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  FM8 Direct Servo bass and midbass subwoofer
Sealed audiophile sub with dual 8" drivers with selectable 50hz HPF
Performance & Specifications

The bass extension of FM8 in Low music and Low HT is same as that of F8. It is only at high bass extension setting, the two are different.

In the chart below, with bass extension controls set to Low Music, the response is 3 db down at 20Hz. The response is flat and extended.

sealed response

FM8 features bass extension switch similar to F8, allowing users to select among 3 different modes: Low Music (Q=0.5), Low HT (with a 18db/oct rumble filter at 20hz), and High (24db L-R filter at 50hz). In the following, we plot the FR of HIGH position (also known as the midbass module position).

sealed response

Integration

F8 provides a 12/24 db/oct switchable low pass filter to so that it can easily integrate with any front speakers.

Another aspect of getting a correct integration is phase alignment between the front speakers and the sub. We have written a guide on how to achieve a phase aligned subwoofer. F8 has a phase/delay adjustment knob. More >

Output, extension and user preferences

The bass extension switch allows the user to customize the deep bass extension and the rumble filter to control cone excursion. For HT application, one can set the extension to Low-HT or High for higher SPL output. For music one may prefer a lower cut off such as Low-Music setting. Changing the settings can also result in a better integration with the acoustic gain of the room.

 

Specifications  
Driver dual 8" high excursion with custom sensing coil
Driver materials paper cone with lightweight foam surround
  Cast aluminum basket
  Copper flux de-modulation shorting rings
Amplifier 600WRMS class D (dual Hypex Ucd modules) patented servo controlled
Dimensions 11"(W) x 20" (H )x 15-1/2" (D) with grille and amplifier knobs
Shipping Weight 68 lbs
Frequency Response 18 - 250 Hz (-3 dB @ 20Hz) 50-250hz (at "HIGH" bass extension setting)
Crossover slope Selectable 12 or 24 dB / octave
Crossover range (Low pass) 50 - 200 Hz
Rumble Filter (High pass ) 20 Hz 18 dB / octave
Phase response 120 degrees phase shift at 20 Hz
Phase adjustment 0 - 180 degrees continuously variable
Bass damping factor Low music (Q=0.5), Low-HT(Q=0.9), and high (Q=0.8)
Standy power 7W (standby, red light), 13W(ON,green light)
Finishes Available in black matte vinyl or black oak vinyl
  (Piano Gloss available in signature edition only)
Warranty 5 years warranty on driver and 3 years on electronics
  45 day satisfaction guarantee