In addition, make sure the subwoofer is enable in the speaker configuration menu (that means set the front
speakers as “small” so that the low frequency signal is redirected to subwoofer). Connect the subwoofer
output on the receiver to the left channel line input. Set the phase to 0 and crossover to max (5 o’clock
position) as a starting point. Gradually fine-tune the crossover and phase controls to get the best result. It is
recommended to keep the phase control at 0 degree and crossover control between 1 to 5 o’clock.
Whenever possible, use crossover control instead of phase control. The main reason is that Linkwitz/Riley
setup theoretically will have phase alignment between the subwoofer and satellite at the crossover point.
For comparative purpose, Figure 5-8 (taken from a Denon AVR-4800 receiver) shows the result when
crossover control is at different setting (5, 3, 2 , and 1 o’clock respectively) while phase control is set at 0
(or 7 o’clock). Note that in Figure 18, a dip is about to form at the crossover point.
Other Recommendations
This subwoofer amplifier is
NOT
recommended for sealed box speakers with DC voice coil resistance of
less than 2.5 ohm, nor for vented box (passive radiator) speakers with DC voice coil resistance of less than
3.0 ohm. Otherwise, the thermal protection circuitry will be activated more often.
Fig 5
Response when crossover is at 5 o’clock
Fig 6
Response when crossover is at 3 o’clock
Fig 7
Response when crossover is at 2 o’clock
Fig 8
Response when crossover is at 1 o’clock
