Setup And Calibration; Adjusting The Parametric Equalizer; Setting Up The Cwa-1 With A Spectrum Analyzer - PSB CWA-1 Installation Manual

X. Setup and Calibration
If you are critical about low-frequency response, there's quite a bit of useful
experimentation you can do, especially in combination with the crossover, level,
phase and parametric equalizer controls of the CWA-1.

Adjusting the Parametric Equalizer

A unique feature of the CWA-1 is its parametric equalizer. No matter how good
the subwoofer, bass response is usually strongly compromised by the
dimensions and material properties of the typical listening room. With the
CWA-1's parametric equalizer you can isolate the worst problem of the room and
equalize it to flat, thereby much improving bass accuracy and naturalness. Unlike
the commonly encountered graphic equalizer, a parametric equalizer allows full
control of frequency, bandwidth and amount (boost or cut) of equalization.
The CWA-1's equalizer, as well as its other controls, can be set by ear or via a
spectrum analyzer. Instructions will be given for both methods in the following
sections:

Setting up the CWA-1 with a spectrum analyzer

A spectrum analyzer will usually be a "real time" 1/3 or 1/6th octave analyzer.
Typically pink noise is sent through the system and a microphone is placed at the
center of the listening area. The system response can then be viewed on the
spectrum analyzer. Feeding pink noise through the system processor or AV
receiver will feed front channels as well as the subwoofer and will allow
optimization of all of the CWA-1's crossover controls. The best method is to feed
the spectrum analyzer to the processor via a "Y" connector to any pair of analog
inputs (left and right). To control which channels are driven, switch between
normal stereo and Dolby Pro Logic. When in Pro Logic the processor will steer
the input to the center channel and subwoofer only. When in stereo, the pink
noise should come out of the front left, front right and the subwoofer (bass
management settings permitting).
Each control will impact a particular bass area. Look for the following response
effects and make adjustments as needed.
CROSSOVER FREQUENCY will determine the upper frequency where the
CWA-1 and subwoofer roll off. This frequency needs to be a good match to the
lower frequency cutoff of the front speakers. If the front speakers are rolled off
beginning at 80Hz then the subwoofer will need to match that. You will see that
raising the crossover frequency above that frequency will cause overlap of
woofer and front speakers and will give more energy around 80 Hz. Turning the
crossover frequency lower will reduce the total energy around 80 Hz and may
even create a response hole.
At the same time try the PHASE (+-) switch in both positions. Usually one
position will give more level in the crossover region. This is the setting that gives
the best phase match between subwoofer and fronts. Try this with both the left
and right front speakers on, and also with just the center on. Leave the switch in
whichever postion gives the most level of mid-bass energy, even if the response
mounds up above flat, then readjust the crossover frequency for flattest response
in the crossover region.
Set the bass level (via the large VOLUME knob) so that it is some amount
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