81FHW

• - Good low frequency response
• - Lightweight surround, stiff paper cone
• - Affordable woofer

ENCLOSURE RECOMMENDATIONS: 81FHWX4-289
Driver: 81FHWX4-289 (81FHW) — 8" Sub-woofer
Key T/S: Fs=39.0Hz, Qts=0.52, Vas=21.5L, Sens=85.94dB
Power: AES 100W / Cont 200W / Peak 400W
Xmax=6.1mm, Sd=201.1cm², Bl=8.25T·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: 10 liters
     Tuning (Fb): 45 Hz
     Est. -3dB: 41 Hz
     HP Filter: 37 Hz (24dB/oct recommended)
     Round Port: 65mm dia × 405mm long
     Slot Port: 144mm W × 40mm H × 722mm L
     Port Velocity: 10.4 m/s
     Notes: Strong mid-bass impact, reduced cone excursion, maximum output
  b) Balanced Response
     Net Volume: 12 liters
     Tuning (Fb): 41 Hz
     Est. -3dB: 38 Hz
     HP Filter: 31 Hz (24dB/oct recommended)
     Round Port: 65mm dia × 413mm long
     Slot Port: 144mm W × 40mm H × 738mm L
     Port Velocity: 9.5 m/s
     Notes: General-purpose PA/subwoofer, even response, good transient behavior
  c) Extended Low Frequency
     Net Volume: 16 liters
     Tuning (Fb): 37 Hz
     Est. -3dB: 31 Hz
     HP Filter: 25 Hz (24dB/oct recommended)
     Round Port: 65mm dia × 430mm long
     Slot Port: 144mm W × 40mm H × 766mm L
     Port Velocity: 8.6 m/s
     Notes: Deep bass extension, requires proper system protection below tuning

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. In 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 405–430 mm and will need to be folded within the enclosure; a slot port may offer a more practical alternative. The 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 25–37 Hz is recommended depending on enclosure tuning, along with appropriate limiting to manage excursion below tuning. Typical operating bandwidth is 31–100 Hz, suitable for integration with a mid-bass or full-range driver in a two-way system. This 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.

AES Power: 100 W, Continuous: 200 W, Peak: 400 W. Sensitivity: 85.94 dB (1W/1m).