass range\n - Qms=11.12 \u2014 low mechanical losses; motor and amplifier provide the\n dominant system damping (Qes=0.33 governs behavior)\n - Neodymium motor \u2014 compact and lightweight for a 21\" sub at 14.85 kg\n total, reducing enclosure and rigging weight in touring applications\n\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented) only\n Qts=0.32 places this driver firmly in the classic pro vented range.\n Sealed enclosures are not recommended: achieving Butterworth (Qtc=0.707)\n would require ~38L \u2014 impractically small for a 21\" baffle, and would\n shift the system resonance to ~77 Hz, far outside useful subwoofer\n operating range. All three alignments below maximize the driver's\n output, extension, and efficiency in vented loading.\nVENTED ALIGNMENTS\nVd = 1662 cm\u00b2 \u00d7 9.0mm = 1495.8 cm\u00b3\n\nBoth slot and dual round port options given per alignment.\nSlot ports are recommended for fixed installation; dual round ports\nfor touring cabinets where slot construction adds weight.\n\n a) High SPL \/ Touring Compact\n Net Volume: 100 liters\n Tuning (Fb): 40 Hz\n Est. -3dB: ~40 Hz\n HP Filter: 35 Hz (24dB\/oct \u2014 essential; excursion rises steeply\n below tuning with Xmax=9mm)\n Slot Port: 250mm W \u00d7 80mm H \u00d7 373mm long\n Dual Round Ports: 125mm dia \u00d7 457mm each\n Port Velocity (slot): 18.8 m\/s \u2713\n Port Velocity (dual round): 15.3 m\/s \u2713\n Notes: Maximum output per unit volume. Compact footprint ideal for\n flyware and ground-stacked touring subwoofer arrays. Strong\n mid-bass punch in the 40\u201380 Hz region, well-matched to kick\n drum and bass guitar fundamental output. High-pass protection\n is critical at full power \u2014 at or near Xmax, excursion below\n Fb is mechanical-limit constrained, not thermally.\n\n b) Balanced \/ General Purpose\n Net Volume: 160 liters\n Tuning (Fb): 35 Hz\n Est. -3dB: ~35 Hz\n HP Filter: 28 Hz (24dB\/oct recommended)\n Slot Port: 250mm W \u00d7 80mm H \u00d7 304mm long\n Dual Round Ports: 125mm dia \u00d7 373mm each\n Port Velocity (slot): 16.5 m\/s \u2713\n Port Velocity (dual round): 13.4 m\/s \u2713\n Notes: Standard professional sub alignment tuned near Fs. Excellent\n balance between low-frequency extension, SPL output, and\n practical cabinet size. Suitable for concert touring, club\n installation, and outdoor events. Dual round ports at\n 13.4 m\/s are comfortably below audible turbulence threshold.\n\n c) Extended Low Frequency\n Net Volume: 220 liters\n Tuning (Fb): 30 Hz\n Est. -3dB: ~30 Hz\n HP Filter: 24 Hz (24dB\/oct recommended)\n Slot Port: 250mm W \u00d7 80mm H \u00d7 301mm long\n Dual Round Ports: 125mm dia \u00d7 369mm each\n Port Velocity (slot): 14.1 m\/s \u2713\n Port Velocity (dual round): 11.5 m\/s \u2713 (very low)\n Notes: Maximum deep bass extension for large venue, stadium, and\n fixed installation subwoofer systems. At 30 Hz tuning with\n a 21\" driver at 1800W AES, acoustic output in the sub-30Hz\n band is exceptional. Dual round ports at 11.5 m\/s produce\n effectively inaudible port noise. Suitable for cinema, live\n event infrastructure, and permanent installation systems.\n\nAMPLIFICATION NOTES:\n - Minimum recommended amplifier power: 1800W AES into 4 ohm\n - Typical operating range: 1800\u20133600W (AES to continuous rating)\n - Peak headroom: up to 7200W \u2014 requires very high-current amplifier\n - Two drivers in parallel: 2 ohm load \u2014 verify amplifier stability\n - Two drivers in series: 8 ohm load \u2014 suitable for 8-ohm amplifiers\n - HP filter required per alignment above; DSP-based limiting\n (excursion and thermal) is essential at sustained high-power levels\n - The 96.32 dB sensitivity allows 3dB SPL gain over a 93dB driver\n at identical amplifier power \u2014 useful for system gain structure\n\nCOMPARISON \u2014 21NPW vs 181NPW (18\"):\n Parameter 21NPWX4-018 181NPWX4-099\n Size 21\" 18\"\n Sensitivity 96.3 dB 94.8 dB +1.5dB\n AES Power 1800W 1500W +300W\n Bl 32.9 T\u00b7m 29.7 T\u00b7m stronger motor\n Fs 35 Hz 28 Hz higher\n Qts 0.32 0.25 slightly higher\n Sd 1662 cm\u00b2 1225 cm\u00b2 +35% radiating area\n Vd (at Xmax) 1496 cm\u00b3 1091 cm\u00b3 +37% displacement\n\n The 21NPW provides higher sensitivity and greater cone displacement\n (Vd) than the 181NPW, at higher Fs and slightly higher Qts.\n For maximum SPL in the 35\u201380 Hz range: 21NPW.\n For deepest extension below 30 Hz (lower Fs=28Hz): 181NPW."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/21NPW-018-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/21NPW-018-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/21NPW-018-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/21NPW-018-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/21NPW-018-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/21NPW-018-3D.STEP"}},{"code":"21XRX8-347A","name":"21XR","slug":"21xrx8-347a","description":"Sub-Woofer\/21inch\/Neo\/Paper\/1500W\/8ohm","url":"https:\/\/redcatt.net\/products\/21xrx8-347a","category":"LF","type":"Sub-woofer","size_inches":21,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1800","continuous_watts":"3600","peak_watts":"7200"},"voice_coil":{"diameter":"134.6","wire":"Copper","former":"Glass Fiber","winding_height":"21"},"thiele_small_parameters":{"fs_hz":32.3,"re_ohm":4.5,"qes":0.51,"qms":16.79,"qts":0.5,"vas_liters":194.45,"sd_cm2":1662,"sensitivity_db":95.7,"mms_grams":488.58,"rms":5.9,"cms":0.05,"bl_tm":29.37,"le_mh":0.65},"physical":{"overall_diameter_mm":549,"bolt_circle_diameter_mm":525,"baffle_cutout_diameter_mm":503,"mounting_holes":"8","depth_mm":287,"net_weight_kg":23.8,"xmax_mm":"22.83","xmech_mm":"89.49"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["linear cone excursion 60mm peak TO peak !!","unparallel low distortion at low frequencies","patented design, innovative magnetic structure & venting system"],"design_notes":"The 21XR is a high efficiency, (96 dB 1watt \/ 1 meter) 21-inch woofer with incredibly linear frequency response characteristics. Our new and patented ground up motor design is a new approach to high-excursion woofers. The voice coil winding is always in the magnetic gap that is extremely wide. This feature ensures extremely low distortion across whole working range of this unique driver. \n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding. This has allowed us to push the cone excursion to 50mm peak to peak. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver. We have also developed a new technique for manufacturing deep copper caps that are implemented in this design and covering the whole voice coil movement.. \n \nThe design further utilizes triple, uncommonly large, spiders, spaced with spacers, hot-pressed tinsel wires onto the top spider, reinforced cone edge, reinforced surround to cone joint, reinforced spider to basket joints, etc.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in touring, installation, and high-SPL applications, where consistent performance, durability, and output capability are critical.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 21XRX8-347A\nDriver: 21XRX8-347A (21XR) \u2014 21\" Sub-woofer\nKey T\/S: Fs=32.3Hz, Qts=0.5, Vas=194.45L, Sens=95.7dB\nPower: AES 1800W \/ Cont 3600W \/ Peak 7200W\nXmax=22.83mm, Sd=1662.0cm\u00b2, Bl=29.37T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 130 liters\n Tuning (Fb): 37 Hz\n Est. -3dB: 34 Hz\n HP Filter: 29 Hz (24dB\/oct recommended)\n Round Ports: 3\u00d7 150mm dia \u00d7 771mm long\n Slot Port: 402mm W \u00d7 90mm H \u00d7 445mm L\n Port Velocity: 16.7 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 165 liters\n Tuning (Fb): 33 Hz\n Est. -3dB: 30 Hz\n HP Filter: 23 Hz (24dB\/oct recommended)\n Round Ports: 2\u00d7 150mm dia \u00d7 464mm long\n Slot Port: 402mm W \u00d7 90mm H \u00d7 431mm L\n Port Velocity: 22.4 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 200 liters\n Tuning (Fb): 29 Hz\n Est. -3dB: 25 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Round Ports: 2\u00d7 150mm dia \u00d7 530mm long\n Slot Port: 402mm W \u00d7 90mm H \u00d7 498mm L\n Port Velocity: 19.5 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 21XRX8-347A is a 21-inch high-output sub-woofer driver designed for professional subwoofer systems requiring high sensitivity (96 dB 1W\/1m) and controlled low-frequency behavior. The driver features a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 130 to 200 liters, tuned between 29 and 37 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 1800 W AES \/ 3600 W continuous) and DSP control. A high-pass filter in the range of 20\u201329 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 25\u2013100 Hz, making it suitable for integration with mid-bass or full-range systems."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/21XR-347A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/21XR-347A-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/21XRX4-347-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/21XR-347A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/21XR-347A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/21XR-347A-3D.STEP"}},{"code":"181NPWX4-099","name":"181NPW","slug":"181npwx4-099","description":"Woofer\/18inch\/Neo\/Paper\/1500W\/4ohm","url":"https:\/\/redcatt.net\/products\/181npwx4-099","category":"LF","type":"Sub-woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1500","continuous_watts":"3000","peak_watts":"6000"},"voice_coil":{"diameter":"134.6","wire":"Copper","former":"Glass Fiber","winding_height":"32.8"},"thiele_small_parameters":{"fs_hz":28,"re_ohm":3.2,"qes":0.25,"qms":15.8,"qts":0.25,"vas_liters":167.7,"sd_cm2":1225.4,"sensitivity_db":94.8,"mms_grams":391.2,"rms":4.35,"cms":0.08,"bl_tm":29.7,"le_mh":1.76},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":426,"mounting_holes":"8","depth_mm":210,"net_weight_kg":13.9,"xmax_mm":"8.9","xmech_mm":"23.9"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["5.3\u201d diameter voice coil, high power handling","Improved coil and magnet air-ventilation system, high temp. Capable voice coil winding","Carbon fiber reinforced paper cone, triple silicone spider"],"design_notes":"The 181NPW is a high efficiency, (95 dB 1watt \/ 1 meter) 18-inch woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts. The 181NPW uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 30.5mm. \n\nPower Handling\nAt the core of the 181NPW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 350C, well beyond the thermal requirements of modern professional audio systems. The 181NPW delivers incredible performance. \n \nREDCATT has implemented a triple layer\/silicone spider design to ensure long term shape memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 181NPWX4-099 is an 18-inch professional woofer and sub-woofer driver rated at 1500 W AES (3000 W continuous) into a nominal 4-ohm impedance, designed for touring, large-venue installation, and high-SPL bass reinforcement systems. The driver features a 5.3-inch (134.6 mm) voice coil wound on a Polyimide composite former rated to 350\u00b0C, enabling sustained operation at continuous power levels that would thermally compromise standard glass fiber or paper formers. The motor-suspension design is optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 80 to 180 liters, tuned between 30 and 40 Hz, with an estimated -3 dB frequency of approximately 29 to 39 Hz. The low Qts (0.25) and exceptionally high motor force (Bl = 29.7 T\u00b7m) make this driver exclusively suited to vented enclosures; sealed alignments require impractically small volumes for an 18-inch frame. Slot ports in the 200 mm \u00d7 80 mm format are recommended for larger cabinets, with port velocities between 12.9 and 17.1 m\/s \u2014 within professional installation standards across all three alignments.\n\nThe driver is intended for use with high-power amplification of approx. 1500 W AES (3000 W continuous) into 4 ohms, with a recommended high-pass filter in the 24\u201335 Hz range depending on alignment. DSP control with excursion limiting and thermal protection is essential at sustained drive levels near the continuous rating. The 4-ohm impedance is suited to high-current solid-state amplification in direct or bridged configurations; parallel wiring of two drivers presents a 2-ohm load for compatible amplifiers.\n\nThe 181NPWX4-099 is intended for single and multi-driver bass reflex enclosures in professional touring and fixed installation applications, including concert sub arrays, club and venue subwoofer systems, cinema low-frequency systems, and large-format PA bass sections where the combination of high sensitivity (94.8 dB), extreme power handling, and very low Qts motor control define the performance envelope.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 181NPWX4-099\nDriver: 181NPWX4-099 (181NPW) \u2014 18\" pro woofer \/ sub-woofer, 4 ohm\nKey T\/S: Fs=28.0Hz, Qts=0.25, Qes=0.25, Qms=15.8, Vas=167.7L, Sens=94.8dB\nPower: AES 1500W \/ Cont 3000W \/ Peak 6000W\nXmax=8.9mm, Xmech=23.9mm, Sd=1225.4cm\u00b2, Bl=29.7T\u00b7m\nLe=1.76mH | Neodymium | 5.3\" voice coil | Polyimide former\n\nDESIGN HIGHLIGHTS:\n - 5.3\" (134.6mm) voice coil on Polyimide composite former, rated to\n 350\u00b0C peak temperature \u2014 enables the AES 1500W \/ continuous 3000W\n power handling that defines this driver's pro touring capability\n - Bl=29.7 T\u00b7m \u2014 one of the highest motor force values in the lineup;\n combined with Qts=0.25, this is a driver with exceptional cone\n control under high-power continuous drive\n - Qms=15.8 \u2014 mechanical losses are negligible; essentially 100% of\n system damping is provided by the electrical circuit (Qes=0.25)\n - CF paper cone (carbon fiber reinforced) \u2014 high rigidity, low mass\n relative to size, resists cone breakup at large excursion\n - Triple roll constant-geometry fabric surround \u2014 maintains consistent\n Cms through the full excursion range; 30.5mm peak-to-peak design\n - Triple layer silicone spider \u2014 long-term shape memory, high\n reliability under sustained touring and installation use\n - Improved coil and magnet air-ventilation \u2014 active cooling of the\n magnetic gap extends thermal endurance at continuous high power\n - 4-ohm nominal: suits high-current amplifiers and bridged\n configurations; parallel wiring of two drivers = 2 ohm\n\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented) only\n With Qts=0.25, this driver is firmly in the strongly-vented alignment\n range. Sealed enclosures require impractically small volumes to reach\n Qtc=0.707 (~24L for an 18\" driver), producing a system resonance near\n 79 Hz \u2014 completely inappropriate for subwoofer applications. Vented\n enclosures fully exploit the low Qts: the port resonance provides\n additional cone control near tuning, and the high motor force (Bl=29.7)\n maintains tight, controlled bass output under continuous drive.\nVENTED ALIGNMENTS\nVd = 1225.4 cm\u00b2 \u00d7 8.9mm = 1090.6 cm\u00b3\n\nBoth round port and slot port options are given. Slot ports are\npreferred for large enclosures due to reduced turbulence and easier\nintegration into the cabinet structure.\n\n a) Compact \/ Touring\n Net Volume: 80 liters\n Tuning (Fb): 40 Hz\n Est. -3dB: ~39 Hz\n HP Filter: 35 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 286mm long\n Slot Port: 200mm W \u00d7 80mm H \u00d7 373mm long\n Port Velocity (round): 22.3 m\/s \u2713 (pro touring acceptable)\n Port Velocity (slot): 17.1 m\/s \u2713\n Notes: Maximum SPL alignment, smallest cabinet for portable and\n flyware touring systems. Strong mid-bass punch; pair with\n DSP high-pass for cone excursion protection. Slot port\n preferred at this velocity. Well-suited for stage monitor\n sub configurations and compact line-array ground stacks.\n\n b) Balanced \/ General Purpose\n Net Volume: 130 liters\n Tuning (Fb): 34 Hz\n Est. -3dB: ~33 Hz\n HP Filter: 28 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 243mm long\n Slot Port: 200mm W \u00d7 80mm H \u00d7 317mm long\n Port Velocity (round): 19.0 m\/s \u2713\n Port Velocity (slot): 14.6 m\/s \u2713\n Notes: Standard professional sub alignment. Good balance between\n output, extension, and cabinet size. Suitable for club\n install, touring subwoofer arrays, and fixed installation\n systems. Slot port operates below 15 m\/s \u2014 very quiet,\n suitable for installed sound applications.\n\n c) Extended Low Frequency\n Net Volume: 180 liters\n Tuning (Fb): 30 Hz\n Est. -3dB: ~29 Hz\n HP Filter: 24 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 226mm long\n Slot Port: 200mm W \u00d7 80mm H \u00d7 294mm long\n Port Velocity (round): 16.8 m\/s \u2713\n Port Velocity (slot): 12.9 m\/s \u2713 (excellent)\n Notes: Maximum extension for large fixed installation, cinema,\n and high-end touring sub systems. Deep output approaching\n 30 Hz at full power. Slot port at 12.9 m\/s is extremely\n quiet \u2014 appropriate for concert hall, broadcast, and\n premium nightclub installations where port noise must be\n inaudible. Large cabinet; internal bracing and damping\n critical at this volume.\n\nWOOFER \/ BASS DRIVER APPLICATION:\nThe 181NPW is labeled woofer in the product description and is\ncapable of serving as a high-power bass driver in large-format PA\nsystems crossed above 100 Hz to a mid driver or compression driver:\n\n - Crossover range: 100\u2013300 Hz (to mid driver or CD horn)\n - The CF paper cone and strong motor (Bl=29.7) provide clean,\n controlled output well into the upper bass range\n - 94.8 dB sensitivity matches closely with typical large-format\n compression drivers (95\u2013106 dB) \u2014 minimal pad required\n - At 1500W AES \/ 4 ohm, suited for high-power touring amplifiers\n in BTL (bridged) configuration\n\nAMPLIFICATION NOTES:\n - Minimum recommended amplifier power: 1500W AES into 4 ohm\n - Typical operating level: 1500\u20133000W (AES to continuous rating)\n - Peak headroom: up to 6000W \u2014 requires high-current amplifier\n - Paralleled pair: 2 ohm load \u2014 verify amplifier 2-ohm stability\n - High-pass filter required (see HP values above per alignment)\n - DSP processing with peak limiting (excursion and thermal) is\n essential at sustained high-power levels"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/181NPW-099-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/181NPW-099-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/181NPW-099-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/181NPW-099-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/181NPW-099-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/181NPW-099-3D.STEP"}},{"code":"18XRX4-304B","name":"18XR","slug":"18xrx4-304b","description":"Woofer\/XR Woofer\/18inch\/Neo\/Paper\/1200W\/4ohm","url":"https:\/\/redcatt.net\/products\/18xrx4-304b","category":"LF","type":"Sub-woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1200","continuous_watts":"2400","peak_watts":"4800"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"22"},"thiele_small_parameters":{"fs_hz":21,"re_ohm":3.3,"qes":0.36,"qms":17,"qts":0.35,"vas_liters":300,"sd_cm2":1256.6,"sensitivity_db":92.07,"mms_grams":402,"rms":3.12,"cms":0.14,"bl_tm":22.2,"le_mh":0.54},"physical":{"overall_diameter_mm":467.6,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":422,"mounting_holes":"8","depth_mm":257.2,"net_weight_kg":14.7,"xmax_mm":"17","xmech_mm":"36"},"materials":{"surround":"SBR","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Cone excursion 56mm !! Patented design.","1 demodulation copper ring, powerful and innovative motor structure, innovative venting system","Double spider with spacer, woven-in tinsel wires, optimized surround"],"design_notes":"The 18XR is a truly groundbreaking subwoofer. REDCATT team has spent countless hours creating something outstanding. Where the conventional sub-woofers stop performing due to the design limitations, the XR series just starts and shines. With huge excursion, high Bl, newly designed suspension system, we are giving you a product that will not limit you to achieve even your wildest sub-woofer dreams. \n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding. This has allowed us to push the cone excursion to 52mm peak to peak. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver. We have also developed a new technique for manufacturing deep copper caps. \n \nThe design further utilizes two, uncommonly large, spiders, spaced apart with spacer, hot-pressed tinsel wires onto the top spider, reinforced cone. The suspension is designed for large excursions. Large lightweight surround sports resonant control features that we fully FEM designed and optimized to provide the best possible performance under large excursions.","hero_text":null,"ai_summary":"The 18XRX4-304B is an 18-inch sub-woofer and bass driver rated at 1200 W AES (2400 W continuous) into a nominal 4-ohm impedance, built around the patented XR (eXtended Range) radial neodymium motor system and featuring an exceptionally low free-air resonance of 21 Hz. Radial neodymium magnets are distributed along the full voice coil winding, maintaining the coil within the magnetic field through 17 mm of linear excursion (Xmax), eliminating the dominant source of harmonic distortion associated with coil overhang in conventional large-excursion drivers. A copper demodulation ring further reduces inductance to 0.54 mH, extending upper-frequency linearity and enabling clean crossover integration up to approximately 500 Hz. The double-spider suspension with spacer and FEM-optimised SBR rubber surround are engineered to provide consistent restoring force and constant cone geometry through the full excursion range.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 100 to 280 liters, tuned between 22 and 35 Hz. Port velocities are maintained below 20 m\/s using slot ports (300 mm \u00d7 80 mm) for compact touring alignments and dual 125 mm round ports for larger cinema and hi-fi installations. The very low Fs (21 Hz) enables the vented -3 dB to reach as low as 21 Hz in the 280-liter alignment \u2014 practical infrasonic extension for cinema LFE and audiophile reference systems. Sealed enclosures produce a notably advantageous alignment: at 100 liters, Qtc = 0.70 (near-perfect Butterworth, fc = 42 Hz), a passive maximally flat sealed response that is unusual for a driver of this size and power class.\n\nThe driver is rated for amplification of approx. 1200 W AES (2400 W continuous) into 4 ohms, with high-pass filtering in the 18\u201328 Hz range recommended for vented systems depending on tuning frequency. DSP control with excursion and thermal limiting is essential at sustained high-power operation. Sealed systems benefit from a Linkwitz Transform targeting fc = 21 Hz, Qtc = 0.707 to extend passive response to the infrasonic register, with the 17 mm Xmax providing sufficient mechanical headroom for the required bass correction.\n\nThe 18XRX4-304B is suited for a broad range of applications: professional touring sub arrays and large-venue PA systems, cinema LFE and screen-channel bass sections, large-format studio reference monitoring, high-end home cinema and audiophile listening room subwoofers, and high-power bass driver duty in large multi-way loudspeaker systems \u2014 anywhere that infrasonic-capable, low-distortion bass reproduction at sustained high output levels is required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 18XRX4-304B\nDriver: 18XRX4-304B (18XR) \u2014 18\" XR sub-woofer \/ woofer, 4 ohm\nKey T\/S: Fs=21.0Hz, Qts=0.35, Qes=0.36, Qms=17.0, Vas=300L, Sens=92.07dB\nPower: AES 1200W \/ Cont 2400W \/ Peak 4800W\nXmax=17.0mm, Xmech=36.0mm, Sd=1256.6cm\u00b2, Bl=22.2T\u00b7m\nLe=0.54mH | XR radial neodymium | 1 copper demodulation ring | SBR rubber surround\n\nDESIGN HIGHLIGHTS:\n - XR (eXtended Range) patented radial neodymium motor: magnets run\n along the full voice coil winding, keeping the coil in the magnetic\n field through virtually the entire rated excursion \u2014 17mm Xmax\n linear, 36mm Xmech mechanical limit. This directly eliminates the\n dominant source of high-order harmonic distortion in conventional\n 18\" drivers at high excursion.\n - Fs=21 Hz \u2014 free-air resonance at the threshold of infrasonic range.\n This is exceptional for a pro\/cinema 18\" driver and defines its\n capability for sub-20 Hz reproduction when properly loaded.\n - Vas=300 L \u2014 very large compliance volume; the suspension is\n extremely compliant, calibrated for maximum cone displacement at\n infrasonic and deep bass frequencies.\n - 4\" (101.6mm) voice coil on glass fiber former \u2014 high thermal mass\n and mechanical strength for continuous 2400W operation.\n - Le=0.54mH \u2014 very low for an 18\" driver of this power class, due to\n XR radial neodymium geometry + 1 copper demodulation ring.\n Extended high-frequency response; clean crossover integration up\n to ~500 Hz.\n - Double spider with spacer \u2014 two large Nomex spiders spaced along\n the former provide linear restoring force through the full Xmax\n without the progressive stiffening that limits conventional\n single-spider designs.\n - SBR (Styrene-Butadiene Rubber) surround \u2014 FEM-optimised geometry\n for constant cone geometry through large excursion, high durability\n for touring and installation environments.\n - Qms=17.0 \u2014 effectively zero mechanical losses; system damping\n is entirely electrical. Ideal for DSP-managed active systems where\n the amplifier's output impedance defines the damping behaviour.\n\nRECOMMENDED ENCLOSURE TYPES:\n PRIMARY: Bass Reflex (Vented) \u2014 for maximum LF extension, output,\n and efficiency. Pro touring, cinema, large install.\n SECONDARY: Sealed (Acoustic Suspension) \u2014 for hi-fi reference and\n large studio monitoring. Uniquely, a 100L sealed box gives\n a near-perfect Butterworth (Qtc\u22480.70) alignment at fc=42Hz\n \u2014 exceptional for passive use or DSP correction baseline.\n\nPORT DESIGN NOTE:\nThe very low Fs (21 Hz) combined with large box volumes and high Vd\n(2136 cm\u00b3) means that port tubes are long regardless of aperture choice.\nSlot ports built into the cabinet rear baffle or base are the practical\nstandard for cinema and large-install cabinets. Dual round ports are\nthe preferred option for touring. All port lengths given below are\nachievable but require careful cabinet design; folded slot port\nconfigurations are recommended where straight ports exceed cabinet depth.\nVENTED ALIGNMENTS (Primary)\nVd = 1256.6 cm\u00b2 \u00d7 17.0mm = 2136.2 cm\u00b3\n\n a) Pro Touring \/ Compact\n Net Volume: 100 liters\n Tuning (Fb): 35 Hz\n Est. -3dB: ~34 Hz\n HP Filter: 28 Hz (24dB\/oct \u2014 essential for excursion protection)\n Slot Port: 300mm W \u00d7 80mm H \u00d7 584mm long (foldable in cabinet)\n Port Velocity (slot): 19.6 m\/s \u2713\n Notes: Maximum SPL in minimum cabinet size. Sub-30Hz extension\n below tuning requires HP filtering; without protection,\n 17mm Xmax is consumed rapidly below Fb. Strong mid-bass\n punch well-suited to touring ground stack and flyware\n sub configurations. The slot port length can be managed\n by routing along the internal cabinet perimeter.\n\n b) Cinema \/ Studio Install\n Net Volume: 180 liters\n Tuning (Fb): 27 Hz\n Est. -3dB: ~27 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Dual Round Ports: 125mm dia \u00d7 557mm each\n Port Velocity: 14.8 m\/s \u2713 (within professional installation limits)\n Notes: Reference cinema LFE alignment. -3dB at 27 Hz in the\n cabinet alone; room gain in a large cinema or studio\n space (+4\u20138 dB below 40 Hz) provides effective flat\n in-room response below 20 Hz. Dual 125mm ports at\n <15 m\/s produce negligible port noise \u2014 appropriate for\n critical listening environments.\n\n c) Hi-Fi Reference\n Net Volume: 280 liters\n Tuning (Fb): 22 Hz\n Est. -3dB: ~21 Hz\n HP Filter: 18 Hz (24dB\/oct recommended)\n Dual Round Ports: 125mm dia \u00d7 540mm each\n Port Velocity: 12.0 m\/s \u2713 (very low \u2014 inaudible port noise)\n Notes: Maximum low-frequency extension, approaching the driver's\n free-air resonance (Fs=21Hz). Anechoic -3dB at 21Hz \u2014\n effectively flat through the infrasonic range in-room.\n Suited for dedicated listening room installations, large\n home cinema, and audiophile bass system designs where\n reproducing the full sub-bass register (16\u201330 Hz) is a\n priority. Port noise is acoustically inaudible at this\n velocity. Cabinet requires substantial internal bracing.\nSEALED ALIGNMENTS (Secondary \u2014 Hi-Fi \/ Studio Active)\nThe relationship between this driver's Qts (0.35) and Vas (300L)\nproduces a remarkable coincidence: a 100L sealed enclosure yields\nQtc = 0.35 \u00d7 \u221a(1 + 300\/100) = 0.35 \u00d7 2.0 = 0.70 \u2014 an essentially\nperfect Butterworth (maximally flat) sealed alignment with fc = 42 Hz.\nThis is unusual in a driver of this size and power class, and makes\nthe 18XR highly suitable for passive sealed hi-fi use before any\nDSP correction.\n\n d) Compact Sealed (80 liters)\n Qtc: 0.76\n fc: 46 Hz\n Est. -3dB (passive): ~43 Hz\n Est. -3dB (with Linkwitz Transform to 0.70\/21Hz): ~21 Hz\n Notes: Slight warm character (+0.5dB region around 45 Hz).\n Smallest practical sealed alignment. Requires DSP for\n hi-fi sub use. Strong crossover platform for large\n 2-way or 3-way systems crossed at 100\u2013200 Hz.\n\n e) Hi-Fi Butterworth Sealed (100 liters)\n Qtc: 0.70\n fc: 42 Hz\n Est. -3dB (passive): ~42 Hz\n Est. -3dB (with Linkwitz Transform to 0.70\/21Hz): ~21 Hz\n Notes: Near-perfect Butterworth alignment \u2014 maximally flat\n sealed response. Can be used entirely passively in a\n large 3-way system crossed below 100 Hz; the 42 Hz\n passive -3dB with room gain provides effective in-room\n bass to ~25 Hz in a typical large room. With DSP\n correction, extends to 21 Hz with exceptional linearity.\n This is the recommended alignment for studio and\n audiophile applications.\n\nROOM GAIN NOTE:\nIn large listening rooms, cinemas, and home theaters, acoustic\nboundary reinforcement contributes +4\u20138 dB below 40 Hz. The in-room\nresponse of alignment (b) vented or alignment (e) sealed is therefore\nflat-to-room below 20 Hz in most large-room environments \u2014 without\nany sub-bass DSP boost.\nWOOFER APPLICATION NOTE\nThe 18XR's very low Le (0.54mH), XR motor linearity, and CF paper cone\nsupport use as a high-power bass\/woofer driver in large-format systems:\n - Crossover range: 100\u2013400 Hz (to compression driver or midrange)\n - At 92 dB sensitivity, closely matched to 95\u2013106 dB compression\n drivers; typically requires 3\u201314 dB attenuation or biamplification\n - The low inductance ensures clean, undistorted output through the\n upper bass \u2014 critical for music reproduction above 200 Hz\n - Suited for large-format horn-loaded woofer systems, cinema screen\n channel arrays, and high-power bi-amp studio monitor bass sections"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/18XR-304B-1.png","https:\/\/redcatt.net\/storage\/products\/web\/18XR-304B-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/18XR-304B-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/18XR-304B-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/18XR-304B-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/18XR-304B-3D.STEP"}},{"code":"181XRX4-350","name":"181XR","slug":"181xrx4-350","description":"XR Woofer\/18inch\/Neo\/Paper\/1200W\/4ohm","url":"https:\/\/redcatt.net\/products\/181xrx4-350","category":"LF","type":"Woofer","size_inches":18,"is_featured":true,"general":{"nominal_impedance":"4","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1200","continuous_watts":"2400","peak_watts":"4800"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"22"},"thiele_small_parameters":{"fs_hz":30,"re_ohm":3.3,"qes":0.24,"qms":13.2,"qts":0.23,"vas_liters":195,"sd_cm2":1256.6,"sensitivity_db":96.54,"mms_grams":306,"rms":4.37,"cms":0.09,"bl_tm":28.3,"le_mh":1.3},"physical":{"overall_diameter_mm":467.6,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":422,"mounting_holes":"8","depth_mm":257.2,"net_weight_kg":14.5,"xmax_mm":"17","xmech_mm":"36"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Cone excursion 56mm !! Patented design.","1 demodulation copper ring, powerful and innovative motor structure, innovative venting system","Double spider with spacer, woven-in tinsel wires, reinforced cone edge."],"design_notes":"Designed based upon the 18XR, the 181XR was designed for professional audio segment.\nThe basic characters and design concept remains the same for the 181XR. We have used newly designed 4 roll waterproof fabric surround that fully supports the high cone excursions of this incredible loudspeaker. The target was to push the envelope of possibilities. We are giving you a product that will not limit you to achieve even your wildest sub-woofer dreams. \n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding. This has allowed us to push the cone excursion to 44mm peak to peak. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver. We have also developed a new technique for manufacturing deep copper caps. \n \nThe design further utilizes dual, uncommonly large, spiders, spaced with spacer, hot-pressed tinsel wires onto the top spider, reinforced cone edge, reinforced surround to cone joint, reinforced spider to basket joints, etc.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in touring, installation, and high-SPL applications, where consistent performance, durability, and output capability are critical.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 181XRX4-350\nDriver: 181XRX4-350 (181XR) \u2014 18\" Sub-woofer\nKey T\/S: Fs=30.0Hz, Qts=0.23, Vas=195.0L, Sens=96.54dB\nPower: AES 1200W \/ Cont 2400W \/ Peak 4800W\nXmax=17.00mm, Sd=1256.6cm\u00b2, Bl=28.3T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 230 liters\n Tuning (Fb): 28 Hz\n Est. -3dB: 24 Hz\n HP Filter: 25 Hz (24dB\/oct recommended)\n Round Ports: 2\u00d7 125mm dia \u00d7 301mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 273mm L\n Port Velocity: 15.5 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 275 liters\n Tuning (Fb): 25 Hz\n Est. -3dB: 21 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Round Ports: 2\u00d7 125mm dia \u00d7 343mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 317mm L\n Port Velocity: 13.6 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 275 liters\n Tuning (Fb): 23 Hz\n Est. -3dB: 20 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Round Ports: 2\u00d7 125mm dia \u00d7 402mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 378mm L\n Port Velocity: 12.7 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 181XRX4-350 is a 18-inch high-output sub-woofer driver designed for professional subwoofer systems requiring high sensitivity (97 dB 1W\/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 230 to 275 liters, tuned between 23 and 28 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 1200 W AES \/ 2400 W continuous) and DSP control. A high-pass filter in the range of 20\u201325 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 20\u2013100 Hz, making it suitable for integration with mid-bass or full-range systems."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/181XR-350-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/181XR-350-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/181XR-350-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/181XR-350-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/181XR-350-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/181XR-350-3D.STEP"}},{"code":"182FINDX8-127","name":"182FIND","slug":"182findx8-127","description":"Woofer\/18inch\/Ferrite\/Paper\/1000W\/8ohm","url":"https:\/\/redcatt.net\/products\/182findx8-127","category":"LF","type":"Woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1000","continuous_watts":"2000","peak_watts":"4000"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"25.5"},"thiele_small_parameters":{"fs_hz":31,"re_ohm":5.5,"qes":0.24,"qms":8.85,"qts":0.23,"vas_liters":208.6,"sd_cm2":1257,"sensitivity_db":97.78,"mms_grams":281,"rms":6.18,"cms":0.093,"bl_tm":35.4,"le_mh":4.92},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":426,"mounting_holes":"8","depth_mm":189,"net_weight_kg":14,"xmax_mm":"5.75","xmech_mm":"19.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Inside \/ outside wound coil","Reinforced half pressed cone","Silicone nomex spider"],"design_notes":"The 182FIND is a high efficiency, (98 dB 1watt \/ 1 meter) 18-inch woofer with extended linear frequency response characteristics. The 182FIND uses durable half-pressed paper cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength at any given situation, high efficiency and a peak to peak maximum excursion of 27mm. \n\nPower Handling\nAt the core of the 182FIND is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 250C, well beyond the thermal requirements of modern professional audio systems. Voice coil winding is wound inside and outside of the former in the 1-3 split.\n\nREDCATT has implemented a silicone spider design to ensure long term shape memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 182FINDX8-127 is an 18-inch professional ferrite woofer designed for high-SPL touring PA, installed sound, and cinema LF applications requiring maximum motor force and deep bass extension from an 8-ohm ferrite motor system. The driver's most distinctive design feature is its inside\/outside wound voice coil (\"1-3 split\"), in which copper winding is applied to both the inner and outer surfaces of the 101.6 mm Polyimide former \u2014 a construction technique that doubles the effective conductor length in the magnetic gap and produces a Bl of 35.4 T\u00b7m, the highest motor force figure in the REDCATT ferrite woofer product range. The former is rated to 250\u00b0C, and the dual-surface winding improves thermal dissipation by radiating heat from both coil faces simultaneously, contributing to the 1000 W AES and 2000 W continuous power handling. The resulting Qts of 0.23 places the 182FIND firmly in the extreme-motor-force professional woofer class. The trade-off of the inside\/outside winding geometry is an elevated voice coil inductance of Le=4.92 mH, which produces inductive rolloff onset at approximately 178 Hz; system designers should apply a low-pass crossover below 500 Hz in two-way configurations, or implement a 2.5-way or 3-way topology crossing the 182FIND to a midrange driver at 250\u2013400 Hz for the cleanest programme integration. The reinforced half-pressed paper cone provides structural rigidity at the large Sd of 1257 cm\u00b2, and the silicone-impregnated Nomex spider is designed for long-term shape memory to maintain consistent Fs over the installation service life. The ferrite motor assembly accounts for the 14 kg net weight \u2014 higher than neodymium equivalents \u2014 while delivering motor performance that equals or exceeds the most demanding neodymium pro woofer designs.\n\nThe 182FINDX8-127 is optimized for vented (bass reflex) enclosures across an 80 to 180 litre net internal volume range, with tuning frequencies from 34 to 48 Hz. The large cone displacement Vd of 722.8 cm\u00b3 (Sd=1257 cm\u00b2 \u00d7 Xmax=5.75 mm) requires a minimum port aperture of 125 mm round or 200\u00d780 mm slot; a standard 100 mm round port produces velocities exceeding 25 m\/s at all alignments and must not be used. The compact 80 L alignment, tuned to 48 Hz, delivers -3 dB at approximately 46 Hz for touring bass cabinets and high-SPL festival woofer modules, with a 125 mm round port of 198 mm length at 17.8 m\/s or a 200\u00d780 mm slot of 259 mm length at 13.6 m\/s. The recommended 130 L standard alignment at 40 Hz tuning extends the -3 dB point to approximately 38 Hz, covering the full bass programme range including the low B-string of 5-string bass guitar (31 Hz) from a standard professional 18-inch bass cabinet format, with slot port velocity of 11.4 m\/s within theatre and installation limits. The extended 180 L alignment at 34 Hz tuning reaches -3 dB at approximately 32 Hz for cinema LF, large-venue installed systems, and 3-way PA main speaker applications. A notable engineering property of this driver's T\/S parameters is that alignments B and C produce identical port lengths \u2014 176 mm for the 125 mm round tube and 229 mm for the 200\u00d780 mm slot \u2014 across two different box volumes and tuning frequencies, allowing cabinet manufacturers to use common port hardware for both enclosure sizes.\n\nThe 182FINDX8-127 requires professional high-power amplification of 1000\u20132000 W into 8 ohms with DSP control mandatory for all alignments. A 24 dB\/octave high-pass filter at 38, 30, or 25 Hz depending on alignment is required to protect the driver below tuning, where cone excursion is unconstrained; displacement-limiting DSP protection is strongly recommended at full programme power given the gap between Fs=31 Hz and the low HP filter frequency in the extended alignments. For two-way integration, a passive RC Zobel network (R=5.5 \u03a9, C\u2248162 \u03bcF) across the voice coil terminals will partially compensate the Le-induced impedance rise through the crossover region and should be considered in all passive crossover designs. DSP active systems should apply Le-compensation EQ above 200 Hz if the crossover frequency exceeds 400 Hz.\n\nThe 182FINDX8-127 is suited for: compact and standard touring PA bass enclosures requiring top-tier motor force from a ferrite 18-inch driver; installed main LF speakers for theatres, houses of worship, stadia, and outdoor arenas; cinema main LF speaker assemblies requiring programme-consistent deep bass reproduction; 3-way professional PA systems using the 182FIND as the bass section with crossover at 250\u2013400 Hz to a midrange driver; and high-SPL festival and touring club sound systems where the weight premium of ferrite over neodymium is acceptable in exchange for the cost advantage and Bl=35.4 T\u00b7m motor performance. Its inside\/outside wound coil technology, reinforced half-pressed cone, and silicone Nomex spider make it a distinctive ferrite-motor option in the REDCATT 18-inch professional woofer portfolio for applications where maximum motor force per unit cost is the primary specification driver.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 182FINDX8-127\nDriver: 182FINDX8-127 (182FIND) \u2014 18\" ferrite pro woofer, 8 ohm\nKey T\/S: Fs=31Hz, Qts=0.23, Qes=0.24, Qms=8.85, Vas=208.6L, Sens=97.78dB\nPower: AES 1000W \/ Cont 2000W \/ Peak 4000W\nXmax=5.75mm (linear), Xmech=19.75mm\nSd=1257cm\u00b2, Bl=35.4T\u00b7m, Le=4.92mH, Re=5.5\u03a9\nVoice coil: 101.6mm (4\"), copper, inside\/outside wound (\"1-3 split\"),\n Polyimide former (250\u00b0C rated)\nCone: half-pressed reinforced paper (GF loaded)\nSurround: fabric, triple roll constant geometry\nSpider: Nomex silicone (long-term shape memory design)\nDepth: 189mm | Baffle cutout: 426mm | Ferrite motor | Aluminum basket\nWeight: 14 kg (net)\n\nMOTOR DESIGN NOTE \u2014 INSIDE\/OUTSIDE WOUND COIL:\n The 182FIND uses REDCATT's inside\/outside wound voice coil technology\n (\"1-3 split\"), in which copper winding is applied to both the inner and\n outer surfaces of the composite Polyimide former. This doubles the\n effective conductor length within the magnetic gap relative to a\n conventional single-surface winding, producing an exceptionally high\n Bl of 35.4 T\u00b7m \u2014 the highest motor force figure in the REDCATT ferrite\n woofer lineup and comparable to reference-class 21-inch professional\n subwoofer motors. The trade-off is a high voice coil inductance of\n Le=4.92mH, which is a natural consequence of the increased total\n winding length. System designers should account for this:\n\n Inductance rolloff onset: f_Le = Re \/ (2\u03c0 \u00d7 Le)\n = 5.5 \/ (2\u03c0 \u00d7 0.00492)\n \u2248 178 Hz\n\n The driver's natural acoustic response begins rolling off due to Le\n above approximately 200\u2013250 Hz. For two-way systems, a low-pass\n crossover at 300\u2013500 Hz is recommended unless DSP Le-compensation\n is applied; for 3-way or 2.5-way systems, a crossover at 300\u2013600 Hz\n to a midrange driver provides the most seamless integration. Passive\n RC zobel networks across the voice coil terminals can partially\n compensate Le at the crossover frequency.\n\n The inside\/outside winding also improves thermal distribution: both\n winding surfaces dissipate heat into the former and surrounding air\n simultaneously, contributing to the 1000W AES \/ 2000W continuous\n rating with a 250\u00b0C-rated former.\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.23 is firmly within the high-motor professional woofer class.\n Vented (bass reflex) enclosures are the only appropriate alignment.\n A sealed enclosure would produce a severely overdamped, low-efficiency\n response with no useful bass output from this driver.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 1257 cm\u00b2 \u00d7 0.575 cm = 722.8 cm\u00b3 (peak, one-way)\n\nPORT SIZING NOTE:\n Vd=722.8cm\u00b3 is large. A 100mm round port produces velocities\n exceeding 25 m\/s at all alignments \u2014 do not use. Minimum port:\n 125mm round tube or 200\u00d780mm slot.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 125mm diameter round tube (Ap=1.227\u00d710\u207b\u00b2 m\u00b2)\n OR 200\u00d780mm slot port (Ap=1.600\u00d710\u207b\u00b2 m\u00b2)\nPort velocity limit (pro PA \/ touring): \u226422 m\/s\nPort velocity limit (install \/ theatre): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (80 L net internal)\n Box volume: 80 L (net internal)\n Tuning freq (Fb): 48 Hz\n 125mm round port: 198mm long\n Port velocity: 17.8 m\/s (peak, at Xmax)\n Slot port (200\u00d780mm): 259mm long\n Port velocity: 13.6 m\/s (peak, at Xmax)\n System f-3dB: ~46 Hz\n HP filter: 38 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~128 dB\n Application: Compact touring PA woofer, 18\" bass cabinet,\n high-SPL bass module in line array system,\n two-way bass cabinet for club and festival.\n Notes: Maximum output from minimum enclosure. Fb=48Hz (1.55\u00d7Fs)\n keeps cone excursion well controlled through the principal\n operating band and delivers -3dB at approximately 46Hz \u2014\n covering the bass guitar open E (41Hz) at high programme\n levels. The 80L cabinet at approximately 560\u00d7540\u00d7320mm\n external is within the compact touring 18\" format.\n The 125mm round port at 198mm length fits any panel position.\n The 200\u00d780mm slot at 259mm length is the preferred option for\n touring cabinetry for structural contribution and lower velocity.\n The 38Hz HP filter is essential at 1000W to prevent excursion\n overshoot below tuning \u2014 at this drive level the gap between\n Fb and Fs (48Hz vs 31Hz) provides limited protection, and\n below 38Hz cone motion is unrestrained.\nALIGNMENT B \u2014 STANDARD PA (130 L net internal)\n Box volume: 130 L (net internal)\n Tuning freq (Fb): 40 Hz\n 125mm round port: 176mm long\n Port velocity: 14.8 m\/s (peak, at Xmax)\n Slot port (200\u00d780mm): 229mm long\n Port velocity: 11.4 m\/s (peak, at Xmax)\n System f-3dB: ~38 Hz\n HP filter: 30 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~128 dB\n Application: Standard touring and installation bass cabinet,\n main LF in two-way or 3-way PA system,\n installed main speaker for HoW, theatre, stadium.\n Notes: The recommended all-purpose alignment. At 38Hz -3dB the\n system resolves the low B-string fundamental (31Hz) and full\n bass guitar range from a cabinet of approximately 640\u00d7600\u00d7360mm\n external. Both port types produce velocities within theatre and\n installation limits. The slot port velocity of 11.4m\/s is\n appropriate for permanent installation in demanding acoustic\n environments. Note that alignment B and C share identical port\n lengths (176mm round, 229mm slot \u2014 see below), allowing a\n common port tube specification across both cabinet sizes.\nALIGNMENT C \u2014 EXTENDED LF (180 L net internal)\n Box volume: 180 L (net internal)\n Tuning freq (Fb): 34 Hz\n 125mm round port: 176mm long \u2190 same as Alignment B\n Port velocity: 12.6 m\/s (peak, at Xmax)\n Slot port (200\u00d780mm): 229mm long \u2190 same as Alignment B\n Port velocity: 9.7 m\/s (peak, at Xmax)\n System f-3dB: ~32 Hz\n HP filter: 25 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~128 dB\n Application: Extended bass installation, cinema main LF,\n large-venue installed woofer, 3-way system\n bass section with crossover at 200-400 Hz.\n Notes: The deepest alignment. At 32Hz -3dB the system approaches\n the lowest fundamentals of extended-range bass guitar (low B\n at 31Hz), pipe organ pedal (C0 at 16Hz harmonics are audible),\n and cinema LFE content. The 180L cabinet at approximately\n 700\u00d7660\u00d7440mm external is a standard large-format 18\" installed\n bass enclosure. Internal bracing is mandatory at this volume.\n\n PORT LENGTH COINCIDENCE (B and C): The 125mm port length of 176mm\n is identical for both 130L\/40Hz and 180L\/34Hz alignments \u2014 and the\n 200\u00d780mm slot at 229mm is also identical. This is a mathematical\n consequence of the larger Vb in alignment C precisely offsetting the\n lower Fb, producing the same Helmholtz resonance with the same port\n geometry. Cabinet builders can use a single common port tube or slot\n specification for both alignment B and C, changing only the internal\n box volume to select the desired tuning.\nHIGH-INDUCTANCE CROSSOVER GUIDANCE\n Le=4.92mH produces significant inductive rolloff above 200Hz.\n Recommended crossover approaches by system type:\n\n 2-way (woofer + compression driver):\n Low-pass at 500\u2013800Hz, 24dB\/oct, with RC Zobel network across\n voice coil terminals (R=Re=5.5\u03a9, C=Le\/Re\u00b2=0.162mF) to flatten\n impedance rise through crossover region.\n\n 2.5-way or 3-way:\n Low-pass the 182FIND at 250\u2013400Hz; midrange driver covers\n 400Hz\u20133kHz; HF compression driver from 3kHz up. This provides\n the cleanest integration with the Le rolloff and is the\n recommended approach for critical installation.\n\n DSP active system:\n Apply HF shelf or Le-compensation EQ above 200Hz to extend\n flat response to 500\u2013800Hz crossover point. Requires DSP\n amplifier with parametric EQ capability.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | 125mm Port | v | 200\u00d780 Slot | v | HP |\n |-------------|---------|-------|-------|------------|--------|-------------|--------|--------|\n | A Compact | 80 L | 48 Hz | ~46Hz | 198mm | 17.8 | 259mm | 13.6 | 38 Hz |\n | B Standard | 130 L | 40 Hz | ~38Hz | 176mm | 14.8 | 229mm | 11.4 | 30 Hz |\n | C Extended | 180 L | 34 Hz | ~32Hz | 176mm * | 12.6 | 229mm * | 9.7 | 25 Hz |\n All velocity figures in m\/s (peak, at Xmax).\n * Identical port dimensions to Alignment B \u2014 common port hardware applies.\n\n Sensitivity: 97.78 dB (1W\/1m)\n Max SPL (1000W): ~128 dB at 1m\n Impedance: 8 ohm nominal (Re=5.5\u03a9)\n Bl: 35.4 T\u00b7m (highest in REDCATT ferrite woofer lineup)\n Le: 4.92mH \u2014 inductive rolloff onset at ~178Hz\n Voice coil: 101.6mm (4\"), copper, inside\/outside wound, Polyimide 250\u00b0C\n WARNING: Do not use 100mm round port \u2014 velocity exceeds limits."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/182FIND-127-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/182FIND-127-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/182FIND-127-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/182FIND-127-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/182FIND-127-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/182FIND-127-3D.STEP"}},{"code":"183FINDX8-297","name":"183FIND","slug":"183findx8-297","description":"Woofer\/18inch\/Ferrite\/Paper\/600W\/8ohm","url":"https:\/\/redcatt.net\/products\/183findx8-297","category":"LF","type":"Woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"600","continuous_watts":"1200","peak_watts":"2400"},"voice_coil":{"diameter":"76","wire":"Copper","former":"Glass Fiber","winding_height":"19.8"},"thiele_small_parameters":{"fs_hz":32,"re_ohm":5.9,"qes":0.43,"qms":13.2,"qts":0.42,"vas_liters":329.5,"sd_cm2":1225.4,"sensitivity_db":97.07,"mms_grams":165,"rms":2.51,"cms":0.15,"bl_tm":21.14,"le_mh":0.73},"physical":{"overall_diameter_mm":461,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":422,"mounting_holes":"8","depth_mm":184,"net_weight_kg":8.8,"xmax_mm":"5.9","xmech_mm":"13.9"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Conex"},"content":{"key_features":["Optimized ferrite magnetic structure","Lightweight, yet strong paper cone","Hi spl"],"design_notes":"183FIND is a cost-effective solution for subwoofers. Its lightweight yet strong cone allows the magnetic circuit to be size optimized while delivering a seizable amount of sound pressure. With its high efficiency (97 dB 1watt \/ 1 meter) and high power handling capabilities, this woofer will excel in all applications with tight budgets. The cone shape and material was developed to provide an optimum low-frequency response, making the woofer good choice for subwoofer systems.\u00a0\n\nPower Handling\nAt the core of the 183FIND is its voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures above 280\u00b0C. The winding with high-temperature specification copper wire ensures the long life of the voice coil, without the costly service cycles.\u00a0\nThe cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 183FINDX8-297\nDriver: 183FINDX8-297 (183FIND) \u2014 18\" Mid-Woofer\nKey T\/S: Fs=32.0Hz, Qts=0.42, Vas=329.5L, Sens=97.07dB\nPower: AES 600W \/ Cont 1200W \/ Peak 2400W\nXmax=5.90mm, Sd=1225.4cm\u00b2, Bl=21.14T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 215 liters\n Tuning (Fb): 37 Hz\n Est. -3dB: 34 Hz\n HP Filter: 29 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 35mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 130mm L\n Port Velocity: 13.6 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 250 liters\n Tuning (Fb): 34 Hz\n Est. -3dB: 31 Hz\n HP Filter: 24 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 38mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 136mm L\n Port Velocity: 12.4 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 275 liters\n Tuning (Fb): 30 Hz\n Est. -3dB: 26 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 52mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 166mm L\n Port Velocity: 11.3 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 183FINDX8-297 is a 18-inch high-output mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (97 dB 1W\/1m) and controlled low-frequency behavior. The driver uses a balanced motor-suspension design that provides good cone control while maintaining usable output across its operating bandwidth.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 215 to 275 liters, tuned between 30 and 37 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control. Note: these enclosures are sizable for a 18-inch driver, a result of the driver's high acoustic compliance (Vas=329.5L). More compact cabinets can be designed \u2014 smaller net volumes are achievable with active DSP correction, accepting some reduction in output and sensitivity below the tuning frequency.\nThe driver is intended for use with high-power amplification (approx. 600 W AES \/ 1200 W continuous) and DSP control. A high-pass filter in the range of 20\u201329 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 26\u20131500 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/183FIND-297-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/183FIND-297-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/183FIND-297-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/183FIND-297-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/183FIND-297-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/183FIND-297-3D.STEP"}},{"code":"186FINDX8-552A","name":"186FIND","slug":"186findx8-552a","description":"Woofer\/18inch\/Ferrite\/Paper\/3600W\/8ohm","url":"https:\/\/redcatt.net\/products\/186findx8-552a","category":"LF","type":"Woofer","size_inches":18,"is_featured":true,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1800","continuous_watts":"3600","peak_watts":"7200"},"voice_coil":{"diameter":"114.3","wire":"Copper","former":"Glass Fiber","winding_height":"31.8"},"thiele_small_parameters":{"fs_hz":33,"re_ohm":5.5,"qes":0.36,"qms":12.1,"qts":0.35,"vas_liters":174.2,"sd_cm2":1256,"sensitivity_db":96,"mms_grams":288,"rms":4.9,"cms":0.081,"bl_tm":30.2,"le_mh":1.51},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":423,"mounting_holes":"8","depth_mm":212,"net_weight_kg":19.3,"xmax_mm":"8.4","xmech_mm":"23.4"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["4.5 inch high temperature voice coil","High Sound pressure level","Very high power handling"],"design_notes":"Introducing 186FIND, the powerhouse woofer designed for superior audio performance. With a staggering 3,600 watts of peak power and a 4.5\" voice coil that can withstand temperatures exceeding 350\u00b0C, this woofer is built to impress. Featuring a new paper pulp mixed with glass fibers, high excursion surround, and an extra large spider, it delivers unparalleled longevity and bass. The motor system's high grade ferrite magnet creates a strong symmetrical flux field, while the extended space below the voice coil allows for maximum excursion. Get ready to be blown away by the 186FIND woofer.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in touring, installation, and high-SPL applications, where consistent performance, durability, and output capability are critical.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 186FINDX8-552A\nDriver: 186FINDX8-552A (186FIND) \u2014 18\" Woofer\nKey T\/S: Fs=33.0Hz, Qts=0.35, Vas=174.2L, Sens=96.0dB\nPower: AES 1800W \/ Cont 3600W \/ Peak 7200W\nXmax=8.40mm, Sd=1256.0cm\u00b2, Bl=30.2T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 135 liters\n Tuning (Fb): 37 Hz\n Est. -3dB: 34 Hz\n HP Filter: 29 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 99mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 263mm L\n Port Velocity: 20.2 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 160 liters\n Tuning (Fb): 33 Hz\n Est. -3dB: 30 Hz\n HP Filter: 23 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 120mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 305mm L\n Port Velocity: 17.7 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 190 liters\n Tuning (Fb): 29 Hz\n Est. -3dB: 25 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 144mm long\n Slot Port: 338mm W \u00d7 75mm H \u00d7 356mm L\n Port Velocity: 15.4 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 186FINDX8-552A is a 18-inch high-output woofer driver designed for professional subwoofer systems requiring high sensitivity (96 dB 1W\/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 135 to 190 liters, tuned between 29 and 37 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 1800 W AES \/ 3600 W continuous) and DSP control. A high-pass filter in the range of 20\u201329 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 25\u2013100 Hz, making it suitable for integration with mid-bass or full-range systems."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/186FINDX8-552A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/186FINDX8-552A-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/186FINDX8-552A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/186FIND-552A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/186FIND-552A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/186FIND-552A-3D.STEP"}},{"code":"18FINDX8-036","name":"18FIND","slug":"18findx8-036","description":"Woofer\/18inch\/Ferrite\/Paper\/1000W\/8ohm","url":"https:\/\/redcatt.net\/products\/18findx8-036","category":"LF","type":"Woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1000","continuous_watts":"2000","peak_watts":"4000"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"23.7"},"thiele_small_parameters":{"fs_hz":36,"re_ohm":5.2,"qes":0.44,"qms":8.4,"qts":0.42,"vas_liters":203.4,"sd_cm2":1257,"sensitivity_db":97.24,"mms_grams":211.8,"rms":5.7,"cms":0.09,"bl_tm":23.6,"le_mh":1.74},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":426,"mounting_holes":"8","depth_mm":184,"net_weight_kg":13.7,"xmax_mm":"5.85","xmech_mm":"17.85"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Optimized venting system","High power handling"],"design_notes":"The 18FIND is a high efficiency, (97 dB 1watt \/ 1 meter) 18-inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. The 18FIND uses a lightweight glass fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 21mm. \n\nPower Handling\nAt the core of the 18FIND is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 250C, well beyond the thermal requirements of modern professional audio systems. \n \nREDCATT has implemented a silicone spider design to ensure long term shape memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 18FINDX8-036 is an 18-inch professional ferrite woofer designed for high-SPL two-way touring PA, installed sound reinforcement, and cinema LF applications requiring broad system compatibility, deep bass extension, and sustained high-power output from a cost-effective 8-ohm ferrite motor. With a sensitivity of 97.24 dB (1 W\/1 m), 1000 W AES power handling, and a 101.6 mm copper voice coil wound on a Polyimide former rated to 250\u00b0C, the 18FIND delivers consistent acoustic performance at continuous programme levels without thermal compression. The Ferrite motor produces a Bl of 23.6 T\u00b7m at a Qts of 0.42, positioning the 18FIND in the moderate-motor professional woofer class and making it the more system-integration-friendly option in the REDCATT 18-inch ferrite range compared to the extreme-motor-force 182FIND variant. The voice coil inductance of Le=1.74 mH yields an inductive rolloff onset at approximately 475 Hz \u2014 well above the operating band \u2014 allowing standard two-way integration with a compression driver or coaxial HF unit at a crossover frequency of 800 Hz to 1.5 kHz without Le compensation, Zobel networks, or modified crossover topology. The carbon fiber loaded paper cone provides structural stiffness and low mass for a driver in this displacement class, and the silicone-impregnated Nomex spider delivers long-term Fs consistency across the installation service life. The optimized basket venting system reduces motor thermal resistance, contributing to the 2000 W continuous power capability.\n\nThe 18FINDX8-036 is optimized for vented (bass reflex) enclosures across a 90 to 180 litre net internal volume range, with tuning frequencies from 38 to 55 Hz. The driver's peak displacement Vd of 735.3 cm\u00b3 (Sd=1257 cm\u00b2 \u00d7 Xmax=5.85 mm) requires a minimum port aperture of 125 mm round or 250\u00d780 mm slot; a standard 100 mm round port generates velocities exceeding 25 m\/s at all alignments and must not be used. The compact 90 L alignment at 55 Hz tuning delivers -3 dB at approximately 53 Hz with a 125 mm round port of 134 mm length at 20.7 m\/s, suited to compact trapezoidal touring cabinets and line array bass extension modules where enclosure volume is constrained. The recommended 130 L standard alignment at 46 Hz extends the -3 dB point to approximately 44 Hz, covering bass guitar open E and the full sub-bass music programme from a standard professional 18-inch two-way enclosure format; slot port velocity of 10.6 m\/s is within theatre and installation limits. The extended 180 L alignment at 38 Hz reaches -3 dB at approximately 36 Hz for cinema LF, large-venue installed systems, and festival main bass cabinets requiring deep bass reproduction. A notable design property is that alignments A and B produce virtually identical port lengths \u2014 133\u2013134 mm for the 125 mm round tube and 217\u2013219 mm for the 250\u00d780 mm slot \u2014 allowing cabinet builders to use common port hardware across two enclosure sizes, selecting tuning frequency by varying only the internal box volume.\n\nThe 18FINDX8-036 requires professional high-power amplification of 1000\u20132000 W into 8 ohms with DSP signal management mandatory for all alignments. A 24 dB\/octave high-pass filter at 42, 35, or 28 Hz depending on alignment is required, as the vented enclosure removes acoustic loading below the tuning frequency and cone excursion rises rapidly. Displacement-limiting and power-limiting DSP algorithms are recommended for all sustained high-programme operation. The operating bandwidth for two-way system integration is approximately 35 Hz to 1.5 kHz; low-pass crossover to a compression driver at 800 Hz\u20131.5 kHz at 24 dB\/octave is the standard integration approach, with no additional Le compensation required.\n\nThe 18FINDX8-036 is suited for: two-way touring PA bass enclosures in compact, standard, and large formats requiring broad DSP-active system compatibility; installed main LF speakers for theatres, houses of worship, stadia, outdoor arenas, and festival sites; cinema main LF speaker assemblies operating at sustained programme levels; mid-to-large-format line array bass extension modules; and high-SPL club and venue main bass systems where cost-effective ferrite motor construction, standard two-way crossover compatibility, and 1000 W AES power handling are the primary selection criteria. Its Le=1.74 mH, Qts=0.42, carbon fiber cone, and silicone Nomex spider make it the practical, versatile choice in the REDCATT 18-inch ferrite woofer portfolio for system designers prioritizing integration simplicity and broad application compatibility alongside high efficiency and output capability.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 18FINDX8-036\nDriver: 18FINDX8-036 (18FIND) \u2014 18\" ferrite pro woofer, 8 ohm\nKey T\/S: Fs=36Hz, Qts=0.42, Qes=0.44, Qms=8.4, Vas=203.4L, Sens=97.24dB\nPower: AES 1000W \/ Cont 2000W \/ Peak 4000W\nXmax=5.85mm (linear), Xmech=17.85mm\nSd=1257cm\u00b2, Bl=23.6T\u00b7m, Le=1.74mH, Re=5.2\u03a9\nVoice coil: 101.6mm (4\"), copper winding, Polyimide former (250\u00b0C rated)\nCone: carbon fiber loaded paper\nSurround: fabric, triple roll constant geometry\nSpider: Nomex silicone (long-term shape memory)\nDepth: 184mm | Baffle cutout: 426mm | Ferrite motor | Aluminum basket\n\nCOMPARISON \u2014 18FIND vs 182FIND:\n The 18FIND (18FINDX8-036) and 182FIND (182FINDX8-127) share the 18-inch\n ferrite platform \u2014 identical Sd, baffle cutout, and power class \u2014 but\n differ substantially in motor design and acoustic character:\n\n | Parameter | 18FIND | 182FIND |\n |-----------|----------|------------|\n | Qts | 0.42 | 0.23 |\n | Bl | 23.6 T\u00b7m | 35.4 T\u00b7m |\n | Le | 1.74 mH | 4.92 mH |\n | Fs | 36 Hz | 31 Hz |\n | Mms | 211.8 g | 281 g |\n | Coil | standard | inside\/out |\n\n The 182FIND uses an inside\/outside wound coil to achieve extreme Bl=35.4T\u00b7m\n at the cost of very high Le=4.92mH, restricting its use in 3-way and 2.5-way\n topologies only. The 18FIND uses a conventional winding, producing a lower\n but still competitive Bl=23.6T\u00b7m, a moderate Le=1.74mH (inductance rolloff\n at ~475Hz), and a higher Qts=0.42 that requires larger enclosures. The 18FIND\n integrates into standard two-way PA systems with crossover at 800Hz\u20131.5kHz\n without Le-related penalties, making it the more versatile and\n system-integration-friendly of the two 18-inch ferrite options.\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.42 is within the vented design region for an 18-inch professional\n woofer. Vented (bass reflex) enclosures are the appropriate and only\n recommended alignment. The moderate Qts requires somewhat larger\n enclosures than the 182FIND (Qts=0.23) for equivalent tuning frequencies,\n but the vented alignment remains highly efficient and produces excellent\n bass output and extension across the 90\u2013180L cabinet range.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 1257 cm\u00b2 \u00d7 0.585 cm = 735.3 cm\u00b3 (peak, one-way)\n\nPORT SIZING NOTE:\n Vd=735.3cm\u00b3 requires a minimum port aperture of 125mm round or\n 250\u00d780mm slot. A 100mm round port produces velocities exceeding\n 25 m\/s at all alignments \u2014 do not use.\n\nINDUCTANCE NOTE:\n Le=1.74mH \u2192 inductance rolloff onset at approximately 475Hz.\n Standard two-way integration with a compression driver or coaxial\n HF unit at 800Hz\u20131.5kHz is fully compatible without inductance\n compensation. No Zobel network or Le equalization is required for\n typical professional two-way crossover designs.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 125mm diameter round tube (Ap=1.227\u00d710\u207b\u00b2 m\u00b2)\n OR 250\u00d780mm slot port (Ap=2.000\u00d710\u207b\u00b2 m\u00b2)\n\nDO NOT use 100mm round port \u2014 velocity exceeds limits at all alignments.\n\nPort velocity limit (pro PA \/ touring): \u226422 m\/s\nPort velocity limit (install \/ theatre): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (90 L net internal)\n Box volume: 90 L (net internal)\n Tuning freq (Fb): 55 Hz\n 125mm round port: 134mm long\n Port velocity: 20.7 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 219mm long\n Port velocity: 12.7 m\/s (peak, at Xmax)\n System f-3dB: ~53 Hz\n HP filter: 42 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~127 dB\n Application: Compact 18\" two-way touring PA cabinet, bass\n module in mid-large format line array, high-SPL\n club and festival bass cabinet.\n Notes: Maximum output from the most compact practical enclosure.\n The 125mm round port velocity of 20.7m\/s is within the pro\n PA limit for touring applications; for installation use the\n 250\u00d780mm slot at 12.7m\/s is strongly preferred to remain\n within the 17m\/s install limit. At 53Hz -3dB the driver covers\n bass guitar, kick drum, and the full sub-bass programme range.\n The 90L cabinet at approximately 590\u00d7560\u00d7330mm external is\n consistent with compact 18\" PA formats. The 134mm round port\n is particularly short \u2014 a consequence of the larger box\n volume at this tuning \u2014 fitting any panel position easily.\nALIGNMENT B \u2014 STANDARD PA (130 L net internal)\n Box volume: 130 L (net internal)\n Tuning freq (Fb): 46 Hz\n 125mm round port: 133mm long \u2190 virtually identical to Alignment A\n Port velocity: 17.3 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 217mm long \u2190 virtually identical to Alignment A\n Port velocity: 10.6 m\/s (peak, at Xmax)\n System f-3dB: ~44 Hz\n HP filter: 35 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~127 dB\n Application: Standard two-way touring and installation bass\n cabinet, installed main LF in HoW, theatre, arena,\n outdoor stadium PA, flyable 18\" bass enclosure.\n Notes: The recommended general-purpose alignment. At 44Hz -3dB the\n system resolves bass guitar open E (41Hz) and covers the full\n music programme with high acoustic output. The 125mm round\n port velocity of 17.3m\/s is within installation limits, and\n the slot at 10.6m\/s is appropriate for theatre and critical\n environments. The 130L cabinet at approximately 640\u00d7610\u00d7360mm\n external is a standard professional 18\" two-way format.\n\n PORT NOTE: The 125mm round port (133mm) and slot port (217mm) for\n alignment B are virtually identical in length to alignment A (134mm,\n 219mm). A single common port tube specification covers both alignments;\n cabinet volume alone determines the tuning frequency. This property\n simplifies production of a two-box range sharing the same port hardware.\nALIGNMENT C \u2014 EXTENDED LF (180 L net internal)\n Box volume: 180 L (net internal)\n Tuning freq (Fb): 38 Hz\n 125mm round port: 141mm long\n Port velocity: 14.3 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 229mm long\n Port velocity: 8.8 m\/s (peak, at Xmax)\n System f-3dB: ~36 Hz\n HP filter: 28 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~127 dB\n Application: Extended bass two-way cabinet, cinema LF section,\n large-venue installed main woofer, festival and\n outdoor event main bass cabinet.\n Notes: The deepest alignment. At 36Hz -3dB the driver reproduces the\n low B fundamental of 5-string bass guitar (31Hz within 5dB) and\n the full cinema LFE bandwidth. The 180L enclosure at approximately\n 700\u00d7660\u00d7440mm external is the upper limit of a standard flyable\n 18\" bass cabinet; fixed-install versions accommodate this volume\n more readily. Internal cross-bracing and damping treatment are\n required. Port velocity of 8.8m\/s on the slot is very low \u2014\n suitable for library-quiet studio and theatre environments.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | 125mm Port | v | 250\u00d780 Slot | v | HP |\n |-------------|---------|-------|-------|------------|--------|-------------|--------|--------|\n | A Compact | 90 L | 55 Hz | ~53Hz | 134mm | 20.7 | 219mm | 12.7 | 42 Hz |\n | B Standard | 130 L | 46 Hz | ~44Hz | 133mm * | 17.3 | 217mm * | 10.6 | 35 Hz |\n | C Extended | 180 L | 38 Hz | ~36Hz | 141mm | 14.3 | 229mm | 8.8 | 28 Hz |\n All velocity figures in m\/s (peak, at Xmax).\n * Port lengths A and B are virtually identical \u2014 common port hardware applicable.\n\n Sensitivity: 97.24 dB (1W\/1m)\n Max SPL (1000W): ~127 dB at 1m\n Impedance: 8 ohm nominal (Re=5.2\u03a9)\n Le: 1.74mH \u2014 rolloff onset ~475Hz; no Zobel network required\n Voice coil: 101.6mm (4\"), copper, Polyimide former (250\u00b0C rated)\n WARNING: Do not use 100mm round port \u2014 velocity exceeds limits."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/18FIND-036-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/18FIND-036-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/18FIND-036-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/18FIND-036-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/18FIND-036-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/18FIND-036-3D.STEP"}},{"code":"18FINDX8-310B","name":"18FIND","slug":"18findx8-310b","description":"Woofer\/18inch\/Ferrite\/Paper\/1000W\/8ohm","url":"https:\/\/redcatt.net\/products\/18findx8-310b","category":"LF","type":"Woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1000","continuous_watts":"2000","peak_watts":"4000"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"23.7"},"thiele_small_parameters":{"fs_hz":34,"re_ohm":5.1,"qes":0.49,"qms":7.95,"qts":0.46,"vas_liters":221,"sd_cm2":1207,"sensitivity_db":96.33,"mms_grams":203.8,"rms":5.5,"cms":0.1,"bl_tm":21.3,"le_mh":1.4},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":426,"mounting_holes":"8","depth_mm":183.5,"net_weight_kg":13.5,"xmax_mm":"5.85","xmech_mm":"17.85"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED LF FREQUENCY RESPONSE","Optimized venting system","Very wide B field"],"design_notes":"The 18FIND is a high efficiency, (97 dB 1watt \/ 1 meter) 18-inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. The 18FIND uses a lightweight glass fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 30mm. \n\nPower Handling\nAt the core of the 18FIND is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 250C, well beyond the thermal requirements of modern professional audio systems. \n \nREDCATT has implemented a silicone spider design to ensure long term shape memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 18FINDX8-310B is an 18-inch professional ferrite woofer designed for high-SPL touring PA, installed sound reinforcement, and cinema LF applications where low harmonic distortion at large cone excursion, deep bass extension, and broad two-way system compatibility are the primary design requirements. The driver uses a 101.6 mm copper voice coil wound on a Polyimide former rated to 250\u00b0C, delivering 1000 W AES and 2000 W continuous at 8 ohms. The motor system is designed around a wide magnetic field geometry \u2014 the -310B's defining engineering characteristic \u2014 in which the magnetic gap is dimensioned to maintain a more uniform Bl product across the full Xmax travel of 5.85 mm. This wide-field approach produces measurably lower BL(x) nonlinearity at large excursion compared to shorter-gap designs of similar peak Bl, resulting in reduced second and third harmonic distortion at sustained programme levels. The resulting Bl of 21.3 T\u00b7m at Qts=0.46 represents a deliberate optimization toward linearity rather than maximum motor force. The voice coil inductance of Le=1.40 mH is the lowest in the 18FIND product family, with an inductive rolloff onset at approximately 580 Hz \u2014 the best native HF bandwidth of the three variants \u2014 making the -310B directly compatible with standard two-way crossover designs at 800 Hz to 1.5 kHz without Le compensation or modified crossover topology. The silicone-impregnated Nomex spider ensures long-term Fs consistency, and the optimized aluminum basket venting reduces thermal resistance for sustained high-power operation.\n\nThe 18FINDX8-310B is optimized for vented (bass reflex) enclosures across a 90 to 200 litre net internal volume range, with tuning frequencies from 36 to 52 Hz. The driver's peak displacement Vd of 706.1 cm\u00b3 (Sd=1207 cm\u00b2 \u00d7 Xmax=5.85 mm) requires a minimum port aperture of 125 mm round or 250\u00d780 mm slot; a standard 100 mm round port produces velocities exceeding 25 m\/s at all alignments and must not be used. The compact 90 L alignment at 52 Hz tuning delivers -3 dB at approximately 50 Hz for compact touring cabinets and line array bass modules, with a 125 mm round port of 150 mm (18.8 m\/s) or a 250\u00d780 mm slot of 245 mm (11.5 m\/s). The recommended 140 L standard alignment at 44 Hz extends the -3 dB point to approximately 42 Hz, covering bass guitar open E and the complete sub-bass programme range from a standard professional two-way 18-inch enclosure; slot port velocity of 9.8 m\/s is comfortably within theatre and installation limits. The extended 200 L alignment at 36 Hz reaches -3 dB at approximately 34 Hz \u2014 at the driver's natural Fs \u2014 for cinema LF, large-venue installed systems, and applications requiring reproduction of bass guitar low B (31 Hz) and sub-bass cinema LFE content at high continuous SPL; slot port velocity of 8.0 m\/s is effectively inaudible in the most acoustically demanding installation environments. The wider enclosure volumes required by the -310B relative to the -036 reflect its higher Qts=0.46, and correspond to the larger Vas=221 L that results from the wide-field motor geometry's compliance optimization.\n\nThe 18FINDX8-310B requires professional high-power amplification of 1000\u20132000 W into 8 ohms with DSP signal management mandatory for all alignments. A 24 dB\/octave high-pass filter at 40, 33, or 26 Hz depending on alignment is required to prevent excursion overshoot below the vented tuning frequency; displacement-limiting DSP is recommended for all sustained full-programme operation. The operating bandwidth is approximately 34 Hz to 1.5 kHz; a 24 dB\/octave low-pass crossover to a compression driver at 800 Hz\u20131.5 kHz is appropriate for standard two-way integration, with no additional Le compensation needed.\n\nThe 18FINDX8-310B is suited for: two-way touring PA enclosures in standard and large formats where reduced harmonic distortion at high programme levels is valued alongside high SPL capability; installed main LF speakers for theatres, cinema, houses of worship, stadia, and large outdoor venues requiring extended bass reproduction with low distortion at sustained power; high-fidelity and critical listening PA systems where the -310B's wide-field BL(x) linearity produces a perceptibly cleaner bass character compared to shorter-gap designs; and festival and outdoor event main bass cabinets in standard and extended LF configurations. Within the REDCATT 18-inch ferrite woofer family, the -310B is the appropriate selection when low distortion at Xmax, deep bass extension to 34 Hz, and unconstrained two-way system integration are the primary performance priorities, with the -036 preferred for higher sensitivity and smaller enclosure requirements, and the 182FIND for maximum motor force in 3-way topologies.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 18FINDX8-310B\nDriver: 18FINDX8-310B (18FIND-310B) \u2014 18\" ferrite pro woofer, 8 ohm\nKey T\/S: Fs=34Hz, Qts=0.46, Qes=0.49, Qms=7.95, Vas=221L, Sens=96.33dB\nPower: AES 1000W \/ Cont 2000W \/ Peak 4000W\nXmax=5.85mm (linear), Xmech=17.85mm\nSd=1207cm\u00b2, Bl=21.3T\u00b7m, Le=1.40mH, Re=5.1\u03a9\nVoice coil: 101.6mm (4\"), copper winding, Polyimide former (250\u00b0C rated)\nCone: carbon fiber loaded paper\nSurround: fabric, triple roll constant geometry\nSpider: Nomex silicone (long-term shape memory)\nDepth: 183.5mm | Baffle cutout: 426mm | Ferrite motor | Aluminum basket\n\n18FIND FAMILY \u2014 THREE-VARIANT COMPARISON:\n The 18FIND product name covers three mechanically distinct drivers.\n All share the 18-inch basket, 101.6mm (4-inch) voice coil, Polyimide\n former, silicone Nomex spider, and 1000W AES power rating. Each is\n tuned for a different balance of motor force, linearity, and frequency\n extension:\n\n | Parameter | -310B (this) | -036 | 182FIND |\n |-----------|--------------|---------------|----------------|\n | Qts | 0.46 | 0.42 | 0.23 |\n | Bl | 21.3 T\u00b7m | 23.6 T\u00b7m | 35.4 T\u00b7m |\n | Le | 1.40 mH | 1.74 mH | 4.92 mH |\n | Fs | 34 Hz | 36 Hz | 31 Hz |\n | Vas | 221 L | 203.4 L | 208.6 L |\n | Sens | 96.33 dB | 97.24 dB | 97.78 dB |\n | B field | Wide (opt.) | Standard | Extreme (I\/O) |\n | 2-way | \u2713 to 1.5kHz | \u2713 to 1.5kHz | \u26a0 3-way pref. |\n\n The -310B is optimized for maximum BL(x) linearity (\"Very wide B field\"):\n the magnetic gap geometry is designed to maintain a more uniform flux\n density across the full Xmax excursion range, reducing harmonic distortion\n at large cone displacement even though the peak Bl figure is lower than\n the other variants. This makes the -310B the preferred choice for\n high-fidelity and critical listening applications where distortion at\n programme levels is a priority alongside high output. The lowest Le in\n the family (1.40mH, rolloff onset ~580Hz) also provides the best native\n high-frequency response, with clean integration in two-way designs at\n crossover frequencies up to 1.5kHz.\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.46 is within the vented design region for an 18-inch professional\n woofer. Vented (bass reflex) enclosures are the recommended alignment.\n The -310B's higher Qts than the -036 and 182FIND variants requires\n somewhat larger enclosures for equivalent tuning \u2014 the standard alignment\n moves from 130L to 140L and the extended from 180L to 200L \u2014 while Fs\n of 34Hz provides useful natural extension down to approximately 34Hz in\n the largest alignment.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 1207 cm\u00b2 \u00d7 0.585 cm = 706.1 cm\u00b3 (peak, one-way)\n\nPORT SIZING NOTE:\n Vd=706.1cm\u00b3 requires a minimum port aperture of 125mm round or\n 250\u00d780mm slot. A 100mm round port produces velocities exceeding\n 25 m\/s at all alignments \u2014 do not use.\n\nINDUCTANCE NOTE:\n Le=1.40mH \u2192 inductance rolloff onset at approximately 580Hz.\n Standard two-way integration at 800Hz\u20131.5kHz crossover to a\n compression driver is fully compatible \u2014 no Le compensation required.\n This is the best native HF bandwidth of the three 18FIND variants.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 125mm diameter round tube (Ap=1.227\u00d710\u207b\u00b2 m\u00b2)\n OR 250\u00d780mm slot port (Ap=2.000\u00d710\u207b\u00b2 m\u00b2)\n\nDO NOT use 100mm round port \u2014 velocity exceeds limits at all alignments.\n\nPort velocity limit (pro PA \/ touring): \u226422 m\/s\nPort velocity limit (install \/ theatre): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (90 L net internal)\n Box volume: 90 L (net internal)\n Tuning freq (Fb): 52 Hz\n 125mm round port: 150mm long\n Port velocity: 18.8 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 245mm long\n Port velocity: 11.5 m\/s (peak, at Xmax)\n System f-3dB: ~50 Hz\n HP filter: 40 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~126 dB\n Application: Compact two-way touring PA cabinet, line array\n bass module, high-SPL club bass enclosure,\n festival and outdoor event woofer.\n Notes: Maximum output from the most compact practical enclosure.\n At 50Hz -3dB the driver covers the full bass programme range\n including bass guitar, kick drum, and sub-bass at high acoustic\n output. The 125mm port velocity of 18.8m\/s is within touring\n PA limits; for installation the 250\u00d780mm slot at 11.5m\/s is\n preferred to remain within the 17m\/s limit. The 90L cabinet\n at approximately 590\u00d7560\u00d7330mm external is consistent with\n compact 18\" PA formats. The 150mm port is moderately longer\n than the -036 compact alignment (134mm), reflecting the -310B's\n higher Qts requiring more port length at the same box volume\n and similar tuning.\nALIGNMENT B \u2014 STANDARD PA (140 L net internal)\n Box volume: 140 L (net internal)\n Tuning freq (Fb): 44 Hz\n 125mm round port: 135mm long\n Port velocity: 15.9 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 220mm long\n Port velocity: 9.8 m\/s (peak, at Xmax)\n System f-3dB: ~42 Hz\n HP filter: 33 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~126 dB\n Application: Standard two-way touring and installation bass\n cabinet, installed main LF in theatre, HoW,\n stadium, outdoor arena; flyable 18\" enclosure.\n Notes: The recommended general-purpose alignment. At 42Hz -3dB\n the system resolves bass guitar open E (41Hz) at full acoustic\n output, covering the complete bass programme bandwidth. Both\n port options are within installation velocity limits. The\n 140L cabinet at approximately 650\u00d7620\u00d7375mm external is a\n standard professional 18\" two-way format. The wide B field\n geometry of the -310B produces measurably lower harmonic\n distortion at sustained high programme levels in this alignment\n compared to shorter-gap designs \u2014 an audible advantage in\n demanding full-power music reproduction and cinema environments.\nALIGNMENT C \u2014 EXTENDED LF (200 L net internal)\n Box volume: 200 L (net internal)\n Tuning freq (Fb): 36 Hz\n 125mm round port: 141mm long\n Port velocity: 13.0 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 230mm long\n Port velocity: 8.0 m\/s (peak, at Xmax)\n System f-3dB: ~34 Hz\n HP filter: 26 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1000W, 1m): ~126 dB\n Application: Extended bass installation woofer, cinema main LF,\n large-venue installed main speaker, 3-way or 2.5-way\n system bass section for programme reproduction to\n below 35Hz.\n Notes: The deepest alignment. At 34Hz -3dB \u2014 close to the driver's\n natural Fs of 34Hz \u2014 the system reproduces bass guitar low B\n (31Hz), sub-bass cinema LFE content, and the lowest audible\n fundamentals of orchestral and electronic bass instruments.\n The 200L enclosure at approximately 710\u00d7670\u00d7500mm external\n is at the upper limit of a flyable 18\" bass cabinet; it is\n more naturally suited to fixed installation. Internal cross-\n bracing and damping treatment are required at this volume.\n Slot port velocity of 8.0m\/s is very low \u2014 appropriate for\n theatre, cinema, and critical installation environments where\n port turbulence noise must be entirely absent. The -310B's\n wide-field motor geometry contributes particularly in this\n alignment, where programme content at 34\u201345Hz exercises the\n cone near Xmax at continuous high power.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | 125mm Port | v | 250\u00d780 Slot | v | HP |\n |-------------|---------|-------|-------|------------|--------|-------------|--------|--------|\n | A Compact | 90 L | 52 Hz | ~50Hz | 150mm | 18.8 | 245mm | 11.5 | 40 Hz |\n | B Standard | 140 L | 44 Hz | ~42Hz | 135mm | 15.9 | 220mm | 9.8 | 33 Hz |\n | C Extended | 200 L | 36 Hz | ~34Hz | 141mm | 13.0 | 230mm | 8.0 | 26 Hz |\n All velocity figures in m\/s (peak, at Xmax).\n\n Sensitivity: 96.33 dB (1W\/1m)\n Max SPL (1000W): ~126 dB at 1m\n Impedance: 8 ohm nominal (Re=5.1\u03a9)\n Le: 1.40mH \u2014 rolloff onset ~580Hz; best HF extension of 18FIND family\n B field: Wide-gap optimized \u2014 reduced BL(x) nonlinearity at Xmax\n Voice coil: 101.6mm (4\"), copper, Polyimide former (250\u00b0C rated)\n WARNING: Do not use 100mm round port \u2014 velocity exceeds limits."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/18FIND-310B-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/18FIND-310B-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/18FINDX8-310B-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/18FIND-310B-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/18FIND-310B-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/18FIND-310B-3D.STEP"}},{"code":"18NPWX8-017","name":"18NPW","slug":"18npwx8-017","description":"Woofer\/18inch\/Neo\/Paper\/1200W\/8ohm","url":"https:\/\/redcatt.net\/products\/18npwx8-017","category":"LF","type":"Woofer","size_inches":18,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1200","continuous_watts":"2400","peak_watts":"4800"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"23.7"},"thiele_small_parameters":{"fs_hz":36,"re_ohm":5.1,"qes":0.28,"qms":8.39,"qts":0.278,"vas_liters":211.5,"sd_cm2":1257,"sensitivity_db":99.14,"mms_grams":199.4,"rms":5.4,"cms":0.1,"bl_tm":27.3,"le_mh":1.51},"physical":{"overall_diameter_mm":468,"bolt_circle_diameter_mm":442,"baffle_cutout_diameter_mm":426,"mounting_holes":"8","depth_mm":189,"net_weight_kg":9.4,"xmax_mm":"4.85","xmech_mm":"18.85"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Strong glass fiber loaded cone","High temperature voice coil, double layer silicone spider","High power handling"],"design_notes":"The 18NPW is a high efficiency, (99 dB 1watt \/ 1 meter) 18-inch woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts. The 18NPW uses a lightweight, but strong, glass fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 21.5mm. \n\nPower Handling\nAt the core of the 18NPW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 350\u00b0C, well beyond the thermal requirements of modern professional audio systems. The 18NPW delivers incredible performance. \n \nREDCATT has implemented a double layer\/silicone spider design to ensure long term Fs memory, consistency and diminish anomalies associated with spider deterioration. The sealed spider works as a air pump and pushes the air trough out motor to increase heat transfer and cooling of the parts.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in touring, installation, and high-SPL applications, where consistent performance, durability, and output capability are critical.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 18NPWX8-017\nDriver: 18NPWX8-017 (18NPW) \u2014 18\" Woofer\nKey T\/S: Fs=36.0Hz, Qts=0.278, Vas=211.5L, Sens=99.14dB\nPower: AES 1200W \/ Cont 2400W \/ Peak 4800W\nXmax=4.85mm, Sd=1257.0cm\u00b2, Bl=27.3T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 210 liters\n Tuning (Fb): 37 Hz\n Est. -3dB: 34 Hz\n HP Filter: 29 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 37mm long\n Slot Port: 341mm W \u00d7 75mm H \u00d7 135mm L\n Port Velocity: 11.5 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 245 liters\n Tuning (Fb): 32 Hz\n Est. -3dB: 27 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 51mm long\n Slot Port: 341mm W \u00d7 75mm H \u00d7 164mm L\n Port Velocity: 10.1 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 275 liters\n Tuning (Fb): 29 Hz\n Est. -3dB: 25 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 68mm long\n Slot Port: 341mm W \u00d7 75mm H \u00d7 200mm L\n Port Velocity: 9.0 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 18NPWX8-017 is a 18-inch high-output woofer driver designed for professional subwoofer systems where high efficiency (99 dB 1W\/1m) and maximum acoustic output are required. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 210 to 275 liters, tuned between 29 and 37 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 1200 W AES \/ 2400 W continuous) and DSP control. A high-pass filter in the range of 20\u201329 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 25\u2013100 Hz, making it suitable for integration with mid-bass or full-range systems."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/18NPW-017-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/18NPW-017-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/18NPW-017-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/18NPW-017-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/18NPW-017-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/18NPW-017-3D.STEP"}},{"code":"152FINDX8-115","name":"152FIND","slug":"152findx8-115","description":"Woofer\/15inch\/Ferrite\/Paper\/800W\/8ohm","url":"https:\/\/redcatt.net\/products\/152findx8-115","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"800","continuous_watts":"1600","peak_watts":"3200"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"18.9"},"thiele_small_parameters":{"fs_hz":44,"re_ohm":4.8,"qes":0.38,"qms":13,"qts":0.37,"vas_liters":128.5,"sd_cm2":829.6,"sensitivity_db":99.03,"mms_grams":95.6,"rms":2,"cms":0.14,"bl_tm":18.3,"le_mh":0.98},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":137,"net_weight_kg":8.5,"xmax_mm":"4.45","xmech_mm":"14.45"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED LOW FREQUENCY RESPONSE","Lightweight carbon fiber loaded paper cone","High spl"],"design_notes":"The 152FIND is a high efficiency, (99 dB 1watt \/ 1 meter) 15-inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. The 152FIND uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 15mm.\n\nPower Handling\nAt the core of the 152FIND is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 280C, well beyond the thermal requirements of modern professional audio systems. \n\tThe 152FIND cone and dust cap are made using an advanced carbon fiber loaded REDCATT pulp. The woofer cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"The 152FINDX8-115 is a 15-inch professional mid-bass woofer designed for high-SPL two-way PA systems, installed loudspeakers, and touring enclosures operating across the 40\u20131000 Hz bandwidth. With a sensitivity of 99.03 dB (1 W\/1 m), it is among the highest-efficiency 15-inch woofer designs in the professional audio market, enabling competitive system SPL output from relatively compact enclosures and modest amplifier power. The driver uses a 76 mm (3-inch) CCAW voice coil wound on a Polyimide former rated to withstand peak temperatures in excess of 280\u00b0C, providing sustained high-power handling without thermal compression across long-duration programme material. The Ferrite motor system delivers a Bl of 18.3 T\u00b7m at a Qts of 0.37, yielding a controlled, motor-damped response optimized for vented (bass reflex) alignment. The Qms of 13.0 indicates near-lossless mechanical suspension; essentially all system damping is provided by the motor and external amplifier, with the suspension contributing minimal resistive losses \u2014 a design approach that maximizes efficiency and sensitivity. The carbon fiber loaded REDCATT paper cone is treated against humidity and environmental exposure, and metal components are coated for weatherization, making the 152FIND suitable for permanent indoor and semi-outdoor installation.\n\nThe 152FINDX8-115 is optimized for vented enclosures across a 45 to 100 litre net internal volume range, with tuning frequencies from 48 to 65 Hz covering compact touring to extended-bass installation formats. The compact 45 L alignment, tuned to 65 Hz, produces -3 dB at approximately 63 Hz with maximum sensitivity and mechanical control in the critical midbass band \u2014 the appropriate choice for touring PA cabinets, column-format line array bass extensions, and club fill systems where output efficiency and cabinet size take priority. The 70 L balanced alignment at 55 Hz tuning extends the -3 dB point to approximately 53 Hz, covering bass guitar, kick drum, and the full music programme bandwidth from a standard professional two-way enclosure format; it is the recommended general-purpose alignment for touring and installation. The extended 100 L alignment at 48 Hz tuning delivers -3 dB at approximately 46 Hz, covering the bass guitar open E fundamental at 41 Hz and the lower sub-octave of programme material in cinema, installed music, and large-format indoor PA applications. Port lengths for the 100 mm round tube range from 102 to 123 mm \u2014 short and practical for all three alignments \u2014 and a 250\u00d780 mm slot port option is provided with velocities from 5.6 to 7.5 m\/s, making it appropriate for even the most noise-sensitive install environments.\n\nThe 152FINDX8-115 requires high-power professional amplification delivering 800\u20131600 W into 8 ohms, with DSP signal management mandatory for all alignments. A minimum 24 dB\/octave high-pass filter at 50, 40, or 35 Hz \u2014 depending on alignment \u2014 must be applied, as cone excursion rises rapidly below the vented tuning frequency where the enclosure no longer provides acoustic loading. Displacement and power limiting are recommended in all DSP presets. The recommended low-pass crossover frequency for integration with a compression driver or high-frequency section is 1.0\u20131.5 kHz at 24 dB\/octave, providing full programme bandwidth from a single two-way system. The CCAW voice coil winding, lighter than equivalent copper, contributes to the high sensitivity figure without sacrificing the current-carrying capacity required at 800 W AES power levels.\n\nThe 152FINDX8-115 is suited for: two-way touring PA enclosures where 15-inch woofer coverage and high sensitivity are required in a compact trapezoidal format; installed main and fill speakers for theatres, houses of worship, stadia, and outdoor amphitheatres; high-SPL club and venue main systems operating at continuous programme levels; mid-bass column and line array modules in large-format installation arrays; and cinema LF speaker assemblies requiring extended bass coverage from a single enclosure. Its 99.03 dB sensitivity, 800 W AES power handling, and Qms=13.0 near-lossless suspension make it a reference-class 15-inch professional woofer for applications where efficiency, SPL headroom, and thermal durability are the primary performance priorities.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 152FINDX8-115\nDriver: 152FINDX8-115 (152FIND) \u2014 15\" ferrite pro mid-bass woofer, 8 ohm\nKey T\/S: Fs=44Hz, Qts=0.37, Qes=0.38, Qms=13.0, Vas=128.5L, Sens=99.03dB\nPower: AES 800W \/ Cont 1600W \/ Peak 3200W\nXmax=4.45mm (linear), Xmech=14.45mm, Xprot=15mm\nSd=829.6cm\u00b2, Bl=18.3T\u00b7m, Le=0.98mH, Re=4.8\u03a9\nVoice coil: 76mm (3\"), CCAW winding, Polyimide former (280\u00b0C rated)\nCone: carbon fiber loaded REDCATT paper pulp, environmentally treated\nSpider: Nomex (double silicone sealed)\nSurround: fabric triple roll constant geometry\nDepth: 137mm | Baffle cutout: 360mm | Ferrite motor\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.37 falls within the standard professional woofer range for vented\n (bass reflex) alignment. The 152FIND operates as a pro mid-bass woofer\n covering approximately 40\u20131000 Hz \u2014 not as a dedicated subwoofer \u2014 so\n enclosure tuning priorities favour midbass impact and output efficiency\n over maximum low-frequency extension. The very high Qms=13.0 indicates\n near-lossless suspension mechanics; essentially all mechanical damping\n is delivered by the motor (Qes=0.38) and amplifier source impedance.\n VENTED enclosures are the primary recommendation. Sealed enclosures are\n omitted as the Butterworth sealed alignment at Qts=0.37 would require\n approximately 98L and produce fc\u224884Hz \u2014 impractical and inefficient for\n a 15-inch pro woofer in full-range PA duty.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 829.6 cm\u00b2 \u00d7 0.445 cm = 369.2 cm\u00b3 (peak, one-way)\n\nWEATHERIZATION:\n The carbon fiber loaded REDCATT paper pulp cone and dust cap are treated\n against humidity and harsh environments. Metal basket parts are coated\n for weather protection. The double silicone sealed Nomex spider resists\n moisture ingress. Suitable for permanent indoor and semi-outdoor PA\n installations; not rated for direct rain exposure without additional\n enclosure sealing at the basket surround joint.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 100mm diameter round tube (Ap=7.854\u00d710\u207b\u00b3 m\u00b2)\n OR 250\u00d780mm slot port (Ap=2.000\u00d710\u207b\u00b2 m\u00b2)\nPort velocity limit (pro PA): \u226422 m\/s\nPort velocity limit (install): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (45 L net internal)\n Box volume: 45 L (net internal)\n Tuning freq (Fb): 65 Hz\n Round port: 100mm dia \u00d7 123mm long\n Port velocity: 19.2 m\/s (peak, at Xmax)\n Slot port: 250\u00d780mm \u00d7 313mm long\n Port velocity: 7.5 m\/s (peak, at Xmax)\n System f-3dB: ~63 Hz\n HP filter: 50 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~128 dB\n Application: Compact two-way touring PA cabinet, 15\" woofer section\n of portable line array, club PA top box, high-SPL\n stage monitor (wedge or column format).\n Notes: The highest-output compact alignment. At 63 Hz -3dB the driver\n delivers maximum sensitivity and cone control across the 65 Hz\u20131 kHz\n midbass band \u2014 the core working range for a 15\" two-way PA woofer.\n The 45 L net volume is compatible with compact trapezoidal touring\n enclosure formats of approximately 500\u00d7500\u00d7240mm external. With\n Qts=0.37, cone excursion rises steeply below Fb; the 50 Hz HP filter\n is essential at full programme power. The round port velocity of\n 19.2 m\/s is acceptable for touring PA; the 250\u00d780mm slot port is\n strongly preferred in any permanently installed application to remain\n within the 17 m\/s install limit.\nALIGNMENT B \u2014 STANDARD PA (70 L net internal)\n Box volume: 70 L (net internal)\n Tuning freq (Fb): 55 Hz\n Round port: 100mm dia \u00d7 111mm long\n Port velocity: 16.3 m\/s (peak, at Xmax)\n Slot port: 250\u00d780mm \u00d7 282mm long\n Port velocity: 6.4 m\/s (peak, at Xmax)\n System f-3dB: ~53 Hz\n HP filter: 40 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~128 dB\n Application: General-purpose two-way PA cabinet, installed main\n speaker (theatre, stadium, house of worship), flyable\n touring enclosure, outdoor installation.\n Notes: The recommended all-purpose alignment. At 53 Hz -3dB the system\n covers bass guitar, kick drum, and the full vocal and instrument\n range from a single enclosure. The 70 L cabinet is compatible with\n standard 15\" professional two-way formats at approximately 560\u00d7510\u00d7290mm\n external. Port velocities are well within both PA and installation\n limits on both port types. The short 111mm round port can be fitted\n in any panel orientation; the 282mm slot port can span the full\n internal width of the cabinet and double as structural bracing.\n With 99.03 dB sensitivity and 800 W AES, this alignment delivers\n system SPL competitive with dual-12\" designs from a single-15\" cabinet.\nALIGNMENT C \u2014 EXTENDED LF (100 L net internal)\n Box volume: 100 L (net internal)\n Tuning freq (Fb): 48 Hz\n Round port: 100mm dia \u00d7 102mm long\n Port velocity: 14.2 m\/s (peak, at Xmax)\n Slot port: 250\u00d780mm \u00d7 259mm long\n Port velocity: 5.6 m\/s (peak, at Xmax)\n System f-3dB: ~46 Hz\n HP filter: 35 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~128 dB\n Application: Two-way bass\/mid-bass cabinet with extended LF,\n cinema main LF section, installed music system main\n speaker, large indoor PA at moderate throw distances.\n Notes: The most extended bass alignment. At 46 Hz -3dB the 152FIND\n reproduces bass guitar open E (41Hz) and the lower range of kick\n drum and piano with full SPL capability. This cabinet size of\n approximately 600\u00d7550\u00d7360mm external approaches the larger end of\n standard 15\" two-way PA formats; internal bracing is recommended\n at this volume. Port lengths are the shortest of the three\n alignments \u2014 a counter-intuitive result of the larger Vb more than\n compensating for the lower Fb \u2014 making both round and slot ports\n particularly straightforward to implement. Slot port velocity of\n 5.6 m\/s is exceptionally low, making this alignment suitable for\n audiophile-level installation environments where port noise must be\n completely inaudible.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | Round Port | Slot Port | HP |\n |-------------|---------|-------|-------|-------------------|-------------------|--------|\n | A Compact | 45 L | 65 Hz | ~63Hz | 100mm \u00d7 123mm | 250\u00d780mm \u00d7 313mm | 50 Hz |\n | | | | | v=19.2 m\/s | v=7.5 m\/s | |\n | B Standard | 70 L | 55 Hz | ~53Hz | 100mm \u00d7 111mm | 250\u00d780mm \u00d7 282mm | 40 Hz |\n | | | | | v=16.3 m\/s | v=6.4 m\/s | |\n | C Extended | 100 L | 48 Hz | ~46Hz | 100mm \u00d7 102mm | 250\u00d780mm \u00d7 259mm | 35 Hz |\n | | | | | v=14.2 m\/s | v=5.6 m\/s | |\n\n Sensitivity: 99.03 dB (1W\/1m)\n Max SPL (800W): ~128 dB at 1m\n Impedance: 8 ohm nominal (Re=4.8\u03a9)\n Voice coil: 76mm (3\"), CCAW, Polyimide former (280\u00b0C rated)\n Qms: 13.0 (near-lossless suspension \u2014 all damping from motor\/amp)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/152FIND-115-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/152FIND-115-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/152FINDX8-115-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/152FIND-115-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/152FIND-115-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/152FIND-115-3D.STEP"}},{"code":"152FINDX8-333","name":"152FIND","slug":"152findx8-333","description":"Woofer\/15inch\/Ferrite\/Paper\/800W\/8ohm","url":"https:\/\/redcatt.net\/products\/152findx8-333","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"800","continuous_watts":"1600","peak_watts":"3200"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"19"},"thiele_small_parameters":{"fs_hz":37,"re_ohm":4.6,"qes":0.46,"qms":10.2,"qts":0.44,"vas_liters":119,"sd_cm2":804,"sensitivity_db":95.62,"mms_grams":140,"rms":3.19,"cms":0.13,"bl_tm":18.4,"le_mh":0.55},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":375,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":143,"net_weight_kg":9,"xmax_mm":"4.5","xmech_mm":"14.5"},"materials":{"surround":"NBR","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED LOW FREQUENCY RESPONSE","Carbon fiber reinforced cone","High excursion rubber surround"],"design_notes":"The 152FIND-333 is a high efficiency, (96 dB 1watt \/ 1 meter) 15-inch woofer with linear frequency response characteristics and high power handling capability. The 152FIND-333 uses a lightweight carbon fiber loaded cone assembly along with a high excursion rubber surround. This combination greatly improves low-frequency response and provides great level of control over the moving cone at high excursion levels. We have designed a lightweight surround, using our own rubber compound. As the result, the SPL is not compromised and the woofer can be used in professional audio applications, where high amounts of low frequencies are required.\n\nPower Handling\nAt the core of the 152FIND-333 is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 280C, well beyond the thermal requirements of modern professional audio systems.\nThe 152FIND-333 cone is extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"The 152FINDX8-333 is a 15-inch professional mid-bass woofer designed for high-SPL two-way PA enclosures, fixed installation systems, and outdoor applications requiring extended low-frequency performance and high mechanical durability. The driver uses a 76 mm (3-inch) CCAW voice coil wound on a Polyimide former rated to 280\u00b0C, delivering 800 W AES and 1600 W continuous power handling at 8 ohms. With a Ferrite motor producing a Bl of 18.4 T\u00b7m and a deliberately elevated moving mass of 140 g, the -333 is tuned to a lower resonant frequency of 37 Hz compared to other drivers in the 152FIND platform \u2014 a design choice that prioritizes bass extension and displacement control over peak sensitivity. The result is a measured sensitivity of 95.62 dB (1 W\/1 m), 3.4 dB below the higher-sensitivity -115 variant, with the trade-off being usable -3 dB output approximately 17 Hz lower. The voice coil inductance of Le=0.55 mH is significantly lower than competing 15-inch PA woofers of similar power class, reducing high-frequency inductance modulation distortion and preserving upper midrange clarity across the 50 Hz\u20131 kHz operating band at high displacement. The NBR rubber surround, produced from a REDCATT proprietary rubber compound, provides superior fatigue resistance, UV stability, ozone resistance, and compliance consistency compared to fabric surrounds under sustained high-excursion programme conditions, making the -333 the preferred choice for permanently installed outdoor systems and touring applications requiring extended service intervals.\n\nThe 152FINDX8-333 is optimized for vented (bass reflex) enclosures across a 50 to 110 litre net internal volume range, with tuning frequencies from 43 to 60 Hz. The compact 50 L alignment, tuned to 60 Hz, delivers -3 dB at approximately 58 Hz for high-output touring PA cabinets and column-format woofer sections; a 100 mm round port tube of 130 mm length is used, as the cabinet depth at this volume is insufficient for the slot port lengths generated by this tuning. The recommended 80 L standard alignment, tuned to 50 Hz, extends the -3 dB point to approximately 48 Hz, covering the full bass and lower midrange programme range from a standard professional two-way cabinet format; both a 100 mm round port (117 mm long, 14.5 m\/s) and a 250\u00d780 mm slot port (298 mm long, 5.7 m\/s) are practical at this volume. The extended 110 L alignment at 43 Hz tuning achieves -3 dB at approximately 41 Hz \u2014 at the bass guitar open E fundamental \u2014 from a single 15-inch two-way enclosure, with slot port velocity of 4.9 m\/s effectively eliminating turbulence noise across all drive levels. Port tube lengths decrease counter-intuitively as box volume increases across all three alignments (130 \u2192 117 \u2192 115 mm round), a product of the larger Vb more than compensating for the lower Fb, making port fabrication straightforward across the range.\n\nThe 152FINDX8-333 requires high-power professional amplification of 800\u20131600 W into 8 ohms, with DSP management mandatory including a 24 dB\/octave high-pass filter at 45, 38, or 33 Hz depending on alignment. Below the tuning frequency, enclosure acoustic loading is removed and cone excursion rises rapidly; the Xprot of 20 mm provides a generous mechanical safety margin, but displacement-limiting in DSP is still essential at full programme power. The recommended operating bandwidth extends from approximately 40 Hz to 1.0\u20131.5 kHz; a 24 dB\/octave low-pass crossover to a compression driver or high-frequency section at this frequency is standard for two-way system integration.\n\nThe 152FINDX8-333 is suited for: two-way touring PA enclosures requiring extended low-frequency performance and high mechanical durability from a 15-inch driver; permanently installed outdoor main speakers for amphitheatres, sports venues, festival sites, and theme parks where NBR rubber surround longevity is a primary service-life consideration; installed main speakers for theatres, houses of worship, and stadia where sub-bass coverage from the main enclosure is desirable; high-SPL club and venue systems operating at continuous programme levels with sustained high displacement; and cinema LF sections requiring bass guitar and low-drum fundamental reproduction without a supplementary subwoofer. Its combination of Fs=37 Hz, Le=0.55 mH, NBR rubber surround, and Polyimide former makes the -333 the acoustically deeper, mechanically more durable, and environmentally more robust variant within the 152FIND product platform.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 152FINDX8-333\nDriver: 152FINDX8-333 (152FIND-333) \u2014 15\" ferrite pro mid-bass woofer, 8 ohm\nKey T\/S: Fs=37Hz, Qts=0.44, Qes=0.46, Qms=10.2, Vas=119L, Sens=95.62dB\nPower: AES 800W \/ Cont 1600W \/ Peak 3200W\nXmax=4.5mm (linear), Xmech=14.5mm, Xprot=20mm\nSd=804cm\u00b2, Bl=18.4T\u00b7m, Le=0.55mH, Re=4.6\u03a9\nVoice coil: 76mm (3\"), CCAW winding, Polyimide former (280\u00b0C rated)\nCone: carbon fiber loaded paper, environmentally treated\nSurround: NBR rubber (high-excursion compound, REDCATT formulation)\nSpider: Nomex\nDepth: 143mm | Baffle cutout: 360mm | Ferrite motor\n\nCOMPARISON NOTE \u2014 152FIND-333 vs 152FIND-115:\n The -333 variant shares the 15\" platform and 76mm voice coil with the\n -115 (see 152FINDX8-115_enclosure_output.txt) but is tuned significantly\n differently. The -333 carries a heavier moving mass (Mms=140g vs 95.6g),\n producing a lower Fs of 37Hz (vs 44Hz) and a reduced sensitivity of\n 95.62dB (vs 99.03dB) \u2014 a deliberate trade-off favouring extended low-\n frequency reach and high-excursion control over raw efficiency. The NBR\n rubber surround replaces the fabric triple-roll, providing superior\n resistance to fatigue, UV exposure, and ozone at large cone displacements.\n Lower voice coil inductance (Le=0.55mH vs 0.98mH) reduces high-frequency\n phase shift and inductance modulation distortion, broadening the usable\n upper bandwidth. The -333 is the preferred choice when low-frequency\n extension, high displacement control under sustained drive, and outdoor\n durability are prioritized over maximum sensitivity.\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.44 is within the upper range of standard vented alignment for a\n 15-inch professional woofer. Vented (bass reflex) enclosures are the\n primary recommendation: the driver's Fs=37Hz and Vas=119L allow tuning\n down to 43Hz in a 110L enclosure, reaching bass guitar open E and\n kick drum sub-fundamental. Sealed alignments are omitted \u2014 the Butterworth\n sealed alignment at Qts=0.44 requires approximately 80L and produces\n fc\u224860Hz, which does not justify the efficiency penalty of a sealed box\n at this Qts level when vented options provide -3dB at 41\u201358Hz.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 804 cm\u00b2 \u00d7 0.450 cm = 361.8 cm\u00b3 (peak, one-way)\n\nWEATHERIZATION:\n The NBR rubber surround (REDCATT proprietary compound) provides high\n resistance to ozone, UV, moisture, and temperature cycling without\n degradation in compliance or fatigue life. The carbon fiber loaded paper\n cone is treated against humidity. Metal basket components are coated for\n weatherization protection. The -333 surround compound is specifically\n designed for applications requiring extended outdoor service life.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 100mm diameter round tube (Ap=7.854\u00d710\u207b\u00b3 m\u00b2)\n OR 250\u00d780mm slot port (Ap=2.000\u00d710\u207b\u00b2 m\u00b2)\nPort velocity limit (pro PA): \u226422 m\/s\nPort velocity limit (install): \u226417 m\/s\n\nNote on slot port for Alignment A: the 331mm slot length is impractical\nin a 50L compact cabinet (internal depth typically 230\u2013270mm). Round port\nor a smaller slot (200\u00d760mm) is recommended for the compact alignment.\n200\u00d760mm slot (Ap=0.012 m\u00b2): length=497mm at Fb=60Hz \u2014 impractical.\nRecommendation: use 100mm round port for Alignment A only.\nALIGNMENT A \u2014 COMPACT (50 L net internal)\n Box volume: 50 L (net internal)\n Tuning freq (Fb): 60 Hz\n Round port: 100mm dia \u00d7 130mm long\n Port velocity: 17.4 m\/s (peak, at Xmax)\n System f-3dB: ~58 Hz\n HP filter: 45 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~125 dB\n Application: Compact two-way touring PA cabinet, outdoor column\n speaker woofer section, high-SPL stage monitor.\n Notes: The compact high-output alignment. Fb=60Hz (1.62\u00d7Fs) keeps the\n tuning well above the driver's lower resonance, maximizing cone\n control and output in the 60Hz\u20131kHz midbass range. The 50L\n cabinet is the smallest practical enclosure for the -333 at this\n Qts; in compact touring formats (approx. 510\u00d7480\u00d7240mm external)\n the single 100mm round port fits any panel orientation. Port\n velocity of 17.4 m\/s is within pro PA limits; a flared port end\n is recommended. At full power the NBR rubber surround provides\n stable compliance under sustained high-excursion drive conditions\n that would cause fatigue in fabric surrounds after extended use.\nALIGNMENT B \u2014 STANDARD PA (80 L net internal)\n Box volume: 80 L (net internal)\n Tuning freq (Fb): 50 Hz\n Round port: 100mm dia \u00d7 117mm long\n Port velocity: 14.5 m\/s (peak, at Xmax)\n Slot port: 250\u00d780mm \u00d7 298mm long\n Port velocity: 5.7 m\/s (peak, at Xmax)\n System f-3dB: ~48 Hz\n HP filter: 38 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~125 dB\n Application: Two-way touring PA cabinet with extended bass, installed\n main speaker (theatre, stadium, HoW, outdoor arena),\n flyable touring enclosure, large-format PA top box.\n Notes: The recommended general-purpose alignment. At 48Hz -3dB the driver\n covers the full music programme including bass guitar, kick drum,\n and piano low register. The 80L cabinet is compatible with standard\n professional 15\" two-way formats at approximately 600\u00d7560\u00d7300mm\n external. Round port velocity of 14.5m\/s is within both PA and\n install limits; slot port velocity of 5.7m\/s is appropriate for\n audiophile-grade installation environments. The 298mm slot port\n can be located as a structural rear-panel element in cabinetry\n with internal widths of 300mm or greater. The lower Le=0.55mH\n of the -333 versus the -115 variant ensures reduced inductance\n modulation distortion across the 50Hz\u20131kHz operating band at\n high displacement, maintaining lower THD under demanding programme.\nALIGNMENT C \u2014 EXTENDED LF (110 L net internal)\n Box volume: 110 L (net internal)\n Tuning freq (Fb): 43 Hz\n Round port: 100mm dia \u00d7 115mm long\n Port velocity: 12.4 m\/s (peak, at Xmax)\n Slot port: 250\u00d780mm \u00d7 293mm long\n Port velocity: 4.9 m\/s (peak, at Xmax)\n System f-3dB: ~41 Hz\n HP filter: 33 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~125 dB\n Application: Extended bass two-way cabinet, cinema main LF section,\n installed music system where sub-bass is required from\n the main loudspeaker, outdoor festival main speaker.\n Notes: The deepest alignment. At 41Hz -3dB the system reaches the bass\n guitar open E (41Hz) and low kick drum fundamentals with full\n acoustic output \u2014 unusual capability for a standalone 15\" two-way\n PA cabinet. The 110L enclosure at approximately 650\u00d7600\u00d7350mm\n external is the practical upper limit for a flyable two-way format;\n non-flyable fixed-install versions may extend to this volume more\n readily. Internal bracing is required to control panel resonances\n at this volume. Port length is the shortest of the three alignments\n (115mm round, 293mm slot) \u2014 a consequence of the larger box volume\n more than compensating for the lower Fb. Slot port velocity of\n 4.9m\/s produces negligible turbulence noise at all drive levels,\n making this alignment suitable for theatre and cinema environments\n where port noise must be completely inaudible. The 33Hz HP filter\n must be robust \u2014 at and below 33Hz, cone excursion increases rapidly\n as the enclosure unloads, and the -333's Xprot of 20mm, while\n generous, must not be challenged without adequate DSP protection.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | Round Port | Slot Port | HP |\n |-------------|---------|-------|-------|-------------------|-------------------|--------|\n | A Compact | 50 L | 60 Hz | ~58Hz | 100mm \u00d7 130mm | \u2014 (impractical) | 45 Hz |\n | | | | | v=17.4 m\/s | | |\n | B Standard | 80 L | 50 Hz | ~48Hz | 100mm \u00d7 117mm | 250\u00d780mm \u00d7 298mm | 38 Hz |\n | | | | | v=14.5 m\/s | v=5.7 m\/s | |\n | C Extended | 110 L | 43 Hz | ~41Hz | 100mm \u00d7 115mm | 250\u00d780mm \u00d7 293mm | 33 Hz |\n | | | | | v=12.4 m\/s | v=4.9 m\/s | |\n\n Sensitivity: 95.62 dB (1W\/1m)\n Max SPL (800W): ~125 dB at 1m\n Impedance: 8 ohm nominal (Re=4.6\u03a9)\n Voice coil: 76mm (3\"), CCAW, Polyimide former (280\u00b0C rated)\n Surround: NBR rubber \u2014 REDCATT proprietary high-excursion compound\n Le: 0.55mH (low inductance \u2014 reduced HF phase shift vs -115)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/152FIND-333-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/152FIND-333-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/152FIND-333-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/152FIND-333-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/152FIND-333-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/152FIND-333-3D.STEP"}},{"code":"155FINDX8-367D","name":"155FIND","slug":"155findx8-367d","description":"Woofer\/15inch\/Ferrite\/Paper\/400W\/8ohm","url":"https:\/\/redcatt.net\/products\/155findx8-367d","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"400","continuous_watts":"800","peak_watts":"1600"},"voice_coil":{"diameter":"63.5","wire":"Copper","former":"Glass Fiber","winding_height":"15.5"},"thiele_small_parameters":{"fs_hz":40,"re_ohm":6.2,"qes":0.79,"qms":11.1,"qts":0.73,"vas_liters":166.5,"sd_cm2":881,"sensitivity_db":94.55,"mms_grams":102.6,"rms":2.32,"cms":0.15,"bl_tm":14.38,"le_mh":0.97},"physical":{"overall_diameter_mm":386,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":352,"mounting_holes":"8","depth_mm":142,"net_weight_kg":4.5,"xmax_mm":"4.75","xmech_mm":"10.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Cost effective design, yet with high spl, extended mid frequency","Good power handling","Lightweight paper cone, conex spider"],"design_notes":"The 154FIND is a cost-effective solution for two-way and multi-way systems, together with subwoofers. It\u2019s lightweight yet strong cone allows the magnetic circuit to be size optimized while delivering a seizable amount of sound pressure. With its high efficiency (97 dB 1watt \/ 1 meter) and high power handling capabilities, this woofer will excel in all applications with tight budgets. The cone shape and material was developed to extend mid-frequency response, making the woofer good choice for two-way and multi-way systems.\u00a0\n\nPower Handling\nAt the core of the 154FIND is its voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures above 280\u00b0C. The winding with high temperature handling copper wire ensures the long life of the voice coil, without the costly service cycles.\u00a0\nThe cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"The 155FINDX8-367D is a 15-inch woofer designed for professional PA, live sound, and installed sound systems with 94.6 dB sensitivity (1W\/1m). The driver features a lightweight paper cone with fabric surround and Nomex spider, utilizing a ferrite magnet motor on a steel basket for cost-effective high-output performance. Weatherized construction with treated cone and coated metal parts supports operation in harsh environments.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 55 to 90 liters, tuned between 36 and 48 Hz. The relatively high Qts (0.73) favors vented alignments with tuning near or above the free-air resonance frequency, providing strong mid-bass output with controlled cone excursion around the port tuning frequency. Lower tuning extends bass response but increases excursion below tuning, requiring appropriate high-pass filtering.\nThe driver is intended for use with high-power amplification (approx. 400 W AES \/ 800 W continuous) and DSP control. A high-pass filter in the range of 32\u201345 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. The extended cone geometry supports midrange response up to 2\u20132.5 kHz, making the driver suitable for two-way system configurations.\nThis design is particularly effective in single or multi-driver bass reflex systems used in PA, live sound, rental, and installed sound applications, where cost-effective performance, weatherized durability, and high output capability are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 155FINDX8-367D\nDriver: 155FINDX8-367D (155FIND) \u2014 15\" woofer\nKey T\/S: Fs=40.0Hz, Qts=0.73, Vas=166.5L, Sens=94.55dB\nPower: AES 400W \/ Cont 800W \/ Peak 1600W\nXmax=4.75mm, Xmech=10.75mm, Sd=881.0cm\u00b2, Bl=14.38T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (125mm diameter) \u2014 recommended for 15\" drivers to maintain low port velocity at high excursion\nNOTES ON Qts:\nThe relatively high Qts (0.73) indicates a softer motor control characteristic\ntypical of cost-optimized ferrite designs. This driver is best suited for vented\nenclosures where the port resonance provides additional cone control near tuning\nfrequency. Sealed enclosures are not recommended as even large volumes (>150L)\nwould result in Qtc values well above 1.0, producing boomy, under-damped response.\n a) High SPL (Compact)\n Net Volume: 55 liters\n Tuning (Fb): 48 Hz\n Est. -3dB: 50 Hz\n HP Filter: 45 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 289mm long\n Slot Port: 200mm W \u00d7 60mm H \u00d7 282mm L\n Port Velocity: 10.3 m\/s\n Notes: Maximum mid-bass punch, compact cabinet, suited for stage monitors\n and horn-loaded sub designs; reduced low-frequency extension\n b) Balanced Response\n Net Volume: 70 liters\n Tuning (Fb): 42 Hz\n Est. -3dB: 42 Hz\n HP Filter: 38 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 296mm long\n Slot Port: 200mm W \u00d7 60mm H \u00d7 290mm L\n Port Velocity: 9.0 m\/s\n Notes: General-purpose PA\/live sound, good balance between output and\n extension; recommended starting point for most applications\n c) Extended Low Frequency\n Net Volume: 90 liters\n Tuning (Fb): 36 Hz\n Est. -3dB: 35 Hz\n HP Filter: 32 Hz (24dB\/oct recommended)\n Round Port: 125mm dia \u00d7 313mm long\n Slot Port: 200mm W \u00d7 60mm H \u00d7 307mm L\n Port Velocity: 7.7 m\/s\n Notes: Deep bass extension for sub-bass reinforcement, larger cabinet;\n requires proper high-pass protection below tuning to prevent\n excessive excursion\nAPPLICATION NOTES:\n- The lightweight paper cone and extended cone geometry provide useful midrange\n response, making this woofer suitable for two-way systems with crossover\n points up to 2\u20132.5 kHz\n- Weatherized construction (treated cone, coated metal parts) supports outdoor\n and harsh-environment installations\n- The ferrite magnet and cost-effective design make this driver ideal for\n budget-conscious multi-box PA systems, rental fleets, and installed sound\n- Glass fiber voice coil former with Polyimide construction handles sustained\n high-power operation with reduced risk of thermal failure\n- For horn-loaded applications, the compact (55L) alignment provides the\n highest efficiency and mid-bass impact"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/155FIND-367D-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/155FIND-367D-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/155FINDX8-367D-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/155FIND-367D-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/155FIND-367D-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/155FIND-367D-3D.STEP"}},{"code":"15FHWX8-089","name":"15FHW","slug":"15fhwx8-089","description":"Woofer\/15inch\/Ferrite\/Paper\/400W\/8ohm","url":"https:\/\/redcatt.net\/products\/15fhwx8-089","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"400","continuous_watts":"800","peak_watts":"1600"},"voice_coil":{"diameter":"76","wire":"Copper","former":"Glass Fiber","winding_height":"19.7"},"thiele_small_parameters":{"fs_hz":24,"re_ohm":5.8,"qes":0.63,"qms":11.9,"qts":0.6,"vas_liters":221.2,"sd_cm2":804,"sensitivity_db":90.67,"mms_grams":169.6,"rms":2.15,"cms":0.26,"bl_tm":15.8,"le_mh":0.96},"physical":{"overall_diameter_mm":385,"bolt_circle_diameter_mm":371,"baffle_cutout_diameter_mm":349,"mounting_holes":"8","depth_mm":168.1,"net_weight_kg":6.8,"xmax_mm":"4.85","xmech_mm":"14.85"},"materials":{"surround":"NBR","cone_dome":"Paper GF","spider":null},"content":{"key_features":["Hi sensitivity, low resonant frequency","Nomex spider","Strong, yet lightweight cone"],"design_notes":"The 15FHW is an ultra low frequency sub-woofer, designed to deliver large amounts of very low frequencies. With 91 dB 1watt \/ 1 meter sensitivity, you find this 15-inch sub-woofer with incredibly linear frequency response characteristics ideally assembled in sub-woofers for hi-fi, gaming, studios or cinema. The 15FHW uses a strong paper cone, along with a high excursion single roll rubber surround. Rubber surround material was specifically developed for this application. The shape of the surround roll was FEM optimized to ensure low distortion in whole working range. \n\nPower Handling\nAt the core of the 15FHW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 200\u00b0C, well beyond the thermal requirements of modern professional audio systems. \n \nREDCATT has implemented a Nomex(r) spider design to ensure long term Fs memory, consistency and diminish anomalies associated with spider deterioration.","hero_text":null,"ai_summary":"The 15FHWX8-089 is a 15-inch cost-effective deep-bass subwoofer designed for home cinema, KTV, studio monitoring, and hi-fi systems where very low-frequency extension is the primary performance objective. With a free-air resonant frequency of 24 Hz \u2014 among the lowest available in a 15-inch driver format \u2014 the 15FHW is optimized to reproduce the full audible bass spectrum and the tactile infrasonic range required by modern object-based cinema audio formats such as Dolby Atmos and DTS:X. The driver uses a 76 mm copper voice coil on a Polyimide former rated to 200\u00b0C, delivering 400 W AES at 8 ohms in a cost-optimized package that includes a steel basket, ferrite motor, and glass fiber reinforced paper cone \u2014 a construction approach that concentrates the acoustic performance budget in the motor system and moving assembly rather than in structural materials. The NBR rubber surround is produced using a FEM-optimized single-roll profile designed to minimize geometric nonlinearity across the full Xmax excursion range, and the Nomex spider is specified for long-term Fs consistency, ensuring that the driver's critically low resonant frequency remains stable over the service life of the installation.\n\nThe 15FHWX8-089 supports both vented (bass reflex) and sealed (acoustic suspension) alignments across the 40 to 120 litre net internal volume range, with the choice between enclosure types determined by system design priorities. Vented alignments spanning 80 to 120 litres, tuned from 32 to 25 Hz, provide natural deep-bass extension from approximately 30 Hz down to 23 Hz (-3dB, anechoic) without requiring DSP correction. The compact vented 80 L alignment at 32 Hz is the recommended starting point for home cinema and KTV installations, delivering -3dB at approximately 30 Hz from a cabinet of approximately 480\u00d7480\u00d7400mm external using a single 100mm round port of 286mm length with a port velocity of 10.0 m\/s. Extending to 100 L tuned at 28 Hz moves the -3dB point to approximately 26 Hz, and the 120 L alignment at 25 Hz reaches 23 Hz \u2014 approaching the organ pedal sub-register and cinema LFE impact range \u2014 with port velocities of 8.7 and 7.8 m\/s respectively, effectively eliminating turbulence noise in library-quiet studio and critical listening environments. In typical domestic rooms, room gain of 3\u20138 dB below 50 Hz adds substantial perceived bass reinforcement, placing in-room extension well below 20 Hz for the extended vented alignments.\n\nSealed alignments of 40, 60, and 80 litres produce system Qtc values of 1.53, 1.30, and 1.16 respectively, with natural -3dB points at 43, 37, and 35 Hz. These alignments are particularly suited to DSP-active subwoofer systems employing Linkwitz Transform (LT) equalization, which corrects the rising sealed response to a flat target alignment and extends usable bass output to 16\u201320 Hz from compact enclosures. The 40 L sealed cabinet achieves extension to approximately 20 Hz with LT correction from an enclosure of approximately 380\u00d7380\u00d7320mm external \u2014 a practical size for built-in, in-wall, and under-seat home cinema installations. The amplifier must provide headroom of approximately 11\u201314 dB at the target low-frequency extension point relative to the unequalized response; a high-quality Class-D amplifier of 400 W or greater with DSP LT capability is the appropriate system amplification for all three sealed alignments.\n\nThe 15FHWX8-089 is suited for: home cinema subwoofer systems requiring LFE channel reproduction to 20\u201330 Hz from a single 15-inch driver; KTV and entertainment venue bass cabinets where deep tactile bass impact is valued at controlled cost; professional studio monitoring subwoofer extensions for bass verification in music production, film post-production, and game audio; audiophile hi-fi subwoofers for music systems where bass guitar, double bass, pipe organ, and synthesizer sub-register reproduction is required; and multimedia subwoofer systems in themed entertainment, simulation, and exhibit environments. Its Fs=24 Hz, FEM-optimized surround, and Nomex spider make it the appropriate choice in the REDCATT portfolio for deep-bass civilian applications where cost-effectiveness and infrasonic extension take precedence over maximum sensitivity and professional output capability.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 15FHWX8-089\nDriver: 15FHWX8-089 (15FHW) \u2014 15\" ferrite deep-bass subwoofer, 8 ohm\nKey T\/S: Fs=24Hz, Qts=0.60, Qes=0.63, Qms=11.9, Vas=221.2L, Sens=90.67dB\nPower: AES 400W \/ Cont 800W \/ Peak 1600W\nXmax=4.85mm (linear), Xmech=14.85mm, Xprot=19.6mm\nSd=804cm\u00b2, Bl=15.8T\u00b7m, Le=0.96mH, Re=5.8\u03a9\nVoice coil: 76mm (3\"), copper winding, Polyimide former (200\u00b0C rated)\nCone: glass fiber reinforced paper (Paper GF)\nSurround: NBR rubber, single roll, FEM optimized profile\nSpider: Nomex (long-term Fs memory design)\nDepth: 168.1mm | Baffle cutout: 349mm | Ferrite motor | Steel basket\n\nDESIGN PHILOSOPHY:\n The 15FHW is a cost-effective deep-bass subwoofer designed for home\n cinema, KTV, studio monitoring, and hi-fi\/multimedia systems where very\n low frequency extension is the primary performance requirement. The steel\n basket, ferrite magnet, and copper voice coil represent a deliberate\n cost-reduction approach relative to aluminum-basket\/neodymium\/CCAW\n professional drivers, without compromising the acoustic core: Fs=24Hz\n is among the lowest resonant frequencies available in a 15-inch format,\n and the FEM-optimized NBR single-roll surround provides controlled\n compliance at large excursion. The Nomex spider is specified to ensure\n long-term Fs consistency, critical for a subwoofer where a drift in\n resonant frequency directly affects perceived bass character.\n\n Qts=0.60 places the 15FHW between the classical sealed and vented design\n regions. Both enclosure types are viable and each offers distinct system\n design advantages: vented enclosures provide the deepest natural extension\n with no DSP requirement; sealed enclosures yield the smallest practical\n cabinet size and the most versatile platform for DSP-corrected active\n systems using Linkwitz Transform processing.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 804 cm\u00b2 \u00d7 0.485 cm = 389.9 cm\u00b3 (peak, one-way)\n\nROOM GAIN NOTE:\n In typical domestic listening rooms and KTV\/studio environments, room\n gain adds 3\u20136 dB below 50 Hz relative to anechoic measurements, and up\n to 8 dB in smaller rooms or vehicles. All f-3dB figures below are\n anechoic; in-room bass extension will be perceived as significantly\n deeper, and many installations will achieve useful output to 18\u201320 Hz\n with the extended alignments.\nVENTED (BASS REFLEX) ALIGNMENTS\nPort: 100mm diameter round tube (Ap=7.854\u00d710\u207b\u00b3 m\u00b2)\n All port velocities are well within hi-fi limits (\u226417 m\/s).\n Flared port ends are recommended to minimise turbulence noise at\n low-frequency excursion peaks. HP filter mandatory to protect cone.\nALIGNMENT A \u2014 COMPACT VENTED (80 L net internal)\n Box volume: 80 L (net internal)\n Tuning freq (Fb): 32 Hz\n Port: 100mm dia \u00d7 286mm long\n Port velocity: 10.0 m\/s (peak, at Xmax)\n System f-3dB: ~30 Hz\n HP filter: 24 Hz, 24 dB\/oct (or DSP shelf, mandatory)\n Max SPL (400W, 1m): ~117 dB\n Application: Home cinema subwoofer, KTV bass cabinet,\n studio monitoring sub, hi-fi floorstanding subwoofer.\n Notes: The most compact vented alignment. At 30 Hz -3dB, the driver\n covers the sub-bass range critical for home cinema (LFE channel\n .1), KTV bass impact, and music production monitoring below the\n fundamental of standard bass instruments. The 80L cabinet can be\n packaged in a typical home cinema tower or cube format at\n approximately 480\u00d7480\u00d7400mm external. The 286mm port tube fits\n a rear or side panel. With room gain, perceived extension in a\n domestic room reaches 22\u201325 Hz in most installations \u2014 approaching\n the limits of human hearing and the reproduction range of Dolby\n Atmos and DTS:X object-based audio formats. HP filter at 24 Hz\n prevents over-excursion during subsonic content or DC offsets.\nALIGNMENT B \u2014 STANDARD VENTED (100 L net internal)\n Box volume: 100 L (net internal)\n Tuning freq (Fb): 28 Hz\n Port: 100mm dia \u00d7 298mm long\n Port velocity: 8.7 m\/s (peak, at Xmax)\n System f-3dB: ~26 Hz\n HP filter: 20 Hz, 24 dB\/oct (mandatory)\n Max SPL (400W, 1m): ~117 dB\n Application: Reference home cinema subwoofer, professional\n studio monitoring system, high-end KTV room,\n hi-fi music reproduction down to 25 Hz.\n Notes: The recommended balanced alignment. At 26 Hz -3dB the system\n produces full acoustic output across the entire audible bass\n spectrum and into the tactile infrasonic range. The 100L\n cabinet at approximately 520\u00d7520\u00d7430mm external is within\n the size range of domestic subwoofer designs in the audiophile\n and semi-professional market. Port velocity of 8.7 m\/s is very\n low \u2014 turbulence noise at the port is negligible even at full\n power, appropriate for critical listening environments. The 20 Hz\n HP filter is essential: at and below port tuning, the cone\n excursion is unrestrained, and signals below 20 Hz (subsonic\n rumble, DC content, record warp artifacts) would drive Xmech\n rapidly at full amplifier power.\nALIGNMENT C \u2014 EXTENDED VENTED (120 L net internal)\n Box volume: 120 L (net internal)\n Tuning freq (Fb): 25 Hz\n Port: 100mm dia \u00d7 312mm long\n Port velocity: 7.8 m\/s (peak, at Xmax)\n System f-3dB: ~23 Hz\n HP filter: 18 Hz, 24 dB\/oct (mandatory)\n Max SPL (400W, 1m): ~117 dB\n Application: Dedicated home cinema LFE subwoofer, large-room\n hi-fi subwoofer, studio main monitoring extension,\n infrasonic reproduction for effects and music.\n Notes: The deepest practical vented alignment. At 23 Hz -3dB, the\n system operates below the conventional audiometric threshold\n of hearing (20 Hz), reaching the organ pedal range (16\u201332 Hz),\n cinema LFE impact content, and subsonic music production material.\n The 120L enclosure at approximately 570\u00d7540\u00d7450mm external is\n the upper practical size for a domestic installation; construction\n should include internal cross-bracing and damping treatment to\n control panel resonances at these cabinet volumes. Port velocity\n of 7.8 m\/s is effectively silent \u2014 appropriate for library-quiet\n studio reference environments. Combined with room gain of 5\u20138 dB\n below 30 Hz in a typical domestic room, effective perceived output\n extends to 18\u201320 Hz or below, covering the full range of any\n commercially released programme material.\nSEALED (ACOUSTIC SUSPENSION) ALIGNMENTS\n With Qts=0.60, sealed enclosures produce Qtc > 1.0 for all practical\n cabinet volumes \u2014 the box is always smaller than the Butterworth optimum\n (which would require approximately 570 L). This results in a rising\n bass response (shelved up near fc) that must be corrected with a\n Linkwitz Transform (LT) in a DSP-active system. The LT equalises the\n sealed response to a new target alignment (typically Q=0.577, any Fc),\n effectively extending the bass response to well below the driver's\n natural Fs. This approach is widely used in audiophile active sealed\n subwoofers; the power requirement increases below the natural fc as the\n amplifier must compensate for the roll-off, so amplifier headroom must\n be calculated accordingly. All sealed alignments below specify natural\n f-3dB; with LT correction, extension to 16\u201320 Hz is achievable from\n 40\u201380 L enclosures.\nSEALED A \u2014 COMPACT SEALED (40 L)\n Box volume: 40 L\n Qtc: 1.53\n System fc: 61 Hz\n Natural f-3dB: ~43 Hz\n With LT (target f-3dB=20Hz): achievable \u2014 requires amplifier headroom\n of approx. +14 dB at 20 Hz relative to the unequalized response;\n recommend 400W+ amp with LT-capable DSP.\n Application: Compact active subwoofer for desktop studio, small\n home cinema room, in-wall installation, KTV corner sub.\n Notes: The smallest sealed alignment. The strong bass presence lift near\n 61 Hz (+6 dB above flat) is prominent without LT correction; it\n works as a non-corrected home cinema sub only in small rooms where\n the peak aligns with room modes below 80 Hz. With LT equalization\n targeting 20 Hz, the 40L sealed box becomes a compact yet deep-\n reaching sub capable of extending to infrasonic frequencies from\n a cabinet of approximately 380\u00d7380\u00d7320mm external.\nSEALED B \u2014 STANDARD SEALED (60 L)\n Box volume: 60 L\n Qtc: 1.30\n System fc: 52 Hz\n Natural f-3dB: ~37 Hz\n With LT (target f-3dB=18Hz): achievable \u2014 requires approx. +12 dB\n amplifier headroom at 18 Hz; recommend 400W+ amp.\n Application: Active DSP subwoofer for home cinema, studio\n monitoring extension, bookshelf hi-fi subwoofer.\n Notes: A useful balance between cabinet size and natural bass extension.\n The 60L enclosure produces -3dB at 37 Hz unequalized \u2014 usable for\n KTV and home cinema without DSP correction in smaller rooms.\n With Linkwitz Transform, bass extension to ~18 Hz is achievable\n at reduced but still audible SPL from a 60L cabinet of\n approximately 420\u00d7420\u00d7380mm external. The +4.5 dB shelved peak\n near fc is moderate and manageable with LT equalization.\nSEALED C \u2014 LARGE SEALED (80 L)\n Box volume: 80 L\n Qtc: 1.16\n System fc: 47 Hz\n Natural f-3dB: ~35 Hz\n With LT (target f-3dB=16Hz): achievable \u2014 requires approx. +11 dB\n amplifier headroom at 16 Hz; recommend 400W+ amp.\n Application: Reference active subwoofer, studio main monitoring\n sub, dedicated hi-fi\/home cinema LFE cabinet.\n Notes: The most extended sealed alignment. At 35 Hz natural -3dB \u2014\n already reaching the bass guitar open E (41Hz) and approaching\n the low D (37Hz) without DSP \u2014 this sealed alignment provides\n a very useful deep bass capability from an 80L enclosure.\n With LT targeting 16 Hz, the system covers the full audible and\n tactile bass range from a cabinet equivalent in size to vented\n Alignment A. The Qtc=1.16 peak of +2.5 dB near 47 Hz is mild\n relative to the smaller sealed variants and requires moderate\n LT correction.\nSYSTEM SUMMARY TABLE\n VENTED ALIGNMENTS:\n | Alignment | Volume | Fb | f-3dB | Port | v | HP |\n |---------------|---------|-------|--------|-------------------|---------|--------|\n | A Compact | 80 L | 32 Hz | ~30 Hz | 100mm \u00d7 286mm | 10.0m\/s | 24 Hz |\n | B Standard | 100 L | 28 Hz | ~26 Hz | 100mm \u00d7 298mm | 8.7m\/s | 20 Hz |\n | C Extended | 120 L | 25 Hz | ~23 Hz | 100mm \u00d7 312mm | 7.8m\/s | 18 Hz |\n\n SEALED ALIGNMENTS (DSP\/Linkwitz Transform recommended):\n | Alignment | Volume | Qtc | fc | Natural f-3dB | LT target |\n |---------------|---------|-------|--------|---------------|-----------|\n | D Compact | 40 L | 1.53 | 61 Hz | ~43 Hz | ~20 Hz |\n | E Standard | 60 L | 1.30 | 52 Hz | ~37 Hz | ~18 Hz |\n | F Large | 80 L | 1.16 | 47 Hz | ~35 Hz | ~16 Hz |\n\n Sensitivity: 90.67 dB (1W\/1m)\n Max SPL (400W): ~117 dB at 1m\n Impedance: 8 ohm nominal (Re=5.8\u03a9)\n Voice coil: 76mm (3\"), copper, Polyimide former (200\u00b0C rated)\n Surround: NBR rubber, single roll, FEM-optimized profile\n Spider: Nomex \u2014 long-term Fs consistency design"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/15FHW-089-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/15FHW-089-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FHW-089-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FHW-089-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FHW-089-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FHW-089-3D.STEP"}},{"code":"15FINDX8-035","name":"15FIND","slug":"15findx8-035","description":"Woofer\/15inch\/Ferrite\/Paper\/1000W\/8ohm","url":"https:\/\/redcatt.net\/products\/15findx8-035","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1000","continuous_watts":"2000","peak_watts":"4000"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"25.5"},"thiele_small_parameters":{"fs_hz":42,"re_ohm":5.4,"qes":0.37,"qms":8.31,"qts":0.36,"vas_liters":96.4,"sd_cm2":881,"sensitivity_db":96.65,"mms_grams":159.6,"rms":5.1,"cms":0.09,"bl_tm":24.6,"le_mh":1.18},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":150,"net_weight_kg":12,"xmax_mm":"6.75","xmech_mm":"18.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Glass fiber and rib reinforced paper cone","fem optimized air circulation","Silicone sealed surround"],"design_notes":"The 15FIND is a high efficiency, (97 dB 1watt \/ 1 meter) 15-inch woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts. The 15FIND uses a lightweight, but strong, glass fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 21mm. \n\nPower Handling\nAt the core of the 15FIND is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 250\u00b0C, well beyond the thermal requirements of modern professional audio systems. Winding if winded on the outside and inside of the former.\n \nREDCATT has implemented a silicone spider design to ensure long term Fs memory, consistency and diminish anomalies associated with spider deterioration. The sealed spider works as a air pump and pushes the air trough out motor to","hero_text":null,"ai_summary":null,"recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 15FINDX8-035\nDriver: 15FINDX8-035 (15FIND) \u2014 15\" Sub-woofer\nKey T\/S: Fs=42.0Hz, Qts=0.36, Vas=96.4L, Sens=96.65dB\nPower: AES 1000W \/ Cont 2000W \/ Peak 4000W\nXmax=6.75mm, Sd=881.0cm\u00b2, Bl=24.6T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 compact cabinet may benefit from precision-tuned cylindrical port\n a) High SPL\n Net Volume: 75 liters\n Tuning (Fb): 48 Hz\n Est. -3dB: 44 Hz\n HP Filter: 40 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 63mm long\n Slot Port: 288mm W \u00d7 60mm H \u00d7 192mm L\n Port Velocity: 22.9 m\/s\n Notes: Strong mid-bass impact, reduc"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/15FIND-035-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/15FIND-035-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FIND-035-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FIND-035-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FIND-035-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FIND-035-3D.STEP"}},{"code":"15NPWX8-016","name":"15NPW","slug":"15npwx8-016","description":"Woofer\/15inch\/Neo\/Paper\/1200W\/8ohm","url":"https:\/\/redcatt.net\/products\/15npwx8-016","category":"LF","type":"Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1200","continuous_watts":"2400","peak_watts":"4800"},"voice_coil":{"diameter":"4","wire":"Copper","former":"Glass Fiber","winding_height":"25.5"},"thiele_small_parameters":{"fs_hz":40,"re_ohm":5.6,"qes":0.28,"qms":8.77,"qts":0.27,"vas_liters":107,"sd_cm2":881,"sensitivity_db":97.34,"mms_grams":155.1,"rms":4.44,"cms":0.1,"bl_tm":28.3,"le_mh":1.65},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":155.5,"net_weight_kg":8.5,"xmax_mm":"5.75","xmech_mm":"19.75"},"materials":{"surround":null,"cone_dome":null,"spider":"Nomex"},"content":{"key_features":["Carbon fiber loaded paper cone","Double silicone spider","High power handling"],"design_notes":"The 15NPW is a high efficiency, (97 dB 1watt \/ 1 meter) 15-inch woofer with linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. The 15NPW uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 15mm. Woofer features REDCATT double silicone sealed spider. \n\nPower Handling\nAt the core of the 15NPW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 350degC, well beyond the thermal requirements of modern professional audio systems. \n\tThe 15NPW cone and dust cap are made using an advanced carbon fiber loaded REDCATT pulp. The woofer cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"The 15NPWX8-016 is a 15-inch professional woofer designed for the highest-demand touring PA, installed sound, and cinema applications requiring maximum acoustic output, thermal durability, and motor linearity from a single 15-inch driver. With a sensitivity of 97.34 dB (1 W\/1 m) and an AES power handling of 1200 W at 8 ohms, the driver delivers a calculated maximum SPL of approximately 128 dB at 1 metre \u2014 among the highest figures available in the professional 15-inch woofer category. The motor system uses a 4-inch copper voice coil wound on a Polyimide former rated to withstand peak temperatures in excess of 350\u00b0C, providing sustained operation at continuous programme levels without thermal compression or former failure under the most demanding long-term drive conditions. The Neodymium magnet structure produces a Bl of 28.3 T\u00b7m at a Qts of 0.27, placing the 15NPW in the strong-motor professional woofer class where vented (bass reflex) enclosures are the only appropriate alignment. The carbon fiber loaded REDCATT paper cone assembly is treated against humidity and environmental exposure; the double silicone sealed Nomex spider provides moisture ingress protection for permanent installation and touring use.\n\nThe 15NPWX8-016 is optimized for vented enclosures across a 45 to 90 litre net internal volume range, with tuning frequencies from 47 to 65 Hz. The large cone area of 881 cm\u00b2 combined with Xmax=5.75 mm produces a peak displacement Vd of 506.6 cm\u00b3, requiring a minimum port aperture of 125 mm round or 250\u00d780 mm slot; a standard 100 mm round port produces velocities exceeding 22 m\/s at all practical tuning frequencies and must not be used with this driver. The compact 45 L alignment, tuned to 65 Hz with a 125 mm round port of 192 mm length (16.9 m\/s) or a 250\u00d780 mm slot of 313 mm length (10.3 m\/s), delivers -3 dB at approximately 63 Hz with maximum cone control and output across the midbass working range \u2014 suited to compact trapezoidal touring cabinets, column array woofer sections, and high-SPL stage monitors. The recommended 65 L balanced alignment at 55 Hz extends the -3 dB point to approximately 53 Hz, covering the complete music programme from bass guitar through upper midrange from a standard professional two-way enclosure format; slot port velocity of 8.8 m\/s is within theatre and critical installation limits. The extended 90 L alignment at 47 Hz delivers -3 dB at approximately 45 Hz, resolving bass guitar open E at 41 Hz and low orchestral bass content in cinema LF, large-venue installation, and theatre main speaker applications. Port tube lengths remain nearly constant across all three alignments (184\u2013192 mm round, 300\u2013313 mm slot), a useful property for cabinet designs sharing common port hardware.\n\nThe 15NPWX8-016 requires professional high-power amplification of 1200\u20132400 W into 8 ohms, with DSP control mandatory for all alignments. A 24 dB\/octave high-pass filter set at 50, 42, or 36 Hz depending on the alignment is required; the vented enclosure unloads the cone below Fb, and with Xprot=14.6 mm, displacement limiting must be active at full amplifier power to prevent progressive mechanical overload below the tuning frequency at high programme levels. The recommended operating bandwidth is approximately 40 Hz to 1.5 kHz, with a 24 dB\/octave low-pass crossover to a compression driver or high-frequency section at 1.0\u20131.5 kHz appropriate for standard two-way system integration.\n\nThe 15NPWX8-016 is suited for: two-way touring PA enclosures requiring maximum SPL from a single 15-inch driver; flyable and fixed-install main speakers for theatres, stadia, arenas, houses of worship, and outdoor festivals; cinema main LF speaker assemblies where thermal durability and programme-consistent output across extended programme durations are required; high-SPL column array woofer sections; and reference two-way installed PA systems for venues where a single 15-inch cabinet must deliver full-bandwidth coverage at continuous programme levels without supplementary sub-bass reinforcement. Its combination of 97.34 dB sensitivity, 1200 W AES power handling, Neodymium motor with 350\u00b0C-rated Polyimide former, and carbon fiber loaded cone positions the 15NPW as the highest-output 15-inch driver in the REDCATT NPW platform for mid-to-large-scale professional audio applications.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 15NPWX8-016\nDriver: 15NPWX8-016 (15NPW) \u2014 15\" neodymium pro woofer, 8 ohm\nKey T\/S: Fs=40Hz, Qts=0.27, Qes=0.28, Qms=8.77, Vas=107L, Sens=97.34dB\nPower: AES 1200W \/ Cont 2400W \/ Peak 4800W\nXmax=5.75mm (linear), Xmech=19.75mm, Xprot=14.6mm\nSd=881cm\u00b2, Bl=28.3T\u00b7m, Le=1.65mH, Re=5.6\u03a9\nVoice coil: 4-inch, copper winding, Polyimide former (350\u00b0C rated)\nCone: carbon fiber loaded REDCATT paper pulp, environmentally treated\nSpider: Nomex, double silicone sealed\nSurround: triple roll constant geometry\nDepth: 155.5mm | Baffle cutout: 360mm | Neodymium motor | Aluminum basket\n\nNPW PLATFORM CONTEXT:\n The 15NPW shares its fundamental motor architecture with the 12NPW\n (122NPWX8-102): 4-inch copper voice coil, Polyimide former rated to\n 350\u00b0C, L-winding=25.5, double silicone sealed Nomex spider, and carbon\n fiber loaded paper cone. The 15-inch format increases Sd by 60% over\n the 12-inch (881 vs 551 cm\u00b2), raising displacement capacity and SPL\n ceiling, while the 1200W AES power rating \u2014 50% above the 12NPW \u2014\n places the 15NPW at the top tier of single-driver professional woofer\n power handling in this format.\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.27 is within the low-motor-force professional woofer range,\n clearly favouring vented (bass reflex) enclosures. A sealed alignment\n would produce an overdamped, low-efficiency system with insufficient\n bass output relative to the driver's acoustic capability. Vented\n enclosures are the only recommended alignment for this driver.\n\n The large Sd=881cm\u00b2 and Xmax=5.75mm produce a peak displacement\n Vd=506.6cm\u00b3 \u2014 the largest of any driver in this series at this excursion\n class. A 100mm round port produces velocities exceeding 22 m\/s at all\n practical tuning frequencies and must not be used. Port sizing requires\n a minimum 125mm round tube or a slot port of at least 200cm\u00b2 aperture\n area. The 250\u00d780mm slot port is the preferred option for touring and\n installation cabinetry.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 881 cm\u00b2 \u00d7 0.575 cm = 506.6 cm\u00b3 (peak, one-way)\n\nWEATHERIZATION:\n The carbon fiber loaded paper cone and dust cap are treated against\n humidity and environmental exposure. Metal basket components are\n aluminum with environmental coating. The double silicone sealed Nomex\n spider resists moisture ingress. Suitable for permanent indoor and\n semi-outdoor installations.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 125mm diameter round tube (Ap=1.227\u00d710\u207b\u00b2 m\u00b2)\n OR 250\u00d780mm slot port (Ap=2.000\u00d710\u207b\u00b2 m\u00b2)\n\nDO NOT use 100mm round port \u2014 velocity exceeds 22 m\/s at all alignments.\n\nPort velocity limit (pro PA \/ touring): \u226422 m\/s\nPort velocity limit (install \/ theatre): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (45 L net internal)\n Box volume: 45 L (net internal)\n Tuning freq (Fb): 65 Hz\n 125mm round port: 192mm long\n Port velocity: 16.9 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 313mm long\n Port velocity: 10.3 m\/s (peak, at Xmax)\n System f-3dB: ~63 Hz\n HP filter: 50 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1200W, 1m): ~128 dB\n Application: Compact two-way touring PA cabinet, 15\" top box,\n column array woofer, high-SPL stage monitor.\n Notes: Maximum output in the smallest enclosure. Fb=65Hz (1.63\u00d7Fs)\n places tuning firmly in the midbass band, delivering maximum\n cone control and output in the 65Hz\u20131.5kHz working range of a\n professional two-way woofer. At 45L, the enclosure is compatible\n with compact trapezoidal touring formats of approximately\n 510\u00d7490\u00d7240mm external. The 125mm round port at 192mm length is\n practical in any panel position; the 250\u00d780mm slot at 313mm is\n appropriate for rear-panel or baffle-integrated installation.\n The 50Hz HP filter is critical \u2014 below Fb, cone excursion rises\n rapidly and at 1200W, Xprot=14.6mm is approached quickly without\n DSP limiting.\nALIGNMENT B \u2014 STANDARD PA (65 L net internal)\n Box volume: 65 L (net internal)\n Tuning freq (Fb): 55 Hz\n 125mm round port: 186mm long\n Port velocity: 14.3 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 303mm long\n Port velocity: 8.8 m\/s (peak, at Xmax)\n System f-3dB: ~53 Hz\n HP filter: 42 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1200W, 1m): ~128 dB\n Application: General-purpose two-way PA cabinet, installed main\n speaker (theatre, stadium, HoW, arena), flyable\n touring enclosure, large-format top box.\n Notes: The recommended all-purpose alignment. At 53Hz -3dB the system\n covers the complete music programme from bass guitar through\n upper vocals. The 65L enclosure is compatible with standard 15\"\n professional two-way formats at approximately 560\u00d7530\u00d7290mm\n external. Both port options produce velocities well within PA\n and install limits. The 303mm slot port velocity of 8.8 m\/s\n is appropriate for theatre and critical installation environments.\n With 97.34dB sensitivity and 1200W AES, peak acoustic output\n of ~128dB at 1m makes the 15NPW one of the highest-output\n single-driver two-way woofer solutions available in the 15-inch\n format.\nALIGNMENT C \u2014 EXTENDED LF (90 L net internal)\n Box volume: 90 L (net internal)\n Tuning freq (Fb): 47 Hz\n 125mm round port: 184mm long\n Port velocity: 12.2 m\/s (peak, at Xmax)\n Slot port (250\u00d780mm): 300mm long\n Port velocity: 7.5 m\/s (peak, at Xmax)\n System f-3dB: ~45 Hz\n HP filter: 36 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (1200W, 1m): ~128 dB\n Application: Extended LF two-way cabinet, cinema main speaker\n LF section, installed music system, large theatre\n or arena main array woofer.\n Notes: The deepest available alignment. At 45Hz -3dB the system\n resolves bass guitar open E (41Hz), bass drum fundamentals, and\n the lower registers of keyboard and orchestral bass instruments.\n The 90L cabinet at approximately 610\u00d7580\u00d7330mm external is\n the practical upper limit for a flyable 15\" two-way format;\n fixed-install enclosures can reach this volume more readily.\n Internal cross-bracing is recommended. Port tube lengths are\n nearly equal across all three alignments (184\u2013192mm round,\n 300\u2013313mm slot) \u2014 a consequence of the larger Vb compensating\n for lower Fb \u2014 simplifying port specification across a product\n family sharing common port hardware.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | 125mm Port | v | Slot 250\u00d780mm | v | HP |\n |-------------|--------|-------|-------|------------|--------|---------------|--------|--------|\n | A Compact | 45 L | 65 Hz | ~63Hz | 192mm | 16.9 | 313mm | 10.3 | 50 Hz |\n | B Standard | 65 L | 55 Hz | ~53Hz | 186mm | 14.3 | 303mm | 8.8 | 42 Hz |\n | C Extended | 90 L | 47 Hz | ~45Hz | 184mm | 12.2 | 300mm | 7.5 | 36 Hz |\n All velocity figures in m\/s (peak, at Xmax).\n\n Sensitivity: 97.34 dB (1W\/1m)\n Max SPL (1200W): ~128 dB at 1m\n Impedance: 8 ohm nominal (Re=5.6\u03a9)\n Voice coil: 4-inch, copper, Polyimide former (350\u00b0C rated)\n WARNING: Do not use 100mm round port \u2014 velocity exceeds limits.\n Minimum port: 125mm round or 250\u00d780mm slot."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/15NPW-016-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/15NPW-016-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/15NPW-016-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/15NPW-016-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/15NPW-016-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/15NPW-016-3D.STEP"}},{"code":"154FINDX8-298","name":"154FIND","slug":"154findx8-298","description":"Mid-Woofer\/15inch\/Ferrite\/Paper\/500W\/8ohm","url":"https:\/\/redcatt.net\/products\/154findx8-298","category":"LF","type":"Mid-Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"500","continuous_watts":"1000","peak_watts":"2000"},"voice_coil":{"diameter":"63.5","wire":"Copper","former":"Glass Fiber","winding_height":"17"},"thiele_small_parameters":{"fs_hz":38,"re_ohm":5.6,"qes":0.43,"qms":8.1,"qts":0.4,"vas_liters":187.2,"sd_cm2":881,"sensitivity_db":97.38,"mms_grams":103,"rms":3.03,"cms":0.17,"bl_tm":18.1,"le_mh":0.97},"physical":{"overall_diameter_mm":387,"bolt_circle_diameter_mm":374,"baffle_cutout_diameter_mm":355,"mounting_holes":"8","depth_mm":155,"net_weight_kg":6.3,"xmax_mm":"4.5","xmech_mm":"12.5"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Cost effective design, yet with high spl, extended mid frequency","Good power handling","Lightweight paper cone, conex spider"],"design_notes":"The 154FIND is a cost-effective solution for two-way and multi-way systems, together with subwoofers. It\u2019s lightweight yet strong cone allows the magnetic circuit to be size optimized while delivering a seizable amount of sound pressure. With its high efficiency (97 dB 1watt \/ 1 meter) and high power handling capabilities, this woofer will excel in all applications with tight budgets. The cone shape and material was developed to extend mid-frequency response, making the woofer good choice for two-way and multi-way systems.\u00a0\n\nPower Handling\nAt the core of the 154FIND is its voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures above 280\u00b0C. The winding with high temperature handling copper wire ensures the long life of the voice coil, without the costly service cycles.\u00a0\nThe cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 154FINDX8-298\nDriver: 154FINDX8-298 (154FIND) \u2014 15\" Mid-Woofer\nKey T\/S: Fs=38.0Hz, Qts=0.4, Vas=187.2L, Sens=97.38dB\nPower: AES 500W \/ Cont 1000W \/ Peak 2000W\nXmax=4.50mm, Sd=881.0cm\u00b2, Bl=18.1T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 125 liters\n Tuning (Fb): 44 Hz\n Est. -3dB: 40 Hz\n HP Filter: 36 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 23mm long\n Slot Port: 284mm W \u00d7 60mm H \u00d7 101mm L\n Port Velocity: 13.9 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 140 liters\n Tuning (Fb): 40 Hz\n Est. -3dB: 37 Hz\n HP Filter: 30 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 33mm long\n Slot Port: 284mm W \u00d7 60mm H \u00d7 122mm L\n Port Velocity: 12.7 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 150 liters\n Tuning (Fb): 36 Hz\n Est. -3dB: 31 Hz\n HP Filter: 24 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 47mm long\n Slot Port: 284mm W \u00d7 60mm H \u00d7 152mm L\n Port Velocity: 11.4 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 154FINDX8-298 is a 15-inch high-output mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (97 dB 1W\/1m) and controlled low-frequency behavior. The driver uses a balanced motor-suspension design that provides good cone control while maintaining usable output across its operating bandwidth.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 125 to 150 liters, tuned between 36 and 44 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 500 W AES \/ 1000 W continuous) and DSP control. A high-pass filter in the range of 24\u201336 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 31\u20131500 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/154FIND-298-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/154FIND-298-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/154FIND-298-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/154FIND-298-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/154FIND-298-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/154FIND-298-3D.STEP"}},{"code":"15FPMX8-063","name":"15FPM","slug":"15fpmx8-063","description":"Mid-Woofer\/15inch\/Ferrite\/Paper\/1000W\/8ohm","url":"https:\/\/redcatt.net\/products\/15fpmx8-063","category":"LF","type":"Mid-Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"1000","continuous_watts":"2000","peak_watts":"4000"},"voice_coil":{"diameter":"101.6","wire":null,"former":"Glass Fiber","winding_height":"21"},"thiele_small_parameters":{"fs_hz":41,"re_ohm":5.2,"qes":0.38,"qms":8.07,"qts":0.36,"vas_liters":134.9,"sd_cm2":908,"sensitivity_db":97.87,"mms_grams":126.6,"rms":4.04,"cms":0.12,"bl_tm":21.3,"le_mh":1.17},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":150,"net_weight_kg":12,"xmax_mm":"4.5","xmech_mm":"16.5"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Carbon fiber reinforced paper cone","Square Aluminum winding wire (ALR)","Great option for powerful 2-way systems"],"design_notes":"The 15FPM is a high efficiency, (98 dB 1watt \/ 1 meter) 15-inch woofer with incredibly linear frequency response characteristics. The 15FPM uses a lightweight, but strong, carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. Cone material was specifically developed with 2-way or multi-way application in mind. The 15FPM has extended mid frequency range, providing possibility for cross overs at higher frequencies.\n\nPower Handling\nAt the core of the 15FPM is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 250\u00b0C, well beyond the thermal requirements of modern professional audio systems. The coil is wound on the outside of the former. Winding material is aluminum ribbon, material that provides ideal transient response.\n \nREDCATT has implemented a silicone spider design to ensure long term Fs memory, consistency and diminish anomalies associated with spider deterioration. The sealed spi","hero_text":null,"ai_summary":null,"recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 15FPMX8-063\nDriver: 15FPMX8-063 (15FPM) \u2014 15\" Mid-Woofer\nKey T\/S: Fs=41.0Hz, Qts=0.36, Vas=134.9L, Sens=97.87dB\nPower: AES 1000W \/ Cont 2000W \/ Peak 4000W\nXmax=4.50mm, Sd=908.0cm\u00b2, Bl=21.3T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Slot port (full-width or L-shaped internal duct) \u2014 provides large cross-sectional area needed for high air displacement; reduces port noise at high SPL\n a) High SPL\n Net Volume: 105 liters\n Tuning (Fb): 47 Hz\n Est. -3dB: 43 Hz\n HP Filter: 39 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 29mm long\n Slot Port: 288mm W \u00d7 60mm H \u00d7 117mm L\n Port Veloci"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/15FPM-063-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/15FPM-063-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FPM-063-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FPM-063-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/15FPM-063-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/15FPM-063-3D.STEP"}},{"code":"15NPMX8-262","name":"15NPM","slug":"15npmx8-262","description":"Mid-Woofer\/15inch\/Neo\/Paper\/800W\/8ohm","url":"https:\/\/redcatt.net\/products\/15npmx8-262","category":"LF","type":"Mid-Woofer","size_inches":15,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"800","continuous_watts":"1600","peak_watts":"3200"},"voice_coil":{"diameter":"101.6","wire":null,"former":"Glass Fiber","winding_height":"23"},"thiele_small_parameters":{"fs_hz":48,"re_ohm":4.7,"qes":0.47,"qms":16.5,"qts":0.46,"vas_liters":89.9,"sd_cm2":855.3,"sensitivity_db":97.73,"mms_grams":123,"rms":2.25,"cms":0.09,"bl_tm":19.3,"le_mh":0.68},"physical":{"overall_diameter_mm":392,"bolt_circle_diameter_mm":373,"baffle_cutout_diameter_mm":360,"mounting_holes":"8","depth_mm":149.5,"net_weight_kg":6.65,"xmax_mm":"5.25","xmech_mm":"17.75"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","2 demodulation rings, lightweight carbon fiber loaded paper cone","Hi BL, Double air-gap, powerful motor structure"],"design_notes":"The 15NPM is a truly unique full range woofer. We have designed cutting edge product, using the best available materials and highly optimized design for the best performance in its class. It delivers very high efficiency, (98 dB 1watt \/ 1 meter), incredibly linear frequency response characteristics with extended HF frequency response, high power handling capability, while generating ultra low harmonic distortion artifacts. The 15NPM uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak linear excursion of 21mm.\n\nMagnetic Circuit\nThe magnetic circuit sports two aluminum shorting rings, double air-gap front plate. The cooling system and the air flow has been designed using modern FEM techniques and further optimized to provide the highest levels of cooling efficiency. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability..","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 15NPMX8-262\nDriver: 15NPMX8-262 (15NPM) \u2014 15\" Mid-Woofer\nKey T\/S: Fs=48.0Hz, Qts=0.46, Vas=89.9L, Sens=97.73dB\nPower: AES 800W \/ Cont 1600W \/ Peak 3200W\nXmax=5.25mm, Sd=855.3cm\u00b2, Bl=19.3T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 compact cabinet may benefit from precision-tuned cylindrical port\n a) High SPL\n Net Volume: 50 liters\n Tuning (Fb): 55 Hz\n Est. -3dB: 51 Hz\n HP Filter: 47 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 74mm long\n Slot Port: 288mm W \u00d7 60mm H \u00d7 214mm L\n Port Velocity: 19.8 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 60 liters\n Tuning (Fb): 50 Hz\n Est. -3dB: 46 Hz\n HP Filter: 40 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 76mm long\n Slot Port: 288mm W \u00d7 60mm H \u00d7 221mm L\n Port Velocity: 18.1 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 75 liters\n Tuning (Fb): 46 Hz\n Est. -3dB: 39 Hz\n HP Filter: 34 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 82mm long\n Slot Port: 288mm W \u00d7 60mm H \u00d7 232mm L\n Port Velocity: 16.4 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 15NPMX8-262 is a 15-inch high-output mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (98 dB 1W\/1m) and controlled low-frequency behavior. The driver features a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 50 to 75 liters, tuned between 46 and 55 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 800 W AES \/ 1600 W continuous) and DSP control. A high-pass filter in the range of 34\u201347 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 39\u20131500 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/15NPM-262-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/15NPM-262-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/15NPM-262-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/15NPM-262-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/15NPM-262-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/15NPM-262-3D.STEP"}},{"code":"12XRX8-270","name":"12XR","slug":"12xrx8-270","description":"XR Sub-Woofer\/12inch\/Neo\/Paper\/500W\/8ohm","url":"https:\/\/redcatt.net\/products\/12xrx8-270","category":"LF","type":"Sub-woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"500","continuous_watts":"1000","peak_watts":"2000"},"voice_coil":{"diameter":"63.5","wire":"Copper","former":"Glass Fiber","winding_height":"12.6"},"thiele_small_parameters":{"fs_hz":35,"re_ohm":5.7,"qes":0.73,"qms":10.5,"qts":0.68,"vas_liters":89.7,"sd_cm2":531,"sensitivity_db":90.95,"mms_grams":88.3,"rms":1.85,"cms":0.23,"bl_tm":12.3,"le_mh":0.24},"physical":{"overall_diameter_mm":320,"bolt_circle_diameter_mm":299,"baffle_cutout_diameter_mm":281,"mounting_holes":"8","depth_mm":172.5,"net_weight_kg":5.7,"xmax_mm":"9.2","xmech_mm":"32.7"},"materials":{"surround":"NBR","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Very high cone excursion, with very low THD","Capable to handle very low frequencies","High power handling, copper cap, stitched tinsel wires"],"design_notes":"The 12XR was designed around our new approach to the magnetic system. Our XR series speaker motors were designed so the voice coil winding doesn\u2019t leave the gap for most of the cone excursion. The desired cone excursion is carefully evaluated and incorporated into the design. The 12XR allows the designer to design sub-woofers with very large cone excursions, without the otherwise present harmonic distortion due to the voice coil leaving the magnetic gap. If you like the sound of a clean, undistorted bass, then the 12XR is the right transducer for your application. \n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding. This has allowed us to push the cone excursion to 28mm peak to peak. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver. We have also developed a new technique for manufacturing deep copper caps. \n \nThe design further sports a large spider on top of which is hot-pressed tinsel wires. Cone is carbon fiber reinforced, with a lightweight foamed rubber surround. The suspension was designed for large excursions.","hero_text":null,"ai_summary":"The 12XRX8-270 is a 12-inch sub-woofer and bass driver rated at 500 W AES (1000 W continuous) into a nominal 8-ohm impedance, built around the XR (eXtended Range) radial neodymium motor system. Large neodymium magnets are positioned along the voice coil winding so the entire coil remains within the magnetic field throughout the rated excursion, minimizing harmonic distortion associated with coil-to-gap overhang at high drive levels. A deep copper cap reduces voice coil inductance to 0.24 mH, extending frequency response and lowering inductance-modulation distortion without the use of a static shorting coil. The high Qms (10.5) indicates a near-lossless suspension in which system damping is governed primarily by the amplifier and enclosure.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 35 to 70 liters, tuned between 28 and 38 Hz, with an estimated -3 dB frequency of approximately 28 to 38 Hz. The relatively high Qts (0.68) produces a moderate mid-bass emphasis near the tuning frequency in vented enclosures, which is readily addressed with a parametric DSP correction of 1\u20132 dB. In sealed enclosures of 35 to 75 liters, Qtc values range from 1.00 to 1.28 with a passive -3 dB between 41 and 48 Hz; DSP shelf correction extends the system response to approximately 25\u201330 Hz in active applications.\n\nThe driver is rated for amplification of approx. 500 W AES (1000 W continuous) into 8 ohms, with a recommended high-pass filter in the 22\u201333 Hz range for vented alignments depending on tuning. Active sealed systems benefit from DSP shelf correction below 50 Hz, with excursion limiting applied below 25 Hz. The 8-ohm impedance suits bridged amplifier configurations, and the low inductance (0.24 mH) enables clean integration at crossover frequencies up to approximately 500 Hz, making the driver suitable as a bass driver in multi-way speaker systems.\n\nThe 12XRX8-270 is intended for dedicated hi-fi subwoofer enclosures, 2.1 and multi-channel home theater systems, large 2-way or 3-way floorstanding loudspeakers, and studio reference monitoring applications where the XR motor's extended linear excursion, the CF paper cone's rigidity, and the low voice coil inductance combine to deliver accurate, low-distortion bass reproduction.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 12XRX8-270\nDriver: 12XRX8-270 (12XR) \u2014 12\" XR sub-woofer \/ woofer, 8 ohm\nKey T\/S: Fs=35.0Hz, Qts=0.68, Qes=0.73, Qms=10.5, Vas=89.7L, Sens=90.95dB\nPower: AES 500W \/ Cont 1000W \/ Peak 2000W\nXmax=9.2mm, Xmech=32.7mm, Sd=531.0cm\u00b2, Bl=12.3T\u00b7m\nLe=0.24mH | Radial neodymium XR motor | Deep copper cap\n\nDESIGN HIGHLIGHTS:\n - XR (eXtended Range) radial neodymium motor: large neodymium magnets\n placed along the voice coil winding, keeping the entire coil in the\n magnetic gap through virtually the full rated excursion. This\n eliminates harmonic distortion caused by the coil exiting the field,\n enabling extremely clean bass at high excursion levels.\n - No shorting coil (unlike 61XR) \u2014 inductance reduced by deep copper\n cap: Le=0.24mH, very low for a 12\" sub. Extended high-frequency\n response and lower inductance-related distortion.\n - High Qms (10.5) \u2014 near-lossless suspension; amplifier and enclosure\n provide essentially all system damping\n - Carbon fiber reinforced paper cone (CF Paper) \u2014 high rigidity, low\n mass, superior cone-breakup resistance compared to plain paper\n - 2.5\" (63.5mm) voice coil on glass fiber former \u2014 thermal headroom\n for sustained 1000W continuous operation\n - Natural rubber (NBR) surround \u2014 large excursion capability, long\n durability, controlled cone velocity at limits\n - 8-ohm nominal impedance suits bridged amplifiers and series wiring\n\nRECOMMENDED ENCLOSURE TYPES:\n PRIMARY: Bass Reflex (Vented) \u2014 Qts=0.68 is at the upper boundary\n of vented alignment range; tuning near or above Fs works\n well; DSP EQ is recommended to correct any mid-bass\n emphasis from the high Qts\n SECONDARY: Sealed (Acoustic Suspension) \u2014 for DSP\/active systems;\n all practical sealed volumes yield Qtc \u2265 1.0 so DSP\n correction is expected in this application\n\nNOTES ON Qts=0.68:\n At 0.68, this driver sits just below the classic sealed-preferred\n threshold. Vented alignments work but will exhibit some mid-bass\n warmth around tuning \u2014 easily managed with DSP parametric EQ.\n Sealed enclosures all produce Qtc >1.0 in practical cabinet sizes,\n which is intentional in active designs where the DSP provides\n shelf correction. The XR motor maintains very low THD even at high\n Qts drive levels, making this trade-off acoustically acceptable.\nVENTED ALIGNMENTS (Primary)\nPort: 100mm diameter round, flared both ends\nVd = 531 cm\u00b2 \u00d7 9.2mm = 488.5 cm\u00b3\n\n a) High SPL \/ Compact\n Net Volume: 35 liters\n Tuning (Fb): 38 Hz\n Est. -3dB: ~38 Hz\n HP Filter: 33 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 463mm long\n Port Velocity: 14.9 m\/s \u2713\n Notes: Strong mid-bass output, compact cabinet. High Qts will\n produce a moderate emphasis near Fb \u2014 apply a parametric\n cut of 1\u20132 dB around 40 Hz if needed. Suited for\n integration into larger speaker systems (2.5-way or 3-way)\n where the enclosure is part of the cabinet.\n\n b) Balanced Response\n Net Volume: 50 liters\n Tuning (Fb): 33 Hz\n Est. -3dB: ~33 Hz\n HP Filter: 28 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 430mm long\n Port Velocity: 12.9 m\/s \u2713\n Notes: General-purpose hi-fi and home theater subwoofer alignment.\n Good balance between extension and cabinet size. Port\n velocity well within hi-fi limits. Recommended starting\n point for dedicated subwoofer enclosures.\n\n c) Extended Deep Bass\n Net Volume: 70 liters\n Tuning (Fb): 28 Hz\n Est. -3dB: ~28 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 426mm long\n Port Velocity: 10.9 m\/s \u2713 (very low \u2014 ideal for critical listening)\n Notes: Reference-level deep bass extending below 30 Hz. Large\n cabinet suited to floorstanding or dedicated subwoofer\n enclosure. Exceptionally quiet port operation makes this\n the audiophile choice. Well suited for music reproduction\n where sub-bass texture and detail are priorities.\nSEALED ALIGNMENTS (Secondary \u2014 Active \/ DSP Systems)\nWith Qts=0.68, sealed enclosures in practical sizes all yield Qtc\nvalues above 1.0 \u2014 a slight under-damped character. In active\nsystems with DSP management this is easily corrected, and the XR\nmotor's inherent low distortion ensures the cone response remains\nclean despite the higher Qtc. The very low Le (0.24mH) also means\nthe driver integrates cleanly at crossover frequencies up to 500 Hz,\nmaking sealed + DSP suitable for use as a bass driver in larger\nmulti-way systems.\n\n d) Compact Active (35 liters)\n Qtc: 1.28\n fc: 66 Hz\n Est. -3dB (passive): ~48 Hz\n Est. -3dB (with DSP shelf correction): ~30 Hz\n Notes: Smallest practical configuration. Requires DSP. Works well\n as a bass\/woofer driver in large 2-way or 3-way speaker\n systems crossed above 200 Hz; the CF paper cone supports\n clean output to 500 Hz.\n\n e) Balanced Active (50 liters)\n Qtc: 1.14\n fc: 58 Hz\n Est. -3dB (passive): ~44 Hz\n Est. -3dB (with DSP shelf correction): ~28 Hz\n Notes: More relaxed sealed alignment. Moderate DSP correction\n required. Suitable for 2.1 home theater systems with\n active sub management at 80 Hz crossover.\n\n f) Near-Butterworth Sealed (75 liters)\n Qtc: 1.00\n fc: 52 Hz\n Est. -3dB (passive): ~41 Hz\n Est. -3dB (with DSP shelf correction): ~25 Hz\n Notes: Most linear passive sealed alignment for this driver.\n Still benefits from mild DSP correction (1\u20132 dB shelf\n below 50 Hz). Room gain (+3\u20136 dB below 50 Hz domestic)\n effectively provides flat in-room response to ~25 Hz\n without DSP in typical listening environments.\nWOOFER APPLICATION NOTE\nThe 12XR is positioned as sub-woofer \/ woofer, and the combination\nof CF paper cone, very low Le (0.24mH), and XR motor linearity\nmakes it a capable bass driver in large 2-way or 3-way systems:\n\n - Typical crossover range: 200\u2013500 Hz to a midrange or compression\n driver\n - At 200\u2013350 Hz: recommend 24dB\/oct Linkwitz-Riley (sealed preferred\n to minimize crossover phase complications)\n - The CF paper cone resists breakup in the upper bass range,\n maintaining smooth response through the crossover region\n - At 500W AES and 8 ohm, works well in high-sensitivity horn systems\n or with high-power solid-state amplifiers in large format hi-fi\nAPPLICATION SUMMARY\n - Hi-fi 2.1 and multi-channel home theater subwoofer (primary)\n - Bass driver in large 2-way or 3-way floorstanding loudspeakers\n - Studio reference monitoring with sub-bass extension\n - Audiophile subwoofer enclosures (vented preferred)\n - Active DSP-managed subwoofer systems (sealed viable)\n - 8-ohm suits bridged amplifiers and high-power solid-state"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/12XR-270-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/12XR-270-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/12XR-270-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/12XR-270-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/12XR-270-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/12XR-270-3D.STEP"}},{"code":"Twiggy12X4-470A","name":"Twiggy12","slug":"twiggy12x4-470a","description":"Slim Sub\/12inch\/Ferrite\/Honeycomb\/200W\/4ohm","url":"https:\/\/redcatt.net\/products\/twiggy12x4-470a","category":"LF","type":"Sub-woofer","size_inches":12,"is_featured":true,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"26.5"},"thiele_small_parameters":{"fs_hz":30,"re_ohm":3.6,"qes":1.16,"qms":16,"qts":1.08,"vas_liters":59.8,"sd_cm2":506.7,"sensitivity_db":84.2,"mms_grams":160.7,"rms":1.9,"cms":0.175,"bl_tm":9.9,"le_mh":1},"physical":{"overall_diameter_mm":323,"bolt_circle_diameter_mm":305,"baffle_cutout_diameter_mm":293.5,"mounting_holes":"8","depth_mm":73.7,"net_weight_kg":5.1,"xmax_mm":"9.25","xmech_mm":"17.25"},"materials":{"surround":"NBR","cone_dome":"GF Honey Comb","spider":"Nomex"},"content":{"key_features":["Shallow, yet high cone excursion","Honeycomb cone","Ideal for 4x4\" wall subwoofer, car underseat subwoofers"],"design_notes":"The ultimate in shallow depth woofer design! We created this powerhouse of a speaker with limited spaces in mind, allowing you to fit it into the most compact areas while still delivering massive low frequencies. The extreme shallowness of the Twiggy 12 opens up a world of possibilities, allowing designers to craft enclosures that seamlessly integrate into typical 4x4\" wall structures, under vehicle seats, beneath sofas, and more.\nBut don't be fooled by its shallow design \u2013 the cone excursion approaches an impressive 22.4mm peak to peak, ensuring that this woofer will deliver sizable amounts of low frequencies without compromising on performance. The cone is constructed with a honeycomb structure and layers of woven glass fibers, adding not only to its strength but also to the overall rigidity and performance.\nOur patented design guarantees that the depth versus cone excursion ratio is the best available in the market, ensuring optimal sound quality in any installation. The unique magnetic structure of the Twiggy 12 delivers a high-strength B field with minimal distortion artifacts, further enhancing the audio experience.\nTo top it off, this little powerhouse can handle up to 800 watts of peak power amplification, making it the go-to choice for delivering excelent sound experience.","hero_text":null,"ai_summary":"This design is particularly effective in sealed enclosure systems used in hi-fi subwoofer systems, home theater, in-wall installations, automotive, and under-seat applications, where low-frequency extension and compact form factor are prioritized over high acoustic efficiency.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: Twiggy12X4-470A\nDriver: Twiggy12X4-470A (Twiggy12) \u2014 12\" Sub-woofer\nKey T\/S: Fs=30.0Hz, Qts=1.08, Vas=59.8L, Sens=84.2dB\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=9.25mm, Sd=506.7cm\u00b2, Bl=9.9T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Sealed\n Sealed Alignment (Qtc = 0.707)\n Net Volume: 20 liters\n Est. -3dB: 60 Hz\n Notes: Sealed enclosure with Butterworth (Qtc=0.707) alignment\n--- Summary ---\nThe Twiggy12X4-470A is a 12-inch sub-woofer driver designed for hi-fi subwoofer systems, home theater, in-wall and under-seat installations, and similar domestic or automotive applications. It operates at 84.2 dB sensitivity (1W\/1m). The driver features a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response.\nIn a sealed enclosure, the driver is best suited to a net internal volume of approximately 20 liters, yielding an estimated \u20133 dB point of 60 Hz. The sealed alignment provides smooth, well-damped response with a predictable second-order roll-off below resonance, well suited to active crossover integration and DSP-controlled bass management.\nThe driver is intended for use with moderate amplification (approx. 200 W AES \/ 400 W continuous) and DSP control. A high-pass filter set at approximately 50 Hz is recommended to protect the driver below its usable range. Typical operating bandwidth is 60\u2013100 Hz, making it suitable for integration with a mid-bass or full-range system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/Twiggy12-470-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/Twiggy12-470-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/Twiggy12X4-470A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/Twiggy12-470A-2D.PDF","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/Twiggy12-470A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/Twiggy12-470A-3D.STEP"}},{"code":"121XRX8-352","name":"121XR","slug":"121xrx8-352","description":"XR Woofer\/12inch\/Neo\/Paper\/500W\/8ohm","url":"https:\/\/redcatt.net\/products\/121xrx8-352","category":"LF","type":"Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"500","continuous_watts":"1000","peak_watts":"2000"},"voice_coil":{"diameter":"63.5","wire":"Copper","former":"Glass Fiber","winding_height":"18.3"},"thiele_small_parameters":{"fs_hz":46,"re_ohm":5.6,"qes":0.42,"qms":1.56,"qts":0.33,"vas_liters":69.1,"sd_cm2":531,"sensitivity_db":95.78,"mms_grams":66.8,"rms":12.37,"cms":0.18,"bl_tm":16,"le_mh":0.16},"physical":{"overall_diameter_mm":320,"bolt_circle_diameter_mm":299,"baffle_cutout_diameter_mm":281,"mounting_holes":"8","depth_mm":172.5,"net_weight_kg":5.1,"xmax_mm":"6.35","xmech_mm":"29.85"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE, high excursion, ultra low THD","Static demodulation coil, large spider with stitched tinsel wires","Carbon fiber loaded paper cone"],"design_notes":"The 121XR was designed to be simply the best driver for 2-way and multi-way systems on the market, yet this driver will also shine in sub-woofer applications. The combination of our XR patented technology with static shorting coil brings an nonparallel opportunity to the audio designers. The common request for 2-way speakers is \u201cmore of everything\u201d. Designers wishes for more bass, more mids. Well, there you have it! But not only that. We bring this with clarity in the mid-frequencies and undistorted bass. Our designers were able to achieve THD below 0.5% from 20Hz up to 2.5kHz. There isn\u2019t another driver like this on the market.\n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding, together with the 2nd and static coil placed on the pole piece. This has allowed us to push the cone excursion to 25mm peak to peak, while lowering the inductance. The shorting coil covers the complete main coil excursion. This is also an improvement compared to some previous designs on the market. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 121XRX8-352\nDriver: 121XRX8-352 (121XR) \u2014 12\" Mid-Woofer\nKey T\/S: Fs=46.0Hz, Qts=0.33, Vas=69.1L, Sens=95.78dB\nPower: AES 500W \/ Cont 1000W \/ Peak 2000W\nXmax=6.35mm, Sd=531.0cm\u00b2, Bl=16.0T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 standard for mid-size professional enclosures; good balance of area and packaging\n a) High SPL\n Net Volume: 55 liters\n Tuning (Fb): 51 Hz\n Est. -3dB: 47 Hz\n HP Filter: 43 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 84mm long\n Slot Port: 225mm W \u00d7 60mm H \u00d7 174mm L\n Port Velocity: 13.7 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 65 liters\n Tuning (Fb): 45 Hz\n Est. -3dB: 38 Hz\n HP Filter: 35 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 101mm long\n Slot Port: 225mm W \u00d7 60mm H \u00d7 203mm L\n Port Velocity: 12.0 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 80 liters\n Tuning (Fb): 39 Hz\n Est. -3dB: 33 Hz\n HP Filter: 27 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 121mm long\n Slot Port: 225mm W \u00d7 60mm H \u00d7 238mm L\n Port Velocity: 10.5 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 121XRX8-352 is a 12-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (96 dB 1W\/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 55 to 80 liters, tuned between 39 and 51 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 500 W AES \/ 1000 W continuous) and DSP control. A high-pass filter in the range of 27\u201343 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 33\u20132000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/121XR-352-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/121XR-352-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/121XR-352-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/121XR-352-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/121XR-352-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/121XR-352-3D.STEP"}},{"code":"122NPWX8-102","name":"122NPW","slug":"122npwx8-102","description":"Woofer\/12inch\/Neo\/Paper\/800W\/8ohm","url":"https:\/\/redcatt.net\/products\/122npwx8-102","category":"LF","type":"Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"800","continuous_watts":"1600","peak_watts":"3200"},"voice_coil":{"diameter":"101.6","wire":"Copper","former":"Glass Fiber","winding_height":"25.5"},"thiele_small_parameters":{"fs_hz":35,"re_ohm":5.5,"qes":0.17,"qms":6.65,"qts":0.17,"vas_liters":81.9,"sd_cm2":551,"sensitivity_db":96.88,"mms_grams":81.9,"rms":2.71,"cms":0.25,"bl_tm":27,"le_mh":1.27},"physical":{"overall_diameter_mm":322,"bolt_circle_diameter_mm":302,"baffle_cutout_diameter_mm":287,"mounting_holes":"8","depth_mm":154,"net_weight_kg":7.6,"xmax_mm":"5.75","xmech_mm":"19.75"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Carbon fiber filled paper cone","Double silicone spider","High power handling"],"design_notes":"The 122NPW is a high efficiency, (97 dB 1watt \/ 1 meter) 12-inch woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts. The 122NPW uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak maximum excursion of 19mm. Woofer features REDCATT double silicone sealed spider. \n\nPower Handling\nAt the core of the 122NPW is it\u2019s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 350degC, well beyond the thermal requirements of modern professional audio systems. \n\tThe woofer cone is also extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.","hero_text":null,"ai_summary":"The 122NPWX8-102 is a 12-inch professional woofer designed for high-SPL PA, touring, and fixed installation systems operating across the 40\u20132000 Hz bandwidth. With a measured sensitivity of 96.88 dB (1 W\/1 m) and a 101.6 mm (4-inch) copper voice coil wound on a composite Polyimide former rated to withstand peak temperatures in excess of 350\u00b0C, the driver delivers exceptional acoustic output per watt across continuous programme material without thermal compression. The Neodymium motor system produces a Bl of 27 T\u00b7m at a Qts of 0.17, placing it in the extreme-motor-force category of professional woofer design. This combination of high motor strength, high sensitivity, and superior thermal management makes the 122NPW a direct competitor to the most demanding 12-inch PA woofer applications in touring, theatre, and high-SPL installation markets. The carbon fiber loaded paper cone assembly is extensively treated for humidity and environmental resistance, and the double silicone sealed Nomex spider provides additional protection against contaminants in field and permanent-installation environments.\n\nThe driver is optimized for vented (bass reflex) enclosures across a 35 to 70 litre net internal volume range, with tuning frequencies from 48 to 70 Hz depending on system application. The compact 35 L alignment, tuned to 70 Hz, produces -3 dB at approximately 68 Hz with maximum sensitivity and cone control in the critical midbass region \u2014 the appropriate choice for high-SPL compact touring cabinets, column array woofer sections, and club fill speakers where output and compactness take priority. The balanced 50 L alignment at 58 Hz tuning extends the -3 dB point to approximately 56 Hz, covering the complete programme frequency range including bass guitar, kick drum, and piano left hand from a standard professional two-way enclosure format. The extended 70 L alignment at 48 Hz tuning provides -3 dB at approximately 46 Hz, with full coverage of the bass guitar open E fundamental at 41 Hz, appropriate for cinema main LF, installed music systems, and two-way theatre cabinets where extended low-frequency reproduction is required. Both 100 mm round and 200 \u00d7 60 mm slot port options are provided for each alignment; slot ports are recommended for touring cabinetry and high-SPL installations due to lower velocity and reduced turbulence.\n\nThe 122NPWX8-102 requires high-power professional amplification in the 800\u20131600 W range into 8 ohms, with DSP-controlled signal management mandatory for all alignments. A 24 dB\/octave high-pass filter is required at 55, 40, or 35 Hz depending on alignment tuning, as the vented enclosure rapidly unloads the cone below the tuning frequency and the Qts=0.17 motor provides no passive self-limiting below resonance. Displacement-limiting and power-limiting algorithms should be included in any DSP preset for this driver. The operating bandwidth is approximately 40 Hz to 2 kHz; low-pass crossover to a compression driver or mid-high section at 1.0\u20131.5 kHz with a 24 dB\/octave slope is standard for two-way system designs using the 122NPW as the LF component.\n\nThe 122NPWX8-102 is suited for: compact and mid-size touring PA enclosures requiring maximum SPL from a 12-inch footprint; two-way professional speaker systems for live sound reinforcement, houses of worship, theatre, and stadium installation; line array bass extension and mid-bass column modules; club and venue main speaker systems operating at continuous high power levels; and cinema LF speaker assemblies where programme-consistent output, thermal durability, and motor linearity across the operating band are required. Its 96.88 dB sensitivity, 800 W AES power handling, and Neodymium motor with Polyimide former represent the specification combination typical of reference-class professional 12-inch woofer designs for mid-to-large-scale sound reinforcement applications.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 122NPWX8-102\nDriver: 122NPWX8-102 (122NPW) \u2014 12\" neodymium pro woofer, 8 ohm\nKey T\/S: Fs=35Hz, Qts=0.17, Qes=0.17, Qms=6.65, Vas=81.9L, Sens=96.88dB\nPower: AES 800W \/ Cont 1600W \/ Peak 3200W\nXmax=5.75mm (linear), Xmech=19.75mm, Xprot=19.2mm\nSd=551cm\u00b2, Bl=27T\u00b7m, Le=1.27mH, Re=5.5\u03a9\nVoice coil: 101.6mm (4\"), copper winding, composite Polyimide former\nCone: carbon fiber loaded paper, environmentally treated\nSpider: double silicone sealed Nomex\nSurround: fabric triple roll constant geometry\nDepth: 154mm | Baffle cutout: 287mm | Neodymium motor\n\nENCLOSURE TYPE RATIONALE:\n Qts=0.17 is among the lowest values in professional woofer design.\n With Bl=27T\u00b7m and a 101.6mm voice coil, the 122NPW is driven by one\n of the strongest motors relative to moving mass (Bl\u00b2\/Mms=8.90) for a\n 12-inch driver. This extreme motor force generates very high electrical\n damping that completely dominates the system Q in any practical enclosure.\n VENTED (bass reflex) enclosures are the only suitable alignment \u2014 a\n sealed enclosure would produce an overdamped response with no low-bass\n output and progressive excursion build-up well above Fs. All three\n alignments below are optimized for professional PA and installation use,\n where output efficiency, headroom above the tuning frequency, and\n mechanical protection below tuning are the primary design goals.\n\nDISPLACEMENT:\n Vd = Sd \u00d7 Xmax = 551 cm\u00b2 \u00d7 0.575 cm = 316.8 cm\u00b3 (peak, one-way)\n\nWEATHERIZATION:\n The carbon fiber loaded paper cone is extensively treated against moisture\n and humidity. Metal basket components are coated for environmental\n protection. The double silicone sealed spider provides additional barrier\n against contaminants. The 122NPW is suitable for permanently installed\n indoor and semi-outdoor applications; it is not rated for direct rain\n exposure without additional enclosure sealing measures.\nVENTED (BASS REFLEX) ALIGNMENTS\nPorts: 100mm diameter round tube (Ap=7.854\u00d710\u207b\u00b3 m\u00b2)\n OR 200\u00d760mm slot port (Ap=1.200\u00d710\u207b\u00b2 m\u00b2)\nPort velocity limit (pro PA): \u226422 m\/s\nPort velocity limit (install\/theatre): \u226417 m\/s\nALIGNMENT A \u2014 COMPACT TOURING (35 L net internal)\n Box volume: 35 L (net internal)\n Tuning freq (Fb): 70 Hz\n Round port: 100mm dia \u00d7 136mm long\n Port velocity: 17.7 m\/s (peak, at Xmax)\n Slot port: 200\u00d760mm \u00d7 209mm long\n Port velocity: 11.6 m\/s (peak, at Xmax)\n System f-3dB: ~68 Hz\n HP filter: 55 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~126 dB\n Application: Compact touring PA, line array bass extension module,\n column array woofer section, club fill speaker,\n high-SPL stage monitor.\n Notes: The highest-SPL compact alignment. Fb=70Hz (2.0\u00d7Fs) places the\n tuning well into the midbass region, providing maximum cone\n control and output in the 70\u20132000Hz working band with very\n low excursion at operating level. The 35 L net cabinet can be\n packaged in a compact trapezoidal or rectangular touring enclosure\n of approximately 400\u00d7400\u00d7250mm (external). With Qts=0.17, cone\n excursion below Fb drops rapidly \u2014 the HP filter at 55Hz is\n critical to prevent over-excursion below tuning at high power.\n The slot port (209mm) is recommended for touring cabinetry for\n its structural contribution and resistance to port whistling.\nALIGNMENT B \u2014 STANDARD PA (50 L net internal)\n Box volume: 50 L (net internal)\n Tuning freq (Fb): 58 Hz\n Round port: 100mm dia \u00d7 139mm long\n Port velocity: 14.7 m\/s (peak, at Xmax)\n Slot port: 200\u00d760mm \u00d7 213mm long\n Port velocity: 9.6 m\/s (peak, at Xmax)\n System f-3dB: ~56 Hz\n HP filter: 40 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~126 dB\n Application: Full-range PA top cabinet, two-way touring speaker,\n installation LF driver, mid-bass horn-loaded cabinet,\n installed main speaker for theatres and houses of worship.\n Notes: The recommended all-purpose alignment. At 56 Hz -3dB the driver\n covers the complete music programme from bass guitar (41Hz E2) through\n upper vocals and strings. The 50 L cabinet is compatible with standard\n professional two-way enclosure formats at approximately 450\u00d7450\u00d7280mm\n external. Port velocities are well within install and PA limits on both\n round and slot configurations. Bl=27T\u00b7m and 96.88dB sensitivity allow\n the 122NPW to maintain consistent output under continuous programme at\n 800W without thermal compression from the Polyimide former.\nALIGNMENT C \u2014 EXTENDED LF (70 L net internal)\n Box volume: 70 L (net internal)\n Tuning freq (Fb): 48 Hz\n Round port: 100mm dia \u00d7 145mm long\n Port velocity: 12.2 m\/s (peak, at Xmax)\n Slot port: 200\u00d760mm \u00d7 222mm long\n Port velocity: 8.0 m\/s (peak, at Xmax)\n System f-3dB: ~46 Hz\n HP filter: 35 Hz, 24 dB\/oct DSP (mandatory)\n Max SPL (800W, 1m): ~126 dB\n Application: Two-way bass\/woofer cabinet with extended LF,\n cinema main speaker LF section, installed hi-SPL\n music system, large theatre or arena fill.\n Notes: The largest practical standalone enclosure for the 122NPW.\n At 46 Hz -3dB, the system reproduces the fundamental of bass\n guitar open E (41Hz), floor tom (40\u201350Hz), and double bass\n resonance in music reproduction and cinema applications. The\n 70 L cabinet at approximately 500\u00d7450\u00d7360mm external is the\n upper limit recommended without structural bracing and damping\n treatment to control panel resonance. Port velocity is low at\n both port types; slot ports with flared ends are preferred for\n this alignment to reduce turbulence at low Fb excursion peaks.\n The 48 Hz tuning with DSP HP at 35 Hz provides meaningful\n bass extension while maintaining appropriate mechanical protection\n for the large Xmech=19.75mm capability of this driver.\nSYSTEM SUMMARY TABLE\n | Alignment | Volume | Fb | f-3dB | Round Port | Slot Port | HP |\n |-------------|--------|-------|-------|-------------------|------------------|--------|\n | A Compact | 35 L | 70 Hz | ~68Hz | 100mm \u00d7 136mm | 200\u00d760mm \u00d7 209mm | 55 Hz |\n | | | | | v=17.7 m\/s | v=11.6 m\/s | |\n | B Standard | 50 L | 58 Hz | ~56Hz | 100mm \u00d7 139mm | 200\u00d760mm \u00d7 213mm | 40 Hz |\n | | | | | v=14.7 m\/s | v=9.6 m\/s | |\n | C Extended | 70 L | 48 Hz | ~46Hz | 100mm \u00d7 145mm | 200\u00d760mm \u00d7 222mm | 35 Hz |\n | | | | | v=12.2 m\/s | v=8.0 m\/s | |\n\n Sensitivity: 96.88 dB (1W\/1m)\n Max SPL (800W): ~126 dB at 1m\n Impedance: 8 ohm nominal (Re=5.5\u03a9)\n Voice coil: 101.6mm (4\"), Polyimide former (350\u00b0C rated)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/122NPW-102-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/122NPW-102-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/122NPW-102-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/122NPW-102-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/122NPW-102-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/122NPW-102-3D.STEP"}},{"code":"121FINDX4-233","name":"121FIND","slug":"121findx4-233","description":"Mid-Woofer\/12inch\/Ferrite\/Paper\/250W\/4ohm","url":"https:\/\/redcatt.net\/products\/121findx4-233","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"250","continuous_watts":"500","peak_watts":"1000"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"Glass Fiber","winding_height":"11.7"},"thiele_small_parameters":{"fs_hz":59,"re_ohm":3.1,"qes":0.56,"qms":7.34,"qts":0.52,"vas_liters":59.1,"sd_cm2":531,"sensitivity_db":96.4,"mms_grams":49.1,"rms":2.48,"cms":0.15,"bl_tm":10.2,"le_mh":0.32},"physical":{"overall_diameter_mm":320,"bolt_circle_diameter_mm":302,"baffle_cutout_diameter_mm":282,"mounting_holes":"8","depth_mm":124,"net_weight_kg":4.6,"xmax_mm":"1.85","xmech_mm":"9.85"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Proven cost effective design","Nomex spider, water-repellent & non-flammable paper cone"],"design_notes":"The 121FIND is a high efficiency, (96 dB 1watt\/ 1 meter) 12inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. 121FIND uses lightweight cone which movement is controlled by \u201cM\u201d shaped surround. Pistonic behavior and the long term stability\nIs supported by Nomex spider. The woofer cone is treated to withstand harsh environments and high humidity.\n\n\tThe 121FIND was design for its best use in the 2-way applications, where excellent midrange response is required. Speaker provides good low frequency extension and delivers seizable amounts of low frequencies.\n\nThe metal parts in the speaker are coated and tested to ensure extreme weatherization protection.","hero_text":null,"ai_summary":"The 121FINDX4-233 is a 12-inch ferrite pro mid-woofer designed for professional 2-way PA speaker systems, compact touring cabinets, and permanently installed enclosures crossed to a compression driver or horn. It features a weatherized glass fiber treated paper cone, M-shaped fabric surround, non-flammable Nomex spider, and coated steel basket for harsh environment and high-humidity protection. The 50.8mm CCAW voice coil on a glass fiber former is rated at 250W AES. Sensitivity is 96.4 dB (1W\/1m). With a Qts of 0.52, this driver uses a compliant suspension design suited to moderate-volume enclosures, and operates effectively in both sealed and vented configurations depending on application.\n\nBoth vented and sealed enclosures are recommended depending on deployment. Vented (bass reflex) alignments using a 75mm round port are preferred for PA and touring: 30 litres tuned to 62 Hz (port 115 mm) for a compact high-SPL touring cabinet; 45 litres tuned to 55 Hz (port 97 mm) as the balanced general-purpose 2-way PA alignment; and 65 litres tuned to 48 Hz (port 88 mm) for maximum bass extension in larger installed enclosures. Sealed alignments are provided for installation and monitoring applications: 35 litres (Qtc=0.85, \u22123 dB \u2248 83 Hz), 22 litres (Qtc=1.00, \u22123 dB \u2248 89 Hz), and 14 litres (Qtc=1.20, \u22123 dB \u2248 100 Hz). The short Xmax of 1.85 mm limits low-frequency excursion capability; a system-level high-pass filter or subwoofer crossover is mandatory in all deployments to protect the driver below its usable output range.\n\nThe 121FINDX4-233 handles approx. 250 W AES and 500 W continuous power into 4 ohms; two drivers wired in series present an 8-ohm load with a combined +3 dB sensitivity gain. A high-pass filter at 40\u201360 Hz is recommended depending on alignment. The operating bandwidth is approximately 65\u2013843 Hz, with cone beaming onset near 843 Hz defining the practical upper limit; a crossover to a compression driver on horn at 800 Hz to 1.2 kHz is required. The very low Le of 0.32 mH keeps impedance rise minimal through the crossover region, simplifying passive network design and improving crossover accuracy compared to higher-inductance alternatives.\n\nThis driver is suited for compact single-driver vented 2-way PA touring cabinets; 2-way portable and installed PA enclosures for live sound and fixed-venue reinforcement; stage monitor wedges crossed to a compression horn at 800 Hz to 1.0 kHz; and compact sealed installed 2-way systems where a subwoofer provides low-frequency support below 80\u2013100 Hz. The weatherized cone, fabric surround, and coated steel basket are suited to demanding outdoor and touring environments where moisture, humidity, and mechanical stress are factors.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 121FINDX4-233\nGenerated: 2026-04-12\nApplication: Professional 2-way PA systems, touring and installation\nDRIVER SPECIFICATIONS\nCode : 121FINDX4-233\nDescription : 12\" Ferrite Pro Mid-Woofer \u2014 Glass Fiber Treated Paper Cone\nNominal Impedance: 4 \u03a9\nAES Power : 250 W\nContinuous Power : 500 W\nPeak Power : 1,000 W\n\nFs : 59 Hz\nRe : 3.1 \u03a9\nQes : 0.56\nQms : 7.34\nQts : 0.52\nVas : 59.1 L\nSd : 531 cm\u00b2\nSensitivity : 96.4 dB (1 W \/ 1 m)\nMms : 49.1 g\nRms : 2.48 kg\/s\nCms : 0.15 mm\/N\nBl : 10.2 T\u00b7m\nLe : 0.32 mH\nXmax : 1.85 mm (one-way, peak)\nXmech : 9.85 mm\n\nVoice Coil : 50.8 mm (2\"), CCAW, Glass Fiber former\nCone : Glass fiber treated paper (weatherized, water-repellent)\nSurround : Fabric, M-shaped profile\nSpider : Nomex (non-flammable)\nBasket : Steel (weatherization coated)\nMagnet : Ferrite\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 531 cm\u00b2 \u00d7 0.185 cm = 98.2 cm\u00b3\n\nNote on Xmax: Xmax = 1.85 mm is short by pro woofer standards.\n This driver is optimized for midrange efficiency and linearity at\n low excursion, not deep bass extension. Maximum SPL at low frequencies\n is excursion-limited; a high-pass filter or subwoofer crossover is\n mandatory in all 2-way deployments.\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 3.1 \/ (2\u03c0 \u00d7 0.00032) \u2248 1,542 Hz\n (Low Le = 0.32 mH provides a flat, predictable impedance curve\n through the crossover region \u2014 a key advantage for midrange fidelity\n and passive crossover precision.)\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(531 \/ 3.14159) = 13.00 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 13.00) \u2248 843 Hz\n\nWorking band : ~65 Hz \u2013 843 Hz\nCrossover to horn : 800 Hz \u2013 1.2 kHz (f_beam at 843 Hz is the\n primary upper constraint; Le onset at 1,542 Hz\n is well above the crossover frequency, ensuring\n flat impedance through the crossover region)\n\nMaximum SPL (anechoic, 1 m)\n At 250 W AES : 96.4 + 10\u00b7log\u2081\u2080(250) = 96.4 + 24.0 = 120.4 dB\n At 500 W cont : 96.4 + 10\u00b7log\u2081\u2080(500) = 96.4 + 27.0 = 123.4 dB\nENCLOSURE RECOMMENDATION\nQts = 0.52 \u2192 Both sealed (acoustic suspension) and vented (bass\nreflex) enclosures are viable. Vented alignments are preferred for\nPA touring applications where efficiency and sensitivity are the\npriority. Sealed alignments are preferred for installation, monitoring,\nand systems requiring tighter transient control.\nVENTED ENCLOSURE ALIGNMENTS (PRIMARY \u2014 PA \/ TOURING)\nPort: 75 mm round (Ap = 44.18 cm\u00b2)\n Port velocity limit: \u2264 17 m\/s (hi-fi \/ install) \/ \u2264 22 m\/s (PA)\n Vd = 98.2 cm\u00b3 is modest; port velocities are comfortably low at\n all three alignments.\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2 ; 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 98.2 cm\u00b3 = 9.82 \u00d7 10\u207b\u2075 m\u00b3 ; Ap = 4.418 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 75mm Port Length \u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 30 L \u2502 62 Hz \u2502 115 mm \u2502 8.7 m\/s \u2713 \u2502\n\u2502 B \u2502 45 L \u2502 55 Hz \u2502 97 mm \u2502 7.7 m\/s \u2713 \u2502\n\u2502 C \u2502 65 L \u2502 48 Hz \u2502 88 mm \u2502 6.7 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (75 mm round port):\n Alignment A: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3844 \u00d7 30,000)\n = 5.228\u00d710\u00b9\u2070 \/ 4.553\u00d710\u2079 = 115 mm\n Alignment B: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3025 \u00d7 45,000)\n = 5.228\u00d710\u00b9\u2070 \/ 5.374\u00d710\u2079 = 97 mm\n Alignment C: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 2304 \u00d7 65,000)\n = 5.228\u00d710\u00b9\u2070 \/ 5.912\u00d710\u2079 = 88 mm\n\n--- Vented Alignment A \u2014 30 L \/ Fb = 62 Hz ---\n Compact PA cabinet, tuned near Fs. Tight response with strong\n excursion protection above 62 Hz. Suited to compact touring\n 2-way cabinets and stage monitors where enclosure volume must\n be minimized.\n\n--- Vented Alignment B \u2014 45 L \/ Fb = 55 Hz ---\n Balanced PA cabinet. Good output balance across the operating\n band with moderate bass extension. The recommended general-purpose\n alignment for standalone 2-way PA and installation enclosures.\n\n--- Vented Alignment C \u2014 65 L \/ Fb = 48 Hz ---\n Extended low-frequency alignment for maximum bass output from this\n driver. Suited to larger installed 2-way enclosures and systems\n used without a dedicated subwoofer.\n Mandatory high-pass filter at 38\u201342 Hz to protect driver below\n port rolloff frequency.\nSEALED ENCLOSURE ALIGNMENTS (INSTALLATION \/ MONITORING)\nFormula: Vb = Vas \/ ((Qtc \/ Qts)\u00b2 \u2212 1)\n fc = Fs \u00d7 (Qtc \/ Qts)\n f-3dB: u = [\u2212(2 \u2212 1\/Qtc\u00b2) + \u221a((2 \u2212 1\/Qtc\u00b2)\u00b2 + 4)] \/ 2\n \u03a9 = \u221au ; f-3dB = \u03a9 \u00d7 fc\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Qtc \u2502 fc \u2502 f\u22123dB \u2502 Character \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 35 L \u2502 0.85 \u2502 96.4 Hz \u2502 83 Hz \u2502 Warm, damped \u2502\n\u2502 B \u2502 22 L \u2502 1.00 \u2502 113.5 Hz \u2502 89 Hz \u2502 Compact\/flat \u2502\n\u2502 C \u2502 14 L \u2502 1.20 \u2502 136.2 Hz \u2502 100 Hz \u2502 Compact sat. \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\n--- Sealed A \u2014 35 L \/ Qtc = 0.85 ---\n fc = 59 \u00d7 (0.85\/0.52) = 96.4 Hz ; f-3dB = 0.859 \u00d7 96.4 = 83 Hz\n Well-damped sealed alignment. Suited to permanent installation\n 2-way speakers and high-fidelity monitoring where transient\n accuracy is prioritized over efficiency.\n\n--- Sealed B \u2014 22 L \/ Qtc = 1.00 ---\n fc = 59 \u00d7 (1.00\/0.52) = 113.5 Hz ; f-3dB = 0.786 \u00d7 113.5 = 89 Hz\n Compact sealed format. A practical balance of box volume and\n controlled low-end for medium-format installed 2-way systems.\n\n--- Sealed C \u2014 14 L \/ Qtc = 1.20 ---\n fc = 59 \u00d7 (1.20\/0.52) = 136.2 Hz ; f-3dB = 0.736 \u00d7 136.2 = 100 Hz\n Minimum practical sealed volume. Suited to compact installations,\n under-stage fill, and systems crossed above 100 Hz to a subwoofer.\n Mandatory high-pass filter at 80\u2013100 Hz; this alignment relies on\n subwoofer support below the crossover.\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to compression driver on horn (acoustic): 800 Hz \u2013 1.2 kHz\n f_beam = 843 Hz (primary upper limit \u2014 cone directivity\n increases rapidly above this frequency)\n f_Le = 1,542 Hz (well above crossover; flat impedance curve\n ensures passive crossover network accuracy)\n\n Recommended crossover: 800 Hz \u2013 1.0 kHz acoustic target.\n Third or fourth-order acoustic slope to control off-axis\n behaviour above 843 Hz. The low Le (0.32 mH) simplifies passive\n crossover design compared to higher-inductance pro drivers.\n\nZobel network:\n R_z = 3.1 \u03a9 (use 3.3 \u03a9 nearest standard)\n C_z = Le \/ Re\u00b2 = 0.32e-3 \/ 9.61 = 33.3 \u03bcF \u2192 use 33 \u03bcF, 100 V non-polar\nIMPEDANCE CONFIGURATIONS\nSingle (standard) : 4 \u03a9\nPair in series : 8 \u03a9 (+3 dB combined sensitivity, standard amp load)\nPair in parallel : 2 \u03a9 (not recommended; exceeds most amplifier ratings)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/121FIND-233-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/121FIND-233-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/121FINDX4-233-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/121FIND-233-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/121FIND-233-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/121FIND-233-3D.STEP"}},{"code":"121FINDX8-234","name":"121FIND","slug":"121findx8-234","description":"Mid-Woofer\/12inch\/Ferrite\/Paper\/250W\/8ohm","url":"https:\/\/redcatt.net\/products\/121findx8-234","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"250","continuous_watts":"500","peak_watts":"1000"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"Glass Fiber","winding_height":"15.5"},"thiele_small_parameters":{"fs_hz":63,"re_ohm":5.3,"qes":0.65,"qms":7.47,"qts":0.6,"vas_liters":49.8,"sd_cm2":531,"sensitivity_db":96.6,"mms_grams":50.8,"rms":2.69,"cms":0.13,"bl_tm":12.9,"le_mh":0.52},"physical":{"overall_diameter_mm":320,"bolt_circle_diameter_mm":302,"baffle_cutout_diameter_mm":282,"mounting_holes":"8","depth_mm":124,"net_weight_kg":4.6,"xmax_mm":"3.75","xmech_mm":"11.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Proven cost effective design","Good power handling, nomex spider, water-repellent & non-flammable paper cone"],"design_notes":"The 121FIND is a high efficiency, (96.5 dB 1watt\/ 1 meter) 12inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. 121FIND uses lightweight cone which movement is controlled by \u201cM\u201d shaped surround. Pistonic behavior and the long term stability\nIs supported by Nomex spider. The woofer cone is treated to withstand harsh environments and high humidity.\n\n\tThe 121FIND was design for its best use in the 2-way applications, where excellent midrange response is required. Speaker provides good low frequency extension and delivers seizable amounts of low frequencies.\n\nThe metal parts in the speaker are coated and tested to ensure extreme weatherization protection.","hero_text":null,"ai_summary":"The 121FINDX8-234 is a 12-inch ferrite pro mid-woofer designed for professional 2-way PA speaker systems, touring cabinets, and permanently installed enclosures crossed to a compression driver or horn. It shares the 121FIND platform with the 4-ohm 121FINDX4-233, featuring the same weatherized glass fiber treated paper cone, M-shaped fabric surround, non-flammable Nomex spider, and coated steel basket. The 8-ohm nominal impedance provides a standard single-driver amplifier load. Sensitivity is 96.6 dB (1W\/1m). With a Qts of 0.60, this driver uses a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response; sealed enclosures are the preferred alignment for this Qts value, with vented available for higher efficiency PA applications.\n\nSealed enclosures are recommended as the primary alignment. Three options are provided: 28 litres (Qtc=1.00, \u22123 dB \u2248 83 Hz) as the practical compact format for stage monitors and 2-way PA; 17 litres (Qtc=1.20, \u22123 dB \u2248 93 Hz) for compact installations relying on subwoofer support below 90\u2013100 Hz; and 49 litres (Qtc=0.85, \u22123 dB \u2248 77 Hz) for permanently installed systems where a larger enclosure is acceptable and maximum sealed bass extension is required. Vented (bass reflex) alignments using a 100mm round port are provided as an alternative for PA and touring: 25 litres tuned to 68 Hz (port 204 mm), 35 litres tuned to 60 Hz (port 187 mm), and 50 litres tuned to 52 Hz (port 174 mm); physical port tube lengths of 99\u2013129 mm fit easily within standard 12\" pro cabinet depths.\n\nThe 121FINDX8-234 handles approx. 250 W AES and 500 W continuous power, delivering a peak SPL of 121 dB at 1 metre (AES). A high-pass filter at 45\u201380 Hz is recommended depending on alignment. Operating bandwidth is approximately 70\u2013843 Hz, with cone beaming onset near 843 Hz defining the upper limit and a required crossover to horn at 800 Hz to 1.2 kHz. The higher Le of 0.52 mH compared to the 4\u03a9-233 variant makes a Zobel network (5.6 \u03a9 \/ 18 \u03bcF) more important to flatten impedance rise through the crossover region.\n\nCompared to the 121FINDX4-233, this 8\u03a9 variant offers twice the Xmax (3.75 mm vs 1.85 mm) and twice the volume displacement, providing substantially more bass output capability at high excursion and better suitability for standalone bass reproduction. It is suited for sealed 2-way PA and stage monitor enclosures; vented touring PA cabinets requiring deeper bass extension; and permanently installed 2-way systems in venues where standard 8-ohm amplifier matching and increased excursion headroom are required.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 121FINDX8-234\nGenerated: 2026-04-12\nApplication: Professional 2-way PA systems, touring and installation\nDRIVER SPECIFICATIONS\nCode : 121FINDX8-234\nDescription : 12\" Ferrite Pro Mid-Woofer \u2014 Glass Fiber Treated Paper Cone\nNominal Impedance: 8 \u03a9\nAES Power : 250 W\nContinuous Power : 500 W\nPeak Power : 1,000 W\n\nFs : 63 Hz\nRe : 5.3 \u03a9\nQes : 0.65\nQms : 7.47\nQts : 0.60\nVas : 49.8 L\nSd : 531 cm\u00b2\nSensitivity : 96.6 dB (1 W \/ 1 m)\nMms : 50.8 g\nRms : 2.69 kg\/s\nCms : 0.13 mm\/N\nBl : 12.9 T\u00b7m\nLe : 0.52 mH\nXmax : 3.75 mm (one-way, peak)\nXmech : 11.75 mm\n\nVoice Coil : 50.8 mm (2\"), CCAW, Glass Fiber former\nCone : Glass fiber treated paper (weatherized, water-repellent)\nSurround : Fabric, M-shaped profile\nSpider : Nomex (non-flammable)\nBasket : Steel (weatherization coated)\nMagnet : Ferrite\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 531 cm\u00b2 \u00d7 0.375 cm = 199.1 cm\u00b3\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 5.3 \/ (2\u03c0 \u00d7 0.00052) \u2248 1,622 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(531 \/ 3.14159) = 13.00 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 13.00) \u2248 843 Hz\n\nWorking band : ~70 Hz \u2013 843 Hz\nCrossover to horn : 800 Hz \u2013 1.2 kHz\n\nMaximum SPL (anechoic, 1 m)\n At 250 W AES : 96.6 + 10\u00b7log\u2081\u2080(250) = 96.6 + 24.0 = 120.6 dB\n At 500 W cont : 96.6 + 10\u00b7log\u2081\u2080(500) = 96.6 + 27.0 = 123.6 dB\nVARIANT COMPARISON: 121FIND FAMILY\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Parameter \u2502 121FINDX4-233 \u2502 121FINDX8-234 \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 Impedance \u2502 4 \u03a9 \u2502 8 \u03a9 \u2502\n\u2502 Fs \u2502 59 Hz \u2502 63 Hz \u2502\n\u2502 Qts \u2502 0.52 \u2502 0.60 \u2502\n\u2502 Sensitivity \u2502 96.4 dB \u2502 96.6 dB \u2502\n\u2502 Bl \u2502 10.2 T\u00b7m \u2502 12.9 T\u00b7m \u2502\n\u2502 Le \u2502 0.32 mH \u2502 0.52 mH \u2502\n\u2502 Xmax \u2502 1.85 mm \u2502 3.75 mm \u2502\n\u2502 Vd \u2502 98.2 cm\u00b3 \u2502 199.1 cm\u00b3 \u2502\n\u2502 Enclosure \u2502 Vented \/ Sealed \u2502 Sealed \/ Vented \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nKey differences:\n \u2022 234 (8\u03a9) has 2\u00d7 the Xmax and 2\u00d7 the Vd \u2192 significantly more\n bass output capability per watt at high excursion\n \u2022 234 has higher Qts (0.60 vs 0.52) \u2192 sealed alignments are more\n natural; vented possible but requires larger enclosures\n \u2022 233 (4\u03a9) has lower Le (0.32 mH) \u2192 flatter impedance through the\n crossover region; preferred where passive crossover accuracy is\n critical\n \u2022 233 suits 4\u03a9 amplifier loads and parallel daisy-chain\n configurations; 234 is the standard 8\u03a9 single-driver load\nENCLOSURE RECOMMENDATION\nQts = 0.60 \u2192 Both sealed and vented enclosures are viable.\nSealed is the preferred alignment for this Qts value, providing\ncontrolled transient response and predictable rolloff. Vented is\nviable where deeper bass extension or higher efficiency are required\nfor PA\/touring applications.\nSEALED ENCLOSURE ALIGNMENTS (PRIMARY)\nFormula: Vb = Vas \/ ((Qtc \/ Qts)\u00b2 \u2212 1)\n fc = Fs \u00d7 (Qtc \/ Qts)\n f-3dB: u = [\u2212(2 \u2212 1\/Qtc\u00b2) + \u221a((2 \u2212 1\/Qtc\u00b2)\u00b2 + 4)] \/ 2\n \u03a9 = \u221au ; f-3dB = \u03a9 \u00d7 fc\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Qtc \u2502 fc \u2502 f\u22123dB \u2502 Character \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 28 L \u2502 1.00 \u2502 105.0 Hz \u2502 83 Hz \u2502 Compact \/ flat \u2502\n\u2502 B \u2502 17 L \u2502 1.20 \u2502 126.0 Hz \u2502 93 Hz \u2502 Very compact \u2502\n\u2502 C \u2502 49 L \u2502 0.85 \u2502 89.3 Hz \u2502 77 Hz \u2502 Maximum ext. \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\n--- Sealed A \u2014 28 L \/ Qtc = 1.00 ---\n Vb = 49.8 \/ ((1.00\/0.60)\u00b2 \u2212 1) = 49.8 \/ 1.778 = 28.0 L\n fc = 63 \u00d7 (1.00\/0.60) = 105.0 Hz\n f-3dB = 0.786 \u00d7 105.0 = 82.5 Hz \u2192 83 Hz\n\n Practical compact sealed format for stage monitors, 2-way PA,\n and installed systems. Controlled transient response; suited to\n applications where excursion protection and predictable rolloff\n above 80 Hz are the priority.\n\n--- Sealed B \u2014 17 L \/ Qtc = 1.20 ---\n Vb = 49.8 \/ ((1.20\/0.60)\u00b2 \u2212 1) = 49.8 \/ 3.00 = 16.6 L \u2192 17 L\n fc = 63 \u00d7 (1.20\/0.60) = 126.0 Hz\n f-3dB = 0.736 \u00d7 126.0 = 92.7 Hz \u2192 93 Hz\n\n Minimum practical sealed volume. Suited to compact installations,\n under-stage fill, and systems relying on a dedicated subwoofer\n for content below 90\u2013100 Hz. Mandatory high-pass filter at\n 80\u2013100 Hz (DSP or passive).\n\n--- Sealed C \u2014 49 L \/ Qtc = 0.85 ---\n Vb = 49.8 \/ ((0.85\/0.60)\u00b2 \u2212 1) = 49.8 \/ 1.007 = 49.4 L \u2192 49 L\n fc = 63 \u00d7 (0.85\/0.60) = 89.3 Hz\n f-3dB = 0.859 \u00d7 89.3 = 76.7 Hz \u2192 77 Hz\n\n Maximum bass extension for a sealed alignment; enclosure volume\n is large for a touring PA cabinet but practical for permanent\n installation. Well-damped response; preferred for installed\n systems where a larger footprint is acceptable and flat extended\n bass is required.\nVENTED ENCLOSURE ALIGNMENTS (ALTERNATIVE \u2014 PA \/ TOURING)\nPort: 100 mm round (Ap = 78.54 cm\u00b2)\n Vd = 199.1 cm\u00b3; a 75mm port approaches the hi-fi velocity limit\n at tighter tunings (>17 m\/s). 100mm is specified for PA\n applications; 75mm may be used for Fb \u2264 55 Hz where velocities\n fall within hi-fi limits.\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb) ; Port velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 1.991 \u00d7 10\u207b\u2074 m\u00b3 ; Ap = 7.854 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 100mm Port Length\u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 25 L \u2502 68 Hz \u2502 204 mm \u2502 10.8 m\/s \u2713 \u2502\n\u2502 B \u2502 35 L \u2502 60 Hz \u2502 187 mm \u2502 9.6 m\/s \u2713 \u2502\n\u2502 C \u2502 50 L \u2502 52 Hz \u2502 174 mm \u2502 8.3 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations:\n Alignment A: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 4624 \u00d7 25,000)\n = 9.298\u00d710\u00b9\u2070 \/ 4.564\u00d710\u2079 = 204 mm\n Alignment B: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3600 \u00d7 35,000)\n = 9.298\u00d710\u00b9\u2070 \/ 4.974\u00d710\u2079 = 187 mm\n Alignment C: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 2704 \u00d7 50,000)\n = 9.298\u00d710\u00b9\u2070 \/ 5.337\u00d710\u2079 = 174 mm\n\nPhysical tube lengths (Leff minus ~75 mm end corrections): 99\u2013129 mm \u2014\neasily accommodated in any standard 12\" pro cabinet depth.\n\n--- Vented Alignment A \u2014 25 L \/ Fb = 68 Hz ---\n Compact PA cabinet, tuned above Fs. Strong mid-bass output and\n excursion protection. Suited to compact 2-way touring cabinets\n and stage monitors.\n\n--- Vented Alignment B \u2014 35 L \/ Fb = 60 Hz ---\n Balanced alignment near Fs. Recommended general-purpose vented\n format for standalone 2-way PA and installation enclosures.\n\n--- Vented Alignment C \u2014 50 L \/ Fb = 52 Hz ---\n Extended low-frequency coverage to approximately 49 Hz.\n Suited to larger installed 2-way enclosures without a dedicated\n subwoofer. Mandatory high-pass filter at 40\u201345 Hz.\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to compression driver on horn (acoustic): 800 Hz \u2013 1.2 kHz\n f_beam = 843 Hz (primary upper constraint \u2014 identical to 4\u03a9 variant)\n f_Le = 1,622 Hz (above crossover; Le rise at crossover is more\n pronounced than the 4\u03a9-233 variant due to higher Le)\n\n Le = 0.52 mH (higher than 233's 0.32 mH); a Zobel network is\n more important for this variant to maintain crossover flatness\n at 800 Hz \u2013 1.2 kHz.\n\nZobel network:\n R_z = 5.3 \u03a9 (use 5.6 \u03a9 nearest standard)\n C_z = Le \/ Re\u00b2 = 0.52e-3 \/ 28.09 = 18.5 \u03bcF \u2192 use 18 \u03bcF, 100 V non-polar"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/121FIND-234-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/121FIND-234-2.jpg"],"freq_response_image":null,"drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/121FIND-233-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/121FIND-233-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/121FIND-233-3D.STEP"}},{"code":"121NPMX8-079","name":"121NPM","slug":"121npmx8-079","description":"Mid woofer\/12inch\/Neo\/Paper\/450W\/8ohm","url":"https:\/\/redcatt.net\/products\/121npmx8-079","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"450","continuous_watts":"900","peak_watts":"1800"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"13"},"thiele_small_parameters":{"fs_hz":50,"re_ohm":6,"qes":0.16,"qms":7.51,"qts":0.16,"vas_liters":59.2,"sd_cm2":531,"sensitivity_db":99.97,"mms_grams":66.7,"rms":2.79,"cms":0.15,"bl_tm":27.8,"le_mh":0.51},"physical":{"overall_diameter_mm":315,"bolt_circle_diameter_mm":298,"baffle_cutout_diameter_mm":285,"mounting_holes":"8","depth_mm":123.5,"net_weight_kg":4,"xmax_mm":"1.5","xmech_mm":"11.5"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Very high efficiency mid-woofer","Linear frequency response, low harmonic distortion","Lightweight carbon fiber loaded paper cone, nomex spider"],"design_notes":"The 121NPM is a ultra high efficiency, (100dB 1watt \/ 1 meter) 12-inch mid bass woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts.-\nThe 121NPM uses a lightweight carbon fiber loaded cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 14.2mm.\n\nMagnetic Circuit\nREDCATT engineers have developed a lightweight, neodymium outside ring based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"The 121NPMX8-079 is a 12-inch neodymium pro mid-woofer designed for professional high-efficiency 2-way PA speaker systems, compact touring cabinets, and permanently installed enclosures crossed to a compression driver or horn. It features a carbon fiber paper cone, double-roll constant-geometry fabric surround, Nomex spider, and a 3-inch CCAW voice coil on a glass fiber former, driven by a neodymium outside ring magnetic circuit optimized for minimum flux modulation and maximum motor linearity. Sensitivity is 99.97 dB (1W\/1m) \u2014 approximately 3.5 dB higher than the ferrite 121FIND variants from the same platform. With a Qts of 0.16, this driver uses a low Qts, high motor strength design optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nThis model requires vented (bass reflex) enclosures. The small volume displacement of 79.7 cm\u00b3 \u2014 a result of the 1.50mm Xmax optimized for midrange motor linearity rather than deep bass excursion \u2014 keeps port velocities very low: all three alignments using a 75mm round port remain below 7.5 m\/s. Three alignments are recommended: 15 litres tuned to 65 Hz (port 209 mm) for a compact high-efficiency touring cabinet with maximum mid-bass punch; 20 litres tuned to 58 Hz (port 197 mm) as the balanced general-purpose 2-way PA alignment; and 28 litres tuned to 50 Hz (port 189 mm) for maximum low-frequency extension. All three alignments accept a common 75 mm \u00d7 200 mm port tube with minor end-trimming, as effective port lengths differ by only 20 mm across the three tunings.\n\nThe 121NPMX8-079 handles approx. 450 W AES and 900 W continuous power, delivering a peak SPL of 126.5 dB at 1 metre (AES) \u2014 the highest of the three 12-inch variants in the 121 family, and 6 dB above the ferrite FIND models at equivalent power. A high-pass filter at 40\u201360 Hz is recommended depending on alignment. The operating bandwidth is approximately 55\u2013843 Hz; cone beaming onset at 843 Hz defines the upper limit, and a crossover to a compression driver on horn at 800 Hz to 1.5 kHz is required. Third or fourth-order crossover slopes are recommended to control directivity above 843 Hz.\n\nThis driver is suited for compact high-efficiency vented 2-way PA touring cabinets where maximum SPL per cabinet weight is the design objective; permanently installed 2-way enclosures in large venues requiring high sensitivity; 2-way stage monitor wedges with horn crossover at 1.0\u20131.2 kHz; and line array or column system applications where high sensitivity, low distortion, and precise midrange reproduction are required. The neodymium outside ring motor and CCAW voice coil on glass fiber former provide a lightweight, high-efficiency transducer capable of sustained high-power output with minimal thermal compression.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 121NPMX8-079\nGenerated: 2026-04-12\nApplication: Professional 2-way PA systems, high-efficiency touring\nDRIVER SPECIFICATIONS\nCode : 121NPMX8-079\nDescription : 12\" Neodymium Pro Mid-Woofer \u2014 Carbon Fiber Paper Cone\nNominal Impedance: 8 \u03a9\nAES Power : 450 W\nContinuous Power : 900 W\nPeak Power : 1,800 W\n\nFs : 50 Hz\nRe : 6.0 \u03a9\nQes : 0.16\nQms : 7.51\nQts : 0.16\nVas : 59.2 L\nSd : 531 cm\u00b2\nSensitivity : 99.97 dB (1 W \/ 1 m)\nMms : 66.7 g\nRms : 2.79 kg\/s\nCms : 0.15 mm\/N\nBl : 27.8 T\u00b7m\nLe : 0.51 mH\nXmax : 1.50 mm (one-way, peak)\nXmech : 11.50 mm\n\nVoice Coil : 76 mm (3\"), CCAW, Glass Fiber former\nCone : Carbon fiber paper (Paper CF)\nSurround : Fabric, double-roll constant geometry\nSpider : Nomex\nBasket : Aluminum\nMagnet : Neodymium (outside ring design)\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 531 cm\u00b2 \u00d7 0.150 cm = 79.7 cm\u00b3\n\nNote on Xmax and motor design: Xmax = 1.50 mm reflects a motor\n optimized for extreme sensitivity and ultra-low distortion at\n minimal excursion, not deep bass. This driver is designed for\n midrange reproduction where motor linearity and efficiency\n are paramount over low-frequency extension. A system-level\n high-pass filter or subwoofer crossover is mandatory.\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 6.0 \/ (2\u03c0 \u00d7 0.00051) \u2248 1,873 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(531 \/ 3.14159) = 13.00 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 13.00) \u2248 843 Hz\n\nWorking band : ~55 Hz \u2013 843 Hz\nCrossover to horn : 800 Hz \u2013 1.5 kHz (f_beam at 843 Hz is the\n primary upper constraint; Le onset at 1,873 Hz\n provides additional rolloff well above crossover)\n\nMaximum SPL (anechoic, 1 m)\n At 450 W AES : 99.97 + 10\u00b7log\u2081\u2080(450) = 99.97 + 26.5 = 126.5 dB\n At 900 W cont : 99.97 + 10\u00b7log\u2081\u2080(900) = 99.97 + 29.5 = 129.5 dB\n12\" FAMILY COMPARISON: 121FIND vs 121NPM\nAll three share the same 531 cm\u00b2 Sd and similar cabinet footprint\n(285\u2013282 mm baffle cutout), enabling direct substitution in a\ncommon 12\" PA enclosure design.\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Parameter \u2502 121FINDX4-233 \u2502 121FINDX8-234 \u2502 121NPMX8-079 \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 Impedance \u2502 4 \u03a9 \u2502 8 \u03a9 \u2502 8 \u03a9 \u2502\n\u2502 AES Power \u2502 250 W \u2502 250 W \u2502 450 W \u2502\n\u2502 Sensitivity \u2502 96.4 dB \u2502 96.6 dB \u2502 100.0 dB \u2502\n\u2502 Fs \u2502 59 Hz \u2502 63 Hz \u2502 50 Hz \u2502\n\u2502 Qts \u2502 0.52 \u2502 0.60 \u2502 0.16 \u2502\n\u2502 Bl \u2502 10.2 T\u00b7m \u2502 12.9 T\u00b7m \u2502 27.8 T\u00b7m \u2502\n\u2502 Le \u2502 0.32 mH \u2502 0.52 mH \u2502 0.51 mH \u2502\n\u2502 Xmax \u2502 1.85 mm \u2502 3.75 mm \u2502 1.50 mm \u2502\n\u2502 Vd \u2502 98.2 cm\u00b3 \u2502 199.1 cm\u00b3 \u2502 79.7 cm\u00b3 \u2502\n\u2502 Magnet \u2502 Ferrite \u2502 Ferrite \u2502 Neodymium \u2502\n\u2502 Peak SPL (AES) \u2502 120.4 dB \u2502 120.6 dB \u2502 126.5 dB \u2502\n\u2502 Enclosure \u2502 Vented \/ Seal \u2502 Sealed \/ Vent \u2502 Vented only \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nThe 121NPMX8-079 provides +3.5 dB sensitivity and +6 dB peak SPL\nversus the FIND variants, at the cost of reduced Xmax and a strictly\nvented-only enclosure requirement. The neodymium outside ring motor\nyields the highest Bl (27.8 T\u00b7m) of the 12\" family.\nENCLOSURE RECOMMENDATION\nQts = 0.16 \u2192 Vented (bass reflex) is the only viable alignment.\nSealed enclosures produce a severely overdamped response with\nresonance frequency far above the useful audio band and are\nnot suitable for this driver.\nVENTED ENCLOSURE ALIGNMENTS\nPort: 75 mm round (Ap = 44.18 cm\u00b2)\n Vd = 79.7 cm\u00b3 is small; port velocities are very low at all\n alignments, well within both hi-fi and PA limits.\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2 ; 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 79.7 cm\u00b3 = 7.97 \u00d7 10\u207b\u2075 m\u00b3 ; Ap = 4.418 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 75mm Port Length \u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 15 L \u2502 65 Hz \u2502 209 mm \u2502 7.4 m\/s \u2713 \u2502\n\u2502 B \u2502 20 L \u2502 58 Hz \u2502 197 mm \u2502 6.6 m\/s \u2713 \u2502\n\u2502 C \u2502 28 L \u2502 50 Hz \u2502 189 mm \u2502 5.7 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (75 mm round port):\n Alignment A: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 4225 \u00d7 15,000)\n = 5.228\u00d710\u00b9\u2070 \/ 2.501\u00d710\u2079 = 209 mm\n Alignment B: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3364 \u00d7 20,000)\n = 5.228\u00d710\u00b9\u2070 \/ 2.655\u00d710\u2079 = 197 mm\n Alignment C: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 2500 \u00d7 28,000)\n = 5.228\u00d710\u00b9\u2070 \/ 2.763\u00d710\u2079 = 189 mm\n\nPort engineering note: All three alignments produce near-identical\neffective port lengths (189\u2013209 mm). This is the characteristic\nnear-constant port behaviour of very low Qts drivers \u2014 larger Vb\nand lower Fb offset each other in the Helmholtz equation. A single\n75 mm \u00d7 ~200 mm port tube serves all three tunings with minor\nend-trimming. Physical tube length (Leff minus ~54 mm end corrections)\nis approximately 135\u2013155 mm \u2014 compact and easily accommodated in\nany standard 12\" PA cabinet depth.\n\n--- Vented Alignment A \u2014 15 L \/ Fb = 65 Hz ---\n Compact high-efficiency cabinet, tuned above Fs. Maximum\n mid-bass punch and excursion protection. Recommended for compact\n touring 2-way PA cabinets and stage monitors where cabinet\n volume and weight are critical. Lower rolloff begins sharply\n below 65 Hz (4th-order slope).\n\n--- Vented Alignment B \u2014 20 L \/ Fb = 58 Hz ---\n Balanced PA cabinet tuned near Fs. Good output balance across\n the mid-bass and low-midrange operating band. The recommended\n general-purpose alignment for standalone 2-way PA and permanent\n installation enclosures.\n\n--- Vented Alignment C \u2014 28 L \/ Fb = 50 Hz ---\n At-Fs tuning for maximum low-frequency extension from this driver.\n Provides coverage to approximately 47 Hz (4th-order rolloff below\n Fb) \u2014 the lowest practical tuning for this motor design.\n Mandatory high-pass filter at 38\u201342 Hz to protect driver below\n port rolloff. Suited to 2-way enclosures used without a dedicated\n subwoofer in applications requiring modest sub-50 Hz coverage.\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to compression driver on horn (acoustic): 800 Hz \u2013 1.5 kHz\n f_beam = 843 Hz (primary upper constraint \u2014 same as 121FIND family)\n f_Le = 1,873 Hz (well above crossover; minimal impedance rise\n at the crossover frequency simplifies network design)\n\n Recommended crossover: 1.0 \u2013 1.2 kHz; third or fourth-order\n acoustic slope to control off-axis directivity above 843 Hz.\n The high Bl and very low Qts make this driver highly tolerant\n of crossover network impedance variations \u2014 motor back-EMF\n damping dominates over passive component tolerance.\n\nZobel network:\n R_z = 6.0 \u03a9 (use standard 5.6 \u03a9 or 6.2 \u03a9)\n C_z = Le \/ Re\u00b2 = 0.51e-3 \/ 36.0 = 14.2 \u03bcF \u2192 use 15 \u03bcF, 100 V non-polar"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/121NPM-079-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/121NPM-079-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/121NPM-079-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/121NPM-079-2D.PDF","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/121NPM-079-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/121NPM-079-3D.STEP"}},{"code":"123FPMX4-188B","name":"123FPM","slug":"123fpmx4-188b","description":"Mid-woofer\/12inch\/Ferrite\/Paper\/300W\/4ohm","url":"https:\/\/redcatt.net\/products\/123fpmx4-188b","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"300","continuous_watts":"600","peak_watts":"1200"},"voice_coil":{"diameter":"63.5","wire":"CCAW","former":"Glass Fiber","winding_height":"13.5"},"thiele_small_parameters":{"fs_hz":45,"re_ohm":3.1,"qes":0.29,"qms":4.96,"qts":0.27,"vas_liters":98.5,"sd_cm2":531,"sensitivity_db":97.75,"mms_grams":52.1,"rms":2.97,"cms":0.24,"bl_tm":12.8,"le_mh":0.42},"physical":{"overall_diameter_mm":320,"bolt_circle_diameter_mm":302,"baffle_cutout_diameter_mm":282,"mounting_holes":"8","depth_mm":127.8,"net_weight_kg":5,"xmax_mm":"2.75","xmech_mm":"10.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Rib reinforced paper cone","High power handling"],"design_notes":"The 123FPM is a high efficiency, (98 dB 1watt \/ 1 meter) 12-inch mid bass woofer with incredibly linear frequency response characteristics. The 123FPM uses a lightweight rib-reinforced cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 10.2mm.\n\n\nMagnetic Circuit\nREDCATT engineers have developed a lightweight, inside-neodymium slug based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 123FPMX4-188B\nDriver: 123FPMX4-188B (123FPM) \u2014 12\" Mid-Woofer\nKey T\/S: Fs=45.0Hz, Qts=0.27, Vas=98.5L, Sens=97.75dB\nPower: AES 300W \/ Cont 600W \/ Peak 1200W\nXmax=2.75mm, Sd=531.0cm\u00b2, Bl=12.8T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 standard for mid-size professional enclosures; good balance of area and packaging\n a) High SPL\n Net Volume: 70 liters\n Tuning (Fb): 52 Hz\n Est. -3dB: 48 Hz\n HP Filter: 44 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 49mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 114mm L\n Port Velocity: 6.0 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 80 liters\n Tuning (Fb): 47 Hz\n Est. -3dB: 43 Hz\n HP Filter: 37 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 59mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 131mm L\n Port Velocity: 5.5 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 90 liters\n Tuning (Fb): 43 Hz\n Est. -3dB: 37 Hz\n HP Filter: 31 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 74mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 157mm L\n Port Velocity: 5.0 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 123FPMX4-188B is a 12-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (98 dB 1W\/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 70 to 90 liters, tuned between 43 and 52 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 300 W AES \/ 600 W continuous) and DSP control. A high-pass filter in the range of 31\u201344 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 37\u20132000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/123FPM-188B-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/123FPM-188B-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/123FPM-188B-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/123FPM-188-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/123FPM-188-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/123FPM-188-3D.STEP"}},{"code":"123NPMX8-185","name":"123NPM","slug":"123npmx8-185","description":"Mid-Woofer\/12inch\/Neo\/Paper\/800W\/8ohm","url":"https:\/\/redcatt.net\/products\/123npmx8-185","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"800","continuous_watts":"1600","peak_watts":"3200"},"voice_coil":{"diameter":"101.6","wire":null,"former":"TIL","winding_height":"23"},"thiele_small_parameters":{"fs_hz":58,"re_ohm":4.7,"qes":0.45,"qms":12.6,"qts":0.43,"vas_liters":31.6,"sd_cm2":551,"sensitivity_db":95.82,"mms_grams":100,"rms":2.89,"cms":0.0753,"bl_tm":19.6,"le_mh":0.71},"physical":{"overall_diameter_mm":320.35,"bolt_circle_diameter_mm":299,"baffle_cutout_diameter_mm":281.9,"mounting_holes":"8","depth_mm":140.5,"net_weight_kg":6.2,"xmax_mm":"5.25","xmech_mm":"17.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["High sensitivity, EXTENDED FREQUENCY RESPONSE","3 demodulation rings, powerful motor structure, dual air-gap","High power handling"],"design_notes":"The 123NPM is a truly unique full range woofer. We have designed cutting edge product, using the best avail-able materials and highly optimized design for the best performance in its class. It delivers very high efficiency, (96 dB 1watt \/ 1 meter), incredibly linear frequency response characteristics with extended HF frequency response, extreme high power handling capability, while generating ultra low harmonic distortion artifacts. The 123NPM uses a lightweight carbon fiber loaded cone assembly along with a high excursion triple roll constant geometry surround. This combination provides remarkable strength, high efficiency and a peak to peak linear excursion of 21mm.\n\nMagnetic Circuit\nThe magnetic circuit features two aluminum shorting rings, double air-gap front plate. The cooling system and the air flow has been designed using the modern FEM techniques and further optimized to provide the highest levels of cooling efficiency. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 123NPMX8-185\nDriver: 123NPMX8-185 (123NPM) \u2014 12\" Mid-Woofer\nKey T\/S: Fs=58.0Hz, Qts=0.43, Vas=31.6L, Sens=95.82dB\nPower: AES 800W \/ Cont 1600W \/ Peak 3200W\nXmax=5.25mm, Sd=551.0cm\u00b2, Bl=19.6T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 standard for mid-size professional enclosures; good balance of area and packaging\n a) High SPL\n Net Volume: 25 liters\n Tuning (Fb): 66 Hz\n Est. -3dB: 61 Hz\n HP Filter: 58 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 145mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 279mm L\n Port Velocity: 15.2 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 35 liters\n Tuning (Fb): 55 Hz\n Est. -3dB: 47 Hz\n HP Filter: 45 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 165mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 313mm L\n Port Velocity: 12.6 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 40 liters\n Tuning (Fb): 47 Hz\n Est. -3dB: 40 Hz\n HP Filter: 35 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 191mm long\n Slot Port: 226mm W \u00d7 60mm H \u00d7 359mm L\n Port Velocity: 10.9 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 123NPMX8-185 is a 12-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (96 dB 1W\/1m) and controlled low-frequency behavior. The driver uses a balanced motor-suspension design that provides good cone control while maintaining usable output across its operating bandwidth.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 25 to 40 liters, tuned between 47 and 66 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 800 W AES \/ 1600 W continuous) and DSP control. A high-pass filter in the range of 35\u201358 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 40\u20132000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/123NPM-185-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/123NPM-185-4.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/123NPM-185-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/123NPM-185-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/123NPM-185-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/123NPM-185-3D.STEP"}},{"code":"125FPMX8-187","name":"125FPM","slug":"125fpmx8-187","description":"Mid-woofer\/12inch\/Ferrite\/Paper\/300W\/8ohm","url":"https:\/\/redcatt.net\/products\/125fpmx8-187","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"300","continuous_watts":"600","peak_watts":"1200"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"15.1"},"thiele_small_parameters":{"fs_hz":63,"re_ohm":4.5,"qes":0.33,"qms":7.13,"qts":0.31,"vas_liters":48.1,"sd_cm2":531,"sensitivity_db":100,"mms_grams":53.2,"rms":2.95,"cms":0.12,"bl_tm":17.2,"le_mh":0.64},"physical":{"overall_diameter_mm":311,"bolt_circle_diameter_mm":295,"baffle_cutout_diameter_mm":282,"mounting_holes":"8","depth_mm":127.3,"net_weight_kg":7,"xmax_mm":"2.55","xmech_mm":"12.55"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Good power handling, nomex spider, water-repellent & non-flammable paper cone"],"design_notes":"The 125FPM is a high efficiency, (97.6 dB 1watt\/ 1 meter) 12inch woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts. 125FPM uses lightweight and reinforced cone which movement is controlled by \u201cM\u201d shaped surround. The woofer cone is treated to withstand harsh environments and high humidity.\n\n\tThe 125FPM was design for its best use in the 2-way applications, where excellent midrange response is required. Speaker provides good low frequency extension and delivers seizable amounts of low frequencies.\n\nThe metal parts in the speaker are coated and tested to ensure extreme weatherization protection.","hero_text":null,"ai_summary":null,"recommended_enclosure":"125FPMX8-187 \u2014 Enclosure Design Reference & AI Summary\nGenerated by REDCATT Speaker Enclosure Tool\n=== DRIVER IDENTITY ===\nCode: 125FPMX8-187\nPlatform: 125FPM\nDescription: 12-inch Pro Mid-Woofer | Ferrite | Carbon Fiber Paper (Weatherized) | 300W AES \/ 8\u03a9\nIntended Use: Professional 2-way PA, outdoor\/weatherized installations, stage monitors\n\n=== THIELE-SMALL PARAMETERS ===\nFs: 63 Hz\nRe: 4.5 \u03a9\nQes: 0.33\nQms: 7.13\nQts: 0.31\nVas: 48.1 L\nSd: 531 cm\u00b2\nSensitivity: 100.0 dB (2.83V\/1m) \/ 97.65 dB (1W\/1m)\nMms: 53.2 g\nRms: 2.95 N\u00b7s\/m\nCms: 0.12 mm\/N\nBl: 17.2 T\u00b7m\nLe: 0.64 mH\nXmax: 2.55 mm (one-way, peak)\nXmech: 12.55 mm\nXprot: 14.6 mm\nPower: 300W AES \/ 600W continuous \/ 1200W peak \/ 8\u03a9 nominal\nVoice Coil: 76mm CCAW on glass fiber former\nCone: Carbon fiber reinforced paper (weatherized \/ humidity resistant)\nSurround: M-shaped constant-geometry fabric\nSpider: Nomex\nBasket: Aluminum\nMagnet: Ferrite\n\n=== DERIVED PARAMETERS ===\nVolume displacement (Vd): Sd \u00d7 Xmax = 531 \u00d7 0.255 cm = 135.4 cm\u00b3\nInductance rolloff onset (f_Le): Re \/ (2\u03c0 \u00d7 Le) = 4.5 \/ (2\u03c0 \u00d7 0.00064) \u2248 1,119 Hz\nCone radius (r_cone): \u221a(Sd\/\u03c0) = \u221a(531\/\u03c0) = 13.00 cm\nCone beaming onset (f_beam): c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (\u03c0 \u00d7 13.00) \u2248 842 Hz\nMax SPL @ 300W AES: 97.65 + 10\u00b7log\u2081\u2080(300) = 122.4 dB (1m)\nMax SPL @ 600W continuous: 97.65 + 10\u00b7log\u2081\u2080(600) = 125.4 dB (1m)\nZobel network: R_z = 4.5 \u03a9 (series), C_z = Le\/Re\u00b2 = 31.6 \u03bcF (series)\n\n=== ENCLOSURE RECOMMENDATION ===\nQts = 0.31 \u2192 Vented (bass-reflex) enclosures only.\n\nSealed enclosures are impractical for this driver. The high motor strength (Bl=17.2 T\u00b7m,\nQts=0.31) requires a vented alignment to achieve a flat, extended low-frequency response.\nA sealed alignment at Qtc=0.707 would require only ~12 L but the high motor damping would\nproduce a steeply rising low-frequency response peak; at Qtc=1.0 the box shrinks further\nand the response becomes grossly peaked. Vented enclosures are the correct and only choice.\n\n--- VENTED ALIGNMENTS (75mm round port) ---\nPort diameter: 75 mm\nPort area (Ap): \u03c0 \u00d7 (3.75 cm)\u00b2 = 44.18 cm\u00b2\nPort velocity limit: \u226422 m\/s (pro\/PA application)\nEnd correction (flanged + unflanged): ~54 mm subtracted from Leff to obtain physical tube length\n\nAlignment 1 \u2014 Compact (stage monitor \/ wedge \/ portable cabinet)\n Cabinet volume (Vb): 15 L\n Tuning frequency (Fb): 68 Hz\n Effective port length (Leff): 191 mm\n Physical tube length: ~137 mm\n Peak port velocity: 13.1 m\/s \u2713\n\nAlignment 2 \u2014 Standard (general-purpose 2-way PA)\n Cabinet volume (Vb): 20 L\n Tuning frequency (Fb): 60 Hz\n Effective port length (Leff): 184 mm\n Physical tube length: ~130 mm\n Peak port velocity: 11.6 m\/s \u2713\n\nAlignment 3 \u2014 Extended low-frequency\n Cabinet volume (Vb): 28 L\n Tuning frequency (Fb): 52 Hz\n Effective port length (Leff): 175 mm\n Physical tube length: ~121 mm\n Peak port velocity: 10.0 m\/s \u2713\n\nNEAR-CONSTANT PORT LENGTH NOTE:\nEffective port lengths range only 175\u2013191 mm across all three alignments (16 mm span).\nA single 75mm \u00d7 130mm port tube serves the standard alignment directly and can be\ntrimmed \u00b19 mm to serve the compact or extended alignments. This simplifies tooling and\nreduces stocking complexity across multiple cabinet designs sharing this driver platform.\n\n=== CROSSOVER \/ DSP GUIDANCE ===\nOperating band: ~65\u2013842 Hz (vented Fb to cone beaming onset)\nHigh-pass filter: Set at or above Fb (52\u201368 Hz depending on alignment);\n 24 dB\/octave Linkwitz-Riley minimum \u2014 mandatory given Xmax = 2.55 mm;\n cone excursion increases steeply below port tuning frequency\nLow-pass crossover: Below 842 Hz (f_beam); 800\u20131000 Hz to compression driver on horn\n recommended; 3rd or 4th-order slopes for directivity control\nInductance rolloff: Begins at ~1,119 Hz; cross well below this point for flat response\nEQ \/ protection: Subsonic filter mandatory at all times; no unfiltered low-frequency\n program material below tuning frequency\n\nZobel network (passive crossover inductance compensation \u2014 place across driver terminals):\n R_z = 4.5 \u03a9 in series with C_z = 31.6 \u03bcF\n\n=== SUMMARY ===\n\nThe 125FPMX8-187 is a 12-inch professional mid-woofer built around a ferrite magnetic circuit with a 76mm CCAW voice coil wound on a glass fiber former and a carbon fiber reinforced paper cone treated for weather resistance, high humidity, and extended outdoor use. The M-shaped constant-geometry fabric surround and Nomex spider provide precise mechanical control across the operating band, while the aluminum basket supports structural rigidity in both permanently installed and portable professional enclosures. Sensitivity is 97.65 dB (1W\/1m) \/ 100.0 dB (2.83V\/1m) with a Bl of 17.2 T\u00b7m, supporting 300W AES \/ 600W continuous power handling. Qts = 0.31 reflects a low Qts, high motor strength design optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nWith a Qts of 0.31, this driver requires vented (bass-reflex) enclosures only. Three alignments are provided using a 75mm round port \u2014 all three share effective port lengths within a 16mm range, and a single 130mm port tube can serve all three alignments with minor end-trimming:\n\n \u2022 15 L \/ 68 Hz \u2014 compact monitor or stage wedge; port ~137 mm physical; 13.1 m\/s\n \u2022 20 L \/ 60 Hz \u2014 standard general-purpose 2-way PA; port ~130 mm physical; 11.6 m\/s\n \u2022 28 L \/ 52 Hz \u2014 extended low-frequency; port ~121 mm physical; 10.0 m\/s\n\nAmplification of 300\u2013600W from an 8\u03a9-rated power amplifier is appropriate, delivering a peak SPL of 122.4 dB at 1 metre (AES rating). A subsonic high-pass filter at the cabinet tuning frequency is mandatory given the 2.55mm Xmax \u2014 excursion rises steeply below the port tuning frequency and unprotected operation risks mechanical damage. Crossover to a compression driver or horn at 800\u20131000 Hz is required; cone beaming onset occurs at approximately 842 Hz and inductance rolloff begins at 1,119 Hz. Third or fourth-order crossover slopes are recommended to maintain controlled directivity above 842 Hz. A Zobel network (4.5\u03a9 series with 31.6 \u03bcF, placed across the driver terminals) is recommended for passive crossover designs to compensate for voice coil inductance rise.\n\nThe 125FPMX8-187 is suited for compact vented 2-way PA enclosures requiring environmental durability and weather resistance; permanently installed systems in outdoor venues, arenas, and harsh-environment applications where humidity and temperature cycling would degrade standard paper-cone drivers; stage monitor wedges crossed to a compression driver or horn at 1.0 kHz; and portable PA systems requiring a combination of high sensitivity, controlled power handling, and extended service life in demanding conditions."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/125FPM-187-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/125FPM-187-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/125FPMX8-187-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/125FPM-187-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/125FPM-187-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/125FPM-187-3D.STEP"}},{"code":"12NPMX8-054","name":"12NPM","slug":"12npmx8-054","description":"Mid-Woofer\/12inch\/Neo\/Paper\/450W\/8ohm","url":"https:\/\/redcatt.net\/products\/12npmx8-054","category":"LF","type":"Mid-Woofer","size_inches":12,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"450","continuous_watts":"900","peak_watts":"1800"},"voice_coil":{"diameter":"76","wire":"CCAW","former":"Glass Fiber","winding_height":"18.6"},"thiele_small_parameters":{"fs_hz":49,"re_ohm":4.7,"qes":0.32,"qms":9.95,"qts":0.31,"vas_liters":63.6,"sd_cm2":531,"sensitivity_db":98,"mms_grams":65.6,"rms":2.03,"cms":0.161,"bl_tm":17.3,"le_mh":0.65},"physical":{"overall_diameter_mm":315,"bolt_circle_diameter_mm":298,"baffle_cutout_diameter_mm":285,"mounting_holes":"8","depth_mm":142.5,"net_weight_kg":4.1,"xmax_mm":"4.05","xmech_mm":"14.55"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Carbon fiber loaded paper cone","Very high efficiency","Lightweight mechanical structure"],"design_notes":"The 12NPM is a high efficiency, (98 dB 1watt \/ 1 meter) 12-inch mid bass woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts.-\nThe 12NPM uses a lightweight carbon fiber loaded cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 18.2mm.\n\nMagnetic Circuit\nREDCATT engineers have developed a lightweight, inside-neodymium slug based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 12NPMX8-054\nDriver: 12NPMX8-054 (12NPM) \u2014 12\" Mid-Woofer\nKey T\/S: Fs=49.0Hz, Qts=0.31, Vas=63.6L, Sens=97.99dB\nPower: AES 450W \/ Cont 900W \/ Peak 1800W\nXmax=4.05mm, Sd=531.0cm\u00b2, Bl=17.3T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (100mm diameter) \u2014 standard for mid-size professional enclosures; good balance of area and packaging\n a) High SPL\n Net Volume: 55 liters\n Tuning (Fb): 53 Hz\n Est. -3dB: 49 Hz\n HP Filter: 45 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 76mm long\n Slot Port: 228mm W \u00d7 60mm H \u00d7 164mm L\n Port Velocity: 9.1 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 65 liters\n Tuning (Fb): 46 Hz\n Est. -3dB: 39 Hz\n HP Filter: 36 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 92mm long\n Slot Port: 228mm W \u00d7 60mm H \u00d7 192mm L\n Port Velocity: 8.0 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 80 liters\n Tuning (Fb): 40 Hz\n Est. -3dB: 34 Hz\n HP Filter: 28 Hz (24dB\/oct recommended)\n Round Port: 100mm dia \u00d7 111mm long\n Slot Port: 228mm W \u00d7 60mm H \u00d7 225mm L\n Port Velocity: 6.9 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 12NPMX8-054 is a 12-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (98 dB 1W\/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 55 to 80 liters, tuned between 40 and 53 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 450 W AES \/ 900 W continuous) and DSP control. A high-pass filter in the range of 28\u201345 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 34\u20132000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/12NPM-054-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/12NPM-054-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/12NPM-054-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/12NPM-054-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/12NPM-054-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/12NPM-054-3D.STEP"}},{"code":"101FHWX4-118","name":"101FHW","slug":"101fhwx4-118","description":"Subwoofer\/10inch\/Ferrite\/Paper\/200W\/4ohm","url":"https:\/\/redcatt.net\/products\/101fhwx4-118","category":"LF","type":"Sub-woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"Copper","former":"Aluminum","winding_height":"32.3"},"thiele_small_parameters":{"fs_hz":27,"re_ohm":3.6,"qes":0.37,"qms":1.5,"qts":0.3,"vas_liters":54.7,"sd_cm2":330.1,"sensitivity_db":87.08,"mms_grams":97.8,"rms":11.1,"cms":0.36,"bl_tm":12.7,"le_mh":0.82},"physical":{"overall_diameter_mm":269,"bolt_circle_diameter_mm":258,"baffle_cutout_diameter_mm":239,"mounting_holes":"8","depth_mm":117,"net_weight_kg":6,"xmax_mm":"12.15","xmech_mm":"20.15"},"materials":{"surround":"NBR","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Glass fiber loaded paper cone and dustcap","Nomex spider with stitched tinsel wires","Excellent low frequency response"],"design_notes":"The 101FHW is a high efficiency, (87dB 1watt \/ 1 meter) 10-inch woofer speaker with extended low frequency response and high power handling capability. The 101FHW uses a strong glass fiber reinforced paper cone assembly along with a single roll rubber surround. Spider is Nomex material with stitched-in tinsel wires. This ensures long lasting performance even in high powered applications. The chosen material combination provides remarkable strength, high efficiency and sustained output under extreme conditions.\n\nThe 101FHW cone and dust cap are made using glass fiber loaded paper pulp. All \u201csoft\u201d parts are bonded together using state of the art high temperature adhesives. Metal parts in the speaker assembly are coated for extreme weatherization protection. Speaker push terminals are gold plated to ensure the best connection.","hero_text":null,"ai_summary":"The 101FHWX4-118 is a 10-inch long-excursion subwoofer designed for hi-fi stereo, home theater, and domestic audio applications requiring deep bass extension and high power handling from a moderate-sized driver. It features a 2-inch copper voice coil on an aluminum former with a 32.3 mm winding height, a glass fiber loaded paper cone with a single roll rubber surround, and a Nomex spider with stitched-in tinsel wires for sustained high-excursion reliability. With 12.15 mm of linear excursion (20.15 mm mechanical), 200 W AES \/ 400 W continuous power handling, a 4-ohm nominal impedance, and a volume displacement of 401 cc, the driver provides substantial low-frequency output capability for its size class. The very low Fs of 27 Hz and low Qts of 0.3 indicate a strong motor design optimized for deep bass reproduction with controlled cone behavior.\nIn sealed enclosures, net internal volumes of 8 to 18 liters produce system resonances between 54 and 76 Hz with Qtc values of 0.6 to 0.85. A 12-liter sealed enclosure (Qtc 0.707, fc 64 Hz) provides a maximally flat Butterworth response and is the recommended sealed starting point, with estimated in-room extension to 40\u201346 Hz in typical domestic listening rooms thanks to boundary reinforcement. Larger sealed volumes (18 liters, Qtc 0.6, fc 54 Hz) extend the anechoic response further for larger rooms. In vented (bass reflex) enclosures, the driver's low Qts and very low Fs produce optimal alignments in 50 to 70 liters with tuning frequencies between 22 and 29 Hz. A 59-liter vented enclosure tuned to 25 Hz is the recommended starting point, providing infrasonic reach (estimated -3 dB at 21 Hz) that covers the deepest musical and home theater content. Port velocities are moderate across all vented alignments (12\u201316 m\/s with a 76 mm round port). A passive radiator of similar Sd and excursion capability is the premium alternative to a ported design, eliminating port noise while maintaining deep tuning.\nThe driver is intended for use with amplification in the 200\u2013400 W range and benefits from DSP management. In sealed configurations, room gain provides the primary mechanism for deep bass extension. In vented configurations, a subsonic high-pass filter (15\u201319 Hz) is essential to protect against excessive excursion below tuning frequency. The 12.15 mm linear Xmax with 20.15 mm mechanical clearance provides substantial headroom for transient peaks beyond the linear operating range.\nThis driver is particularly effective in compact sealed hi-fi subwoofers, medium-sized vented or passive radiator subwoofer cabinets, and home theater LFE systems where deep infrasonic extension, high excursion linearity, and long-term reliability are required. The glass fiber loaded cone, Nomex spider with stitched tinsel wires, weatherization-coated metalwork, and gold-plated terminals provide durable construction suited to sustained high-power subwoofer duty.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 101FHWX4-118\nDriver: 101FHWX4-118 (101FHW) \u2014 10\" Hi-Fi Subwoofer\nKey T\/S: Fs=27Hz, Qts=0.3, Vas=54.7L, Sens=87dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=12.15mm (one-way linear), Xmech=20.15mm, Sd=330.1cm\u00b2\nBl=12.7T\u00b7m, Re=3.6\u03a9 (4-ohm nominal), Mms=97.8g\nVoice Coil: 2\" copper on aluminum former (32.3mm winding height)\nMagnet: Ferrite (weatherization-coated) | Basket: Aluminum\nCone: Glass fiber loaded paper pulp | Surround: Rubber (single roll)\nSpider: Nomex with stitched-in tinsel wires\nVolume Displacement (Vd): 401 cc\nNOTE: This is a high-excursion 10\" hi-fi subwoofer with a very low\nFs (27 Hz) and substantial volume displacement (401 cc). The low\nQts (0.3) and strong motor (Bl=12.7 T\u00b7m) combined with the very\nlow resonant frequency make this driver exceptionally well-suited\nto vented enclosures, where it can reach genuine infrasonic\nfrequencies. Sealed enclosures are viable for more compact builds,\nrelying on room gain for deep bass extension. The Nomex spider\nwith stitched-in tinsel wires and weatherization-coated metalwork\nensure long-term reliability under sustained high-excursion use.\n SEALED ENCLOSURES\nSealed enclosures provide the simplest build with smooth, predictable\nrolloff. The low Qts (0.3) produces compact sealed enclosures with\nmoderate-to-high fc values. Room gain (typically +3\u20136 dB below\n50\u201360 Hz in domestic rooms) significantly extends the effective\nin-room bass response.\n a) SEALED \u2014 Compact (Qtc \u2248 0.85)\n Net Volume: 8 liters\n System Resonance (fc): 76 Hz\n Qtc: 0.85\n Anechoic -3dB: ~76 Hz\n Estimated in-room -3dB: ~48\u201355 Hz (with typical room gain)\n Response: Slightly warm with gentle resonance lift\n Notes: Very compact enclosure for a 10\" subwoofer. The\n elevated fc (76 Hz) means the anechoic response rolls off\n above typical subwoofer expectations, but room gain in a\n domestic environment effectively extends usable bass into\n the upper 40s Hz. Best suited to smaller listening rooms\n or as a space-efficient sub under a desk or beside furniture.\n The strong motor keeps transient response tight even in\n this compact volume.\n b) SEALED \u2014 Butterworth (Qtc \u2248 0.707)\n Net Volume: 12 liters\n System Resonance (fc): 64 Hz\n Qtc: 0.707\n Anechoic -3dB: ~64 Hz\n Estimated in-room -3dB: ~40\u201346 Hz (with typical room gain)\n Response: Maximally flat sealed amplitude\n Notes: Classic Butterworth alignment providing the flattest\n sealed response. With room gain, in-room response extends\n usably to the low 40s Hz \u2014 satisfactory for most music\n and home theater content. A practical balance between\n enclosure size and bass depth for a compact sealed sub.\n *** RECOMMENDED SEALED ALIGNMENT ***\n c) SEALED \u2014 Extended (Qtc \u2248 0.6)\n Net Volume: 18 liters\n System Resonance (fc): 54 Hz\n Qtc: 0.60\n Anechoic -3dB: ~54 Hz\n Estimated in-room -3dB: ~34\u201338 Hz (with typical room gain)\n Response: Overdamped, smooth gradual rolloff\n Notes: Larger sealed enclosure with substantially lower fc.\n The overdamped alignment rolls off gradually, providing\n in-room response well into the 30s Hz. Good for medium\n listening rooms where genuine deep bass from a sealed\n enclosure is desired. The gentle rolloff integrates\n naturally with room acoustics.\n VENTED ENCLOSURES (Bass Reflex)\nVented enclosures are the optimal configuration for this driver's\nlow Qts and very low Fs. The vented alignments reach genuine\ninfrasonic frequencies (low 20s Hz) that are simply not achievable\nin sealed configurations without heavy EQ. The trade-off is larger\ncabinet volumes (50\u201370L).\nPORT RECOMMENDATION: 76mm round port is practical for all alignments\n(port lengths 266\u2013343mm, velocities 12\u201316 m\/s). A 100mm round port\nreduces velocity further but requires longer port tubes (480\u2013620mm),\nwhich may need to be angled or L-bent inside the cabinet. Flared\nport ends are recommended at all diameters for minimum turbulence\nnoise at high excursion.\n d) VENTED \u2014 High Output\n Net Volume: 50 liters\n Tuning (Fb): 29 Hz\n Est. -3dB: 27 Hz\n HP Filter: 19 Hz (24dB\/oct recommended)\n Round Port (76mm): 76mm dia \u00d7 266mm long\n Round Port (100mm): 100mm dia \u00d7 483mm long\n Port Velocity (76mm): 16.1 m\/s\n Port Velocity (100mm): 9.3 m\/s\n Notes: Moderately compact vented alignment with tuning\n just above Fs. Strong output in the 25\u201360 Hz region with\n excellent excursion control near tuning. The -3 dB point\n at 27 Hz means genuine deep bass reproduction. 76mm port\n is the most practical option (manageable 266mm length).\n Well-suited to a medium-sized hi-fi subwoofer cabinet.\n e) VENTED \u2014 Balanced\n Net Volume: 59 liters\n Tuning (Fb): 25 Hz\n Est. -3dB: 21 Hz\n HP Filter: 15 Hz (24dB\/oct or subsonic)\n Round Port (76mm): 76mm dia \u00d7 311mm long\n Round Port (100mm): 100mm dia \u00d7 562mm long\n Port Velocity (76mm): 13.9 m\/s\n Port Velocity (100mm): 8.0 m\/s\n Notes: The recommended vented alignment for most hi-fi\n applications. Tuning at 25 Hz provides infrasonic reach\n that covers the deepest musical and home theater content\n (pipe organ pedal notes, film LFE). Port velocities are\n moderate. This alignment reaches frequencies that sealed\n enclosures of any size cannot match without heavy EQ.\n *** RECOMMENDED VENTED ALIGNMENT ***\n f) VENTED \u2014 Extended Low Frequency\n Net Volume: 70 liters\n Tuning (Fb): 22 Hz\n Est. -3dB: 19 Hz\n HP Filter: 15 Hz (24dB\/oct or subsonic)\n Round Port (76mm): 76mm dia \u00d7 343mm long\n Round Port (100mm): 100mm dia \u00d7 618mm long\n Port Velocity (76mm): 12.2 m\/s\n Port Velocity (100mm): 7.1 m\/s\n Notes: Maximum infrasonic extension for dedicated deep-bass\n systems. The -3 dB at 19 Hz covers the entire audible\n spectrum and into tactile\/infrasonic territory. Largest\n cabinet but provides the deepest possible response. Best\n for dedicated listening rooms, home theater reference\n systems, and enthusiasts prioritizing absolute low-frequency\n extension. Requires subsonic high-pass protection to manage\n excursion below tuning.\nPASSIVE RADIATOR ALTERNATIVE:\nA passive radiator (PR) can replace the port in any vented alignment\nwhile eliminating port length constraints and turbulence noise. For\nthis driver, a PR should have:\n - Sd equal to or greater than the active driver (~330 cm\u00b2)\n - Tuning mass selected for the desired Fb (22\u201329 Hz)\n - Xmax equal to or greater than the active driver (\u226512 mm)\n - Compliance equal to or greater than the active driver\nA 10\" or 12\" passive radiator in a 50\u201370 liter enclosure tuned to\n25 Hz provides deep, clean infrasonic reproduction without port noise.\nThis is the premium implementation for a modern hi-fi subwoofer.\nEXCURSION NOTE: The 12.15 mm linear Xmax with 20.15 mm mechanical\nclearance provides substantial displacement capability (Vd = 401 cc)\nfor a 10\" driver. This supports high SPL at very low frequencies.\nBelow vented tuning frequency, excursion rises rapidly \u2014 a subsonic\nfilter is essential in vented configurations.\nCONSTRUCTION NOTE: The glass fiber loaded paper cone with Nomex spider\nand stitched-in tinsel wires provide the durability required for\nsustained high-excursion subwoofer operation. The aluminum former\non the 2\" copper voice coil ensures efficient heat dissipation during\ncontinuous high-power use. All metal parts are weatherization-coated\nand push terminals are gold plated."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/101FHW-118-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/101FHW-118-3D.STEP"}},{"code":"101FHWX8-118D","name":"101FHW","slug":"101fhwx8-118d","description":"Subwoofer\/10inch\/Ferrite\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/101fhwx8-118d","category":"LF","type":"Sub-woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"Copper","former":"Aluminum","winding_height":"32.3"},"thiele_small_parameters":{"fs_hz":25,"re_ohm":5.8,"qes":0.43,"qms":1.76,"qts":0.34,"vas_liters":73.3,"sd_cm2":363,"sensitivity_db":87,"mms_grams":100.2,"rms":8.94,"cms":0.4,"bl_tm":14.6,"le_mh":0.63},"physical":{"overall_diameter_mm":269,"bolt_circle_diameter_mm":257,"baffle_cutout_diameter_mm":238,"mounting_holes":"8","depth_mm":123,"net_weight_kg":6,"xmax_mm":"12.15","xmech_mm":"20.15"},"materials":{"surround":"NBR","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["FIBER REINFORCED PAPER CONE","TWO DEMODULATION RINGS","OPTMIZED AIR VENTILATION"],"design_notes":"Introducing the 101FHW: the latest iteration of our award-winning 10FHW woofer model. This high-efficiency 10-inch subwoofer delivers an impressive 87dB sensitivity (1 watt \/ 1 meter), offering extended low-frequency response and robust power handling capabilities.\n\nCrafted with a fiber-reinforced paper cone assembly and a single roll rubber surround, the 101FHW is built for durability and performance. Its Nomex spider, featuring stitched tinsel wires, ensures long-lasting reliability even in high-powered applications. Enhanced back plate space and additional venting have been integrated to optimize power handling and cooling, making this woofer truly exceptional.\n\nThe carefully selected materials provide remarkable strength, high efficiency, and sustained output under extreme conditions.\n\nOn the magnetic front, our REDCATT engineers have designed a cutting-edge ferrite-based magnetic circuit that sets a new standard for performance. This innovative design features a consistent, high-integrity magnetic flux gap, ultra-low distortion characteristics, and an efficient cooling system. With integrated aluminum shorting rings, the magnetic circuit minimizes flux modulation, ensuring exceptional stability and reliability.\n\nExperience the power and precision of the 101FHW\u2014where cutting-edge technology meets outstanding performance.","hero_text":null,"ai_summary":"The 101FHWX8-118D is a 10-inch hi-fi subwoofer driver rated at 200 W AES (400 W continuous) with a nominal 8-ohm impedance, designed for high-fidelity home audio, studio monitoring, and active bass management systems. Featuring a ferrite-based magnetic circuit with two aluminum demodulation rings, the driver provides low inductance, reduced flux modulation, and extended linearity throughout its operating range. The motor-suspension design is optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 30 to 70 liters, tuned between 22 and 30 Hz, delivering an estimated -3 dB frequency of 22 to 30 Hz. Due to the very low free-air resonance (25 Hz), compact vented alignments produce long port tubes; a passive radiator is recommended for the smallest (30L) configuration. Sealed enclosures in the 10 to 22 liter range produce Qtc values of 0.71 to 0.98 with a passive -3 dB at 52 to 57 Hz, but are well suited to active DSP correction (Linkwitz Transform) extending the system response to approximately 25 Hz with the available 12.15 mm Xmax providing sufficient mechanical headroom.\n\nThe driver is intended for use with amplification of approx. 200 W AES (400 W continuous) into 8 ohms, with a recommended high-pass filter in the 18\u201325 Hz range for vented systems, depending on tuning frequency. Sealed active systems should incorporate a Linkwitz Transform targeting fc = 25 Hz, Qtc = 0.707 with appropriate power limiting below 25 Hz. Cone excursion increases rapidly below enclosure tuning in vented systems, and below the transform frequency in DSP-corrected sealed systems; active protection is essential.\n\nThe 101FHWX8-118D is suited for single-driver hi-fi subwoofers, 2.1 and multi-channel home theater systems, studio reference monitoring with sub-bass extension, and audiophile-grade active loudspeaker systems where low distortion, deep extension, and precise transient reproduction are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 101FHWX8-118D\nDriver: 101FHWX8-118D (101FHW) \u2014 10\" hi-fi subwoofer, 8 ohm\nKey T\/S: Fs=25.0Hz, Qts=0.34, Vas=73.3L, Sens=87.0dB\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=12.15mm, Xmech=20.15mm, Sd=363.0cm\u00b2, Bl=14.6T\u00b7m\nLe=0.63mH | Two aluminum demodulation rings\n\nNOTE: This is the 8-ohm variant (Re=5.8\u03a9) of the 101FHW series.\nThe equivalent 4-ohm version is 101FHWX4-118.\n\nRECOMMENDED ENCLOSURE TYPES:\n PRIMARY: Bass Reflex (Vented) \u2014 Qts=0.34 is in the classic vented\n alignment range; excellent motor control, deep extension\n SECONDARY: Sealed (Acoustic Suspension) \u2014 for DSP\/active systems\n with Linkwitz Transform bass correction\nVENTED ALIGNMENTS (Primary)\nPort: 75mm diameter round, flared both ends (Hi-fi preferred)\nVd = 363 cm\u00b2 \u00d7 12.15mm = 441.1 cm\u00b3\n\nIMPORTANT NOTE ON TUNING: The very low Fs (25 Hz) combined with\ncompact box volumes produces long port tube lengths in alignment (a).\nA passive radiator is strongly recommended as an alternative to a port\nfor alignment (a), and is a viable option for alignments (b) and (c).\n\n a) Deep Extension\n Net Volume: 30 liters\n Tuning (Fb): 30 Hz\n Est. -3dB: ~30 Hz\n HP Filter: 25 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 487mm long [!]\n Passive Radiator (recommended): Sd \u2265 363cm\u00b2, mmd \u2248 120g\n tuned to 30 Hz (add mass to PR if required)\n Port Velocity: 18.8 m\/s \u2713\n Notes: Compact hi-fi sub with very deep extension approaching\n infrasonic range. Long port makes passive radiator the\n preferred solution. Room gain (+3\u20136dB below 50Hz) provides\n additional effective bass extension.\n\n b) Balanced Response\n Net Volume: 50 liters\n Tuning (Fb): 26 Hz\n Est. -3dB: ~26 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 389mm long\n Port Velocity: 16.3 m\/s \u2713\n Notes: Best balance of low-frequency extension and cabinet size.\n General-purpose hi-fi, home theater, and studio subwoofer.\n Port length is practical.\n\n c) Extended Deep Bass\n Net Volume: 70 liters\n Tuning (Fb): 22 Hz\n Est. -3dB: ~22 Hz\n HP Filter: 18 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 388mm long\n Port Velocity: 13.8 m\/s \u2713\n Notes: Reference-grade extension well below 30 Hz. Large cabinet\n suitable for floorstanding integration or under-room\n installations. Room modes engaged below 20 Hz \u2014 appropriate\n for critical listening environments with DSP room correction.\nSEALED ALIGNMENTS (Secondary \u2014 DSP\/Active Systems)\nSealed enclosures offer superior transient response and smoother\nrolloff (12dB\/oct) ideal for active systems with DSP crossover and\nbass management. With 12.15mm Xmax and a Linkwitz Transform, the\nsystem can be corrected to flat response down to ~25 Hz.\n\n d) Compact Monitor (10 liters)\n Qtc: 0.98\n fc: 72 Hz\n Est. -3dB (passive): ~57 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: Small footprint for desktop or surround subwoofer use.\n Requires DSP bass correction for hi-fi application.\n Xmax headroom accommodates the boost required.\n\n e) Balanced Sealed (14 liters)\n Qtc: 0.85\n fc: 62 Hz\n Est. -3dB (passive): ~54 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: More relaxed sealed alignment, reduced excursion vs (d).\n Good platform for sealed\/sub integration in 2.1 systems\n with DSP high-pass to satellite speakers.\n\n f) Butterworth Sealed (22 liters)\n Qtc: 0.707\n fc: 52 Hz\n Est. -3dB (passive): ~52 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: Maximally flat sealed alignment. Can be used passively\n in 2-way systems crossed below 100Hz; with DSP correction\n provides the best combination of linearity and extension.\n\nROOM GAIN NOTE:\nIn typical domestic rooms, low-frequency room gain of +3\u20136 dB below\n50\u201360 Hz effectively extends apparent bass response by approximately\none octave. In-room performance of vented alignment (b) or sealed\nalignment (f) is therefore equivalent to a flat anechoic response\nextending to ~15\u201320 Hz before room correction.\nAPPLICATION SUMMARY\n - Hi-fi 2.1, 2.2, or multi-channel home theater subwoofers\n - Studio reference monitors with sub integration\n - Compact audiophile subwoofer enclosures\n - DSP-managed active subwoofer systems (sealed preferred)\n - 8-ohm impedance suits bridged amplifier configurations or series\n wiring of two drivers per channel (8+8=16 ohm)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118D-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118D-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/101FHWX8-118D-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FHW-117D-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/10FHW-117D-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FHW-117D-3D.STEP"}},{"code":"10FHWX4-117","name":"10FHW","slug":"10fhwx4-117","description":"Subwoofer\/10inch\/Ferrite\/Aluminum\/200W\/4ohm","url":"https:\/\/redcatt.net\/products\/10fhwx4-117","category":"LF","type":"Sub-woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"Copper","former":"Glass Fiber","winding_height":"32.3"},"thiele_small_parameters":{"fs_hz":25,"re_ohm":3.6,"qes":0.4,"qms":13.72,"qts":0.39,"vas_liters":57.9,"sd_cm2":330.1,"sensitivity_db":86.5,"mms_grams":110.4,"rms":1.26,"cms":0.37,"bl_tm":12.7,"le_mh":0.62},"physical":{"overall_diameter_mm":269,"bolt_circle_diameter_mm":258,"baffle_cutout_diameter_mm":239,"mounting_holes":"8","depth_mm":117,"net_weight_kg":6,"xmax_mm":"12.15","xmech_mm":"20.15"},"materials":{"surround":"NBR","cone_dome":"Aluminum","spider":"Nomex"},"content":{"key_features":["Good low frequency extension","Aluminum chassis, aluminum cone, nomex spider with attached tinsel wire","High power handling"],"design_notes":"The 10FHW is a high efficiency, (87dB 1watt \/ 1 meter) 10-inch sub-woofer speaker with extended low frequency response and high power handling capability. The 10FHW uses a strong anodized aluminum cone assembly along with a single roll rubber surround. Spider is Nomex material with stitched-on tinsel wires. This ensures long lasting performance even in high powered applications. The chosen material combination provides remarkable strength, high efficiency and sustained output under extreme conditions. \n\nMagnetic Circuit\nREDCATT engineers have developed a ferrite based magnetic circuit, capable of delivering the highest level of performance, providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic structure has integrated two aluminum shorting rings. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"The 10FHWX4-117 is a 10-inch hi-fi subwoofer driver rated at 200 W AES (400 W continuous) into a nominal 4-ohm impedance, designed for high-fidelity home audio and studio monitoring applications. The driver features an anodized aluminum cone for high rigidity and low mechanical losses, paired with a natural rubber surround and Nomex spider. The ferrite-based magnetic circuit integrates two aluminum demodulation rings to minimize inductance modulation and reduce distortion under large-excursion drive conditions. The exceptionally high Qms (13.72) indicates a near-lossless suspension system in which the amplifier and enclosure provide essentially all system damping \u2014 a characteristic of precision hi-fi subwoofer design optimized for pitch accuracy and transient clarity.\n\nIn bass reflex enclosures, the driver performs best in net internal volumes of 30 to 60 liters, tuned between 22 and 28 Hz, with an estimated -3 dB frequency of approximately 22 to 28 Hz. Due to the very low free-air resonance (25 Hz), the compact (30L) alignment produces a port tube length exceeding 550 mm; a passive radiator is strongly recommended for that configuration. Alignments of 45 and 60 liters use practical 75 mm round ports of 433 and 453 mm respectively, with port velocities below 15 m\/s consistent with hi-fi quality standards. Sealed enclosures in the 10 to 25 liter range deliver Qtc values of 0.71 to 1.00 with a passive -3 dB between 45 and 50 Hz, well suited to active DSP correction extending system response to approximately 25 Hz.\n\nThe driver is designed for use with amplification of approx. 200 W AES (400 W continuous) into 4 ohms, with a high-pass filter recommended in the 18\u201322 Hz range for vented systems. DSP-corrected sealed systems should implement a Linkwitz Transform targeting fc = 25 Hz and Qtc = 0.707, with excursion limiting below 25 Hz. The 12.15 mm Xmax provides mechanical headroom sufficient for the boost required. The 4-ohm impedance is well suited to high-current solid-state amplification and bridged amplifier configurations.\n\nThe 10FHWX4-117 is intended for single-driver hi-fi subwoofer enclosures, 2.1 and multi-channel home theater systems, active studio monitor subwoofer sections, and audiophile-grade loudspeaker systems where the aluminum cone's rigidity, the near-lossless suspension, and the low-distortion magnetic circuit provide accurate and extended low-frequency reproduction.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 10FHWX4-117\nDriver: 10FHWX4-117 (10FHW) \u2014 10\" hi-fi subwoofer, 4 ohm\nKey T\/S: Fs=25.0Hz, Qts=0.39, Qes=0.40, Qms=13.72, Vas=57.9L, Sens=86.5dB\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=12.15mm, Xmech=20.15mm, Sd=330.1cm\u00b2, Bl=12.7T\u00b7m\nLe=0.62mH | Two aluminum demodulation rings\n\nDESIGN HIGHLIGHTS:\n - Anodized aluminum cone \u2014 high rigidity, low mass-to-stiffness ratio,\n extended pistonic range, clean and precise bass reproduction\n - Very high Qms (13.72) \u2014 exceptionally low mechanical losses; the\n suspension (rubber surround + Nomex spider) contributes virtually\n no damping. Electrical damping (Qes=0.40) dominates entirely.\n This is a characteristic of precision hi-fi subwoofer design:\n the amplifier and enclosure provide all the system damping.\n - Two aluminum demodulation rings integrated into the magnetic circuit\n \u2014 reduce inductance modulation and flux compression under drive,\n lowering distortion especially at large excursion\n - Glass fiber voice coil former (50.8mm) \u2014 improved thermal stability\n over paper, handles sustained 400W continuous\n\nRECOMMENDED ENCLOSURE TYPES:\n PRIMARY: Bass Reflex (Vented) \u2014 Qts=0.39, Qms=13.72; near-optimal\n vented range with excellent motor control\n SECONDARY: Sealed (Acoustic Suspension) \u2014 for DSP\/active systems with\n Linkwitz Transform; also viable passively in near-Butterworth\n alignment (25L, Qtc=0.707) for system integration\nVENTED ALIGNMENTS (Primary)\nPort: 75mm diameter round, flared both ends\nVd = 330.1 cm\u00b2 \u00d7 12.15mm = 401.1 cm\u00b3\n\nNOTE: The very low Fs (25 Hz) combined with small-to-mid box volumes\nproduces long port tube lengths. A passive radiator is the preferred\nsolution for alignment (a); alignments (b) and (c) use practical\nport lengths.\n\n a) Compact Deep Bass\n Net Volume: 30 liters\n Tuning (Fb): 28 Hz\n Est. -3dB: ~28 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 560mm long [impractical \u2014 see note below]\n Passive Radiator (strongly recommended): Sd \u2265 330cm\u00b2, mmd \u2248 95g\n tuned to 28 Hz (add tungsten or lead putty mass to PR if needed)\n Port Velocity (if ported): 16.0 m\/s \u2713\n Notes: Despite the acceptable port velocity, a 560mm tube does not\n fit practically inside a 30L cabinet without folding. A PR\n eliminates this constraint, reduces cabinet complexity, and\n maintains full tuning accuracy. Compact footprint ideal\n for bookshelf-integrated or under-furniture placement.\n\n b) Balanced Response\n Net Volume: 45 liters\n Tuning (Fb): 26 Hz\n Est. -3dB: ~26 Hz\n HP Filter: 20 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 433mm long\n Port Velocity: 14.8 m\/s \u2713\n Notes: Optimal balance of extension, output, and enclosure size.\n Recommended general-purpose hi-fi sub alignment. Port length\n is practical. Suits standalone subwoofer cabinets for 2.1\n and multi-channel systems.\n\n c) Extended Deep Bass\n Net Volume: 60 liters\n Tuning (Fb): 22 Hz\n Est. -3dB: ~22 Hz\n HP Filter: 18 Hz (24dB\/oct recommended)\n Port: 75mm dia \u00d7 453mm long\n Port Velocity: 12.5 m\/s \u2713 (very low \u2014 excellent for hi-fi)\n Notes: Reference-level deep bass extension. Low port velocity\n minimizes turbulence noise \u2014 this is the quietest alignment\n at maximum output, ideal for critical and studio listening.\n Well suited for floorstanding enclosure integration.\nSEALED ALIGNMENTS (Secondary \u2014 Active \/ DSP Systems)\nThe very high Qms (13.72) makes sealed enclosures particularly\neffective: the amplifier provides all system damping, which is ideal\nfor DSP-managed amplifiers with adjustable damping factor. The aluminum\ncone's high rigidity ensures clean transient reproduction in sealed\nsystems without port-phase artifacts.\n\n d) Compact Sealed (10 liters)\n Qtc: 1.00\n fc: 64 Hz\n Est. -3dB (passive): ~50 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: Smallest practical sealed alignment. Requires DSP correction\n for subwoofer use. Xmax of 12.15mm provides ample headroom\n for the bass boost below fc.\n\n e) Balanced Sealed (15 liters)\n Qtc: 0.85\n fc: 55 Hz\n Est. -3dB (passive): ~47 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: Well-damped sealed response. Good integration platform for\n 2.1 systems with a sub-satellite crossover at 80\u2013100 Hz.\n\n f) Butterworth Sealed (25 liters)\n Qtc: 0.707\n fc: 45 Hz\n Est. -3dB (passive): ~45 Hz\n Est. -3dB (with Linkwitz Transform to 0.707\/25Hz): ~25 Hz\n Notes: Maximally flat passive alignment \u2014 no eq required from\n fc upward. Useful in passive 2-way systems with sub crossed\n below 80 Hz. DSP correction extends the bottom octave.\n This alignment combined with room gain (~+4dB below 50Hz)\n gives effective flat-to-room response to ~20 Hz.\n\nROOM GAIN NOTE:\nIn typical domestic rooms, boundary reinforcement provides +3\u20136 dB\nbelow 50\u201360 Hz, effectively extending in-room bass response by roughly\none octave. Alignment (f) passive + room gain approximates an anechoic\n-3dB of ~20 Hz in most rooms \u2014 without any DSP bass correction.\nAPPLICATION SUMMARY\n - Hi-fi 2.1 and multi-channel home theater subwoofer\n - Studio monitoring with active sub-bass management\n - Audiophile subwoofer enclosures (standalone or integrated)\n - DSP-managed active systems (sealed preferred for phase alignment)\n - Passive 2-way sub configurations in larger floorstanding systems\n - 4-ohm impedance suits high-current amplifiers; parallel wiring of\n two drivers (4+4=2\u03a9) for amplifiers rated into 2 ohm"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/10FHW-117-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/101FHW-118-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/10FHWX4-117-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FHW-117-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/10FHW-117-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FHW-117-3D.STEP"}},{"code":"Twiggy10X8-475A","name":"Twiggy10","slug":"twiggy10x8-475a","description":"Slim Sub\/0inch\/Ferrite\/Honeycomb\/8ohm","url":"https:\/\/redcatt.net\/products\/twiggy10x8-475a","category":"LF","type":"Sub-woofer","size_inches":10,"is_featured":true,"general":{"nominal_impedance":"4","magnet":"Neodymium","basket_material":"Steel"},"power_handling":{"aes_watts":"150","continuous_watts":"300","peak_watts":"600"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"kapton","winding_height":"28.12"},"thiele_small_parameters":{"fs_hz":40.7,"re_ohm":3.5,"qes":0.33,"qms":16.61,"qts":0.33,"vas_liters":14.57,"sd_cm2":305.42,"sensitivity_db":87,"mms_grams":138.3,"rms":2.1,"cms":0.11,"bl_tm":19.24,"le_mh":0.9},"physical":{"overall_diameter_mm":264,"bolt_circle_diameter_mm":246,"baffle_cutout_diameter_mm":224,"mounting_holes":"8","depth_mm":80,"net_weight_kg":null,"xmax_mm":"10.06","xmech_mm":"18.06"},"materials":{"surround":"NBR","cone_dome":"GF Honey Comb","spider":"Nomex"},"content":{"key_features":["Ultra-Shallow Design","Composite, honeycomb structure cone","High Motor Strength & Precision Control"],"design_notes":"Twiggy 10 brings the proven Twiggy concept into a compact 10-inch platform \u2014 engineered for applications where mounting depth is limited but performance cannot be compromised.\nDesigned around an extended voice coil architecture and optimized motor structure, Twiggy 10 delivers exceptional linear excursion while maintaining shallow installation depth. The result is powerful, controlled low-frequency output from compact enclosures.\nWith strong motor force (high Bl), low distortion behavior and carefully balanced suspension compliance, Twiggy 10 provides fast transient response, impressive punch, and extended bandwidth for modern slim-profile systems. Ideal for: Slim subwoofers, Shallow line arrays, Compact high-output installations, Space-restricted portable systems.","hero_text":"Maximum excursion. Minimal depth. Serious low-frequency performance.","ai_summary":"The Twiggy10X8-475A is a 10-inch ultra-shallow subwoofer driver designed for space-restricted applications where conventional driver mounting depth is prohibitive. With a mounting depth of only 80 mm \u2014 roughly half that of a conventional 10-inch woofer \u2014 the driver fits under sofas, behind wall panels, beneath car seats, and inside slim furniture-integrated audio systems. It achieves 10.06 mm of linear excursion (18.06 mm mechanical) through an extended voice coil architecture featuring a 2-inch CCAW voice coil on a Kapton former with a 28.12 mm winding height and a neodymium motor with Bl of 19.24 T\u00b7m. The glass fiber honeycomb composite cone provides a stiff, lightweight radiating surface, and the rubber surround and Nomex spider support the full excursion range with controlled linearity. Volume displacement is 307 cc, providing substantial low-frequency output capability despite the shallow profile.\nIn sealed enclosures, the driver's low Qts of 0.33 produces remarkably compact alignments. For under-sofa and hidden installations, net internal volumes of 1.8 to 2.6 liters (Qtc 0.85\u20131.0) produce system resonances of 105\u2013123 Hz, with boundary reinforcement from floor and wall proximity extending effective in-room bass to 45\u201360 Hz. For automotive shallow-mount applications, 2.6 to 4.1 liters (Qtc 0.707\u20130.85) provide Butterworth-class to slightly warm response, with vehicle cabin gain extending effective in-cabin response to 28\u201340 Hz. For in-wall installations, a 4 to 6 liter sealed back-box provides Butterworth to overdamped response (Qtc 0.6\u20130.707) with half-space wall loading. For free-standing hi-fi subwoofers, 6 to 10 liters (Qtc 0.5\u20130.6) provide deeper anechoic extension to 64\u201374 Hz with in-room response to 40\u201354 Hz, all from a cabinet only approximately 125 mm (5 inches) deep.\nFor applications requiring deeper anechoic extension, vented or passive radiator configurations in 12 to 17 liters tuned between 34 and 45 Hz extend the -3 dB point to 29\u201341 Hz. Port lengths exceed 500 mm at these tuning frequencies, making folded slot ports or passive radiators the practical implementation. A passive radiator of matching shallow profile and excursion capability is the preferred solution, enabling a slim panel subwoofer approximately 125 mm deep with genuine deep bass extension to the low 30s Hz. The driver is rated for 150 W AES \/ 300 W continuous power handling at 4-ohm nominal impedance.\nThis driver is particularly effective in under-sofa and furniture-hidden subwoofers, automotive shallow-mount installations, in-wall and in-ceiling distributed bass systems, slim panel subwoofers for modern living spaces, and shallow line array bass sections. The ultra-shallow mounting depth, high motor force, extended voice coil excursion, and honeycomb composite cone construction enable deep, controlled bass reproduction from enclosures and installation spaces that cannot accommodate conventional subwoofer drivers.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: Twiggy10X8-475A\nDriver: Twiggy10X8-475A (Twiggy10) \u2014 10\" Ultra-Shallow Subwoofer\nKey T\/S: Fs=40.7Hz, Qts=0.33, Vas=14.57L, Sens=87dB 1W\/1m\nPower: AES 150W \/ Cont 300W \/ Peak 600W\nXmax=10.06mm (one-way linear), Xmech=18.06mm\nSd=305.4cm\u00b2, Bl=19.24T\u00b7m, Re=3.5\u03a9 (4-ohm nominal), Mms=138.3g\nVoice Coil: 2\" CCAW on Kapton former (28.12mm extended winding height)\nMagnet: Neodymium (inside slug) | Basket: Steel\nCone: Glass fiber honeycomb composite | Surround: Rubber\nSpider: Nomex\nMOUNTING DEPTH: 80 mm\nVolume Displacement (Vd): 307 cc\nNOTE: The Twiggy10 brings the proven Twiggy ultra-shallow concept to\na 10-inch platform. The extended voice coil architecture (28.12 mm\nwinding height) delivers exceptional linear excursion (10.06 mm) from\na driver only 80 mm deep \u2014 roughly half the mounting depth of a\nconventional 10\" woofer. The low Qts (0.33) and strong neodymium\nmotor (Bl=19.24 T\u00b7m) combined with the glass fiber honeycomb cone\nprovide controlled, low-distortion bass from extremely compact and\nshallow enclosures. This driver is uniquely suited to space-restricted\napplications: under-sofa subwoofers, in-wall\/in-ceiling systems,\nautomotive installations, slim furniture-integrated audio, and\nshallow line array bass sections, as well as conventional compact\nhi-fi subwoofers where the shallow depth enables creative form factors.\nCABINET DEPTH REFERENCE:\n Driver mounting depth: 80 mm\n Minimum internal depth: ~95 mm (driver + rear clearance)\n With 15 mm walls: ~125 mm total external depth (~5\")\nThis means a complete subwoofer cabinet can be built under 13 cm\n(5 inches) deep \u2014 thin enough to slide under most sofas, mount\nflush in a standard wall cavity, or fit under a car seat.\n SEALED ENCLOSURES \u2014 BY APPLICATION\nThe low Qts (0.33) produces remarkably compact sealed volumes for a\n10\" driver. Room gain and boundary reinforcement play a major role\nin all shallow-mount applications, so estimated in-room response\nis provided for each alignment.\n UNDER-SOFA \/ FURNITURE-INTEGRATED\nThese alignments prioritize extreme compactness. The elevated Qtc\nvalues are intentional \u2014 placement under a sofa or against a wall\nprovides substantial boundary reinforcement (+6\u201310 dB below 80 Hz)\nthat compensates for the high fc and produces satisfying in-room\nbass extension.\n a) SEALED \u2014 Ultra-Compact (Qtc \u2248 1.0)\n Net Volume: 1.8 liters\n System Resonance (fc): 123 Hz\n Qtc: 1.0\n Anechoic -3dB: ~123 Hz\n Estimated in-room -3dB: ~50\u201360 Hz (under-sofa placement)\n Cabinet face (at 95mm depth): ~14 \u00d7 14 cm (tiny!)\n Notes: The smallest practical sealed enclosure for the\n Twiggy10. The high fc (123 Hz) looks alarming in anechoic\n terms, but under-sofa and against-wall placement provides\n massive boundary reinforcement. Combined with DSP bass EQ\n (shelving boost below 100 Hz), this configuration produces\n surprisingly deep and satisfying bass from an enclosure\n barely larger than the driver itself. The broad resonance\n peak at fc provides a natural bass lift that works with,\n rather than against, the room acoustics. Ideal for hidden\n subwoofers where invisibility is the primary requirement.\n b) SEALED \u2014 Compact (Qtc \u2248 0.85)\n Net Volume: 2.6 liters\n System Resonance (fc): 105 Hz\n Qtc: 0.85\n Anechoic -3dB: ~105 Hz\n Estimated in-room -3dB: ~45\u201355 Hz (under-sofa placement)\n Cabinet face (at 95mm depth): ~17 \u00d7 17 cm\n Notes: Slightly larger than ultra-compact but still very\n small. The Qtc of 0.85 provides a smooth, warm response\n with less peaking than Qtc=1.0. Under-sofa placement extends\n effective bass well below 60 Hz. A good balance between\n compactness and response quality for hidden subwoofers.\n *** RECOMMENDED FOR UNDER-SOFA \/ HIDDEN INSTALLATIONS ***\n AUTOMOTIVE \/ SHALLOW-MOUNT\nThese alignments are sized for under-seat, door panel, or shallow\ntrunk installations where the 80 mm driver depth is a critical\nadvantage. Vehicle cabin gain provides +10\u201315 dB of reinforcement\nbelow 60 Hz.\n c) SEALED \u2014 Automotive Compact (Qtc \u2248 0.85)\n Net Volume: 2.6 liters\n System Resonance (fc): 105 Hz\n Qtc: 0.85\n Estimated in-cabin -3dB: ~35\u201340 Hz (with cabin gain)\n Notes: Extremely compact sealed enclosure for under-seat\n installation. The vehicle cabin's massive acoustic gain\n at low frequencies transforms the 105 Hz anechoic fc into\n effective in-cabin response well below 40 Hz. The Twiggy10's\n 80 mm depth fits under most vehicle seats with clearance\n to spare. The 4-ohm impedance is standard for automotive\n amplifiers.\n d) SEALED \u2014 Automotive Standard (Qtc \u2248 0.707)\n Net Volume: 4.1 liters\n System Resonance (fc): 87 Hz\n Qtc: 0.707\n Estimated in-cabin -3dB: ~28\u201335 Hz (with cabin gain)\n Notes: Butterworth alignment providing flat anechoic response.\n With cabin gain, in-car bass extends into the upper 20s Hz \u2014\n genuine infrasonic territory from a shallow-mount 10\". A\n 4.1-liter enclosure at 95 mm depth requires a face of only\n ~21 \u00d7 21 cm, easily fitting behind a rear seat panel or in\n a shallow trunk enclosure.\n *** RECOMMENDED FOR AUTOMOTIVE ***\n IN-WALL \/ IN-CEILING\nStandard wall cavities (89\u2013140 mm depth for 2\u00d74 and 2\u00d76 framing)\neasily accommodate the Twiggy10's 80 mm mounting depth. The wall\ncavity itself forms part of the sealed enclosure volume, though\nback-box isolation is recommended for consistent performance.\n e) SEALED \u2014 In-Wall Standard (Qtc \u2248 0.707)\n Net Volume: 4 liters (sealed back-box)\n System Resonance (fc): 87 Hz\n Qtc: 0.707\n Estimated in-room -3dB: ~50\u201358 Hz (flush wall mount)\n Notes: A sealed back-box of approximately 4 liters behind\n the driver provides Butterworth-class response. The flush\n wall mount provides half-space loading (+3 dB sensitivity\n boost) and boundary reinforcement. Well-suited for\n distributed in-wall subwoofer systems where multiple\n Twiggy10 units supplement in-wall\/in-ceiling full-range\n speakers.\n f) SEALED \u2014 In-Wall Extended (Qtc \u2248 0.6)\n Net Volume: 6 liters (sealed back-box)\n System Resonance (fc): 74 Hz\n Qtc: 0.60\n Estimated in-room -3dB: ~42\u201350 Hz (flush wall mount)\n Notes: Larger back-box providing deeper bass extension.\n The overdamped response rolls off gradually, integrating\n smoothly with room acoustics. Well-suited for dedicated\n home theater in-wall subwoofer installations where deeper\n bass is required from a single driver location.\n STANDARD HI-FI SUBWOOFER\nFor conventional free-standing subwoofer cabinets where the shallow\ndepth enables slim, furniture-friendly form factors (e.g., a\nsubwoofer that stands upright like a thin panel or slides into a\nbookshelf space).\n g) SEALED \u2014 Butterworth (Qtc \u2248 0.707)\n Net Volume: 4 liters\n System Resonance (fc): 87 Hz\n Qtc: 0.707\n Anechoic -3dB: ~87 Hz\n Estimated in-room -3dB: ~55\u201362 Hz (corner or near-wall)\n Cabinet (at 95mm depth): ~21 \u00d7 21 cm face, 12.5 cm deep\n Notes: Maximally flat sealed alignment. Room gain extends\n usable bass into the upper 50s Hz. A very slim, compact\n subwoofer that can stand upright beside furniture or mount\n on a wall. The Twiggy10's 307 cc displacement provides\n meaningful output at these frequencies.\n h) SEALED \u2014 Extended (Qtc \u2248 0.6)\n Net Volume: 6 liters\n System Resonance (fc): 74 Hz\n Qtc: 0.60\n Anechoic -3dB: ~74 Hz\n Estimated in-room -3dB: ~46\u201354 Hz (corner or near-wall)\n Cabinet (at 95mm depth): ~25 \u00d7 25 cm face, 12.5 cm deep\n Notes: Larger sealed enclosure with better bass extension.\n The overdamped alignment integrates well with room acoustics\n for natural-sounding bass. Still a very slim form factor.\n *** RECOMMENDED FOR FREE-STANDING HI-FI SUB ***\n i) SEALED \u2014 Large (Qtc \u2248 0.5)\n Net Volume: 10 liters\n System Resonance (fc): 64 Hz\n Qtc: 0.50\n Anechoic -3dB: ~64 Hz\n Estimated in-room -3dB: ~40\u201348 Hz (corner or near-wall)\n Cabinet (at 95mm depth): ~32 \u00d7 32 cm face, 12.5 cm deep\n Notes: Largest practical sealed alignment. Deep bass\n extension with heavily overdamped response. In-room with\n corner placement, usable response approaches 40 Hz \u2014\n genuine subwoofer territory from a slim cabinet only\n 12.5 cm deep.\n VENTED \/ PASSIVE RADIATOR ENCLOSURES\nVented enclosures extend the low-frequency response significantly\nbeyond what sealed can achieve. However, the shallow cabinet depth\nmakes conventional round ports impractical (port lengths of 500\u2013\n630 mm are required). Two practical solutions are provided:\nfolded slot ports and passive radiators.\nPORT NOTE: Round port lengths exceed 500 mm at all tuning frequencies,\nwhich is impractical for shallow cabinets. Slot ports (200 \u00d7 30 mm\ncross-section) can be folded internally within the shallow cabinet\ngeometry. Passive radiators eliminate the port entirely and are the\npreferred solution for shallow-mount vented enclosures.\n j) VENTED \u2014 Compact\n Net Volume: 12 liters\n Tuning (Fb): 45 Hz\n Est. -3dB: 41 Hz\n HP Filter: 35 Hz (24dB\/oct recommended)\n Slot Port (200\u00d730mm): ~672mm long (folded internally)\n Port Velocity (slot): 14.5 m\/s\n Cabinet (at 95mm depth): ~36 \u00d7 36 cm face, 12.5 cm deep\n Notes: Compact vented alignment reaching into the low\n 40s Hz anechoic. With room gain, in-room response extends\n below 30 Hz. Requires folded slot port or passive radiator.\n k) VENTED \u2014 Balanced\n Net Volume: 14 liters\n Tuning (Fb): 40 Hz\n Est. -3dB: 34 Hz\n HP Filter: 30 Hz (24dB\/oct recommended)\n Slot Port (200\u00d730mm): ~734mm long (folded internally)\n Port Velocity (slot): 12.9 m\/s\n Cabinet (at 95mm depth): ~38 \u00d7 38 cm face, 12.5 cm deep\n Notes: Excellent balance of extension and cabinet size.\n Anechoic -3 dB at 34 Hz is genuine deep bass from a slim\n panel cabinet. With room gain, usable response approaches\n the mid-20s Hz.\n *** RECOMMENDED VENTED ALIGNMENT ***\n l) VENTED \u2014 Extended\n Net Volume: 17 liters\n Tuning (Fb): 34 Hz\n Est. -3dB: 29 Hz\n HP Filter: 24 Hz (24dB\/oct recommended)\n Slot Port (200\u00d730mm): ~846mm long (folded internally)\n Port Velocity (slot): 10.9 m\/s\n Cabinet (at 95mm depth): ~42 \u00d7 42 cm face, 12.5 cm deep\n Notes: Maximum extension, reaching below 30 Hz anechoic.\n Largest cabinet but still only 12.5 cm deep. Requires the\n longest folded port path \u2014 a passive radiator is strongly\n recommended for this alignment.\nPASSIVE RADIATOR NOTE:\nA passive radiator (PR) is the ideal partner for the Twiggy10 in\nvented applications, especially in shallow enclosures where port\nlength is impractical. A matching shallow-profile 10\" PR should have:\n - Sd approximately equal to the active driver (~305 cm\u00b2)\n - Mounting depth compatible with the shallow cabinet (~80 mm)\n - Tuning mass selected for the desired Fb (34\u201345 Hz)\n - Xmax equal to or greater than the active driver (\u226510 mm)\nA Twiggy10 + matching PR in a 12\u201317 liter shallow enclosure produces\na slim panel subwoofer (~12.5 cm deep) with genuine deep bass\nextension to the low 30s Hz \u2014 a compelling product for modern\nliving spaces.\nMULTI-DRIVER NOTE: The shallow form factor and compact sealed\nvolumes make it practical to use multiple Twiggy10 drivers in a\nsingle shallow enclosure. Two Twiggy10 units in a 6\u20138 liter sealed\nenclosure (3\u20134L per driver) produce +6 dB more output than a single\ndriver while maintaining the ultra-slim cabinet profile. This\ndistributed approach is particularly effective for in-wall systems\nand slim soundbar-style subwoofers."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/Twiggy10-475A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/Twiggy10-475A-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/Twiggy10X4-475A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/Twiggy10X4-475A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/Twiggy10X4-475A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/Twiggy10X4-475A-3D.STEP"}},{"code":"101NPMX8-119","name":"101NPM","slug":"101npmx8-119","description":"Mid-woofer\/10inch\/Neo\/Paper\/150W\/8ohm","url":"https:\/\/redcatt.net\/products\/101npmx8-119","category":"LF","type":"Mid-Woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"150","continuous_watts":"300","peak_watts":"600"},"voice_coil":{"diameter":"50.8","wire":"CCAR","former":"Glass Fiber","winding_height":"14.5"},"thiele_small_parameters":{"fs_hz":53,"re_ohm":5,"qes":0.61,"qms":5.51,"qts":0.55,"vas_liters":49.7,"sd_cm2":363,"sensitivity_db":94.56,"mms_grams":32.6,"rms":1.97,"cms":0.28,"bl_tm":9.6,"le_mh":0.53},"physical":{"overall_diameter_mm":262,"bolt_circle_diameter_mm":246,"baffle_cutout_diameter_mm":230,"mounting_holes":"8","depth_mm":111.5,"net_weight_kg":1.97,"xmax_mm":"3.25","xmech_mm":"11.25"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Ultra lightweight, designed for portable products","High efficiency, low harmonic distortion","Carbon fiber loaded paper cone"],"design_notes":"The 101NPM is a high efficiency, (95 dB 1watt \/ 1 meter) 10-inch mid-woofer with incredibly linear frequency response characteristics, high power handling capability, while generating ultra low harmonic distortion artifacts. The 101NPM uses a lightweight glass fiber loaded cone assembly along with a high excursion triple roll surround. This combination provides a lightweight, yet strong, piston, high efficiency and a peak to peak maximum excursion of 13.6.\n\nMagnetic Circuit\nREDCATT engineers have developed a ultra lightweight, inside neodymium slug based magnetic circuit, capable of delivering the highest level of performance, providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic structure has integrated two aluminum shorting rings. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"The 101NPMX8-119 is a 10-inch high-efficiency neodymium mid-woofer designed for lightweight, portable professional loudspeaker systems where minimum weight and maximum sensitivity are critical design parameters. It features a 2-inch CCAR (copper clad aluminum round wire) voice coil on a glass fiber former, a carbon fiber loaded paper cone with a triple roll fabric surround, and an inside neodymium slug motor with 2 aluminum shorting rings for minimized flux modulation and very low harmonic distortion. At 95 dB sensitivity (1W\/1m) with an exceptionally light moving mass of 32.6 grams \u2014 roughly half that of a typical professional 10-inch woofer \u2014 the driver achieves its high output through efficiency rather than excursion, making it ideal for portable systems where amplifier power and cabinet weight must be minimized.\nIn bass reflex enclosures, recommended net internal volumes range from 23 to 32 liters with tuning frequencies between 50 and 61 Hz. Smaller volumes (23\u201327 liters tuned to 56\u201361 Hz) maximize mid-bass output and minimize cabinet size and weight for portable 2-way tops and stage monitors, while 32 liters tuned to 50 Hz extends the usable low-frequency response to approximately 42 Hz (\u20133 dB) for stand-alone applications without dedicated subwoofers. Port velocities are negligible across all alignments (8\u201310 m\/s with a 76 mm round port) and port lengths are short (~100 mm), making port design completely uncritical. In sealed enclosures, the driver's Qts of 0.55 produces practical alignments at 22 to 50 liters with system resonances between 75 and 96 Hz. A 22-liter sealed enclosure (Qtc 1.0, fc 96 Hz) provides a compact mid-bass module for multi-way systems with subwoofer support, while larger sealed volumes extend the response for moderate stand-alone use.\nThe driver is rated for approximately 150 W AES \/ 300 W continuous power handling and is intended for use with DSP-controlled amplification. A high-pass filter in the range of 40\u201351 Hz (24 dB\/octave Linkwitz-Riley) is recommended for vented alignments depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.5\u20133 kHz. The modest linear excursion (3.25 mm) reflects the efficiency-first design approach \u2014 the driver's 95 dB sensitivity delivers high SPL from moderate amplifier power, with the triple roll surround providing controlled mechanical excursion to 13.6 mm peak-to-peak for transient headroom.\nThis driver is particularly effective in lightweight portable 2-way and multi-way PA tops, stage monitors, column speakers, and installation systems where system weight, high sensitivity, and low distortion are priorities. The inside neodymium slug motor, carbon fiber loaded paper cone, aluminum basket, and triple roll surround provide a lightweight, durable package suited to demanding portable and touring applications where equipment must be carried, rigged, and transported frequently.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 101NPMX8-119\nDriver: 101NPMX8-119 (101NPM) \u2014 10\" Mid-Woofer\nKey T\/S: Fs=53Hz, Qts=0.55, Vas=49.7L, Sens=95dB 1W\/1m\nPower: AES 150W \/ Cont 300W \/ Peak 600W\nXmax=3.25mm (one-way linear), Xmech=11.25mm (protection at 13.6mm p-p)\nSd=363cm\u00b2, Bl=9.6T\u00b7m, Re=5\u03a9, Mms=32.6g (exceptionally light for 10\")\nVoice Coil: 2\" CCAR (copper clad aluminum round wire) on glass fiber former\n(14.5mm winding height)\nMagnet: Neodymium (inside slug) with 2 aluminum shorting rings\nCone: Carbon fiber loaded paper pulp | Surround: Fabric (triple roll)\nSpider: Nomex | Basket: Aluminum\nNOTE: This driver is engineered specifically for lightweight, portable\nprofessional loudspeaker products. The combination of an inside\nneodymium slug motor, carbon fiber loaded paper cone, and exceptionally\nlow moving mass (32.6g for a 10\" \u2014 roughly half the mass of a typical\nprofessional 10\" woofer) produces a very high sensitivity (95 dB)\nmid-woofer that gets loud with minimal amplifier power. The 2 aluminum\nshorting rings in the neodymium motor minimize flux modulation for very\nlow harmonic distortion. The triple roll fabric surround provides\ncontrolled long-excursion behavior (13.6 mm peak-to-peak mechanical)\nwhile maintaining the lightweight design ethos. Vented enclosures in\nthe 23\u201332 liter range are the optimal configuration.\n PRIMARY \u2014 Bass Reflex (Vented)\nUse case: Portable 2-way and multi-way PA tops, stage monitors,\nlightweight installation systems, and column speakers where the\n101NPM handles the low-frequency and lower-midrange content,\ntypically crossed over to a compression driver or tweeter at\n1.5\u20133 kHz. The lightweight motor and cone assembly make this\ndriver ideal for systems where total cabinet weight is a critical\ndesign parameter.\nPORT RECOMMENDATION: Round port (76mm diameter) \u2014 standard for 10\"\nbass reflex enclosures. Port velocities are very low across all\nalignments (8\u201310 m\/s) and port lengths are short (~100 mm), making\nport design completely uncritical. A simple straight 76mm tube is\nmore than adequate. No flaring required.\n a) VENTED \u2014 High SPL\n Net Volume: 23 liters\n Tuning (Fb): 61 Hz\n Est. -3dB: 56 Hz\n HP Filter: 51 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 102mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 143mm L\n Port Velocity: 10.0 m\/s\n Notes: Most compact vented alignment, optimized for maximum\n output per unit volume and minimum cabinet weight. Higher\n tuning provides punchy, controlled mid-bass with excellent\n transient response. Ideal for lightweight portable 2-way\n tops and stage monitors paired with subwoofers, where the\n 95 dB sensitivity maximizes system headroom. A 23-liter\n cabinet with this driver and a neodymium compression driver\n produces an exceptionally lightweight, high-output system.\n b) VENTED \u2014 Balanced Response\n Net Volume: 27 liters\n Tuning (Fb): 56 Hz\n Est. -3dB: 52 Hz\n HP Filter: 46 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 104mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 146mm L\n Port Velocity: 9.2 m\/s\n Notes: General-purpose alignment with even response through\n the bass region. Good balance between low-frequency extension,\n cabinet size, and weight. Well-suited for most portable PA\n tops, multi-way systems, and lightweight installation\n loudspeakers. Provides moderate stand-alone bass capability\n when subwoofer support is intermittent.\n c) VENTED \u2014 Extended Low Frequency\n Net Volume: 32 liters\n Tuning (Fb): 50 Hz\n Est. -3dB: 42 Hz\n HP Filter: 40 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 113mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 158mm L\n Port Velocity: 8.2 m\/s\n Notes: Maximum low-frequency extension for stand-alone use\n without subwoofers. Reaches into the low 40s Hz, providing\n substantial bass from a lightweight 10\" system. The larger\n cabinet is still very manageable for portable applications\n given the lightweight neodymium motor. Best for applications\n where full-range bass coverage is needed from a single\n cabinet (e.g., portable entertainment, corporate events,\n smaller live venues).\nWEIGHT ADVANTAGE: A typical professional 10\" mid-woofer with ferrite\nmotor weighs 3\u20135 kg. This driver's inside neodymium slug motor,\ncarbon fiber loaded cone, and aluminum basket keep the total driver\nweight to a minimum. Combined with lightweight enclosure materials\n(plywood or composite), the complete system weight is significantly\nbelow comparable ferrite-based designs.\n ALTERNATIVE \u2014 Sealed Enclosures (Compact Portable)\nSealed enclosures are viable where the driver is used as a mid-bass\nin a multi-way system with a dedicated subwoofer handling the deep\nbass. The higher Qts (0.55) means sealed Butterworth requires a very\nlarge box (76L), so practical sealed volumes produce elevated Qtc\nvalues. This is acceptable when the driver operates above 80\u2013100 Hz\nwith active crossover filtering.\n d) SEALED \u2014 Ultra-Compact (Qtc \u2248 1.0)\n Net Volume: 22 liters\n System Resonance (fc): 96 Hz\n Qtc: 1.0\n HP Crossover: 100\u2013150 Hz (24dB\/oct LR recommended)\n Notes: Very compact sealed alignment for mid-bass use in\n multi-way systems. The fc of 96 Hz means this configuration\n is NOT suitable for stand-alone bass reproduction \u2014 it\n requires a dedicated subwoofer. However, for a crossed-over\n mid-bass driver in a 3-way or 4-way system, the compact\n cabinet and high sensitivity make this an efficient choice.\n The broad resonance peak at fc can be equalized flat with\n minimal DSP effort.\n e) SEALED \u2014 Compact (Qtc \u2248 0.85)\n Net Volume: 36 liters\n System Resonance (fc): 82 Hz\n Qtc: 0.85\n HP Crossover: 80\u2013120 Hz (24dB\/oct LR recommended)\n Notes: Larger sealed enclosure with more useful bass\n extension. The fc of 82 Hz provides some stand-alone bass\n capability in smaller rooms, with room gain extending usable\n response into the 60s Hz. A practical option for portable\n systems where sealed construction simplicity and controlled\n rolloff are preferred over vented bass extension.\n f) SEALED \u2014 Moderate (Qtc \u2248 0.78)\n Net Volume: 50 liters\n System Resonance (fc): 75 Hz\n Qtc: 0.78\n HP Crossover: 70\u2013100 Hz (24dB\/oct LR recommended)\n Notes: Largest practical sealed alignment. Provides near-flat\n response with good bass extension. The 50-liter cabinet is\n substantial for a portable product, so this alignment is\n better suited to semi-permanent installation or larger\n portable systems where deep sealed bass is a priority over\n cabinet compactness.\nSEALED NOTE: For this driver's Qts of 0.55, vented enclosures\nprovide significantly better bass extension in smaller cabinet\nvolumes. Sealed enclosures are recommended only when the simpler\nconstruction, absence of port artifacts, or specific mid-bass\ncrossover integration are design priorities.\nEXCURSION NOTE: The linear Xmax of 3.25 mm is modest for a 10\",\nreflecting the efficiency-first design philosophy. The driver\nproduces high SPL from its sensitivity (95 dB) rather than from\nexcursion-limited brute force. The triple roll surround provides\ncontrolled mechanical excursion to 13.6 mm peak-to-peak for\ntransient peaks well beyond the linear range. In systems requiring\nhigh output below 60 Hz, dedicated subwoofers should supplement\nthis driver."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/101NPM-119-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/101NPM-119-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/101NPM-119-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/101NPM-119-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/101NPM-119-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/101NPM-119-3D.STEP"}},{"code":"103FINDX8-583B","name":"103FIND","slug":"103findx8-583b","description":"Woofer\/10inch\/Ferrite\/Paper\/250W\/8ohm","url":"https:\/\/redcatt.net\/products\/103findx8-583b","category":"LF","type":"Mid-Woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"250","continuous_watts":"500","peak_watts":"1000"},"voice_coil":{"diameter":"63.5","wire":"Copper","former":"TIL","winding_height":"16.1"},"thiele_small_parameters":{"fs_hz":56.2,"re_ohm":7.2,"qes":0.32,"qms":3.66,"qts":0.29,"vas_liters":32.75,"sd_cm2":349,"sensitivity_db":95,"mms_grams":42.38,"rms":4.09,"cms":0.19,"bl_tm":18.2,"le_mh":0.7},"physical":{"overall_diameter_mm":256,"bolt_circle_diameter_mm":246.5,"baffle_cutout_diameter_mm":228.5,"mounting_holes":"8","depth_mm":109.5,"net_weight_kg":4.5,"xmax_mm":"4.05","xmech_mm":"12.05"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":null,"design_notes":null,"hero_text":null,"ai_summary":"The 103FINDX8-583B is a 10-inch ferrite mid-woofer designed for professional 2-way PA speaker systems, compact touring cabinets, and permanent installation enclosures crossed to a compression driver or horn. It features a carbon fiber paper cone, fabric surround, Nomex spider, and a 63.5mm copper voice coil on a Titanium Imide Laminate (TIL) former, providing high thermal stability for sustained high-power operation. Sensitivity is 95 dB (1W\/1m). With a Qts of 0.29, this driver uses a low Qts, high motor strength design optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nThis model requires vented (bass reflex) enclosures. Three recommended alignments using a 75mm round port are provided: 15 litres tuned to 70 Hz (port 180 mm) for a compact high-SPL touring cabinet with strong mechanical protection above the port frequency; 20 litres tuned to 62 Hz (port 172 mm) as the balanced general-purpose alignment for 2-way touring and installation PA; and 28 litres tuned to 55 Hz (port 156 mm) for extended low-frequency coverage to approximately 52 Hz in larger installation enclosures. A 100mm round port is an alternative offering lower port velocities at the cost of longer tube lengths (278\u2013320mm), which may require a folded or bent port in compact cabinets.\n\nThe 103FINDX8-583B handles approx. 250 W AES and 500 W continuous power, with a peak SPL of 119 dB at 1 metre (AES) and 122 dB at continuous rated power. A high-pass filter in the 45\u201360 Hz range is recommended depending on alignment. The operating bandwidth is approximately 65\u20131,000 Hz, with cone beaming onset near 1,039 Hz and inductance rolloff near 1,637 Hz; a crossover to a compression driver on horn at 800 Hz to 1.5 kHz is required. Third or fourth-order crossover slopes are recommended to control directivity above 1,039 Hz.\n\nThis driver is suited for compact single-driver vented 2-way PA touring cabinets; 2-way portable and installed PA enclosures for live sound and fixed venue reinforcement; stage monitor wedges crossed to a compression horn at 1 kHz; and installed permanent-mount 2-way enclosures in venues where a dedicated subwoofer is available. The high motor strength, TIL former, Nomex spider, and fabric surround prioritize consistent output and thermal reliability during sustained high-power operation.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 103FINDX8-583B\nGenerated: 2026-04-12\nApplication: Professional 2-way PA systems, touring and installation\nDRIVER SPECIFICATIONS\nCode : 103FINDX8-583B\nDescription : 10\" Ferrite Pro Mid-Woofer \u2014 Carbon Fiber Paper Cone\nNominal Impedance: 8 \u03a9\nAES Power : 250 W\nContinuous Power : 500 W\nPeak Power : 1,000 W\n\nFs : 56.2 Hz\nRe : 7.2 \u03a9\nQes : 0.32\nQms : 3.66\nQts : 0.29\nVas : 32.75 L\nSd : 349 cm\u00b2\nSensitivity : 95.0 dB (1 W \/ 1 m)\nMms : 42.38 g\nRms : 4.09 kg\/s\nCms : 0.19 mm\/N\nBl : 18.2 T\u00b7m\nLe : 0.70 mH\nXmax : 4.05 mm (one-way, peak)\nXmech : 12.05 mm\n\nVoice Coil : 63.5 mm (2.5\"), Copper, TIL former\nCone : Carbon fiber paper (Paper CF)\nSurround : Fabric\nSpider : Nomex\nBasket : Steel\nMagnet : Ferrite\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 349 cm\u00b2 \u00d7 0.405 cm = 141.3 cm\u00b3\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 7.2 \/ (2\u03c0 \u00d7 0.00070) \u2248 1,637 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(349 \/ 3.14159) = 10.54 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 10.54) \u2248 1,039 Hz\n\nWorking band : ~65 Hz \u2013 1,000 Hz\nCrossover to horn : 800 Hz \u2013 1.5 kHz (f_beam at 1,039 Hz defines the\n upper usable limit; Le onset at 1,637 Hz provides\n additional natural rolloff above crossover)\n\nMaximum SPL (anechoic, 1 m)\n At 250 W AES : 95.0 + 10\u00b7log\u2081\u2080(250) = 95.0 + 24.0 = 119.0 dB\n At 500 W cont : 95.0 + 10\u00b7log\u2081\u2080(500) = 95.0 + 27.0 = 122.0 dB\nENCLOSURE RECOMMENDATION\nQts = 0.29 \u2192 Vented (bass reflex) is the required alignment.\nSealed enclosures are not recommended for this driver; the low Qts\nproduces a severely underdamped response in any practical sealed volume.\nVENTED ENCLOSURE ALIGNMENTS\nPrimary port: 75 mm round (Ap = 44.18 cm\u00b2)\n Provides manageable physical tube lengths for compact 10\" PA cabinets.\n Port velocity limit: \u2264 17 m\/s (hi-fi \/ install) \/ \u2264 22 m\/s (PA)\n\nAlternative port: 100 mm round (Ap = 78.54 cm\u00b2)\n Lower velocity at cost of longer physical tube; suited to larger\n installation cabinets where port length is not space-constrained.\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2 ; 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 141.3 cm\u00b3 = 1.413 \u00d7 10\u207b\u2074 m\u00b3\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 75mm Port Length \u2502 Port Velocity \u2502 \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524 \u2502\n\u2502 A \u2502 15 L \u2502 70 Hz \u2502 180 mm \u2502 14.1 m\/s \u2713 \u2502 \u2502\n\u2502 B \u2502 20 L \u2502 62 Hz \u2502 172 mm \u2502 12.5 m\/s \u2713 \u2502 \u2502\n\u2502 C \u2502 28 L \u2502 55 Hz \u2502 156 mm \u2502 11.1 m\/s \u2713 \u2502 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (75 mm round port):\n Alignment A: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 4900 \u00d7 15,000)\n = 5.228\u00d710\u00b9\u2070 \/ 2.902\u00d710\u2079 = 180 mm\n Alignment B: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3844 \u00d7 20,000)\n = 5.228\u00d710\u00b9\u2070 \/ 3.036\u00d710\u2079 = 172 mm\n Alignment C: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3025 \u00d7 28,000)\n = 5.228\u00d710\u00b9\u2070 \/ 3.343\u00d710\u2079 = 156 mm\n\nAlternative 100 mm port lengths (lower velocity, longer tube):\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 100mm Port Length\u2502 Port Velocity \u2502 \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524 \u2502\n\u2502 A \u2502 15 L \u2502 70 Hz \u2502 320 mm \u2502 7.9 m\/s \u2713 \u2502 \u2502\n\u2502 B \u2502 20 L \u2502 62 Hz \u2502 306 mm \u2502 7.0 m\/s \u2713 \u2502 \u2502\n\u2502 C \u2502 28 L \u2502 55 Hz \u2502 278 mm \u2502 6.2 m\/s \u2713 \u2502 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nNote: 100mm tube lengths (278\u2013320mm) exceed the internal depth of compact\n10\" cabinets (~200\u2013260mm). Specify a folded or bent port tube if the\n100mm option is used in Alignments A or B.\n\n--- Vented Alignment A \u2014 15 L \/ Fb = 70 Hz ---\n High-SPL compact cabinet. Tuning above Fs provides strong mechanical\n protection against cone over-excursion above the port frequency.\n Maximum mid-bass punch with the smallest practical enclosure volume.\n Suited to compact portable touring 2-way cabinets and stage monitors.\n\n--- Vented Alignment B \u2014 20 L \/ Fb = 62 Hz ---\n Balanced PA cabinet. Near-Fs tuning; good output balance between\n mid-bass punch and lower-frequency extension to ~60 Hz.\n The recommended general-purpose alignment for 2-way touring\n and installation PA enclosures where both output and extension matter.\n\n--- Vented Alignment C \u2014 28 L \/ Fb = 55 Hz ---\n Extended LF response. Below-Fs tuning provides coverage to\n approximately 52 Hz (4th-order rolloff below Fb), reducing the\n need for a subwoofer in applications requiring modest low-frequency\n coverage. Suited to larger installed 2-way enclosures and\n medium-throw installation speakers in venues with limited sub support.\n Mandatory high-pass filter at 40\u201345 Hz to protect driver\n below port tuning.\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to compression driver on horn (acoustic): 800 Hz \u2013 1.5 kHz\n f_beam = 1,039 Hz (cone directivity increases rapidly above this)\n f_Le = 1,637 Hz (inductive rolloff onset)\n\n Recommended crossover frequency: 1.0 kHz for most 2-way PA designs;\n 1.5 kHz is achievable if off-axis coverage above 1.0 kHz is not\n critical. Third or fourth-order acoustic slope recommended to\n suppress cone beaming above the crossover point.\n\nZobel network (passive crossover impedance compensation):\n R_z = 7.2 \u03a9 (use 6.8 \u03a9 nearest standard)\n C_z = Le \/ Re\u00b2 = 0.70e-3 \/ 51.84 = 13.5 \u03bcF \u2192 use 15 \u03bcF, 100 V non-polar"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/103FINDX4-583A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/103FINDX4-583A-2.jpg"],"freq_response_image":null,"drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/103FINDX4-583A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/103FINDX4-583A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/103FINDX4-583A-3D.STEP"}},{"code":"10FINDX8-033","name":"10FIND","slug":"10findx8-033","description":"Mid-Woofer\/10inch\/Ferrite\/Paper\/250W\/8ohm","url":"https:\/\/redcatt.net\/products\/10findx8-033","category":"LF","type":"Mid-Woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"250","continuous_watts":"500","peak_watts":"1000"},"voice_coil":{"diameter":"63.5","wire":"CCAW","former":"Glass Fiber","winding_height":"13.5"},"thiele_small_parameters":{"fs_hz":66,"re_ohm":5.5,"qes":0.41,"qms":13.13,"qts":0.39,"vas_liters":23.5,"sd_cm2":346,"sensitivity_db":95.81,"mms_grams":41.3,"rms":1.3,"cms":0.14,"bl_tm":15.5,"le_mh":0.68},"physical":{"overall_diameter_mm":262,"bolt_circle_diameter_mm":246,"baffle_cutout_diameter_mm":230,"mounting_holes":"8","depth_mm":108.5,"net_weight_kg":4.55,"xmax_mm":"2.75","xmech_mm":"10.75"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Glass fiber loaded paper cone","2 demodulation rings, powerful motor structure","High spl, low thd"],"design_notes":"The 10FIND is a high efficiency, (96 dB 1watt \/ 1 meter) 10-inch woofer with linear frequency response characteristics, high power handling capability, while generating ultra low harmonic distortion artifacts. The 10FIND uses a lightweight glass fiber loaded cone assembly along with a high excursion double roll surround. This combination provides a lightweight, yet strong, piston.\n\n\nMagnetic Circuit\nREDCATT engineers have developed a ferrite based magnetic circuit, capable of delivering the highest level of performance, providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic structure has integrated two aluminum shorting rings. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 10FINDX8-033\nDriver: 10FINDX8-033 (10FIND) \u2014 10\" Mid-Woofer\nKey T\/S: Fs=66.0Hz, Qts=0.39, Vas=23.5L, Sens=95.81dB\nPower: AES 250W \/ Cont 500W \/ Peak 1000W\nXmax=2.75mm, Sd=346.0cm\u00b2, Bl=15.5T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (76mm diameter) \u2014 standard for mid-size professional enclosures; good balance of area and packaging\n a) High SPL\n Net Volume: 15 liters\n Tuning (Fb): 76 Hz\n Est. -3dB: 70 Hz\n HP Filter: 68 Hz (24dB\/oct recommended)\n Round Port: 76mm dia \u00d7 88mm long\n Slot Port: 184mm W \u00d7 46mm H \u00d7 189mm L\n Port Velocity: 10.0 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 20 liters\n Tuning (Fb): 69 Hz\n Est. -3dB: 63 Hz\n HP Filter: 59 Hz (24dB\/oct recommended)\n Round Port: 76mm dia \u00d7 91mm long\n Slot Port: 184mm W \u00d7 46mm H \u00d7 196mm L\n Port Velocity: 9.1 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 25 liters\n Tuning (Fb): 60 Hz\n Est. -3dB: 51 Hz\n HP Filter: 48 Hz (24dB\/oct recommended)\n Round Port: 76mm dia \u00d7 108mm long\n Slot Port: 184mm W \u00d7 46mm H \u00d7 227mm L\n Port Velocity: 7.9 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 10FINDX8-033 is a 10-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (96 dB 1W\/1m) and controlled low-frequency behavior. The driver uses a balanced motor-suspension design that provides good cone control while maintaining usable output across its operating bandwidth.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 15 to 25 liters, tuned between 60 and 76 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with high-power amplification (approx. 250 W AES \/ 500 W continuous) and DSP control. A high-pass filter in the range of 48\u201368 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 51\u20132000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/10FIND-033-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/10FIND-033-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/10FIND-033-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FIND-033-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/10FIND-033-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/10FIND-033-3D.STEP"}},{"code":"10NPMX8-055","name":"10NPM","slug":"10npmx8-055","description":"Mid-Woofer\/10inch\/Neo\/Paper\/400W\/8ohm","url":"https:\/\/redcatt.net\/products\/10npmx8-055","category":"LF","type":"Mid-Woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"400","continuous_watts":"800","peak_watts":"1600"},"voice_coil":{"diameter":"76.2","wire":"CCAW","former":"Glass Fiber","winding_height":"18.6"},"thiele_small_parameters":{"fs_hz":64,"re_ohm":4.7,"qes":0.29,"qms":7.7,"qts":0.28,"vas_liters":23,"sd_cm2":363,"sensitivity_db":97.48,"mms_grams":50.7,"rms":2.65,"cms":0.125,"bl_tm":18.3,"le_mh":0.52},"physical":{"overall_diameter_mm":262,"bolt_circle_diameter_mm":246,"baffle_cutout_diameter_mm":234,"mounting_holes":"4","depth_mm":107.8,"net_weight_kg":3.8,"xmax_mm":"4.05","xmech_mm":"14.55"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Hi sensitivity, hi power handling","Carbon fiber loaded paper cone, nomex spider","Excellent frequency response"],"design_notes":"The 10NPM is a high efficiency, (95 dB 1watt \/ 1 meter) 10-inch mid bass woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts.-\nThe 10NPM uses a lightweight carbon fiber loaded cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 7.5mm.\n\nMagnetic Circuit\nREDCATT engineers have developed a lightweight, inside-neodymium slug based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"The 10NPMX8-055 is a 10-inch high-efficiency neodymium mid-woofer designed for high-output professional two-way, multi-way, and line array systems requiring extreme sensitivity (97.5 dB 1W\/1m), high power handling (400 W AES \/ 800 W continuous), and controlled low-distortion performance. It features a 3-inch CCAW voice coil on a glass fiber former, a carbon fiber loaded paper cone with a precision double roll constant geometry fabric surround delivering 7.5 mm peak-to-peak excursion linearity, and an inside neodymium slug motor optimized for minimum flux modulation and very low harmonic distortion. With a low Qts of 0.28 and strong motor force (Bl 18.3 T\u00b7m), the motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nThis driver is suitable for both vented (mid-woofer) and sealed (midrange) enclosure configurations depending on the system architecture. In bass reflex enclosures, recommended net internal volumes range from 23 to 31 liters with tuning frequencies between 50 and 66 Hz. Smaller volumes (23\u201327 liters tuned to 58\u201366 Hz) prioritize mid-bass output and cabinet compactness for large-format 2-way tops and touring cabinets, while 31 liters tuned to 50 Hz extends the usable low-frequency response to approximately 42 Hz (\u20133 dB) for stand-alone applications without dedicated subwoofers. Port velocities are moderate across all vented alignments (10\u201313 m\/s with a 76 mm round port) and port lengths are short (79\u2013119 mm). In sealed enclosures for midrange duty, the driver performs in compact net internal volumes of 2.0 to 4.3 liters, producing system resonances between 162 and 229 Hz. Smaller sealed volumes (2.0\u20132.8 liters, Qtc 0.85\u20131.0) maximize acoustic output in the midrange passband for large-format line array modules and horn-loaded midrange systems, while 4.3 liters yields a Butterworth-class response (Qtc 0.707) with maximally flat amplitude for accuracy-focused applications. The larger Sd (363 cm\u00b2) compared to 8-inch midranges provides higher midrange output per driver, a key advantage in large-format arrays.\nThe driver requires active DSP crossover management in both configurations. In vented mid-woofer use, a high-pass filter in the range of 40\u201356 Hz (24 dB\/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency compression driver at 1.2\u20132.5 kHz. In sealed midrange use, a high-pass filter in the range of 150\u2013300 Hz is recommended depending on enclosure volume and system architecture. In both cases, the 400 W AES power handling supports sustained high-output operation with appropriate limiting.\nThis driver is particularly effective in large-format touring line arrays, high-output 2-way portable loudspeakers, multi-way point-source cabinets, and high-SPL installation systems where per-driver output, sensitivity, power handling, and low distortion are priorities. The inside neodymium slug motor, flux-modulation-optimized magnetic circuit, carbon fiber loaded cone, and aluminum basket provide consistent, durable performance in the most demanding professional touring and installation environments.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 10NPMX8-055\nDriver: 10NPMX8-055 (10NPM) \u2014 10\" Mid-Woofer \/ Midrange\nKey T\/S: Fs=64Hz, Qts=0.28, Vas=23L, Sens=97.5dB 1W\/1m\nPower: AES 400W \/ Cont 800W \/ Peak 1600W\nXmax=4.05mm (one-way linear), Xmech=14.55mm (protection at 17.2mm p-p)\nSd=363cm\u00b2, Bl=18.3T\u00b7m, Re=4.7\u03a9, Mms=50.7g\nVoice Coil: 3\" CCAW on glass fiber former (18.6mm winding height)\nMagnet: Neodymium (inside slug, flux-modulation optimized)\nCone: Carbon fiber loaded paper | Surround: Fabric (double roll,\nconstant geometry) | Spider: Nomex | Basket: Aluminum\nNOTE: This driver's very low Qts (0.28), extremely high sensitivity\n(97.5 dB), and powerful neodymium motor (Bl=18.3 T\u00b7m) make it\nsuitable for BOTH vented mid-woofer and sealed midrange applications.\nThe 400 W AES power handling \u2014 double that of the 8\" NPM variants \u2014\npositions this driver for high-output professional systems. The inside\nneodymium slug motor design is optimized for minimum flux modulation,\nproviding exceptional linearity and very low harmonic distortion. The\ncarbon fiber loaded paper cone with precision double roll constant\ngeometry surround delivers 7.5 mm of excursion linearity (peak-to-\npeak). Six enclosure alignments are provided below \u2014 three vented\n(mid-woofer use) and three sealed (midrange use).\n MID-WOOFER APPLICATION \u2014 Bass Reflex (Vented)\nUse case: 2-way and multi-way systems, large-format line arrays, and\nhigh-output PA systems where the 10NPM handles the low-frequency and\nlower-midrange content, typically crossed over to a compression driver\nat 1.2\u20132.5 kHz. The extreme sensitivity (97.5 dB) and high power\nhandling (400W AES) make this driver capable of very high continuous\nSPL from each cabinet.\nPORT RECOMMENDATION: Round port (76mm diameter) \u2014 standard for 10\"\nbass reflex enclosures. Port velocities are moderate (10\u201313 m\/s) and\nport lengths are short (79\u2013119 mm), making port design straightforward.\nFlared port ends are recommended for best practice but not critical\nat these velocities.\n a) VENTED \u2014 High SPL\n Net Volume: 23 liters\n Tuning (Fb): 66 Hz\n Est. -3dB: 61 Hz\n HP Filter: 56 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 79mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 111mm L\n Port Velocity: 13.4 m\/s\n Notes: Compact alignment with strong mid-bass control and\n maximum output per cabinet volume. Higher tuning provides\n tight, punchy low end with excellent transient response.\n Ideal for large-format 2-way tops, high-output stage\n monitors, and touring cabinets paired with subwoofers.\n The 97.5 dB sensitivity combined with 400W AES delivers\n exceptional continuous SPL from a compact enclosure.\n b) VENTED \u2014 Balanced Response\n Net Volume: 27 liters\n Tuning (Fb): 58 Hz\n Est. -3dB: 49 Hz\n HP Filter: 48 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 93mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 130mm L\n Port Velocity: 11.8 m\/s\n Notes: General-purpose alignment with even response through\n the bass region and good transient behavior. Well-suited\n for most PA tops, multi-way systems, and installation\n loudspeakers. Provides good stand-alone bass capability\n when subwoofer support is unavailable.\n c) VENTED \u2014 Extended Low Frequency\n Net Volume: 31 liters\n Tuning (Fb): 50 Hz\n Est. -3dB: 42 Hz\n HP Filter: 40 Hz (24dB\/oct LR recommended)\n Round Port: 76mm dia \u00d7 119mm long\n Slot Port: 184mm W \u00d7 45mm H \u00d7 167mm L\n Port Velocity: 10.2 m\/s\n Notes: Maximum low-frequency extension for stand-alone use\n without subwoofers. Reaches into the low 40s Hz while\n maintaining the strong motor control characteristic of the\n low Qts design. Best for applications where full-range bass\n coverage from a single 10\" cabinet is required (corporate\n events, larger live venues, portable entertainment systems).\n Requires proper high-pass protection below tuning.\n MIDRANGE APPLICATION \u2014 Sealed\nUse case: Large-format line array midrange sections, horn-loaded\nmidrange systems, coaxial cabinets, and dedicated mid-high enclosures\nwhere the 10NPM handles the midrange band (typically 200\u20132500 Hz or\nnarrower), with bass duties handled by separate woofer\/subwoofer\nsections. The larger Sd (363 cm\u00b2) compared to 8\" midranges provides\nhigher midrange output per driver \u2014 a key advantage in large-format\nline arrays and high-SPL point-source designs.\n d) SEALED \u2014 High SPL (Qtc \u2248 1.0)\n Net Volume: 2.0 liters\n System Resonance (fc): 229 Hz\n Qtc: 1.0\n Response: Broad gentle lift near fc, maximum midrange output\n Crossover HP: 220\u2013300 Hz (24dB\/oct LR recommended)\n Notes: Compact sealed chamber for maximum acoustic output\n in the midrange passband. The elevated Qtc provides a gentle\n broad peak near system resonance that can be equalized flat\n via DSP or used as a passband sensitivity boost. Ideal for\n high-output touring line arrays and horn-loaded midrange\n systems where output per driver is the primary requirement.\n The 97.5 dB sensitivity in a 2-liter sealed chamber makes\n this a formidable midrange source.\n e) SEALED \u2014 Balanced (Qtc \u2248 0.85)\n Net Volume: 2.8 liters\n System Resonance (fc): 194 Hz\n Qtc: 0.85\n Response: Slightly warm, smooth transition through resonance\n Crossover HP: 180\u2013250 Hz (24dB\/oct LR recommended)\n Notes: Good compromise between midrange output and response\n flatness. Suitable for most professional midrange applications\n including line arrays, point-source cabinets, and large-format\n stage monitors. The slight warmth near resonance is easily\n managed with DSP.\n f) SEALED \u2014 Butterworth (Qtc \u2248 0.707)\n Net Volume: 4.3 liters\n System Resonance (fc): 162 Hz\n Qtc: 0.707\n Response: Maximally flat amplitude, textbook Butterworth alignment\n Crossover HP: 150\u2013200 Hz (24dB\/oct LR recommended)\n Notes: Flattest possible sealed response with lowest system\n resonance. Allows a lower crossover frequency and extended\n lower-midrange coverage. Best for applications prioritizing\n accuracy, smooth crossover integration, and minimal DSP\n correction. The larger volume (4.3L) is still very compact\n for a 10\" driver.\nTHERMAL NOTE: The 3\" CCAW voice coil on glass fiber former, combined\nwith the inside neodymium slug motor and aluminum basket, provides an\nefficient thermal path. The 400W AES rating represents genuine\nsustained power handling capability \u2014 double the 8\" NPM variants \u2014\nmaking this driver suitable for the most demanding continuous-duty\napplications in touring and installation.\nDESIGN NOTE: The flux-modulation-optimized inside neodymium slug\nmotor with aluminum shorting features minimizes harmonic and\nintermodulation distortion across the full operating range. The carbon\nfiber loaded paper cone with precision double roll constant geometry\nsurround provides 7.5 mm peak-to-peak excursion linearity with a\nlightweight, stiff piston characteristic. The Nomex spider ensures\nconsistent restoring force throughout the excursion range.\nCOMPARISON vs 8\" NPM VARIANTS:\n Parameter 8NPM (157) 81NPM (373A) 10NPM (055)\n Size 8\" 8\" 10\"\n Qts 0.29 0.28 0.28\n Sensitivity 96 dB 93 dB 97.5 dB\n AES Power 200W 200W 400W\n Bl 14.2 T\u00b7m 19.3 T\u00b7m 18.3 T\u00b7m\n Xmax 3.7mm 4.05mm 4.05mm\n Sd 213.8 cm\u00b2 219 cm\u00b2 363 cm\u00b2\n Vented volumes 10\u201314L 10\u201314L 23\u201331L\n Sealed volumes 1.0\u20132.2L 0.9\u20131.9L 2.0\u20134.3L\nThe 10NPM scales the NPM platform to 10\" with proportionally\nlarger enclosure volumes, +1.5 dB sensitivity gain, and double\nthe power handling \u2014 making it the natural choice for larger-format\nsystems and line arrays requiring higher per-driver output."},"assets":{"photos":[],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/10NPMX8-055-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/10NPM-055-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/10NPM-055-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/10NPM-055-3D.STEP"}},{"code":"10NPMX8-319","name":"10NPM","slug":"10npmx8-319","description":"Mid-Woofer\/10inch\/Neo\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/10npmx8-319","category":"LF","type":"Mid-Woofer","size_inches":10,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"3","wire":"CCAW","former":"Glass Fiber","winding_height":"23.2"},"thiele_small_parameters":{"fs_hz":58,"re_ohm":6.5,"qes":0.36,"qms":4.68,"qts":0.33,"vas_liters":29.3,"sd_cm2":363.1,"sensitivity_db":95.07,"mms_grams":47,"rms":3.66,"cms":0.16,"bl_tm":17.9,"le_mh":0.79},"physical":{"overall_diameter_mm":262,"bolt_circle_diameter_mm":246,"baffle_cutout_diameter_mm":234,"mounting_holes":"4","depth_mm":107.8,"net_weight_kg":3.5,"xmax_mm":"6.35","xmech_mm":"16.85"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["High sensitivity, hi power handling","Carbon fiber loaded paper cone, nomex spider","Excellent frequency response"],"design_notes":"The 10NPM is a high efficiency, (95 dB 1watt \/ 1 meter) 10-inch mid bass woofer with incredibly linear frequency response characteristics, extreme high power handling capability while generating low harmonic distortion artifacts.-\nThe 10NPM uses a lightweight carbon fiber loaded cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 15.4mm.\n\nMagnetic Circuit\nREDCATT engineers have developed a lightweight, inside-neodymium slug based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"The 10NPMX8-319 is a 10-inch neodymium pro mid-woofer designed for professional 2-way PA speaker systems, compact touring cabinets, and permanently installed enclosures crossed to a compression driver or horn. It features a carbon fiber paper cone, double-roll constant-geometry fabric surround, Nomex spider, and a 3-inch CCAW voice coil on a glass fiber former, driven by an inside-slug neodymium magnetic circuit designed for minimized flux modulation and high flux-gap integrity. Sensitivity is 95.07 dB (1W\/1m). With a Qts of 0.33, this driver uses a low Qts, high motor strength design optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\n\nThis model requires vented (bass reflex) enclosures. The volume displacement of 230.6 cm\u00b3 \u2014 large for a 10-inch driver due to an extended Xmax of 6.35mm \u2014 requires a minimum 100mm round port; a 75mm port exceeds the 22 m\/s PA velocity limit at the tighter tuning frequencies and must not be used. Three alignments are recommended: 20 litres tuned to 68 Hz (port 255 mm) for a compact high-SPL touring cabinet; 28 litres tuned to 60 Hz (port 234 mm) as the balanced general-purpose alignment for 2-way touring and installation PA; and 38 litres tuned to 52 Hz (port 229 mm) for extended low-frequency coverage to approximately 49 Hz. Physical port tube lengths are approximately 154\u2013180 mm after end correction \u2014 suitable for standard 10\" pro cabinet depths.\n\nThe 10NPMX8-319 handles approx. 200 W AES and 400 W continuous power, with a peak SPL of 118 dB at 1 metre (AES) and 121 dB at continuous rated power. A high-pass filter in the 45\u201360 Hz range is recommended depending on alignment. The operating bandwidth is approximately 65\u20131,000 Hz, with cone beaming onset near 1,018 Hz and inductance rolloff near 1,309 Hz; a crossover to a compression driver on horn at 800 Hz to 1.5 kHz is required. Third or fourth-order crossover slopes are recommended to control directivity above 1,018 Hz.\n\nThis driver is suited for compact single-driver vented 2-way PA touring cabinets; 2-way portable and installed PA enclosures for live sound and fixed-venue reinforcement; stage monitor wedges crossed to a compression horn at 1 kHz; and installed 2-way enclosures where a neodymium motor's reduced weight is advantageous. The inside-slug neodymium magnetic circuit, CCAW voice coil, and glass fiber former provide a lightweight motor assembly and consistent high-efficiency output for demanding sustained-power PA applications.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 10NPMX8-319\nGenerated: 2026-04-12\nApplication: Professional 2-way PA systems, touring and installation\nDRIVER SPECIFICATIONS\nCode : 10NPMX8-319\nDescription : 10\" Neodymium Pro Mid-Woofer \u2014 Carbon Fiber Paper Cone\nNominal Impedance: 8 \u03a9\nAES Power : 200 W\nContinuous Power : 400 W\nPeak Power : 800 W\n\nFs : 58 Hz\nRe : 6.5 \u03a9\nQes : 0.36\nQms : 4.68\nQts : 0.33\nVas : 29.3 L\nSd : 363.1 cm\u00b2\nSensitivity : 95.07 dB (1 W \/ 1 m)\nMms : 47 g\nRms : 3.66 kg\/s\nCms : 0.16 mm\/N\nBl : 17.9 T\u00b7m\nLe : 0.79 mH\nXmax : 6.35 mm (one-way, peak)\nXmech : 16.85 mm\n\nVoice Coil : 3\" (76.2 mm), CCAW, Glass Fiber former\nCone : Carbon fiber paper (Paper CF)\nSurround : Fabric (double-roll, constant geometry)\nSpider : Nomex\nBasket : Aluminum\nMagnet : Neodymium (inside slug design)\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 363.1 cm\u00b2 \u00d7 0.635 cm = 230.6 cm\u00b3\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 6.5 \/ (2\u03c0 \u00d7 0.00079) \u2248 1,309 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(363.1 \/ 3.14159) = 10.75 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 10.75) \u2248 1,018 Hz\n\nWorking band : ~65 Hz \u2013 1,000 Hz\nCrossover to horn : 800 Hz \u2013 1.5 kHz (f_beam at 1,018 Hz is the\n practical upper limit; Le onset at 1,309 Hz provides\n additional natural rolloff above crossover)\n\nMaximum SPL (anechoic, 1 m)\n At 200 W AES : 95.07 + 10\u00b7log\u2081\u2080(200) = 95.07 + 23.0 = 118.1 dB\n At 400 W cont : 95.07 + 10\u00b7log\u2081\u2080(400) = 95.07 + 26.0 = 121.1 dB\n\nNote on motor design: Inside-slug neodymium magnetic circuit provides\na consistent, high-integrity flux gap with minimized flux modulation.\nThe CCAW voice coil on a glass fiber former reduces moving mass and\nimproves high-frequency motor response compared to copper-wound designs.\nENCLOSURE RECOMMENDATION\nQts = 0.33 \u2192 Vented (bass reflex) is the required alignment.\nSealed enclosures are not recommended for this driver.\n\nPORT SIZE WARNING: Vd = 230.6 cm\u00b3 is large for a 10\" driver.\n A 75 mm round port produces port velocities \u2265 22 m\/s at the\n tighter tuning frequencies \u2014 exceeding the PA\/touring limit.\n Minimum port: 100 mm round (Ap = 78.54 cm\u00b2).\n Do not specify a 75 mm or smaller round port for this driver.\nVENTED ENCLOSURE ALIGNMENTS\nPort: 100 mm round (Ap = 78.54 cm\u00b2) \u2190 minimum acceptable size\n Port velocity limit: \u2264 17 m\/s (hi-fi \/ install) \/ \u2264 22 m\/s (PA)\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2 ; 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 230.6 cm\u00b3 = 2.306 \u00d7 10\u207b\u2074 m\u00b3 ; Ap = 7.854 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 100mm Port Length\u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 20 L \u2502 68 Hz \u2502 255 mm \u2502 12.6 m\/s \u2713 \u2502\n\u2502 B \u2502 28 L \u2502 60 Hz \u2502 234 mm \u2502 11.1 m\/s \u2713 \u2502\n\u2502 C \u2502 38 L \u2502 52 Hz \u2502 229 mm \u2502 9.6 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (100 mm round port):\n Alignment A: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 4624 \u00d7 20,000)\n = 9.298\u00d710\u00b9\u2070 \/ 3.652\u00d710\u2079 = 255 mm\n Alignment B: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 3600 \u00d7 28,000)\n = 9.298\u00d710\u00b9\u2070 \/ 3.979\u00d710\u2079 = 234 mm\n Alignment C: Leff = (78.54 \u00d7 1,183,360,000) \/ (39.478 \u00d7 2704 \u00d7 38,000)\n = 9.298\u00d710\u00b9\u2070 \/ 4.058\u00d710\u2079 = 229 mm\n\nPort engineering note: All three alignments produce near-identical\neffective port lengths (229\u2013255 mm). This is the characteristic\nnear-constant port behaviour of low-Qts drivers: larger Vb and lower\nFb compensate each other in the Helmholtz equation. Physical tube\nlength (Leff minus end corrections of ~75 mm) is approximately\n154\u2013180 mm \u2014 manageable within a standard 10\" pro cabinet.\n\n--- Vented Alignment A \u2014 20 L \/ Fb = 68 Hz ---\n Compact high-SPL cabinet, tuned slightly above Fs for maximum\n mid-bass punch and strongest mechanical excursion protection.\n Suited to compact portable touring 2-way cabinets and stage monitors\n where cabinet volume is at a premium.\n\n--- Vented Alignment B \u2014 28 L \/ Fb = 60 Hz ---\n Balanced PA cabinet tuned near Fs. Good balance of output,\n low-frequency extension, and enclosure size. The recommended\n general-purpose alignment for 2-way touring and installation\n PA enclosures.\n\n--- Vented Alignment C \u2014 38 L \/ Fb = 52 Hz ---\n Extended low-frequency response to approximately 49 Hz (4th-order\n rolloff below Fb). Suited to larger installed 2-way enclosures\n and medium-throw installation systems where modest sub-60 Hz\n coverage is needed without a dedicated subwoofer.\n Mandatory high-pass filter at 40\u201345 Hz to protect driver below\n port tuning.\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to compression driver on horn (acoustic): 800 Hz \u2013 1.5 kHz\n f_beam = 1,018 Hz (cone directivity increases rapidly above this)\n f_Le = 1,309 Hz (inductive rolloff onset)\n\n Recommended crossover frequency: 1.0 kHz; third or fourth-order\n acoustic slope to suppress cone beaming above f_beam.\n The Le onset at 1,309 Hz provides additional natural attenuation\n above the crossover point, aiding horn loading.\n\nZobel network (passive crossover impedance compensation):\n R_z = 6.5 \u03a9 (use 6.8 \u03a9 nearest standard)\n C_z = Le \/ Re\u00b2 = 0.79e-3 \/ 42.25 = 18.7 \u03bcF \u2192 use 18 or 22 \u03bcF, 100 V non-polar"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/10NPM-319-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/10NPM-319-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/10NPMX8-319-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/10NPM-319-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/10NPM-319-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/10NPM-319-3D.STEP"}},{"code":"81FHWX4-289","name":"81FHW","slug":"81fhwx4-289","description":"Woofer\/8inch\/Ferrite\/Paper\/100W\/4ohm","url":"https:\/\/redcatt.net\/products\/81fhwx4-289","category":"LF","type":"Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"100","continuous_watts":"200","peak_watts":"400"},"voice_coil":{"diameter":"35.6","wire":"Copper","former":"Aluminum","winding_height":"18.2"},"thiele_small_parameters":{"fs_hz":39,"re_ohm":3.6,"qes":0.58,"qms":5.4,"qts":0.52,"vas_liters":21.5,"sd_cm2":201.1,"sensitivity_db":85.94,"mms_grams":44,"rms":2,"cms":0.38,"bl_tm":8.25,"le_mh":1.12},"physical":{"overall_diameter_mm":209,"bolt_circle_diameter_mm":197,"baffle_cutout_diameter_mm":180,"mounting_holes":"8","depth_mm":95,"net_weight_kg":1.7,"xmax_mm":"6.1","xmech_mm":"12.1"},"materials":{"surround":"Foam","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Good low frequency response","Lightweight surround, stiff paper cone","Affordable woofer"],"design_notes":"The 81FHW woofer was designed with smaller hi-fi subwoofers in mind. The woofer works well in vented enclosures or combined with a passive radiator. Optimized magnetic structure delivers good level of performance and balancing well performance vs cost.\n\tWe have chosen lightweight foam surround in this design. Our extensive development and testing of this material yielded in custom formulation of the raw material we use for the surround and guaranties its long lasting performance.","hero_text":null,"ai_summary":"The 81FHWX4-289 is an 8-inch sub-woofer driver designed for compact hi-fi subwoofer systems, home audio, and cost-effective installation applications. It operates at 85.9 dB sensitivity (1W\/1m) and features a compliant suspension design suited to moderate-volume vented or passive-radiator enclosures with extended low-frequency response.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 10 to 16 liters, tuned between 37 and 45 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases output in the upper bass region while improving mechanical control. Note: the 65mm round port at these tuning frequencies requires a length of approximately 405\u2013430 mm and will need to be folded within the enclosure; a slot port may offer a more practical alternative.\nThe driver is intended for use with moderate amplification (approx. 100 W AES \/ 200 W continuous) and DSP control. A high-pass filter in the range of 25\u201337 Hz is recommended depending on enclosure tuning, along with appropriate limiting to manage excursion below tuning. Typical operating bandwidth is 31\u2013100 Hz, suitable for integration with a mid-bass or full-range driver in a two-way system.\nThis design is well suited for single-driver compact bass reflex or passive-radiator enclosures in hi-fi, home theater, and cost-conscious installation applications, where a balance of low-frequency extension, compactness, and value are the primary priorities.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 81FHWX4-289\nDriver: 81FHWX4-289 (81FHW) \u2014 8\" Sub-woofer\nKey T\/S: Fs=39.0Hz, Qts=0.52, Vas=21.5L, Sens=85.94dB\nPower: AES 100W \/ Cont 200W \/ Peak 400W\nXmax=6.1mm, Sd=201.1cm\u00b2, Bl=8.25T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 adequate for compact enclosures with lower air volume velocity\n a) High SPL\n Net Volume: 10 liters\n Tuning (Fb): 45 Hz\n Est. -3dB: 41 Hz\n HP Filter: 37 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 405mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 722mm L\n Port Velocity: 10.4 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 12 liters\n Tuning (Fb): 41 Hz\n Est. -3dB: 38 Hz\n HP Filter: 31 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 413mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 738mm L\n Port Velocity: 9.5 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 16 liters\n Tuning (Fb): 37 Hz\n Est. -3dB: 31 Hz\n HP Filter: 25 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 430mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 766mm L\n Port Velocity: 8.6 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/81FHW-289-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/81FHW-289-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/81FHW-289-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/81FHW-289-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/81FHW-289-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/81FHW-289-3D.STEP"}},{"code":"8FHWX4-088","name":"8FHW","slug":"8fhwx4-088","description":"Woofer\/8inch\/Ferrite\/Paper\/200W\/4ohm","url":"https:\/\/redcatt.net\/products\/8fhwx4-088","category":"LF","type":"Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"35.6","wire":"Copper","former":"Aluminum","winding_height":"25.4"},"thiele_small_parameters":{"fs_hz":41,"re_ohm":4,"qes":0.75,"qms":4.2,"qts":0.6,"vas_liters":19.6,"sd_cm2":202.3,"sensitivity_db":84.4,"mms_grams":45.9,"rms":2.81,"cms":0.33,"bl_tm":7.88,"le_mh":0.72},"physical":{"overall_diameter_mm":214,"bolt_circle_diameter_mm":204,"baffle_cutout_diameter_mm":181,"mounting_holes":"8","depth_mm":105,"net_weight_kg":2.1,"xmax_mm":"8.7","xmech_mm":"16.7"},"materials":{"surround":"NBR","cone_dome":"Paper GF","spider":"Conex"},"content":{"key_features":["Heavy-duty rubber surround and paper cone","Ideal for small subwoofers, hi-fi applications","High power handling"],"design_notes":"The 8FHW is 8-inch low frequency woofer with linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts.\nThe single roll rubber surround design allows the cone to travel in long linear motion. Together with lightweight, yet strong cone,this combination provides remarkable strength, high efficiency and a excursion linearity of 13mm (one direction).\n\nMagnetic Circuit\nREDCATT engineers have developed an efficient, ferrite based magnetic circuit, capable of delivering the high level of performance providing a consistent, high integrity magnetic flux gap, low distortion characteristic. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This driver is particularly effective in compact sealed and passive-radiator hi-fi subwoofers, bookshelf-paired bass modules, and home theater systems where deep, controlled bass from a small enclosure is required. The flux-modulation-optimized ferrite motor, long-excursion rubber surround, and high mechanical clearance (16.7 mm) provide consistent, low-distortion performance across the driver's full excursion range.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 8FHWX4-088\nDriver: 8FHWX4-088 (8FHW) \u2014 8\" Hi-Fi Subwoofer\nKey T\/S: Fs=41Hz, Qts=0.6, Vas=19.6L, Sens=84.4dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=8.7mm (one-way linear), Xmech=16.7mm, Sd=202.3cm\u00b2\nBl=7.88T\u00b7m, Re=4\u03a9 (4-ohm nominal), Mms=45.9g\nVoice Coil: 1.4\" copper on aluminum former (25.4mm winding height)\nMagnet: Ferrite (flux-modulation optimized) | Cone: Paper\nSurround: Rubber (single roll, long-excursion) | Spider: Conex\nNOTE: With Qts=0.6, high Xmax (8.7mm linear \/ 16.7mm mechanical),\nand Fs=41Hz, this driver is best suited to SEALED hi-fi subwoofer\nenclosures. The compliant suspension and moderate Qts produce\nwell-controlled sealed alignments in practical cabinet volumes.\nVented designs are possible but require very long ports (>500mm) at\nthese tuning frequencies and cabinet sizes \u2014 a passive radiator\nalternative is noted below.\n PRIMARY \u2014 Sealed Enclosures\nSealed enclosures are the recommended configuration for this driver\nin hi-fi subwoofer applications. The smooth, predictable roll-off\nbelow resonance integrates well with room gain (typically +3\u20136 dB\nbelow 50\u201360 Hz in domestic rooms), which effectively extends the\nin-room response below the anechoic -3dB point.\n a) SEALED \u2014 Compact (Qtc \u2248 1.0)\n Net Volume: 11 liters\n System Resonance (fc): 68 Hz\n Qtc: 1.0\n Anechoic -3dB: ~68 Hz\n Estimated in-room -3dB: ~45\u201350 Hz (with typical room gain)\n Response: Broad lift near resonance (~+3dB peak at fc),\n punchy character with strong upper-bass impact\n Notes: Most compact practical enclosure. The elevated Qtc\n produces a broad resonance peak that adds warmth and punch\n in the 60\u201380 Hz region. Combined with typical domestic room\n gain, usable in-room response extends well below 50 Hz.\n Well-suited to smaller listening rooms or where cabinet size\n is the primary constraint. Can be EQ'd flat with modest DSP.\n b) SEALED \u2014 Balanced\/Musical (Qtc \u2248 0.85)\n Net Volume: 20 liters\n System Resonance (fc): 58 Hz\n Qtc: 0.85\n Anechoic -3dB: ~58 Hz\n Estimated in-room -3dB: ~38\u201342 Hz (with typical room gain)\n Response: Slightly warm, smooth rolloff with gentle lift near fc\n Notes: Excellent all-round hi-fi alignment. The gentle warmth\n near resonance sounds natural and musical, integrating smoothly\n with room acoustics. In-room, this alignment typically delivers\n the most satisfying subjective bass quality without EQ. This is\n the recommended starting point for most hi-fi applications.\n *** RECOMMENDED FOR MOST HI-FI APPLICATIONS ***\n c) SEALED \u2014 Extended (Qtc \u2248 0.80)\n Net Volume: 25 liters\n System Resonance (fc): 55 Hz\n Qtc: 0.80\n Anechoic -3dB: ~55 Hz\n Estimated in-room -3dB: ~35\u201340 Hz (with typical room gain)\n Response: Near-flat amplitude, smooth extended rolloff\n Notes: Larger enclosure with extended low-frequency response.\n The near-Butterworth alignment produces a smooth, accurate\n response with minimal resonance peak. Best for larger listening\n rooms, critical listening applications, or when accurate tonal\n balance is prioritized over maximum output. Pairs well with\n room correction systems (Dirac, Audyssey, etc.).\nROOM GAIN NOTE: In typical domestic rooms (15\u201340 m\u00b2), boundary\nreinforcement provides +3\u20136 dB of gain below 50\u201360 Hz. Corner\nplacement adds further gain. This means the effective in-room\n-3dB point is significantly lower than the anechoic figure.\nSealed alignments with Qtc 0.8\u20130.9 typically sound best in-room\nbecause room gain compensates for the gentle rolloff, producing\na naturally flat in-room response.\n SECONDARY \u2014 Bass Reflex (Vented) \/ Passive Radiator\nVented enclosures extend the low-frequency response below what sealed\ncan achieve in the same volume, but the long port lengths required\n(>500mm for a 65mm port) make conventional round ports impractical\nfor these cabinet sizes. Two practical options are noted below.\nOPTION 1: VENTED WITH FOLDED SLOT PORT\n d) VENTED \u2014 High Output\n Net Volume: 8 liters\n Tuning (Fb): 47 Hz\n Est. -3dB: 43 Hz\n HP Filter: 37 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 512mm long (impractical \u2014 use slot)\n Slot Port: 161mm W \u00d7 40mm H \u00d7 750mm L (folded internally)\n Port Velocity: 15.7 m\/s\n Notes: Compact vented alignment. The slot port must be folded\n inside the cabinet (L-shaped or U-shaped path). Provides\n strong output in the 40\u201380 Hz region with good excursion\n control near tuning.\n e) VENTED \u2014 Balanced\n Net Volume: 9 liters\n Tuning (Fb): 43 Hz\n Est. -3dB: 40 Hz\n HP Filter: 33 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 547mm long (impractical \u2014 use slot)\n Slot Port: 161mm W \u00d7 40mm H \u00d7 800mm L (folded internally)\n Port Velocity: 14.3 m\/s\n Notes: Good balance between extension and cabinet size.\n Slot port must be folded. Reaches usably into the low 30s Hz\n in-room with room gain.\n f) VENTED \u2014 Extended Low Frequency\n Net Volume: 11 liters\n Tuning (Fb): 39 Hz\n Est. -3dB: 33 Hz\n HP Filter: 29 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 544mm long (impractical \u2014 use slot)\n Slot Port: 161mm W \u00d7 40mm H \u00d7 790mm L (folded internally)\n Port Velocity: 13.0 m\/s\n Notes: Maximum extension, reaching into the low 30s Hz\n anechoic and below 30 Hz in-room. Larger cabinet but still\n practical for an 8\" hi-fi subwoofer. Requires high-pass\n protection below tuning.\nPORT NOTE: All vented alignments require port lengths exceeding\n500mm, which is impractical for straight round ports in cabinets\nof this size. Folded slot ports (L-shaped or U-shaped internal\nducting) are the practical solution. Ensure the slot port has a\nminimum height of 40mm to avoid whistling artifacts.\nOPTION 2: PASSIVE RADIATOR (Recommended Alternative to Vented)\nA passive radiator (PR) eliminates the long port entirely and\nprovides the same acoustic loading in a compact, sealed-looking\nenclosure. The PR should have:\n - Sd approximately equal to the active driver (~200 cm\u00b2)\n - Tuning mass selected to achieve the desired Fb (39\u201347 Hz)\n - Compliance similar to or higher than the active driver\n - Xmax equal to or greater than the active driver (\u22658.7mm)\nA passive radiator configuration in 8\u201311 liters tuned to 40\u201345 Hz\nprovides deep, clean bass extension without the port noise and\nlength constraints of a vented design. This is the preferred\napproach for modern compact hi-fi subwoofers.\nEXCURSION NOTE: The 8FHW has substantial linear excursion (8.7mm)\nwith further mechanical clearance to 16.7mm. This provides significant\ndisplacement capability (Vd = 176 cc) for an 8\" driver, supporting\nmeaningful output to low frequencies. However, below the tuning\nfrequency in vented\/PR configurations, excursion rises rapidly \u2014\na subsonic high-pass filter is essential.\nThe 8FHWX4-088 is an 8-inch ferrite woofer designed for hi-fi subwoofer and home audio applications requiring deep bass extension, high excursion linearity, and low harmonic distortion. It features a 1.4-inch copper voice coil on an aluminum former with 25.4 mm winding height, a lightweight paper cone with a long-excursion single-roll rubber surround, and a ferrite motor circuit optimized for minimum flux modulation and low distortion. With 8.7 mm of linear excursion (16.7 mm mechanical), 200 W AES \/ 400 W continuous power handling, and a 4-ohm nominal impedance, the driver provides substantial low-frequency displacement capability for its size class.\nIn sealed enclosures, the driver's Qts of 0.6 produces well-controlled alignments in net internal volumes of 11 to 25 liters. A compact 11-liter sealed enclosure (Qtc 1.0, fc 68 Hz) provides a punchy, space-efficient design that relies on room gain for in-room extension below 50 Hz. A 20-liter sealed enclosure (Qtc 0.85, fc 58 Hz) is the recommended starting point for most hi-fi applications, producing a warm, musical response with estimated in-room extension to 38\u201342 Hz in typical domestic listening rooms. A 25-liter enclosure (Qtc 0.80, fc 55 Hz) extends the anechoic response further and provides near-flat amplitude for critical listening applications. In all sealed alignments, typical domestic room gain (+3\u20136 dB below 50\u201360 Hz) significantly extends the effective in-room bass response below the anechoic -3 dB point.\nFor applications requiring deeper anechoic extension, vented or passive radiator configurations in 8 to 11 liters tuned between 39 and 47 Hz extend the -3 dB point to approximately 33\u201343 Hz. Port lengths exceed 500 mm at these tuning frequencies, making folded slot ports or passive radiators the practical implementation choices. A passive radiator of similar Sd and excursion capability, tuned to 40\u201345 Hz, provides clean bass extension without port noise artifacts and is the recommended alternative to vented loading for compact hi-fi subwoofer enclosures."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/8FHW-088-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/8FHW-088-1.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHW-088-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHW-088-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHW-088-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHW-088-3D.STEP"}},{"code":"81FINDX8-290","name":"81FIND","slug":"81findx8-290","description":"Mid-Woofer\/8inch\/Ferrite\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/81findx8-290","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"Glass Fiber","winding_height":"12.5"},"thiele_small_parameters":{"fs_hz":80,"re_ohm":4.7,"qes":0.53,"qms":8.35,"qts":0.5,"vas_liters":11.3,"sd_cm2":213.8,"sensitivity_db":94.68,"mms_grams":22.6,"rms":1.36,"cms":0.18,"bl_tm":10.2,"le_mh":0.44},"physical":{"overall_diameter_mm":209,"bolt_circle_diameter_mm":197,"baffle_cutout_diameter_mm":180,"mounting_holes":"8","depth_mm":91.5,"net_weight_kg":2.8,"xmax_mm":"2.25","xmech_mm":"10.25"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Ideal for small and portable 2-way systems","Affordable, yet very capable design for cost sensitive product"],"design_notes":"The 81FIND is a high efficiency, (95 dB 1watt \/ 1 meter) 8-inch woofer with linear frequency response characteristics, good power handling capability while generating low harmonic distortion artifacts. The 81FIND uses a lightweight glass-fiber loaded cone assembly along with a high excursion M-roll surround. This combination provides a lightweight, yet strong, piston.\n\nMagnetic Circuit\n\nFerrite based magnetic circuit, capable of delivering the good level of performance, providing a consistent, high integrity magnetic flux gap, low distortion characteristic and high-efficiency cooling system. The metal parts are extensively coated to provide the maximum weather protection. \n\n\nThis driver has been chosen by many audio engineers for smaller sized, or portable audio products. It has proven its capability over and over again all around the world, many times in challenging applications or environments. 81FIND is proven design that delivers good balance between performance and cost.","hero_text":null,"ai_summary":"This driver is particularly effective in compact 2-way portable loudspeakers, small-format installation systems, and cost-effective product lines for touring, rental, and fixed-install applications. The weather-coated ferrite motor assembly and proven construction provide long-term reliability in demanding environments, and the balanced cost-to-performance ratio makes it an established choice for engineers designing competitively priced professional audio products.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 81FINDX8-290\nDriver: 81FINDX8-290 (81FIND) \u2014 8\" Mid-Woofer\nKey T\/S: Fs=80Hz, Qts=0.5, Vas=11.3L, Sens=94.7dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=2.25mm, Sd=213.8cm\u00b2, Bl=10.2T\u00b7m, Re=4.7\u03a9\nVoice Coil: 2\" CCAW on glass fiber former (12.5mm winding height)\nMagnet: Ferrite | Cone: Glass-fiber loaded paper | Surround: Fabric (M-roll)\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nNOTE: With Qts=0.5 and Vas=11.3L, this 8\" mid-woofer is well-suited\nto compact vented enclosures in the 6\u20139 liter range. The moderate Qts\nprovides good cone control while maintaining usable output across the\nlow-frequency bandwidth. Port velocities remain very low (<9 m\/s)\nacross all alignments due to the modest Xmax, indicating clean port\nbehavior at all drive levels.\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 standard for compact\n8\" enclosures; provides adequate cross-sectional area with low air\nvelocity at all alignments.\nVENTED ALIGNMENTS:\n a) High SPL\n Net Volume: 6 liters\n Tuning (Fb): 92 Hz\n Est. -3dB: 83 Hz\n HP Filter: 84 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 147mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 275mm L\n Port Velocity: 8.4 m\/s\n Notes: Compact enclosure, strong mid-bass impact, maximum\n output per cabinet volume. Ideal for small portable 2-way\n systems where cabinet size is the primary constraint.\n b) Balanced Response\n Net Volume: 7 liters\n Tuning (Fb): 85 Hz\n Est. -3dB: 76 Hz\n HP Filter: 75 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 148mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 277mm L\n Port Velocity: 7.7 m\/s\n Notes: General-purpose alignment, even response through the\n low-frequency range with good transient behavior. Suitable for\n most 2-way portable and installation applications.\n c) Extended Low Frequency\n Net Volume: 9 liters\n Tuning (Fb): 76 Hz\n Est. -3dB: 68 Hz\n HP Filter: 64 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 143mm long\n Slot Port: 144mm W \u00d7 40mm H \u00d7 267mm L\n Port Velocity: 6.9 m\/s\n Notes: Maximum low-frequency extension, deeper bass response.\n Requires proper high-pass protection below tuning. Best for\n applications where low-end reach is prioritized over cabinet\n compactness.\nSEALED ALTERNATIVE (for reference):\nFor applications requiring sealed enclosure simplicity (e.g., compact\nmonitors or bandpass-filtered mid-bass systems):\n Butterworth (Qtc\u22480.707): 11L, fc=113Hz\n Compact sealed (Qtc\u22480.8): 7L, fc=129Hz\nSealed volumes are larger relative to bass reflex for equivalent LF\nextension, making vented the preferred choice for this driver.\nDESIGN NOTE: The ferrite motor with weather-coated metalwork and\nthe proven glass-fiber loaded paper cone make this driver particularly\nsuitable for portable and semi-outdoor applications. The balanced\ncost-to-performance ratio positions the 81FIND as an effective choice\nfor cost-sensitive product lines without compromising reliability.\n--- AI SUMMARY (copy\/paste ready) ---\nThe 81FINDX8-290 is an 8-inch ferrite mid-woofer designed for professional portable and installation loudspeaker systems requiring reliable performance across the 70\u20133000 Hz operating range. With a sensitivity of 95 dB (1W\/1m), a 2-inch CCAW voice coil on a glass fiber former, and a glass-fiber loaded paper cone with M-roll fabric surround, the driver provides a balanced combination of efficiency, power handling, and extended frequency response. The motor-suspension design (Qts 0.5) provides good cone control while maintaining usable output across its operating bandwidth, making it well-suited to compact vented enclosures.\nRecommended enclosure alignments (bass reflex) use net internal volumes of 6 to 9 liters with tuning frequencies between 76 and 92 Hz. Smaller volumes (6\u20137 liters tuned to 85\u201392 Hz) maximize mid-bass output and cabinet compactness, ideal for portable 2-way systems where size and weight are primary constraints. Larger volumes approaching 9 liters with lower tuning (76 Hz) extend the usable low-frequency response to approximately 68 Hz (\u20133 dB), suitable for applications where deeper bass extension is required. Port velocities remain well below critical limits across all alignments, ensuring clean port behavior at rated power.\nThe driver is rated for approximately 200 W AES \/ 400 W continuous power handling and is intended for use with DSP-controlled amplification. A high-pass filter in the range of 64\u201384 Hz (24 dB\/octave Linkwitz-Riley) is recommended depending on enclosure tuning, along with appropriate limiting to manage thermal and mechanical stress during sustained operation. Typical crossover to a high-frequency driver is in the 1.5\u20133 kHz region depending on system architecture."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/81FIND-290-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/81FIND-290-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/81FIND-290-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/81FIND-290-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/81FIND-290-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/81FIND-290-3D.STEP"}},{"code":"81NPMX8-373A","name":"81NPM","slug":"81npmx8-373a","description":"Mid-Range\/8inch\/Neo\/400W\/8ohm","url":"https:\/\/redcatt.net\/products\/81npmx8-373a","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"76.2","wire":"CCAW","former":"Glass Fiber","winding_height":"18.6"},"thiele_small_parameters":{"fs_hz":69,"re_ohm":7.4,"qes":0.29,"qms":4.84,"qts":0.28,"vas_liters":10.3,"sd_cm2":219,"sensitivity_db":93.05,"mms_grams":34.2,"rms":3.06,"cms":0.156,"bl_tm":19.3,"le_mh":0.75},"physical":{"overall_diameter_mm":210,"bolt_circle_diameter_mm":195.5,"baffle_cutout_diameter_mm":186.88,"mounting_holes":"8","depth_mm":101.3,"net_weight_kg":3.2,"xmax_mm":"4.05","xmech_mm":"14.55"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","2 demodulation rings powerful motor structure","Designed for 2-way and multi-way speaker systems"],"design_notes":"The 81NPM was designed for good reproduction of voice. With an extended low-frequency response, this mid-woofer is highly suitable for two-way and multi-way systems. It\u2019s high power handling capabilities extend the ideal usage as a mid-range driver in line-array systems. The 81NPM uses a lightweight half-pressed paper cone reinforced by our proprietary cone treatment, which also works as weatherization protection. The used high-quality components ensure long-lasting performance even in high powered applications. The chosen material combination provides remarkable strength, high efficiency and\u00a0sustained output under extreme conditions.\u00a0\n\nPower Handling\nThe voice coil sports Kapton former material capable of withstanding peak temperatures above 300\u00b0C, well beyond the thermal requirements of modern audio systems. Former strength provides the ideal transfer of power between the voice coil and the cone assembly and assists in reducing distortion artifacts. By combining this material with state of the art adhesives and our winding voice coil technology, the 81NPM delivers incredibly high performance.","hero_text":null,"ai_summary":"This driver is suitable for both vented (mid-woofer) and sealed (midrange) enclosure configurations depending on the system architecture. In bass reflex enclosures, recommended net internal volumes range from 10 to 14 liters with tuning frequencies between 54 and 71 Hz. Smaller volumes (10\u201312 liters tuned to 62\u201371 Hz) prioritize mid-bass output and cabinet compactness for portable 2-way systems, while 14 liters tuned to 54 Hz extends the usable low-frequency response to approximately 46 Hz (\u20133 dB) for stand-alone applications without dedicated subwoofers. Port velocities remain very low (9\u201312 m\/s) across all vented alignments. In sealed enclosures for midrange duty, the driver performs in very compact net internal volumes of 0.9 to 1.9 liters, producing system resonances between 174 and 246 Hz. Smaller sealed volumes (0.9\u20131.3 liters, Qtc 0.85\u20131.0) maximize acoustic output in the midrange passband for line array modules and horn-loaded midrange systems, while 1.9 liters yields a Butterworth-class response (Qtc 0.707) with maximally flat amplitude for accuracy-focused applications.\nThe driver requires active DSP crossover management in both configurations. In vented mid-woofer use, a high-pass filter in the range of 44\u201361 Hz (24 dB\/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.2\u20133 kHz. In sealed midrange use, a high-pass filter in the range of 170\u2013350 Hz is recommended depending on enclosure volume and system architecture. In both cases, appropriate limiting is required to manage thermal and mechanical stress during sustained operation.\nThis driver is particularly effective in professional touring line arrays, compact 2-way portable loudspeakers, multi-way point-source cabinets, and installation systems where versatility across mid-woofer and midrange roles, high power handling, low distortion, and environmental durability are priorities. The neodymium motor with demodulation rings, lightweight cone assembly, and weatherized treatment provide consistent performance in demanding touring and outdoor environments.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 81NPMX8-373A\nDriver: 81NPMX8-373A (81NPM) \u2014 8\" Mid-Woofer \/ Midrange\nKey T\/S: Fs=69Hz, Qts=0.28, Vas=10.3L, Sens=93dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=4.05mm, Sd=219cm\u00b2, Bl=19.3T\u00b7m, Re=7.4\u03a9, Mms=34.2g\nVoice Coil: 3\" CCAW on glass fiber former (18.6mm winding height)\nMagnet: Neodymium | Cone: Half-pressed paper (weatherized treatment)\nSurround: Fabric | Spider: Nomex | Basket: Aluminum\nMotor: 2 demodulation rings, neodymium\nNOTE: This driver's very low Qts (0.28) and strong neodymium motor\n(Bl=19.3 T\u00b7m) with demodulation rings make it highly suited to BOTH\nvented mid-woofer and sealed midrange applications. Compared to the\n81NPMX8-263 variant, this model has a stronger motor, lighter moving\nmass (34.2g vs 40.5g), lower Qts (0.28 vs 0.33), and reduced Xmax\n(4.05mm vs 6mm). This shifts the design toward tighter cone control\nand lower distortion at the expense of maximum excursion-limited output.\nSix enclosure alignments are provided below \u2014 three vented (mid-woofer\nuse) and three sealed (midrange use).\n MID-WOOFER APPLICATION \u2014 Bass Reflex (Vented)\nUse case: 2-way and multi-way systems where the 81NPM handles the\nlow-frequency and lower-midrange content, typically crossed over to\na compression driver or tweeter at 1.2\u20133 kHz.\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 standard for compact\n8\" bass reflex enclosures. Port velocities are very low across all\nalignments (9\u201312 m\/s), well within limits for all professional\napplications including studio monitors. No flaring required, though\nrecommended for best practice.\n a) VENTED \u2014 High SPL\n Net Volume: 10 liters\n Tuning (Fb): 71 Hz\n Est. -3dB: 65 Hz\n HP Filter: 61 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 149mm long\n Slot Port: 156mm W \u00d7 40mm H \u00d7 278mm L\n Port Velocity: 11.9 m\/s\n Notes: Compact alignment with strong mid-bass control.\n The very low Qts provides tight, well-damped low-frequency\n response with excellent transient behavior. Ideal for compact\n 2-way tops, stage monitors, and portable systems where\n controlled bass and vocal clarity are priorities.\n b) VENTED \u2014 Balanced Response\n Net Volume: 12 liters\n Tuning (Fb): 62 Hz\n Est. -3dB: 53 Hz\n HP Filter: 52 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 167mm long\n Slot Port: 156mm W \u00d7 40mm H \u00d7 311mm L\n Port Velocity: 10.4 m\/s\n Notes: General-purpose alignment with even response through\n the bass region. Good balance between low-frequency extension\n and cabinet size. Well-suited for most 2-way PA tops, multi-way\n systems, and installation loudspeakers.\n c) VENTED \u2014 Extended Low Frequency\n Net Volume: 14 liters\n Tuning (Fb): 54 Hz\n Est. -3dB: 46 Hz\n HP Filter: 44 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 195mm long\n Slot Port: 156mm W \u00d7 40mm H \u00d7 363mm L\n Port Velocity: 9.1 m\/s\n Notes: Maximum low-frequency extension, reaching well into\n the sub-bass region. The strong motor maintains cone control\n even at these lower tuning frequencies. Best for stand-alone\n 2-way systems without dedicated subwoofers, or applications\n where deep bass extension is a requirement. Requires proper\n high-pass protection below tuning.\n MIDRANGE APPLICATION \u2014 Sealed\nUse case: Line array midrange sections, coaxial cabinets, horn-loaded\nmidrange systems, or dedicated mid-high enclosures where the 81NPM\nhandles the midrange band (typically 250\u20133000 Hz or narrower), with\nbass duties handled by separate woofer\/subwoofer sections.\n d) SEALED \u2014 High SPL (Qtc \u2248 1.0)\n Net Volume: 0.9 liters\n System Resonance (fc): 246 Hz\n Qtc: 1.0\n Response: Broad gentle lift near fc, maximum midrange output\n Crossover HP: 250\u2013350 Hz (24dB\/oct LR recommended)\n Notes: Very compact sealed chamber for maximum acoustic\n output in the midrange passband. The elevated Qtc provides\n a gentle broad peak near system resonance that can be\n equalized flat via DSP or used as a passband sensitivity\n boost. Ideal for high-SPL touring line arrays and horn-loaded\n midrange systems where output per driver is the primary\n requirement. The very low Qts (0.28) keeps the resonance\n peak well-controlled even at Qtc=1.0.\n e) SEALED \u2014 Balanced (Qtc \u2248 0.85)\n Net Volume: 1.3 liters\n System Resonance (fc): 209 Hz\n Qtc: 0.85\n Response: Slightly warm, smooth transition through resonance\n Crossover HP: 200\u2013280 Hz (24dB\/oct LR recommended)\n Notes: Good compromise between midrange output and response\n flatness. The slight warmth near resonance is easily managed\n with DSP. Suitable for most professional midrange applications\n including line arrays, point-source cabinets, and stage monitors.\n f) SEALED \u2014 Butterworth (Qtc \u2248 0.707)\n Net Volume: 1.9 liters\n System Resonance (fc): 174 Hz\n Qtc: 0.707\n Response: Maximally flat amplitude, textbook Butterworth alignment\n Crossover HP: 170\u2013220 Hz (24dB\/oct LR recommended)\n Notes: Flattest possible sealed response with lowest system\n resonance. Allows a lower crossover frequency if needed,\n providing extended lower-midrange coverage. Best for\n applications prioritizing accuracy, smooth crossover\n integration, and minimal DSP correction.\nTHERMAL NOTE: The neodymium motor and aluminum basket provide efficient\nthermal dissipation. The 3\" CCAW voice coil on glass fiber former\nsupports sustained high-power operation. For sealed midrange chambers\n(especially \u22641.0L), ensure adequate ventilation or thermal coupling\nbetween the motor and the enclosure structure. The hero text notes\nKapton-grade thermal tolerance (>300\u00b0C peak) on the former material.\nDESIGN NOTE: The 2 demodulation rings reduce harmonic and\nintermodulation distortion \u2014 particularly beneficial in midrange\napplications where distortion artifacts are more audible. The\nweatherized cone treatment provides environmental protection for\noutdoor and semi-permanent installation use.\nCOMPARISON vs 81NPMX8-263:\n Parameter 263 373A Implication\n Qts 0.33 0.28 373A: tighter motor control\n Bl 16.7 T\u00b7m 19.3 T\u00b7m 373A: stronger motor force\n Mms 40.5g 34.2g 373A: lighter, faster response\n Xmax 6.0mm 4.05mm 263: more excursion headroom\n Vented volumes 9\u201312L 10\u201314L 373A: slightly larger boxes\n Sealed volumes 1.3\u20132.9L 0.9\u20131.9L 373A: more compact midrange\n Port velocity 15\u201320 m\/s 9\u201312 m\/s 373A: lower (less Xmax)\nThe 373A variant favors midrange clarity and low distortion with its\nstronger motor and lighter cone, while the 263 offers more excursion\ncapability for higher-SPL mid-woofer applications.\n--- AI SUMMARY (copy\/paste ready) ---\nThe 81NPMX8-373A is an 8-inch neodymium mid-woofer designed for professional two-way, multi-way, and line array systems requiring high power handling (200 W AES \/ 400 W continuous), tight motor control, and low-distortion reproduction. It features a 3-inch CCAW voice coil on a glass fiber former with Kapton-grade thermal tolerance, a weatherized half-pressed paper cone with fabric surround, and a neodymium motor with 2 demodulation rings for reduced harmonic and intermodulation distortion. With a sensitivity of 93 dB (1W\/1m) and a very low Qts of 0.28, the motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/81NPM-373A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/81NPM-373A-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/81NPM-373A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/81NPM-373A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/81NPM-373A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/81NPM-373A-3D.STEP"}},{"code":"81XRX8-424A","name":"81XR","slug":"81xrx8-424a","description":"Woofer\/XR Woofer\/8inch\/Neo\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/81xrx8-424a","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":true,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"63.5","wire":null,"former":"Glass Fiber","winding_height":"18.3"},"thiele_small_parameters":{"fs_hz":73,"re_ohm":5.5,"qes":0.37,"qms":1.47,"qts":0.3,"vas_liters":7.2,"sd_cm2":201,"sensitivity_db":93,"mms_grams":38,"rms":11.9,"cms":0.13,"bl_tm":16,"le_mh":0.19},"physical":{"overall_diameter_mm":210,"bolt_circle_diameter_mm":195,"baffle_cutout_diameter_mm":186.88,"mounting_holes":"8","depth_mm":128.3,"net_weight_kg":4.9,"xmax_mm":"6.35","xmech_mm":"25"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["Nonparallel voice and low frequency reproduction quality","Patented magnetic circuit and air venting design","Extremely low harmonic distortion"],"design_notes":"The 81XR was designed to be simply the best driver for 2-way and multi-way systems on the market, yet this driver will also shine in sub-woofer applications. The combination of our XR patented technology with static shorting coil brings an nonparallel opportunity to the audio designers. The common request for 2-way speakers is \u201cmore of everything\u201d. Designers wishes for more bass, more mids. Well, there you have it! But not only that. We bring this with clarity in the mid-frequencies and undistorted bass. Our designers were able to achieve THD below 0.5% from 20Hz up to 2.5kHz. There isn\u2019t another driver like this on the market.\n\nMotor Design\nThe magnetic design incorporates large neodymium magnets placed along the voice coil winding, together with the 2nd and static coil placed on the pole piece. This has allowed us to push the cone excursion to 30mm peak to peak, while lowering the inductance. The shorting coil covers the complete main coil excursion. This is also an improvement compared to some previous designs on the market that utilizes static coil. Unique gap side venting ensures good air circulation, lowers air noise and greatly improves the reliability of this driver.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 81XRX8-424A\nDriver: 81XRX8-424A (81XR) \u2014 8\" Mid-Woofer\nKey T\/S: Fs=73.0Hz, Qts=0.3, Vas=7.2L, Sens=93.0dB\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=6.35mm, Sd=201.0cm\u00b2, Bl=16.0T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 adequate for compact enclosures with lower air volume velocity\n a) High SPL\n Net Volume: 8 liters\n Tuning (Fb): 75 Hz\n Est. -3dB: 69 Hz\n HP Filter: 67 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 201mm long\n Slot Port: 150mm W \u00d7 40mm H \u00d7 384mm L\n Port Velocity: 18.2 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 8 liters\n Tuning (Fb): 68 Hz\n Est. -3dB: 58 Hz\n HP Filter: 58 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 230mm long\n Slot Port: 150mm W \u00d7 40mm H \u00d7 436mm L\n Port Velocity: 16.4 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 10 liters\n Tuning (Fb): 59 Hz\n Est. -3dB: 50 Hz\n HP Filter: 47 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 262mm long\n Slot Port: 150mm W \u00d7 40mm H \u00d7 493mm L\n Port Velocity: 14.3 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 81XRX8-424A is a 8-inch mid-woofer driver designed for professional 2-way and multi-way systems with 93.0 dB sensitivity (1W\/1m). The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 8 to 10 liters, tuned between 59 and 75 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with moderate amplification (approx. 200 W AES \/ 400 W continuous) and DSP control. A high-pass filter in the range of 47\u201367 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 50\u20132500 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/81XR-424A-1.png","https:\/\/redcatt.net\/storage\/products\/web\/81XR-424A-2.png"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/81XR-424A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/81XR-424A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/81XR-424A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/81XR-424A-3D.STEP"}},{"code":"82FHMX8-445A","name":"82FHW","slug":"82fhmx8-445a","description":"Woofer\/8inch\/Ferrite\/Aluminium\/60W\/8ohm","url":"https:\/\/redcatt.net\/products\/82fhmx8-445a","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"60","continuous_watts":"120","peak_watts":"240"},"voice_coil":{"diameter":"38","wire":"Copper","former":"Aluminum","winding_height":"15.9"},"thiele_small_parameters":{"fs_hz":42,"re_ohm":5.7,"qes":0.76,"qms":3.1,"qts":0.61,"vas_liters":33.6,"sd_cm2":213.8,"sensitivity_db":88.31,"mms_grams":28.3,"rms":2.41,"cms":0.51,"bl_tm":7.56,"le_mh":0.47},"physical":{"overall_diameter_mm":223.5,"bolt_circle_diameter_mm":210,"baffle_cutout_diameter_mm":189,"mounting_holes":"6","depth_mm":87.5,"net_weight_kg":1.8,"xmax_mm":"5.45","xmech_mm":"10.45"},"materials":{"surround":"NBR","cone_dome":"Aluminum","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","Hard anodized aluminum cone with rubber surround","Aluminum basket"],"design_notes":"82FHM is mid-woofer driver, designed for hi-fi, studio monitors and outdoor applications. Design sports hard-anodized aluminum cone and dustcap. These two key components extend the working range of the woofer. The parameters were optimized for usage in sealed enclosures. \n\tAll metal parts are coated to further increase weatherized protection, surround has UV stabilizers. \n\tStrong aluminum basket was used in this design which further improves the mechanical fatigue and allow the speaker to be used in demanding portable products. \n\tFurther more, we have developed new magnetic circuit for this model. Our clever engineering takes the best balance between the performance and cost. Rest assure we have FEM optimized air-venting of this design that minimizes the air-noise and greatly improves voice coil winding venting.","hero_text":null,"ai_summary":"The 82FHMX8-445A is an 8-inch mid-woofer designed for outdoor hi-fi systems, bar and hospitality installations, and two-way domestic enclosures. It features a hard-anodized aluminum cone and dustcap, UV-stabilized NBR rubber surround, coated aluminum basket, and Nomex spider, providing weatherized construction rated from \u221230 \u00b0C to +70 \u00b0C. With a sensitivity of 88.31 dB (1 W\/1 m) and a Qts of 0.61, this driver uses a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response.\n\nThis model is optimized for sealed (acoustic suspension) enclosures, as specified by the manufacturer. Three alignments are recommended:\n- 10 litres (Qtc = 1.27, \u22123 dB \u2248 63 Hz) \u2192 compact bookshelf or satellite; pair with subwoofer at 80\u2013120 Hz\n- 15 litres (Qtc = 1.10, \u22123 dB \u2248 57 Hz) \u2192 compact stand-mount 2-way; mild low-bass warmth in domestic rooms\n- 20 litres (Qtc = 1.00, \u22123 dB \u2248 54 Hz) \u2192 flat monitor alignment; floor-standing hi-fi and bar satellite cabinets\n\nFor high-output bar and outdoor applications, vented (bass reflex) enclosures of 35\u201370 litres tuned to 33\u201348 Hz are a supplementary option, using a 75 mm round port of approximately 164\u2013174 mm length across all three tunings.\n\nThe 82FHMX8-445A handles approx. 60 W AES and 120 W continuous power. A high-pass filter in the 40\u201380 Hz range is recommended depending on alignment and application. The operating bandwidth is approximately 50\u20131,300 Hz, with cone beaming onset near 1,327 Hz and inductance rolloff near 1,930 Hz; a crossover to a dome tweeter or compression driver at 1.5\u20133.0 kHz is required in all two-way systems. DSP or passive high-pass filtering is mandatory in compact satellite alignments to prevent over-excursion below the box tuning frequency.\n\nThis driver is suited for single-driver two-way sealed enclosures in outdoor hi-fi speakers, patio and garden speakers, bar and restaurant background-music satellite cabinets, bookshelf and stand-mount monitors, subwoofer-satellite home audio systems, and surface-mount or column speakers in humidity- and UV-exposed installed audio environments. The weatherized materials and aluminum cone construction prioritize long-term durability and consistent acoustic performance across varying environmental conditions.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 82FHMX8-445A\nGenerated: 2026-04-12\nApplication: Outdoor hi-fi, bars\/hospitality, 2-way home systems\nDRIVER SPECIFICATIONS\nCode : 82FHMX8-445A\nDescription : 8\" Ferrite Mid-Woofer \u2014 Hard-Anodized Aluminum Cone\nNominal Impedance: 8 \u03a9\nAES Power : 60 W\nContinuous Power : 120 W\nPeak Power : 240 W\n\nFs : 42 Hz\nRe : 5.7 \u03a9\nQes : 0.76\nQms : 3.1\nQts : 0.61\nVas : 33.6 L\nSd : 213.8 cm\u00b2\nSensitivity : 88.31 dB (1 W \/ 1 m)\nMms : 28.3 g\nRms : 2.41 kg\/s\nCms : 0.51 mm\/N\nBl : 7.56 T\u00b7m\nLe : 0.47 mH\nXmax : 5.45 mm (one-way, peak)\nXmech : 10.45 mm\n\nVoice Coil : 38 mm, Copper wire, Aluminum former\nCone \/ Dustcap : Hard-anodized aluminum\nSurround : NBR rubber (UV-stabilized)\nSpider : Nomex\nBasket : Aluminum (coated)\nMagnet : Ferrite\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 213.8 cm\u00b2 \u00d7 0.545 cm = 116.5 cm\u00b3\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 5.7 \/ (2\u03c0 \u00d7 0.00047) \u2248 1,930 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(213.8 \/ 3.14159) = 8.25 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 8.25) \u2248 1,327 Hz\n\nWorking band : ~50 Hz \u2013 1,300 Hz\nTweeter crossover : 1.5 \u2013 3.0 kHz (acoustic target)\n Le onset at ~1,930 Hz provides a natural HF roll-off before\n the crossover network; a 2nd-order passive network at 2.0\u20132.5 kHz\n is the typical design point.\n\nMaximum SPL (anechoic, 1 m)\n At 60 W AES : 88.31 + 10\u00b7log\u2081\u2080(60) = 88.31 + 17.8 = 106.1 dB\n At 120 W cont : 88.31 + 10\u00b7log\u2081\u2080(120) = 88.31 + 20.8 = 109.1 dB\n In-room \/ bar : add ~3\u20136 dB room gain below 80 Hz\nENCLOSURE RECOMMENDATION\nQts = 0.61 \u2192 Sealed (acoustic suspension) is the primary\nrecommendation. The manufacturer explicitly states that\nparameters are optimized for sealed enclosures. Room gain in\nhome and bar environments further extends perceived bass.\n\nVented (bass reflex) alignments are provided below as an\nalternative for high-output bar and outdoor applications\nwhere maximum SPL and lower excursion at moderate levels are\nprioritized over transient accuracy. Vented boxes are\nsignificantly larger than their sealed counterparts.\nSEALED ENCLOSURE ALIGNMENTS\nFormula: Vb = Vas \/ ((Qtc \/ Qts)\u00b2 \u2212 1)\n fc = Fs \u00d7 (Qtc \/ Qts)\n f-3dB: u = [\u2212(2 \u2212 1\/Qtc\u00b2) + \u221a((2 \u2212 1\/Qtc\u00b2)\u00b2 + 4)] \/ 2\n \u03a9 = \u221au ; f-3dB = \u03a9 \u00d7 fc\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Qtc \u2502 fc \u2502 f\u22123dB \u2502 Character \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 20 L \u2502 1.00 \u2502 68.9 Hz\u2502 54 Hz \u2502 Flat, monitor \u2502\n\u2502 B \u2502 15 L \u2502 1.10 \u2502 75.7 Hz\u2502 57 Hz \u2502 Compact 2-way \u2502\n\u2502 C \u2502 10 L \u2502 1.27 \u2502 87.5 Hz\u2502 63 Hz \u2502 Bookshelf \/ sat \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\n--- Alignment A \u2014 20 L sealed \/ Qtc = 1.00 ---\n Vb = 33.6 \/ ((1.00\/0.61)\u00b2 \u2212 1) = 33.6 \/ 1.687 = 19.9 L \u2192 20 L\n fc = 42 \u00d7 (1.00\/0.61) = 68.9 Hz\n f-3dB: 2\u22121\/Qtc\u00b2=1.000; \u221a(1+4)=2.236; u=(\u22121+2.236)\/2=0.618; \u03a9=0.786\n f-3dB = 0.786 \u00d7 68.9 = 54 Hz\n\n Target applications: Floor-standing hi-fi 2-way; large stand-mount\n monitor; bar or restaurant satellite enclosure placed near walls.\n Flat bass response with no overhang; preferred for studio monitors\n and audiophile stereo. With 3\u20135 dB room gain in a domestic room,\n perceived bass extends to ~45 Hz.\n\n--- Alignment B \u2014 15 L sealed \/ Qtc = 1.10 ---\n Vb = 33.6 \/ ((1.10\/0.61)\u00b2 \u2212 1) = 33.6 \/ 2.252 = 14.9 L \u2192 15 L\n fc = 42 \u00d7 (1.10\/0.61) = 75.7 Hz\n f-3dB: 2\u22121\/1.21=1.174; \u221a(1.379+4)=2.319; u=(\u22121.174+2.319)\/2=0.573; \u03a9=0.757\n f-3dB = 0.757 \u00d7 75.7 = 57 Hz\n\n Target applications: Compact 2-way stand-mount; bar satellite\n speaker; outdoor column speaker housing; 2-way portable enclosure.\n Mild low-bass shelf boost (~1\u20132 dB around 75\u2013100 Hz) gives a\n subjectively warm, full bass in domestic rooms. A practical balance\n between box size and low-frequency extension.\n\n--- Alignment C \u2014 10 L sealed \/ Qtc = 1.27 ---\n Vb = 33.6 \/ ((1.27\/0.61)\u00b2 \u2212 1) = 33.6 \/ 3.335 = 10.1 L \u2192 10 L\n fc = 42 \u00d7 (1.27\/0.61) = 87.5 Hz\n f-3dB: 2\u22121\/1.613=1.380; \u221a(1.904+4)=2.430; u=(\u22121.380+2.430)\/2=0.525; \u03a9=0.725\n f-3dB = 0.725 \u00d7 87.5 = 63 Hz\n\n Target applications: Bookshelf speaker; compact outdoor enclosure;\n under-bar fill speaker; satellite in a subwoofer-satellite system.\n Prominent bass shelf boost (~3 dB around 80\u2013100 Hz); perceived bass\n sounds full in small rooms due to coincident room gain.\n High-pass filter mandatory: 80 Hz, 12\u201324 dB\/oct (DSP or passive\n Butterworth) to prevent over-excursion below fc.\n Best paired with subwoofer crossed over at 80\u2013120 Hz.\n\n--- Notes for all sealed alignments ---\n \u2022 Recommended system-level high-pass filter: 40\u201380 Hz (selection\n depends on alignment and application).\n \u2022 Room gain adds 3\u20136 dB below 80 Hz in typical home\/bar rooms;\n anechoic f-3dB values above will be 1.0\u20131.5 octaves higher than\n the in-room perceived bass extension.\n \u2022 Zobel network improves crossover flatness where passive networks\n are used: R_z = Re = 5.7 \u03a9 ; C_z = Le \/ Re\u00b2 = 0.47e-3 \/ 32.49\n = 14.5 \u03bcF \u2192 use 15 \u03bcF, 100 V non-polar standard value.\nVENTED ENCLOSURE ALIGNMENTS (HIGH-OUTPUT OPTION)\nFor bars, outdoor installations, and applications where\nmaximum SPL and reduced cone excursion at moderate levels\nare prioritized. Boxes are 1.5\u20133\u00d7 larger than sealed.\n\nPort: 75 mm round (Ap = 44.18 cm\u00b2)\n Port velocity limit: \u2264 17 m\/s (hi-fi \/ install standard)\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2\n 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 116.5 cm\u00b3 = 1.165 \u00d7 10\u207b\u2074 m\u00b3 ; Ap = 4.418 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 75mm Port Length \u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 35 L \u2502 48 Hz \u2502 164 mm \u2502 7.9 m\/s \u2713 \u2502\n\u2502 B \u2502 50 L \u2502 40 Hz \u2502 166 mm \u2502 6.6 m\/s \u2713 \u2502\n\u2502 C \u2502 70 L \u2502 33 Hz \u2502 174 mm \u2502 5.5 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (75 mm round port):\n Alignment A: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 2304 \u00d7 35,000)\n = 5.228\u00d710\u00b9\u2070 \/ 3.183\u00d710\u2079 = 164 mm\n Alignment B: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 1600 \u00d7 50,000)\n = 5.228\u00d710\u00b9\u2070 \/ 3.158\u00d710\u2079 = 166 mm\n Alignment C: Leff = (44.18 \u00d7 1,183,360,000) \/ (39.478 \u00d7 1089 \u00d7 70,000)\n = 5.228\u00d710\u00b9\u2070 \/ 3.010\u00d710\u2079 = 174 mm\n\nPort engineering note: All three vented alignments produce\nnear-identical port lengths (164\u2013174 mm). Larger box volume and\nlower tuning frequency cancel each other in the Helmholtz equation\n\u2014 lower Fb\u00b2 is offset by proportionally larger Vb. A single\n75 mm \u00d7 170 mm port tube (with minor end-trimming) serves all\nthree tunings, simplifying production tooling.\n\n--- Vented Alignment A \u2014 35 L \/ Fb = 48 Hz ---\n Tuning above Fs (48 Hz vs Fs 42 Hz). Modest bass extension with\n strong output protection above the port tuning frequency. Clean\n output from ~50 Hz in a compact(ish) vented cabinet. Good for\n bar fill speakers and outdoor stereo where sub-50 Hz bass is\n not required.\n\n--- Vented Alignment B \u2014 50 L \/ Fb = 40 Hz ---\n Near-Fs tuning. Extended response to ~38 Hz (4th-order rolloff\n below Fb). Preferred for high-quality outdoor stereo or bar\n stereo where ~40 Hz bass reproduction is required without a\n separate subwoofer.\n\n--- Vented Alignment C \u2014 70 L \/ Fb = 33 Hz ---\n Below-Fs tuning. Maximum bass extension into the upper 30s Hz.\n Large box for an 8\" driver; suited for floor-standing or tower\n vented enclosures in bar or patio stereo systems.\n Mandatory high-pass filter at 25\u201330 Hz to protect driver\n below the port roll-off (4th-order slope begins below Fb).\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to tweeter (acoustic target): 1.5 \u2013 3.0 kHz\n f_beam = 1,327 Hz (cone directivity increases above this)\n f_Le = 1,930 Hz (inductive roll-off onset)\n\nRecommended crossover order: 2nd-order (12 dB\/oct) minimum;\n 3rd or 4th-order preferred at 2.0\u20132.5 kHz for controlled\n off-axis response above 1.3 kHz. Aluminum cone maintains\n pistonic response closer to f_Le than paper or PP cones of\n equal diameter, allowing a higher crossover frequency if\n directivity is not a primary concern.\n\nZobel network (for passive crossover precision):\n R_z = 5.7 \u03a9 (standard 5.6 \u03a9 resistor acceptable)\n C_z = 15 \u03bcF, 100 V non-polar (nearest standard to 14.5 \u03bcF)\n Place across driver terminals inside the enclosure.\nMATERIALS AND DURABILITY NOTES\n \u2022 Hard-anodized aluminum cone: rigid, damp-proof, UV-stable;\n extends HF pistonic range; resists condensation and salt air.\n \u2022 NBR rubber surround: UV-stabilized; rated \u221230 \u00b0C to +70 \u00b0C;\n suitable for all-season outdoor and coastal installations.\n \u2022 Aluminum basket (coated): corrosion-resistant; structurally\n rigid; reduces chassis resonance in portable enclosures.\n \u2022 Nomex spider: heat-resistant; suited for sustained high-power\n bar operation in warm ambient environments.\n \u2022 Ferrite magnet: thermally stable; no demagnetization risk\n in normal audio operating temperature ranges."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/82FHM-445A-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/82FHM-445A-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/82FHM-445A-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/82FHM-445A-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/82FHM-445A-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/82FHM-445A-3D.STEP"}},{"code":"8FHMX4-091","name":"8FHM","slug":"8fhmx4-091","description":"Woofer\/8inch\/Ferrite\/Paper Honeycomb\/50W\/4ohm","url":"https:\/\/redcatt.net\/products\/8fhmx4-091","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"50","continuous_watts":"100","peak_watts":"200"},"voice_coil":{"diameter":"35.6","wire":"CCAW","former":"kapton","winding_height":"18"},"thiele_small_parameters":{"fs_hz":38,"re_ohm":3.6,"qes":0.41,"qms":12.9,"qts":0.39,"vas_liters":32.1,"sd_cm2":206.1,"sensitivity_db":89.04,"mms_grams":31.5,"rms":0.58,"cms":0.56,"bl_tm":8.19,"le_mh":0.46},"physical":{"overall_diameter_mm":223.5,"bolt_circle_diameter_mm":210,"baffle_cutout_diameter_mm":189,"mounting_holes":"6","depth_mm":94.5,"net_weight_kg":2.8,"xmax_mm":"5","xmech_mm":"13"},"materials":{"surround":"NBR","cone_dome":"Composite","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE","1k carbon-fiber nomex core honeycomb cone","Ideal for high quality hi-fi applications, studio monitors"],"design_notes":"The 8FHM is a high efficiency, (89 dB 1watt \/ 1 meter) 8-inch mid-woofer with incredibly linear frequency response characteristics and ultra low harmonic distortion artifacts. The 8FHM uses a lightweight 1k carbon fiber material, assembled from both sides of Nomex honey-comb core. This unique cone provides the ideal weight to strength ratio. The rubber surround has been FEM modeled and optimized. The honeycomb cone with high end 1k carbon fiber material provides remarkable strength, while pushing the cone break-up modes to high frequencies, significantly extending the working range of the speaker.\n\nThe cone\nThe 8FHM cone is made using 1k carbon fiber hone-comb, placed from both sides of Nomex core, while the dustcap is made off hard-anodization reinforced aluminum. The dustcap shape and the hard anodizing are further improving the high frequency behavior.","hero_text":null,"ai_summary":"The 8FHMX4-091 is an 8-inch ferrite mid-woofer designed for high-fidelity two-way speaker systems and studio monitors. Its cone is a 1K carbon fiber \/ Nomex honeycomb sandwich construction \u2014 carbon fiber skins laminated to both faces of a Nomex honeycomb core \u2014 delivering an exceptional stiffness-to-mass ratio that pushes cone resonance modes well above the conventional pistonic limit, extending the effective working range and reducing harmonic distortion artifacts across the operating band. The hard-anodized aluminum dustcap further improves high-frequency behaviour at the cone apex. Sensitivity is 89.04 dB (1 W\/1 m) into 4 ohms. With a Qts of 0.39, this driver uses a balanced motor-suspension design that provides good cone control while maintaining usable output across its operating bandwidth. The very high Qms of 12.9 indicates near-zero mechanical losses; system damping is almost entirely electrical, resulting in clean, low-distortion bass and precise transient behaviour.\n\nThis driver operates effectively in both sealed and vented enclosures. Sealed alignments are recommended for studio monitor and accurate hi-fi applications: a 14-litre Butterworth (Qtc=0.707) alignment achieves a maximally flat response to 69 Hz (\u22123 dB) and is the preferred format for reference monitoring; an 8.5-litre alignment at Qtc=0.85 provides a compact stand-mount option with \u22123 dB at 71 Hz and mild low-bass warmth; a 5.8-litre alignment at Qtc=1.00 gives a very compact bookshelf or satellite format with \u22123 dB at 77 Hz. Vented (bass reflex) alignments using a 50 mm round port extend bass further for hi-fi floorstanding enclosures: 25 litres tuned to 42 Hz (port 133 mm), 30 litres tuned to 38 Hz (port 136 mm), and 40 litres tuned to 32 Hz (port 144 mm). All three vented tunings accept a near-identical port length (133\u2013144 mm), as lower tuning frequency and larger volume offset each other in the Helmholtz relationship.\n\nThe 8FHMX4-091 handles approx. 50 W AES and 100 W continuous power into 4 ohms. A high-pass filter in the 28\u201340 Hz range is recommended depending on alignment. The operating bandwidth is approximately 40\u20131,250 Hz; inductance rolloff onset is near 1,246 Hz and cone beaming onset near 1,352 Hz, with the carbon fiber composite permitting a crossover to a dome tweeter or ribbon at 1.5\u20133.0 kHz. A passive crossover with a Zobel network (3.6 \u03a9 \/ 33\u201339 \u03bcF) is recommended to flatten the impedance rise at the crossover frequency. Two drivers wired in series present an 8-ohm nominal load for standard amplifier compatibility.\n\nThis driver is suited for sealed Butterworth-aligned studio monitor enclosures; compact sealed or vented stand-mount hi-fi speakers; vented floorstanding hi-fi speakers with extended bass to 32\u201342 Hz; and any two-way high-fidelity system where low harmonic distortion, extended pistonic frequency response, and precise transient behaviour are required. The carbon fiber Nomex honeycomb cone distinguishes this driver from conventional paper or polypropylene cone designs in its class.","recommended_enclosure":"LOUDSPEAKER ENCLOSURE DESIGN REPORT\nDriver: 8FHMX4-091\nGenerated: 2026-04-12\nApplication: Hi-fi two-way systems, studio monitors\nDRIVER SPECIFICATIONS\nCode : 8FHMX4-091\nDescription : 8\" Ferrite Mid-Woofer \u2014 Carbon Fiber Nomex Honeycomb Composite Cone\nNominal Impedance: 4 \u03a9\nAES Power : 50 W\nContinuous Power : 100 W\nPeak Power : 200 W\n\nFs : 38 Hz\nRe : 3.6 \u03a9\nQes : 0.41\nQms : 12.9\nQts : 0.39\nVas : 32.1 L\nSd : 206.1 cm\u00b2\nSensitivity : 89.04 dB (1 W \/ 1 m)\nMms : 31.5 g\nRms : 0.58 kg\/s\nCms : 0.56 mm\/N\nBl : 8.19 T\u00b7m\nLe : 0.46 mH\nXmax : 5.0 mm (one-way, peak)\nXmech : 13.0 mm\n\nVoice Coil : 35.6 mm, CCAW, Kapton former\nCone : 1K carbon fiber \/ Nomex honeycomb composite (sandwich)\nDustcap : Hard-anodized aluminum\nSurround : NBR rubber (FEM-optimized)\nSpider : Nomex\nBasket : Aluminum\nMagnet : Ferrite\nDERIVED PARAMETERS\nVolume displacement\n Vd = Sd \u00d7 Xmax = 206.1 cm\u00b2 \u00d7 0.50 cm = 103.1 cm\u00b3\n\nInductance rolloff onset\n f_Le = Re \/ (2\u03c0 \u00d7 Le) = 3.6 \/ (2\u03c0 \u00d7 0.00046) \u2248 1,246 Hz\n\nCone beaming onset\n r_cone = \u221a(Sd \/ \u03c0) = \u221a(206.1 \/ 3.14159) = 8.10 cm\n f_beam = c \/ (\u03c0 \u00d7 r_cone) = 34,400 \/ (3.14159 \u00d7 8.10) \u2248 1,352 Hz\n\nNote on cone extension: The carbon fiber Nomex honeycomb sandwich\nconstruction pushes cone resonance (breakup) modes well above the\nconventional pistonic limit. The driver retains usable, low-distortion\noutput beyond f_Le and f_beam; the practical crossover ceiling is set\nby cone directivity, not resonance artifacts.\n\nWorking band : ~40 Hz \u2013 1,250 Hz (conservative pistonic limit)\nTweeter crossover : 1.5 \u2013 3.0 kHz; carbon fiber composite permits\n crossover placement up to 3 kHz before directivity\n becomes the primary constraint.\n\nMaximum SPL (anechoic, 1 m)\n At 50 W AES : 89.04 + 10\u00b7log\u2081\u2080(50) = 89.04 + 17.0 = 106.0 dB\n At 100 W cont : 89.04 + 10\u00b7log\u2081\u2080(100) = 89.04 + 20.0 = 109.0 dB\n\nNote on Qms: Qms = 12.9 is exceptionally high, indicating near-zero\nmechanical losses. System damping is almost entirely electrical (Qes).\nThis results in very low harmonic distortion and highly controlled\ncone motion \u2014 a key characteristic of this driver's hi-fi performance.\nENCLOSURE RECOMMENDATION\nQts = 0.39 \u2192 Both sealed and vented (bass reflex) enclosures\nare viable. Sealed is preferred for studio monitor accuracy and\ncontrolled transient response. Vented extends bass output and\nreduces excursion at tuning frequency, suited to hi-fi floorstanding\nand stand-mount enclosures where deeper bass extension is required.\nSEALED ENCLOSURE ALIGNMENTS\nFormula: Vb = Vas \/ ((Qtc \/ Qts)\u00b2 \u2212 1)\n fc = Fs \u00d7 (Qtc \/ Qts)\n f-3dB: u = [\u2212(2 \u2212 1\/Qtc\u00b2) + \u221a((2 \u2212 1\/Qtc\u00b2)\u00b2 + 4)] \/ 2\n \u03a9 = \u221au ; f-3dB = \u03a9 \u00d7 fc\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Qtc \u2502 fc \u2502 f\u22123dB \u2502 Character \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 14 L \u2502 0.707 \u2502 68.9 Hz\u2502 69 Hz \u2502 Butterworth\/flat \u2502\n\u2502 B \u2502 8.5 L \u2502 0.85 \u2502 82.8 Hz\u2502 71 Hz \u2502 Compact, warm \u2502\n\u2502 C \u2502 5.8 L \u2502 1.00 \u2502 97.4 Hz\u2502 77 Hz \u2502 Bookshelf \/ sat \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\n--- Alignment A \u2014 14 L sealed \/ Qtc = 0.707 (Butterworth) ---\n Vb = 32.1 \/ ((0.707\/0.39)\u00b2 \u2212 1) = 32.1 \/ 2.286 = 14.0 L \u2192 14 L\n fc = 38 \u00d7 (0.707\/0.39) = 68.9 Hz\n f-3dB = fc = 68.9 Hz (Butterworth by definition)\n\n Maximally flat sealed alignment; no bass shelf boost or hump.\n The ideal format for studio monitors and reference hi-fi systems\n where transient accuracy and flat frequency response are required.\n Deepest sealed bass extension for this driver at a practical volume.\n\n--- Alignment B \u2014 8.5 L sealed \/ Qtc = 0.85 ---\n Vb = 32.1 \/ ((0.85\/0.39)\u00b2 \u2212 1) = 32.1 \/ 3.750 = 8.56 L \u2192 8.5 L\n fc = 38 \u00d7 (0.85\/0.39) = 82.8 Hz\n f-3dB: 2\u22121\/0.722=0.616; \u221a(0.379+4)=2.093; u=(\u22120.616+2.093)\/2=0.739; \u03a9=0.859\n f-3dB = 0.859 \u00d7 82.8 = 71 Hz\n\n Compact sealed format with mild low-bass warmth (~1 dB broad shelf\n around 80 Hz). Suited to stand-mount hi-fi speakers and compact\n two-way monitors where cabinet volume is constrained.\n A practical balance of box size, bass extension, and subjective warmth.\n\n--- Alignment C \u2014 5.8 L sealed \/ Qtc = 1.00 ---\n Vb = 32.1 \/ ((1.00\/0.39)\u00b2 \u2212 1) = 32.1 \/ 5.575 = 5.76 L \u2192 5.8 L\n fc = 38 \u00d7 (1.00\/0.39) = 97.4 Hz\n f-3dB: 2\u22121\/1.00=1.000; \u221a(1+4)=2.236; u=(\u22121+2.236)\/2=0.618; \u03a9=0.786\n f-3dB = 0.786 \u00d7 97.4 = 77 Hz\n\n Very compact bookshelf or satellite format. Bass shelf boost (~3 dB\n around 90\u2013100 Hz) subjectively full-sounding in small rooms.\n Mandatory high-pass filter at 60\u201380 Hz (DSP or passive) to prevent\n over-excursion below fc.\n Best deployed with a subwoofer crossed over at 80\u2013100 Hz.\n\n--- Notes for all sealed alignments ---\n \u2022 High-pass filter recommended: 30\u201360 Hz depending on alignment.\n \u2022 Zobel network improves passive crossover accuracy:\n R_z = Re = 3.6 \u03a9 ; C_z = Le \/ Re\u00b2 = 0.46e-3 \/ 12.96 = 35.5 \u03bcF\n \u2192 use 33 \u03bcF or 39 \u03bcF, 100 V non-polar.\nVENTED ENCLOSURE ALIGNMENTS\nSuited for hi-fi floorstanding and larger stand-mount enclosures\nwhere extended bass and reduced mid-bass excursion are priorities.\n\nPort: 50 mm round (Ap = 19.64 cm\u00b2)\n Port velocity limit: \u2264 17 m\/s (hi-fi standard)\n\nLeff = (Ap \u00d7 c\u00b2) \/ (4\u03c0\u00b2 \u00d7 Fb\u00b2 \u00d7 Vb)\n c = 34,400 cm\/s ; c\u00b2 = 1,183,360,000 cm\u00b2\/s\u00b2\n 4\u03c0\u00b2 = 39.478\n\nPort velocity: v_peak = Vd \u00d7 2\u03c0 \u00d7 Fb \/ Ap\n Vd = 103.1 cm\u00b3 = 1.031 \u00d7 10\u207b\u2074 m\u00b3 ; Ap = 1.964 \u00d7 10\u207b\u00b3 m\u00b2\n\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Alignment \u2502 Vb (net) \u2502 Fb \u2502 50mm Port Length \u2502 Port Velocity \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502 A \u2502 25 L \u2502 42 Hz \u2502 133 mm \u2502 13.9 m\/s \u2713 \u2502\n\u2502 B \u2502 30 L \u2502 38 Hz \u2502 136 mm \u2502 12.5 m\/s \u2713 \u2502\n\u2502 C \u2502 40 L \u2502 32 Hz \u2502 144 mm \u2502 10.6 m\/s \u2713 \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n\nPort length calculations (50 mm round port):\n Alignment A: Leff = (19.64 \u00d7 1,183,360,000) \/ (39.478 \u00d7 1764 \u00d7 25,000)\n = 2.323\u00d710\u00b9\u2070 \/ 1.741\u00d710\u2079 = 133 mm\n Alignment B: Leff = (19.64 \u00d7 1,183,360,000) \/ (39.478 \u00d7 1444 \u00d7 30,000)\n = 2.323\u00d710\u00b9\u2070 \/ 1.710\u00d710\u2079 = 136 mm\n Alignment C: Leff = (19.64 \u00d7 1,183,360,000) \/ (39.478 \u00d7 1024 \u00d7 40,000)\n = 2.323\u00d710\u00b9\u2070 \/ 1.617\u00d710\u2079 = 144 mm\n\nPort engineering note: All three vented alignments produce\nnear-identical port lengths (133\u2013144 mm). This occurs because\nlower Fb\u00b2 is offset by proportionally larger Vb in the Helmholtz\nequation. A single 50 mm \u00d7 138 mm port tube can serve all three\ntunings with minor end-correction trimming.\n\n--- Vented Alignment A \u2014 25 L \/ Fb = 42 Hz ---\n Near-Fs tuning in a compact vented cabinet. Good mid-bass\n output and strong mechanical protection above port tuning.\n Suited to compact stand-mount vented enclosures where the\n driver replaces the sealed A alignment at lower excursion cost.\n\n--- Vented Alignment B \u2014 30 L \/ Fb = 38 Hz ---\n On-Fs tuning. Balanced response with extended bass to ~36 Hz\n (4th-order rolloff below Fb). The recommended general-purpose\n hi-fi vented alignment for two-way floorstanding or large\n stand-mount speakers.\n\n--- Vented Alignment C \u2014 40 L \/ Fb = 32 Hz ---\n Below-Fs tuning. Maximum bass extension into the low 30s Hz.\n Suited to two-way floorstanding hi-fi where sub-35 Hz reproduction\n is required without a separate subwoofer.\n Mandatory high-pass filter at 25\u201328 Hz to protect driver below\n the port rolloff (4th-order slope below Fb).\nCROSSOVER AND SYSTEM INTEGRATION\nCrossover to tweeter (acoustic target): 1.5 \u2013 3.0 kHz\n f_beam = 1,352 Hz (cone directivity increases above this)\n f_Le = 1,246 Hz (inductive rolloff onset)\n\nThe carbon fiber Nomex honeycomb composite cone pushes structural\nresonance modes beyond 3 kHz. Crossover at 2.0\u20132.5 kHz is\nrecommended as the design point; 3.0 kHz is achievable where\noff-axis directivity at the crossover frequency is not critical.\n\nRecommended crossover order: 2nd-order (12 dB\/oct) minimum.\n 3rd or 4th-order preferred for controlled off-axis behaviour\n above 1.3 kHz at a 2.0\u20132.5 kHz acoustic crossover target.\n\nZobel network (for passive crossover flatness):\n R_z = 3.6 \u03a9 (use 3.6 \u03a9 standard, or 3.3 \u03a9 nearest)\n C_z = 35 \u03bcF, 100 V non-polar (use 33 \u03bcF or 39 \u03bcF standard value)\n Place across driver terminals inside the enclosure.\nIMPEDANCE CONFIGURATIONS\nSingle (standard) : 4 \u03a9\nPair in series : 8 \u03a9 (+3 dB sensitivity, standard amplifier load)\nPair in parallel : 2 \u03a9 (not recommended; exceeds most amplifier ratings)"},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/8FHM-091-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/8FHM-091-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHM-091-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHM-091-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHM-091-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHM-091-3D.STEP"}},{"code":"8FHWX4-382","name":"8FHW","slug":"8fhwx4-382","description":"Mid-Woofer\/8inch\/Ferrite\/PP\/100W\/4ohm","url":"https:\/\/redcatt.net\/products\/8fhwx4-382","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"4","magnet":"Ferrite","basket_material":"Steel"},"power_handling":{"aes_watts":"100","continuous_watts":"200","peak_watts":"400"},"voice_coil":{"diameter":"30.5","wire":"Copper","former":"Aluminum","winding_height":"15.3"},"thiele_small_parameters":{"fs_hz":36,"re_ohm":3.3,"qes":0.38,"qms":4.53,"qts":0.35,"vas_liters":34.3,"sd_cm2":213.8,"sensitivity_db":89.12,"mms_grams":36.59,"rms":1.83,"cms":0.53,"bl_tm":8.6,"le_mh":0.89},"physical":{"overall_diameter_mm":209.5,"bolt_circle_diameter_mm":197,"baffle_cutout_diameter_mm":184.5,"mounting_holes":"8","depth_mm":86.5,"net_weight_kg":1.5,"xmax_mm":"3.65","xmech_mm":"11.65"},"materials":{"surround":"NBR","cone_dome":"PP","spider":"Nomex"},"content":{"key_features":["Mid-woofer designed for outdoor or indoor applications","UV stabilized Polypropylene cone and rubber surround","Components are treated to survive harsh outdoor environments"],"design_notes":"8FHW was designed as mid-woofer, with extended frequency response to low frequencies, as well as good extension into the mid-frequencies. All parts are intensively treated for outdoor usage, cone, surround material are with UV stabilizers. The used adhesives make sure the driver is waterproof.\n\n\tThe cone utilizes polypropylene material and rubber surround. This combination sports sizable amounts of low frequencies and good behavior in the higher mid-frequencies.","hero_text":null,"ai_summary":"This design is particularly effective in single or multi-driver bass reflex systems used in hi-fi, home theater, and cost-conscious installation applications, where a balance of low-frequency extension, compactness, and value are the primary priorities.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 8FHWX4-382\nDriver: 8FHWX4-382 (8FHW) \u2014 8\" Sub-woofer\nKey T\/S: Fs=36.0Hz, Qts=0.35, Vas=34.3L, Sens=89.12dB\nPower: AES 100W \/ Cont 200W \/ Peak 400W\nXmax=3.65mm, Sd=213.8cm\u00b2, Bl=8.6T\u00b7m\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 adequate for compact enclosures with lower air volume velocity\n a) High SPL\n Net Volume: 20 liters\n Tuning (Fb): 41 Hz\n Est. -3dB: 38 Hz\n HP Filter: 33 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 234mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 437mm L\n Port Velocity: 6.1 m\/s\n Notes: Strong mid-bass impact, reduced cone excursion, maximum output\n b) Balanced Response\n Net Volume: 24 liters\n Tuning (Fb): 38 Hz\n Est. -3dB: 35 Hz\n HP Filter: 28 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 229mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 429mm L\n Port Velocity: 5.6 m\/s\n Notes: General-purpose PA\/subwoofer, even response, good transient behavior\n c) Extended Low Frequency\n Net Volume: 24 liters\n Tuning (Fb): 34 Hz\n Est. -3dB: 29 Hz\n HP Filter: 22 Hz (24dB\/oct recommended)\n Round Port: 65mm dia \u00d7 291mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 538mm L\n Port Velocity: 5.1 m\/s\n Notes: Deep bass extension, requires proper system protection below tuning\n--- Summary ---\nThe 8FHWX4-382 is a 8-inch sub-woofer driver designed for compact hi-fi subwoofer systems, home audio, and cost-effective installation applications. It operates at 89.1 dB sensitivity (1W\/1m). The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, the driver performs best in net internal volumes of 20 to 24 liters, tuned between 34 and 41 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.\nThe driver is intended for use with moderate amplification (approx. 100 W AES \/ 200 W continuous) and DSP control. A high-pass filter in the range of 22\u201333 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 29\u2013100 Hz, suitable for integration with a mid-bass or full-range driver in a two-way system."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/8FHW-382-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/8FHW-382-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHW-382-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHW-382-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FHW-382-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FHW-382-3D.STEP"}},{"code":"8FINDX8-030","name":"8FIND","slug":"8findx8-030","description":"Woofer\/8inch\/Ferrite\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/8findx8-030","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Ferrite","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"Glass Fiber","winding_height":"12.4"},"thiele_small_parameters":{"fs_hz":70,"re_ohm":5.7,"qes":0.25,"qms":6.4,"qts":0.25,"vas_liters":18.2,"sd_cm2":227,"sensitivity_db":97.33,"mms_grams":20.7,"rms":1.42,"cms":0.25,"bl_tm":14.3,"le_mh":0.48},"physical":{"overall_diameter_mm":209.5,"bolt_circle_diameter_mm":197.5,"baffle_cutout_diameter_mm":185,"mounting_holes":"8","depth_mm":91.5,"net_weight_kg":3.73,"xmax_mm":"2.2","xmech_mm":"10.2"},"materials":{"surround":"fabric","cone_dome":"Paper GF","spider":"Nomex"},"content":{"key_features":["EXTENDED FREQUENCY RESPONSE, high efficiency","Carbon fiber loaded and reinforced paper cone","Nomex spider"],"design_notes":"The 8FIND is a high efficiency, (97 dB 1watt \/ 1 meter) 8-inch mid bass woofer with incredibly linear frequency response characteristics, high power handling capability while generating low harmonic distortion artifacts.\nThe 8FIND uses a lightweight carbon fiber loaded cone assembly along with a precision double roll surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 9.4mm.\n\nMagnetic Circuit\nREDCATT engineers have developed an efficient, ferrite based magnetic circuit, capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, low distortion characteristic. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.","hero_text":null,"ai_summary":"This driver is designed for efficiency-\nfirst applications where high sensitivity (97 dB) provides large SPL\nfrom moderate amplifier power, rather than brute-force excursion-\nlimited output. In systems requiring high SPL below 80 Hz, dedicated\nsubwoofers should supplement this driver. The mechanical excursion\nprotection at 9.4mm provides substantial headroom beyond the linear\nrange for transient peaks.\nDESIGN NOTE: The carbon fiber loaded paper cone and precision double\nroll surround provide a lightweight, stiff piston with extended\nfrequency response. The flux-modulation-optimized ferrite motor\nreduces harmonic distortion, particularly beneficial in the critical\nmidrange frequencies where this driver operates above its bass range.\nThe aluminum basket provides good thermal dissipation.\n--- SUMMARY (copy\/paste ready) ---\nThe 8FINDX8-030 is an 8-inch high-efficiency ferrite mid-woofer designed for professional two-way, multi-way, and installation loudspeaker systems where maximum sensitivity and controlled low-distortion performance are required. With a sensitivity of 97 dB (1W\/1m), a 2-inch CCAW voice coil on a glass fiber former, and a lightweight carbon fiber loaded paper cone with a precision double roll fabric surround, the driver achieves a very low Qts of 0.25. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nIn bass reflex enclosures, recommended net internal volumes range from 22 to 30 liters with tuning frequencies between 51 and 66 Hz. These volumes are larger than typical for an 8-inch driver due to the very low Qts and high Vas (18.2 liters), which is characteristic of high-efficiency pro-audio mid-woofer designs where motor control and sensitivity are prioritized. Smaller volumes (22\u201325 liters tuned to 58\u201366 Hz) maximize mid-bass output and efficiency for 2-way tops paired with subwoofers, while 30 liters tuned to 51 Hz extends the usable low-frequency response to approximately 43 Hz (\u20133 dB) for stand-alone applications. Port velocities are negligible across all alignments (5\u20136 m\/s) due to the modest linear excursion (2.2 mm), making port design uncritical.\nThe driver is rated for approximately 200 W AES \/ 400 W continuous power handling and is intended for use with DSP-controlled amplification. A high-pass filter in the range of 41\u201356 Hz (24 dB\/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.5\u20133 kHz. Below tuning frequency, excursion increases and high-pass protection is required to manage mechanical stress, particularly given the modest linear excursion capability. The driver's extreme sensitivity means high SPL is achievable with moderate amplifier power.\nThis driver is particularly effective in high-efficiency 2-way portable loudspeakers, compact PA tops, stage monitors, and installation systems where maximum sensitivity, extended frequency response, and low distortion are priorities. The carbon fiber loaded paper cone, flux-modulation-optimized ferrite motor, and aluminum basket provide consistent, durable performance in demanding professional environments.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 8FINDX8-030\nDriver: 8FINDX8-030 (8FIND) \u2014 8\" Mid-Woofer\nKey T\/S: Fs=70Hz, Qts=0.25, Vas=18.2L, Sens=97.3dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=2.2mm (one-way linear), Xmech=10.2mm (protection at 9.4mm)\nSd=227cm\u00b2, Bl=14.3T\u00b7m, Re=5.7\u03a9, Mms=20.7g\nVoice Coil: 2\" CCAW on glass fiber former (12.4mm winding height)\nMagnet: Ferrite (flux-modulation optimized) | Basket: Aluminum\nCone: Carbon fiber loaded paper | Surround: Fabric (double roll)\nSpider: Nomex\nRECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)\nNOTE: This is a very high efficiency driver (97.3 dB 1W\/1m) with an\nexceptionally low Qts (0.25) and strong ferrite motor (Bl=14.3 T\u00b7m),\npaired with a very light carbon fiber loaded paper cone (Mms=20.7g).\nThe low Qts and high Vas-to-size ratio (18.2L for an 8\") produce\noptimal vented alignments in larger-than-typical enclosures for the\nspeaker size (22\u201330L). This is characteristic of high-efficiency\npro-audio mid-woofers where sensitivity and motor control are\nprioritized over excursion-limited maximum output. The modest Xmax\n(2.2mm linear) results in extremely low port velocities across all\nalignments \u2014 port design is uncritical.\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 port lengths are\nvery short (56\u201383mm) due to the high tuning frequencies relative to\ncabinet volume. Port velocities are negligible (5\u20136 m\/s). A single\n65mm round port is more than adequate. Flaring is optional but not\nrequired at these velocities.\nVENTED ALIGNMENTS:\n a) VENTED \u2014 High SPL\n Net Volume: 22 liters\n Tuning (Fb): 66 Hz\n Est. -3dB: 56 Hz\n HP Filter: 56 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 56mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 105mm L\n Port Velocity: 6.2 m\/s\n Notes: Smaller alignment with higher tuning for maximum\n mid-bass efficiency and output. The tight coupling between\n driver and port provides strong output in the 60\u2013200 Hz\n region with excellent transient response. Ideal for compact\n 2-way tops and stage monitors paired with subwoofers, where\n the extreme sensitivity (97+ dB) maximizes system headroom.\n b) VENTED \u2014 Balanced Response\n Net Volume: 25 liters\n Tuning (Fb): 58 Hz\n Est. -3dB: 49 Hz\n HP Filter: 48 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 70mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 131mm L\n Port Velocity: 5.5 m\/s\n Notes: General-purpose alignment with good balance between\n low-frequency extension and output capability. Provides\n even response through the bass region. Well-suited for\n 2-way PA tops, multi-way systems, and installation\n loudspeakers where the system either operates with a\n subwoofer or needs moderate stand-alone bass coverage.\n c) VENTED \u2014 Extended Low Frequency\n Net Volume: 30 liters\n Tuning (Fb): 51 Hz\n Est. -3dB: 43 Hz\n HP Filter: 41 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 79mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 147mm L\n Port Velocity: 4.8 m\/s\n Notes: Maximum low-frequency extension for stand-alone use\n without subwoofers. The larger cabinet allows the driver to\n reach into the low 40s Hz while maintaining the high motor\n control characteristic of the low Qts design. Requires\n proper high-pass protection below tuning. Best for\n applications where deep bass reach and high efficiency are\n both required from a single 8\" system.\nVOLUME NOTE: The recommended volumes (22\u201330L) are larger than typical\nfor an 8\" driver because of the very low Qts (0.25) and large Vas\n(18.2L). This is normal for high-efficiency pro-audio mid-woofers \u2014\ncomparable professional designs (e.g., premium 8\" 2-way tops from\nmajor manufacturers) commonly use 15\u201330L net internal volumes for\ndrivers in this Qts\/Vas class. The strong motor demands adequate air\nvolume for proper port loading and controlled low-frequency behavior.\nEXCURSION NOTE: The linear Xmax of 2.2mm limits maximum acoustic\noutput at low frequencies."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/8FIND-030-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/8FIND-030-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FIND-030-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FIND-030-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/8FIND-030-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/8FIND-030-3D.STEP"}},{"code":"8NPMX8-157","name":"8NPM","slug":"8npmx8-157","description":"Mid-Woofer\/8inch\/Neo\/Paper\/200W\/8ohm","url":"https:\/\/redcatt.net\/products\/8npmx8-157","category":"LF","type":"Mid-Woofer","size_inches":8,"is_featured":false,"general":{"nominal_impedance":"8","magnet":"Neodymium","basket_material":"Aluminum"},"power_handling":{"aes_watts":"200","continuous_watts":"400","peak_watts":"800"},"voice_coil":{"diameter":"50.8","wire":"CCAW","former":"Kapton","winding_height":"15.4"},"thiele_small_parameters":{"fs_hz":79,"re_ohm":5.4,"qes":0.31,"qms":3.85,"qts":0.29,"vas_liters":10.9,"sd_cm2":213.8,"sensitivity_db":96.06,"mms_grams":23.9,"rms":3.1,"cms":0.17,"bl_tm":14.2,"le_mh":0.6},"physical":{"overall_diameter_mm":209.5,"bolt_circle_diameter_mm":197.5,"baffle_cutout_diameter_mm":185,"mounting_holes":"8","depth_mm":87.3,"net_weight_kg":1.8,"xmax_mm":"3.7","xmech_mm":"11.7"},"materials":{"surround":"fabric","cone_dome":"Paper CF","spider":"Nomex"},"content":{"key_features":["Hi sensitivity","Hi power handling","Designed for applications where are sizable amounts of mid-frequencies required"],"design_notes":"The 8NPM is a high efficiency, (96dB 1watt \/ 1 meter) 8-inch mid-woofer with extended mid frequency response and high power handling capability. The 8NPM uses a lightweight half pressed paper cone along with a double roll fabric surround. Spider is made of Nomex material with optimized shape for well controlled pistonic motion. The used high quality components ensure long lasting performance even in high powered applications. The chosen material combination provides remarkable strength, high efficiency and sustained output under extreme conditions. \n\nPower Handling\nThe voice coil featuring Kapton former material capable of withstanding peak temperatures in excess of 280C, well beyond the thermal requirements of modern audio systems. Former strength provides the ideal transfer of power between the voice coil and the cone assembly and assists in reducing distortion artifacts. By combining this material with state of the art adhesives and our winding voice coil technology, the 8NPM delivers incredibly high performance.","hero_text":null,"ai_summary":"The 8NPMX8-157 is an 8-inch high-efficiency neodymium mid-woofer designed for professional two-way, multi-way, and line array systems requiring high sensitivity (96 dB 1W\/1m), extended mid-frequency response, and sustained high-power operation. It features a 2-inch CCAW voice coil on a Kapton former with peak temperature tolerance exceeding 280\u00b0C, a lightweight half-pressed paper cone with a double roll fabric surround, and a Nomex spider with optimized geometry for controlled pistonic motion. With a low Qts of 0.29 and strong neodymium motor (Bl 14.2 T\u00b7m), the motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.\nThis driver is suitable for both vented (mid-woofer) and sealed (midrange) enclosure configurations depending on the system architecture. In bass reflex enclosures, recommended net internal volumes range from 10 to 14 liters with tuning frequencies between 63 and 82 Hz. Smaller volumes (10\u201312 liters tuned to 72\u201382 Hz) prioritize mid-bass output and cabinet compactness for portable 2-way systems and stage monitors, while 14 liters tuned to 63 Hz extends the usable low-frequency response to approximately 54 Hz (\u20133 dB) for stand-alone applications without dedicated subwoofers. Port velocities remain low (9\u201312 m\/s) across all vented alignments. In sealed enclosures for midrange duty, the driver performs in very compact net internal volumes of 1.0 to 2.2 liters, producing system resonances between 193 and 272 Hz. Smaller sealed volumes (1.0\u20131.4 liters, Qtc 0.85\u20131.0) maximize acoustic output in the midrange passband for line array modules and horn-loaded midrange systems, while 2.2 liters yields a Butterworth-class response (Qtc 0.707) with maximally flat amplitude for accuracy-focused applications.\nThe driver requires active DSP crossover management in both configurations. In vented mid-woofer use, a high-pass filter in the range of 53\u201372 Hz (24 dB\/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.5\u20133 kHz. In sealed midrange use, a high-pass filter in the range of 180\u2013350 Hz is recommended depending on enclosure volume and system architecture. In both cases, appropriate limiting is required to manage mechanical stress during sustained operation, though the Kapton former provides exceptional thermal headroom.\nThis driver is particularly effective in professional touring line arrays, compact 2-way portable loudspeakers, multi-way point-source cabinets, stage monitors, and installation systems where versatility across mid-woofer and midrange roles, high sensitivity, high power handling, and extended mid-frequency performance are priorities. The neodymium motor, Kapton former, and aluminum basket provide consistent, durable performance in demanding professional environments.","recommended_enclosure":"ENCLOSURE RECOMMENDATIONS: 8NPMX8-157\nDriver: 8NPMX8-157 (8NPM) \u2014 8\" Midrange \/ Mid-Woofer\nKey T\/S: Fs=79Hz, Qts=0.29, Vas=10.9L, Sens=96dB 1W\/1m\nPower: AES 200W \/ Cont 400W \/ Peak 800W\nXmax=3.7mm (one-way linear), Xmech=11.7mm (protection at 10.2mm)\nSd=213.8cm\u00b2, Bl=14.2T\u00b7m, Re=5.4\u03a9, Mms=23.9g\nVoice Coil: 2\" CCAW on Kapton former (15.4mm winding height)\nMagnet: Neodymium | Cone: Half-pressed paper\nSurround: Fabric (double roll) | Spider: Nomex (optimized shape)\nBasket: Aluminum\nNOTE: This driver's low Qts (0.29) and high sensitivity (96 dB)\ncombined with a strong neodymium motor (Bl=14.2 T\u00b7m) make it suitable\nfor BOTH vented mid-woofer and sealed midrange applications. The Kapton\nvoice coil former provides peak temperature tolerance in excess of\n280\u00b0C, well beyond the thermal demands of modern high-power systems.\nThe Nomex spider with optimized shape ensures well-controlled pistonic\nmotion across the operating range. Six enclosure alignments are provided\nbelow \u2014 three vented (mid-woofer use) and three sealed (midrange use).\n MID-WOOFER APPLICATION \u2014 Bass Reflex (Vented)\nUse case: 2-way and multi-way systems where the 8NPM handles low-\nfrequency and lower-midrange content, typically crossed over to a\ncompression driver or tweeter at 1.5\u20133 kHz. The high sensitivity\n(96 dB) makes this driver particularly effective in efficiency-\ncritical applications.\nPORT RECOMMENDATION: Round port (65mm diameter) \u2014 standard for\ncompact 8\" bass reflex enclosures. Port velocities are low across\nall alignments (9\u201312 m\/s), well within limits for all applications\nincluding studio monitors. No flaring required.\n a) VENTED \u2014 High SPL\n Net Volume: 10 liters\n Tuning (Fb): 82 Hz\n Est. -3dB: 75 Hz\n HP Filter: 72 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 100mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 187mm L\n Port Velocity: 12.3 m\/s\n Notes: Compact alignment with strong mid-bass control and\n maximum output per cabinet volume. The higher tuning provides\n tight, punchy low end with excellent transient response.\n Ideal for compact 2-way tops and stage monitors paired with\n subwoofers, where the 96 dB sensitivity maximizes system\n headroom from moderate amplifier power.\n b) VENTED \u2014 Balanced Response\n Net Volume: 12 liters\n Tuning (Fb): 72 Hz\n Est. -3dB: 61 Hz\n HP Filter: 62 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 111mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 207mm L\n Port Velocity: 10.8 m\/s\n Notes: General-purpose alignment with even response through\n the bass region and good transient behavior. Well-suited for\n most 2-way PA tops, multi-way systems, and installation\n loudspeakers where the system operates with or without\n subwoofer support.\n c) VENTED \u2014 Extended Low Frequency\n Net Volume: 14 liters\n Tuning (Fb): 63 Hz\n Est. -3dB: 54 Hz\n HP Filter: 53 Hz (24dB\/oct LR recommended)\n Round Port: 65mm dia \u00d7 130mm long\n Slot Port: 148mm W \u00d7 40mm H \u00d7 242mm L\n Port Velocity: 9.4 m\/s\n Notes: Maximum low-frequency extension for stand-alone use\n without subwoofers. The strong motor maintains tight cone\n control even at this lower tuning. Best for applications\n where deeper bass reach is required from a single 8\" system.\n Requires proper high-pass protection below tuning.\n MIDRANGE APPLICATION \u2014 Sealed\nUse case: Line array midrange sections, coaxial cabinets, horn-loaded\nmidrange systems, or dedicated mid-high enclosures where the 8NPM\nhandles the midrange band (typically 250\u20133000 Hz or narrower), with\nbass duties handled by separate woofer\/subwoofer sections. The high\nsensitivity and extended mid-frequency response make this driver\nparticularly effective where sizable midrange output is required.\n d) SEALED \u2014 High SPL (Qtc \u2248 1.0)\n Net Volume: 1.0 liters\n System Resonance (fc): 272 Hz\n Qtc: 1.0\n Response: Broad gentle lift near fc, maximum midrange output\n Crossover HP: 250\u2013350 Hz (24dB\/oct LR recommended)\n Notes: Very compact sealed chamber for maximum acoustic\n output in the midrange passband. The elevated Qtc provides\n a gentle broad peak near system resonance that can be\n equalized flat via DSP or used as a passband sensitivity\n boost. Ideal for high-SPL touring line arrays and horn-\n loaded midrange systems where output per driver is the\n primary requirement.\n e) SEALED \u2014 Balanced (Qtc \u2248 0.85)\n Net Volume: 1.4 liters\n System Resonance (fc): 232 Hz\n Qtc: 0.85\n Response: Slightly warm, smooth transition through resonance\n Crossover HP: 220\u2013300 Hz (24dB\/oct LR recommended)\n Notes: Good compromise between midrange output and response\n flatness. Suitable for most professional midrange applications\n including line arrays, point-source cabinets, and stage\n monitors. The Kapton former's thermal resilience supports\n sustained high-power operation in these compact volumes.\n f) SEALED \u2014 Butterworth (Qtc \u2248 0.707)\n Net Volume: 2.2 liters\n System Resonance (fc): 193 Hz\n Qtc: 0.707\n Response: Maximally flat amplitude, textbook Butterworth alignment\n Crossover HP: 180\u2013250 Hz (24dB\/oct LR recommended)\n Notes: Flattest possible sealed response with lowest system\n resonance. Allows a lower crossover frequency and extended\n lower-midrange coverage. Best for applications prioritizing\n accuracy, smooth crossover integration, and minimal DSP\n correction.\nTHERMAL NOTE: The Kapton voice coil former withstands peak temperatures\nexceeding 280\u00b0C, providing significant thermal headroom beyond the\ndemands of modern amplification systems. Combined with the neodymium\nmotor's direct thermal coupling to the aluminum basket, this allows\nsustained high-power operation in both vented and sealed configurations\nwithout thermal compression concerns.\nDESIGN NOTE: The Nomex spider with optimized geometry provides\nwell-controlled pistonic motion across the full excursion range. The\nhalf-pressed paper cone and double roll fabric surround deliver a\nlightweight, stiff piston with extended mid-frequency response \u2014 a\nkey requirement in midrange applications where vocal clarity and\npresence are critical."},"assets":{"photos":["https:\/\/redcatt.net\/storage\/products\/web\/8NPM-157-1.jpg","https:\/\/redcatt.net\/storage\/products\/web\/8NPM-157-2.jpg"],"freq_response_image":"https:\/\/redcatt.net\/storage\/products\/web\/8NPM-157-SPL.jpg","drawing_2d_pdf":"https:\/\/redcatt.net\/storage\/products\/downloads\/8NPM-157-2D.pdf","drawing_2d_image":"https:\/\/redcatt.net\/storage\/products\/web\/8NPM-157-2D.jpg","step_3d":"https:\/\/redcatt.net\/storage\/products\/downloads\/8NPM-157-3D.STEP"}}],"links":{"first":"https:\/\/redcatt.net\/api\/v1\/products?page=1","last":"https:\/\/redcatt.net\/api\/v1\/products?page=3","prev":null,"next":"https:\/\/redcatt.net\/api\/v1\/products?page=2"},"meta":{"current_page":1,"from":1,"last_page":3,"links":[{"url":null,"label":"« Previous","page":null,"active":false},{"url":"https:\/\/redcatt.net\/api\/v1\/products?page=1","label":"1","page":1,"active":true},{"url":"https:\/\/redcatt.net\/api\/v1\/products?page=2","label":"2","page":2,"active":false},{"url":"https:\/\/redcatt.net\/api\/v1\/products?page=3","label":"3","page":3,"active":false},{"url":"https:\/\/redcatt.net\/api\/v1\/products?page=2","label":"Next »","page":2,"active":false}],"path":"https:\/\/redcatt.net\/api\/v1\/products","per_page":50,"to":50,"total":110}}