NHT iWS Owner's Manual page 15

frequencies below 100Hz. The LFE input is not affected by this control.
Adjust the Low Pass Filter to approximately the same setting as the High Pass Filter as a starting point. Adjust the Low
Pass Filter in small increments up or down until the blend between the Evolution Subwoofer and your main speakers is
seamless and the subwoofer does not call attention to itself. Music featuring male vocals, cello and acoustic bass, bass
guitar and certain wind instruments (like saxophone and trombone) is useful for setting the low pass frequency.
Phase Controls (Front Panel)
The Subwoofer Phase switch and continuously variable control change the phase of the subwoofer
output anywhere from 0° to 270° relative to the high pass output. Proper subwoofer phase is impor-
tant to achieve smooth bass response. An improper phase setting causes a dip in the frequency
response of the combined subwoofer/satellite system at the listening position. The result of this dip
is low frequency production that is very deficient around the crossover frequency and a lack of seamless integration
between the satellites and subwoofer.
The optimal phase setting will vary depending on room conditions and placement. While fine tuning the phase controls,
have a familiar stereo CD available. You should listen to the same song while alternating phase settings. Find the best
setting while sitting at the primary listening position.
Begin by setting the phase knob at 0°, alternating the switch position between 0° and 180°. From the listening position,
choose the switch position that yields the most bass output and leave the switch in that position. Then use the knob to
fine-tune the phase setting. Slowly twist the knob, listening for the point at which the bass at the listening position is the
loudest. Small changes in phase generally produce subtle changes in bass output. You may have to adjust the knob now
and again over a period of a few weeks to find the best setting for your listening room.
Gain Switch (Rear Panel)
The Subwoofer Gain switch allows you to increase the gain of the X1 subwoofer output by 10dB.
Normally, the factory default "0" position will give you a wide range of volume adjustment. However,
if the sensitivity of your satellite speakers is greater than 93dB, your range of volume adjustment on
the X1 may be limited. In this case, set the Gain Switch to 10dB.
Boundary EQ (Front Panel)
Reflective boundaries (such as walls) reinforce a speaker's bass output (3dB for two walls, 6dB for
a corner) if the subwoofer is placed near them. Conversely, placing a subwoofer out in the room
results in a relative decrease in bass output. Boundary reinforcement may lead to low frequency
response that is uneven. Some frequencies will sound exaggerated relative to others, or the sub-
woofer will sound thin and lack impact. The Boundary EQ control allows you to compensate for the effects of room bound-
aries on the frequency response of the subwoofer. Adjusting the control enables you to achieve smooth low frequency
output from the subwoofer regardless of its location in your room.
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