- EXTENDED FREQUENCY RESPONSE
- 2 demodulation rings powerful motor structure
- Designed for 2-way and multi-way speaker systems
- 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’s 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 sustained output under extreme conditions. Power HandlingThe voice coil sports Kapton former material capable of withstanding peak temperatures above
- 300°C, 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
General specs Nominal Diameter: 8 in. Rated Impedance: 8 Ohm Power handling AES Power: 200 Watts Program Power: 400 Watts Voice Coil Diameter: 3 in. Winding wire: CCAW Former: kapton Winding height: 22.5 mm T/S Parameters Resonant frequency: 72 Hz Re: 5.2 ohm Qes: 0.34 Qms: 7.97 Qts: 0.33 Vas: 10.3 liters Sd: 219 cm2 Mms: 40.5 grams Bl: 16.7 Le: 0.5 mH Sensitivity: 93 dB Design details Surround Material: Fabric Cone material: Paper Spider: Nomex Plate thickness: 10.5 mm Peak to peak linear cone Displacement 15 mm Overall diameter: 210 mm Bolt circle diameter: 195.5 mm Baffle cutout dia.: 186.88 mm Number of mounting holes: 8 Depth (flange to rear): 101.3 mm Net weight: 3.2 kg Ordering codes: 8 ohm version: 81NPMX8-263 Recone kits: Download: Spec download 2D drawing 3D model
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PRODUCT CODE: 81NPMX8-263
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--- ENCLOSURE RECOMMENDATIONS ---
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ENCLOSURE RECOMMENDATIONS: 81NPMX8-263
======================================================================
Driver: 81NPMX8-263 (81NPM) — 8" Mid-Woofer / Midrange
Key T/S: Fs=72Hz, Qts=0.33, Vas=10.3L, Sens=93dB 1W/1m
Power: AES 200W / Cont 400W / Peak 800W
Xmax=6mm, Sd=219cm², Bl=16.7T·m, Re=5.2Ω, Mms=40.5g
Voice Coil: 3" CCAW on glass fiber former (22.5mm winding height)
Magnet: Neodymium | Cone: Half-pressed paper (treated/weatherized)
Surround: Fabric | Spider: Nomex | Basket: Aluminum
Motor: 2 demodulation rings, neodymium
NOTE: This driver's low Qts (0.33) and strong neodymium motor with
demodulation rings make it suitable for BOTH vented mid-woofer and
sealed midrange applications. Six enclosure alignments are provided
below — three vented (mid-woofer use) and three sealed (midrange use).
======================================================================
MID-WOOFER APPLICATION — Bass Reflex (Vented)
======================================================================
Use case: 2-way and multi-way systems where the 81NPM handles the
low-frequency and lower-midrange content, typically crossed over to
a compression driver or tweeter at 1.2–3 kHz.
PORT RECOMMENDATION: Round port (65mm diameter) — standard for compact
8" bass reflex enclosures. Port velocities are moderate across all
alignments (15–20 m/s), acceptable for professional touring use.
Flared port ends recommended to reduce turbulence at high excursion.
a) VENTED — High SPL
Net Volume: 9 liters
Tuning (Fb): 80 Hz
Est. -3dB: 74 Hz
HP Filter: 70 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 124mm long
Slot Port: 156mm W × 40mm H × 231mm L
Port Velocity: 19.9 m/s
Notes: Compact cabinet with strong mid-bass output. Maximum SPL
per unit volume. The higher tuning provides tight, controlled
low-end with excellent transient response. Ideal for portable
2-way tops and compact stage monitors.
b) VENTED — Balanced Response
Net Volume: 10 liters
Tuning (Fb): 70 Hz
Est. -3dB: 60 Hz
HP Filter: 60 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 154mm long
Slot Port: 156mm W × 40mm H × 287mm L
Port Velocity: 17.4 m/s
Notes: General-purpose alignment with even response through the
bass region and good transient behavior. Well-suited for most
2-way PA tops, multi-way systems, and installation loudspeakers.
c) VENTED — Extended Low Frequency
Net Volume: 12 liters
Tuning (Fb): 61 Hz
Est. -3dB: 52 Hz
HP Filter: 51 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 174mm long
Slot Port: 156mm W × 40mm H × 324mm L
Port Velocity: 15.2 m/s
Notes: Maximum low-frequency extension, reaching into the
sub-bass region. Requires proper high-pass protection below
tuning. Best for stand-alone 2-way systems without dedicated
subwoofers, or applications prioritizing deep bass reach.
======================================================================
MIDRANGE APPLICATION — Sealed
======================================================================
Use case: Line array midrange sections, coaxial cabinets, horn-loaded
midrange systems, or dedicated mid-high enclosures where the 81NPM
handles the midrange band (typically 250–3000 Hz or narrower), with
bass duties handled by separate woofer/subwoofer sections.
d) SEALED — High SPL (Qtc ≈ 1.0)
Net Volume: 1.3 liters
System Resonance (fc): 218 Hz
Qtc: 1.0
Response: Broad gentle lift near fc, maximum midrange output
Crossover HP: 200–300 Hz (24dB/oct LR recommended)
Notes: Very compact sealed chamber for maximum acoustic output
in the midrange passband. The elevated Qtc provides a gentle
broad peak near system resonance that can be equalized flat via
DSP or used as a passband sensitivity boost. Ideal for high-SPL
touring line arrays and horn-loaded midrange systems where
output per driver is the primary requirement.
e) SEALED — Balanced (Qtc ≈ 0.85)
Net Volume: 1.8 liters
System Resonance (fc): 185 Hz
Qtc: 0.85
Response: Slightly warm, smooth transition through resonance
Crossover HP: 180–250 Hz (24dB/oct LR recommended)
Notes: Good compromise between midrange output and response
flatness. The slight warmth near resonance is easily managed
with DSP. Suitable for most professional midrange applications
including line arrays, point-source cabinets, and stage monitors.
f) SEALED — Butterworth (Qtc ≈ 0.707)
Net Volume: 2.9 liters
System Resonance (fc): 154 Hz
Qtc: 0.707
Response: Maximally flat amplitude, textbook Butterworth alignment
Crossover HP: 150–200 Hz (24dB/oct LR recommended)
Notes: Flattest possible sealed response with lowest system
resonance. Allows a lower crossover frequency if needed. Best
for applications prioritizing accuracy, smooth crossover
integration, and extended lower-midrange coverage.
THERMAL NOTE: The neodymium motor and aluminum basket provide efficient
thermal dissipation. The 3" CCAW voice coil on glass fiber former with
Kapton-grade thermal tolerance supports sustained high-power operation.
For sealed midrange chambers (especially ≤1.5L), ensure adequate
ventilation or thermal coupling between the motor and the enclosure
structure to manage heat under continuous high-power conditions.
DESIGN NOTE: The 2 demodulation rings in the motor structure reduce
harmonic and intermodulation distortion, particularly beneficial in
midrange applications where distortion artifacts are more audible.
The weatherized paper cone treatment provides environmental protection
for outdoor and semi-permanent installation use.
--- AI SUMMARY (copy/paste ready) ---
The 81NPMX8-263 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) and controlled, low-distortion performance across a wide operating bandwidth. It features a 3-inch CCAW voice coil on a glass fiber former, 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 low Qts of 0.33, 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.
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 9 to 12 liters with tuning frequencies between 61 and 80 Hz. Smaller volumes (9–10 liters tuned to 70–80 Hz) prioritize mid-bass output and cabinet compactness for portable 2-way systems, while 12 liters tuned to 61 Hz extends the usable low-frequency response to approximately 52 Hz (–3 dB) for stand-alone applications without dedicated subwoofers. In sealed enclosures for midrange duty, the driver performs in very compact net internal volumes of 1.3 to 2.9 liters, producing system resonances between 154 and 218 Hz. Smaller sealed volumes (1.3–1.8 liters, Qtc 0.85–1.0) maximize acoustic output in the midrange passband for line array modules and horn-loaded midrange systems, while 2.9 liters yields a Butterworth-class response (Qtc 0.707) with maximally flat amplitude for accuracy-focused applications.
The driver requires active DSP crossover management in both configurations. In vented mid-woofer use, a high-pass filter in the range of 51–70 Hz (24 dB/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.2–3 kHz. In sealed midrange use, a high-pass filter in the range of 150–300 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.
This 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 and weatherized cone treatment provide consistent performance in demanding touring and outdoor environments.
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======================================================================
PRODUCT CODE: 81NPMX8-263
======================================================================
--- ENCLOSURE RECOMMENDATIONS ---
======================================================================
ENCLOSURE RECOMMENDATIONS: 81NPMX8-263
======================================================================
Driver: 81NPMX8-263 (81NPM) — 8" Mid-Woofer / Midrange
Key T/S: Fs=72Hz, Qts=0.33, Vas=10.3L, Sens=93dB 1W/1m
Power: AES 200W / Cont 400W / Peak 800W
Xmax=6mm, Sd=219cm², Bl=16.7T·m, Re=5.2Ω, Mms=40.5g
Voice Coil: 3" CCAW on glass fiber former (22.5mm winding height)
Magnet: Neodymium | Cone: Half-pressed paper (treated/weatherized)
Surround: Fabric | Spider: Nomex | Basket: Aluminum
Motor: 2 demodulation rings, neodymium
NOTE: This driver's low Qts (0.33) and strong neodymium motor with
demodulation rings make it suitable for BOTH vented mid-woofer and
sealed midrange applications. Six enclosure alignments are provided
below — three vented (mid-woofer use) and three sealed (midrange use).
======================================================================
MID-WOOFER APPLICATION — Bass Reflex (Vented)
======================================================================
Use case: 2-way and multi-way systems where the 81NPM handles the
low-frequency and lower-midrange content, typically crossed over to
a compression driver or tweeter at 1.2–3 kHz.
PORT RECOMMENDATION: Round port (65mm diameter) — standard for compact
8" bass reflex enclosures. Port velocities are moderate across all
alignments (15–20 m/s), acceptable for professional touring use.
Flared port ends recommended to reduce turbulence at high excursion.
a) VENTED — High SPL
Net Volume: 9 liters
Tuning (Fb): 80 Hz
Est. -3dB: 74 Hz
HP Filter: 70 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 124mm long
Slot Port: 156mm W × 40mm H × 231mm L
Port Velocity: 19.9 m/s
Notes: Compact cabinet with strong mid-bass output. Maximum SPL
per unit volume. The higher tuning provides tight, controlled
low-end with excellent transient response. Ideal for portable
2-way tops and compact stage monitors.
b) VENTED — Balanced Response
Net Volume: 10 liters
Tuning (Fb): 70 Hz
Est. -3dB: 60 Hz
HP Filter: 60 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 154mm long
Slot Port: 156mm W × 40mm H × 287mm L
Port Velocity: 17.4 m/s
Notes: General-purpose alignment with even response through the
bass region and good transient behavior. Well-suited for most
2-way PA tops, multi-way systems, and installation loudspeakers.
c) VENTED — Extended Low Frequency
Net Volume: 12 liters
Tuning (Fb): 61 Hz
Est. -3dB: 52 Hz
HP Filter: 51 Hz (24dB/oct LR recommended)
Round Port: 65mm dia × 174mm long
Slot Port: 156mm W × 40mm H × 324mm L
Port Velocity: 15.2 m/s
Notes: Maximum low-frequency extension, reaching into the
sub-bass region. Requires proper high-pass protection below
tuning. Best for stand-alone 2-way systems without dedicated
subwoofers, or applications prioritizing deep bass reach.
======================================================================
MIDRANGE APPLICATION — Sealed
======================================================================
Use case: Line array midrange sections, coaxial cabinets, horn-loaded
midrange systems, or dedicated mid-high enclosures where the 81NPM
handles the midrange band (typically 250–3000 Hz or narrower), with
bass duties handled by separate woofer/subwoofer sections.
d) SEALED — High SPL (Qtc ≈ 1.0)
Net Volume: 1.3 liters
System Resonance (fc): 218 Hz
Qtc: 1.0
Response: Broad gentle lift near fc, maximum midrange output
Crossover HP: 200–300 Hz (24dB/oct LR recommended)
Notes: Very compact sealed chamber for maximum acoustic output
in the midrange passband. The elevated Qtc provides a gentle
broad peak near system resonance that can be equalized flat via
DSP or used as a passband sensitivity boost. Ideal for high-SPL
touring line arrays and horn-loaded midrange systems where
output per driver is the primary requirement.
e) SEALED — Balanced (Qtc ≈ 0.85)
Net Volume: 1.8 liters
System Resonance (fc): 185 Hz
Qtc: 0.85
Response: Slightly warm, smooth transition through resonance
Crossover HP: 180–250 Hz (24dB/oct LR recommended)
Notes: Good compromise between midrange output and response
flatness. The slight warmth near resonance is easily managed
with DSP. Suitable for most professional midrange applications
including line arrays, point-source cabinets, and stage monitors.
f) SEALED — Butterworth (Qtc ≈ 0.707)
Net Volume: 2.9 liters
System Resonance (fc): 154 Hz
Qtc: 0.707
Response: Maximally flat amplitude, textbook Butterworth alignment
Crossover HP: 150–200 Hz (24dB/oct LR recommended)
Notes: Flattest possible sealed response with lowest system
resonance. Allows a lower crossover frequency if needed. Best
for applications prioritizing accuracy, smooth crossover
integration, and extended lower-midrange coverage.
THERMAL NOTE: The neodymium motor and aluminum basket provide efficient
thermal dissipation. The 3" CCAW voice coil on glass fiber former with
Kapton-grade thermal tolerance supports sustained high-power operation.
For sealed midrange chambers (especially ≤1.5L), ensure adequate
ventilation or thermal coupling between the motor and the enclosure
structure to manage heat under continuous high-power conditions.
DESIGN NOTE: The 2 demodulation rings in the motor structure reduce
harmonic and intermodulation distortion, particularly beneficial in
midrange applications where distortion artifacts are more audible.
The weatherized paper cone treatment provides environmental protection
for outdoor and semi-permanent installation use.
--- AI SUMMARY (copy/paste ready) ---
The 81NPMX8-263 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) and controlled, low-distortion performance across a wide operating bandwidth. It features a 3-inch CCAW voice coil on a glass fiber former, 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 low Qts of 0.33, 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.
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 9 to 12 liters with tuning frequencies between 61 and 80 Hz. Smaller volumes (9–10 liters tuned to 70–80 Hz) prioritize mid-bass output and cabinet compactness for portable 2-way systems, while 12 liters tuned to 61 Hz extends the usable low-frequency response to approximately 52 Hz (–3 dB) for stand-alone applications without dedicated subwoofers. In sealed enclosures for midrange duty, the driver performs in very compact net internal volumes of 1.3 to 2.9 liters, producing system resonances between 154 and 218 Hz. Smaller sealed volumes (1.3–1.8 liters, Qtc 0.85–1.0) maximize acoustic output in the midrange passband for line array modules and horn-loaded midrange systems, while 2.9 liters yields a Butterworth-class response (Qtc 0.707) with maximally flat amplitude for accuracy-focused applications.
The driver requires active DSP crossover management in both configurations. In vented mid-woofer use, a high-pass filter in the range of 51–70 Hz (24 dB/octave Linkwitz-Riley) is recommended depending on enclosure tuning, with a typical crossover to a high-frequency driver at 1.2–3 kHz. In sealed midrange use, a high-pass filter in the range of 150–300 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.
This 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 and weatherized cone treatment provide consistent performance in demanding touring and outdoor environments.
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