3Com CP-1 Two-Way Radio User Manual

Page 10
The output level potentiomenters (the small knobs above the output con-
nectors on the CP-1 rear panel) allow you to balance the sound levels of all
the channels in your system relative to each other. The most important thing
to keep in mind when calibrating the system is to keep these potentiometers
set as low as possible. Your normal listening level (not background muzak
level) shouldbe with the system volume (as indicated by the front panel
LCD) set to around -06dB. This keeps the processor at its optimum signal
levels while allowing headroom if you really want to crank it up.
If you are using only two audio channels, level adjustment is now complete.
If you have additional channels, use the following procedure to set their
levels to match the main stereo pair.
Use the VOLUME DOWN button to reduce the CP-1’s level to about -20 dB.
If the EFFECT MUTE LED is on, push EFFECT MUTE to cancel it. Push
program button 12; the display will read: PRESET 12 on the left and
SURROUND PRO LOGIC on the right. Push PARAM four times or until
the display reads: CALIBRATE. Push PARAM UP to turn on the calibration
The sound you hear is a band of noise centered around 1 kHz, being sent in
sequence to: all channels, left side plus left front, center, right side plus right
front and rear channel(s). If you have a center speaker, the rear-panel
CENTER/PHANTOM button should be out. Since all levels are down
except for MAIN, you will hear only: both fronts, left only, silence, right
only, silence. If you have no center speaker, the rear-panel button should
be in and you will hear: both fronts, left-only, both fronts,right only, silence.
Now turn on the remaining power amplifiers and turn up SIDE, REAR and
CENTER gain until the individual loudness of the sounds reaching your
listening position is the same and the all-channel signal is evenly distributed
from all speakers. The CALIBRATE ON display will remain for as long as
you use this mode. When the front, center, side and rear channels are
balanced, press PARAM DOWN to turn off the calibration signal.
Finally, if you are using a separate low-frequency channel, use music or the
test signal of your choice to adjust the SUB WOOFER gain until the low bass
balances the rest of the spectrum. This completes the initial connections and
level adjustments of the CP-1.
Main Output
Set Main Output so system is as
loud as you are ever going to need it.
(Be careful that this level does not
cause speaker distortion or amplifier
Additional Channels
1. Select
Pro Logic
2.Push Param to
3.Push UP
for ON
Adjust other output levels until all
directions are equally loud.
Output Levels