Your ULW-10 Subwoofer features a continuously variable crossover that allows you to set a low-pass
filter at any point between 40Hz and 150Hz. In addition, many popular receivers and surround proces-
sors also feature built-in electronic crossovers (please consult your receiver’s instruction manual).
If present, we recommend using your receiver’s crossover and rotating the crossover dial to ‘bypass’ on
the subwoofer, thus disabling it.
After setup is completed, during which an 80Hz crossover is recommended, you can adjust your
crossover accordingly either in the subwoofer itself or as recommended in your receiver’s setup menu.
Typically, the smaller your speaker OR the louder the system will be played, the higher the crossover
point. Conversely, larger speakers OR lower volumes allow for lower crossover settings. The THX
standard, what AV123 recommends is using an 80Hz crossover.
4.3 Crossover Settings
U
LW
-1
0
The phase dial (see “I” on figure 1.1) controls the relative phase of the subwoofer to best reinforce
the other loudspeakers in your system. Adjustments to this control will change your ULW-10’s
interaction with the rest of your speaker system, providing the least cancellation, and thus the best
response in any room. With SPL meter in hand (or, better yet, on a tripod), play an 80Hz tone (for
this exercise the crossover point must be set to 80Hz) and slowly rotate the phase control from 0
towards 180. Watching your SPL meter, find the point that results in the biggest peaks in sound
pressure levels (i.e. reads highest on the meter). This setting indicates the least amount of bass
wave cancellation, and should be held constant until the subwoofer or other speakers in your room
are moved, or placement is altered in any way. With typical front corner placement in most rooms,
you may very well find the 0 setting to be optimum.
4.4 ULW-10 Phase Adjustment
9.
