Lexicon CP-1 Owner's Manual page 21

Speaker
Set-Up and
Configuration
CP-1 Digital Audio Environment Processor
The Subwoofer Output is a monaural signal created by summing the left,
Subwoofer Connections
right and center outputs, then filtering out frequencies above 100 Hz at a
rate of 12 dB per octave.
Connecting a subwoofer to the CP-1 rear-panel Subwoofer Output, adds
bass energy without removing any from your main speakers. Note, how-
ever, that many of the subwoofers curently on the market have their own
crossover (complementary low and high pass filters) and amp built in.
Often it is better not to use the CP-1 Subwoofer output (which is already
filtered at 100Hz 12dB/octave). Instead, we recommend using the main
outputs as follows.
Connect the CP-1 main (front) and left and right outputs to the inputs of the
subwoofer crossover. Then connect the subwoofer output (high pass fil-
tered version of the input) to the amplifier driving the main speakers. This
has the advantage of bi-amping the main speakers — all the low bass is
handled by the subwoofer and the main speakers only handle mid-bass on
up. This usually reasults in a better-sounding main speaker.
If you want to run the main speakers full range, the subwoofer can be wired
in parallel to the main amp using a Y-connector. Alternatively, the CP-1
Subwoofer ouput can, of course, be used. If there is not enough gain for the
subwoofer (because it's being filtered by both the CP-1 and its own cross-
over), use one of the methods described above.
Since the center channel will still be runing full range, you should use the
Bass Blend parameter in the Pro Logic and Stereo Logic modes. This protects
the center channel speaker by splitting low frequencies off the center
channel and feeding them to the left and right front outputs. Remember to
turn up this parameter in any User Register you program, particularly in
Stereo Logic. A little experimentation goes a long way in determining the
optimum value for Bass Blend. Around 6 is usually best. When this
parameter is set too high, some male vocals will sound chesty; too low and
you lose bass.
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