- Nonparallel voice and low frequency reproduction quality
- Patented magnetic circuit and air venting design
- Extremely low harmonic distortion
- 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 “more of everything”. 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’t another driver like this on the market.Motor DesignThe 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.
General specs Nominal Diameter: 8 in. Rated Impedance: 8 Ohm Power handling AES Power: 200 Watts Program Power: 400 Watts Voice Coil Diameter: 2.5 in. Winding wire: Copper Sq. Former: kapton Winding height: 18.3 mm T/S Parameters Resonant frequency: 73 Hz Re: 5.5 ohm Qes: 0.37 Qms: 1.47 Qts: 0.3 Vas: 7.2 liters Sd: 201 cm2 Mms: 38 grams Bl: 16 Le: 0.19 mH Sensitivity: 93 dB Design details Surround Material: Fabric Cone material: Paper Spider: Nomex Plate thickness: 31 mm Peak to peak linear cone Displacement 28.4 mm Overall diameter: 210 mm Bolt circle diameter: 195 mm Baffle cutout dia.: 186.88 mm Number of mounting holes: 8 Depth (flange to rear): 128.3 mm Net weight: 4.9 kg Ordering codes: 8 ohm version: 81XR-X8 ohm-424A Recone kits: Download: Spec download 2D drawing 3D model
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PRODUCT CODE: 81XRX8-424A
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--- ENCLOSURE RECOMMENDATIONS ---
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ENCLOSURE RECOMMENDATIONS: 81XRX8-424A
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Driver: 81XRX8-424A (81XR) — 8" Mid-Woofer
Key T/S: Fs=73.0Hz, Qts=0.3, Vas=7.2L, Sens=93.0dB
Power: AES 200W / Cont 400W / Peak 800W
Xmax=6.35mm, Sd=201.0cm², Bl=16.0T·m
RECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)
PORT RECOMMENDATION: Round port (65mm diameter) — adequate for compact enclosures with lower air volume velocity
a) High SPL
Net Volume: 8 liters
Tuning (Fb): 75 Hz
Est. -3dB: 69 Hz
HP Filter: 67 Hz (24dB/oct recommended)
Round Port: 65mm dia × 201mm long
Slot Port: 150mm W × 40mm H × 384mm L
Port Velocity: 18.2 m/s
Notes: Strong mid-bass impact, reduced cone excursion, maximum output
b) Balanced Response
Net Volume: 8 liters
Tuning (Fb): 68 Hz
Est. -3dB: 58 Hz
HP Filter: 58 Hz (24dB/oct recommended)
Round Port: 65mm dia × 230mm long
Slot Port: 150mm W × 40mm H × 436mm L
Port Velocity: 16.4 m/s
Notes: General-purpose PA/subwoofer, even response, good transient behavior
c) Extended Low Frequency
Net Volume: 10 liters
Tuning (Fb): 59 Hz
Est. -3dB: 50 Hz
HP Filter: 47 Hz (24dB/oct recommended)
Round Port: 65mm dia × 262mm long
Slot Port: 150mm W × 40mm H × 493mm L
Port Velocity: 14.3 m/s
Notes: Deep bass extension, requires proper system protection below tuning
--- Summary ---
The 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.
In 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.
The 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 47–67 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 50–2500 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system.
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.
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