5
Setting up the Subwoofer
Hookup
If the subwoofer is being used with a THIEL PXO Passive
Crossover, a balanced XLR interconnect cable is connected
from the unit’s subwoofer output to the subwoofer’s Normal
Input. If more than one subwoofer is used, they are “daisy-
chained” by connecting an additional XLR interconnect cable
from the Normal Output connector of the first subwoofer to the
Normal Input of the next subwoofer. Move the 1/2 subwoofer
switch to 2 on both subwoofers to maintain proper levels when
2 subwoofers are “daisy-chained” from one crossover.
If the PXO is not used, then an RCA interconnect cable is
connected from the processor’s subwoofer output jack to the
subwoofer’s LFE Input. If more than one subwoofer is used, an
additional cable is connected from the LFE Output connector
of the first subwoofer to the LFE Input of the next subwoofer.
Both LFE Input and Normal Input connections may be
connected simultaneously as well. See Diagram 2 on page 6.
The subwoofer’s power cord must be plugged into an AC outlet
and the power switch turned to the “on” position.
Setting the Surround Processor
Tell the processor that you have a subwoofer.
If you are using a Passive Crossover then the surround
processor should be set to deliver the left/right channel bass to
the main speaker channels by telling it that the main speakers
are full-range or “large” (even if they are not).
If you are not using a Passive Crossover, and the main speakers
are not able to reproduce deep bass, you can tell the processor
that the front speakers are “small” so that the main channel
bass is redirected to the subwoofer.
Control Settings
The LFE Level is functional only for the LFE input. If you are
not using the LFE input, set this to minimum (OFF). If you
are using the LFE input, then the subwoofer level must be
adjusted to achieve the proper balance with the other speakers.
It is usually more convenient to adjust the subwoofer level
with the processor’s subwoofer level control, and in this case,
a good starting point for the level setting is 90. If the system’s
processor cannot control subwoofer level, then the subwoofer’s
level adjustment is used. The level can be adjusted “by ear”
to achieve a pleasing balance so that the low frequency sound
effects are not too weak or too strong. Unfortunately, an
SPL meter cannot be used to adjust subwoofer level due to
differences in bandwidth between the subwoofer and the main
speakers.
The placement settings should be adjusted to correspond to
the placement of the subwoofer. Set the Side Wall Distance to
the distance from the side of the subwoofer to the side wall
and the Rear Wall Distance to the distance from the rear of the
subwoofer to the rear wall. The distance is marked in meters,
which is the distance in feet divided by 3.3. If a distance
is greater than maximum indication set the control to Off
(maximum). If the subwoofer is placed in a cabinet, the settings
should correspond to the room wall distances, not the distances
to internal cabinet walls. If the subwoofer is recessed into the
wall so the front is flush with the wall, then the rear control
should be set to its minimum (negative) setting.
If the norm/auto switch is turned to the “On” position, the
subwoofer is always on, ready to reproduce a signal. If the
switch is set to the “Auto” position, the unit which is equipped
with a control input will turn the unit on when a DC voltage
between 5 and 25 volts is applied, if the Auto/On switch is set
to the “Auto” position.
Auto shutdown
The subwoofer is equipped with an automatic shutdown feature
that will turn off the output of the subwoofer if the drivers,
amplifier or rear panel get too hot or if the line voltage is too
low. This can occur if a very high input level lasts too long or
if the subwoofer has insufficient ventilation. If the automatic
shutdown is activated, subwoofer output will be interrupted
and the light color will change to yellow. The unit will resume
operation when conditions return to safe levels.
If the unit shuts down often, this indicates that you should
improve its ventilation, turn down the system’s volume control,
turn down the subwoofer’s level control or add an additional
subwoofer. You may wish to purchase an additional USS
subwoofer to increase the system’s bass output level as desired.
Feet
The USS is supplied with four pointed, screw-in feet that can
be used to provide firmer coupling to the floor for slightly
better sound quality and to prevent the unit from moving
during use. Please be advised that their use can put dents in
hardwood floors. They are screwed into the bottom of the unit,
and should be individually adjusted until the unit is firmly
seated onto the floor without rocking. Then tighten each of the
back-nuts to lock the feet in place.
