61FHM

ENCLOSURE RECOMMENDATIONS: 61FHMX4-430C
Driver: 61FHMX4-430C (61FHM) — 6" Mid-Woofer
Key T/S: Fs=35.0Hz, Qts=0.53, Vas=28.6L, Sens=86.01dB
Power: AES 60W / Cont 120W / Peak 240W
Xmax=6.40mm, Sd=132.7cm², Bl=5.01T·m
RECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)
PORT RECOMMENDATION: Round port (50mm diameter) — adequate for compact enclosures with lower air volume velocity
  a) High SPL
     Net Volume: 8 liters
     Tuning (Fb): 40 Hz
     Est. -3dB: 37 Hz
     HP Filter: 32 Hz (24dB/oct recommended)
     Round Port: 50mm dia × 404mm long
     Slot Port: 121mm W × 40mm H × 1027mm L
     Port Velocity: 10.9 m/s
     ⚠ Port length exceeds practical limits for this cabinet size.
       Consider a passive radiator or aeroport as an alternative to a tuned port.
     Notes: Strong mid-bass impact, reduced cone excursion, maximum output
  b) Balanced Response
     Net Volume: 10 liters
     Tuning (Fb): 37 Hz
     Est. -3dB: 34 Hz
     HP Filter: 27 Hz (24dB/oct recommended)
     Round Port: 50mm dia × 440mm long
     Slot Port: 121mm W × 40mm H × 1114mm L
     Port Velocity: 10.0 m/s
     ⚠ Port length exceeds practical limits for this cabinet size.
       Consider a passive radiator or aeroport as an alternative to a tuned port.
     Notes: General-purpose PA/subwoofer, even response, good transient behavior
  c) Extended Low Frequency
     Net Volume: 10 liters
     Tuning (Fb): 33 Hz
     Est. -3dB: 28 Hz
     HP Filter: 21 Hz (24dB/oct recommended)
     Round Port: 50mm dia × 493mm long
     Slot Port: 121mm W × 40mm H × 1245mm L
     Port Velocity: 9.0 m/s
     ⚠ Port length exceeds practical limits for this cabinet size.
       Consider a passive radiator or aeroport as an alternative to a tuned port.
     Notes: Deep bass extension, requires proper system protection below tuning
--- Summary ---
The 61FHMX4-430C is a 6-inch mid-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 86.0 dB sensitivity (1W/1m). The driver features a compliant suspension design suited to moderate-volume enclosures with extended low-frequency response.
In bass reflex enclosures, the driver performs best in net internal volumes of 8 to 10 liters, tuned between 33 and 40 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. 60 W AES / 120 W continuous) and DSP control. A high-pass filter in the range of 21–32 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 28–100 Hz, suitable for integration with a mid-bass or full-range driver in a two-way system.