3Com CP-1 owner manual Output Levels, Balancing Additional Channels

Connection and Calibration

Lexicon

Output Levels

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 clipping.)

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.

Balancing Additional Channels

1. Select	2.Push Param to
Pro Logic		CALIBRATE

3.Push UP for ON

Adjust other output levels until all directions are equally loud.

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 signal.

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.

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