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Adjustments – FSR ML-800 User Manual

Page 33

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ML - 800

33

ADJUSTMENTS

As with any high performance audio system, proper adjustment is key to achieving optimum S/

N (signal to noise) ratio and performance characteristics.

Once the system is fully assembled including the mixers, amplifiers and other audio processing equip-

ment, you may begin.

In order to properly calibrate the system, you will need a signal source capable of providing a mic and

line level signal. You will also need a VTVM or other instrument that can measure voltages, preferably

with a dBm scale.

Begin by injecting a 1 Khz. typical mic level signal into a mic input of the Room One mixer. Monitor the

output of the mixer using the VTVM while adjusting the mixer channel and main out controls to achieve

a 0 dBm level. The mixer controls should not be set to their extreme settings for best performance. Mark

the settings so that users may re-establish them after changes are made. Continue by moving the input

signal to each of the mixers mic input channels, and calibrating them in turn.

CAUTION: At no time in the following procedure should you change levels by adjusting the
volume up down switches at the Wallplates or ML-800 Monitor Panel. Doing so will invalidate
your calibrations resulting in a lot of wasted time.
If you should accidently alter the volume settings, reset the system to a known state by turning
the power off and on, and reselecting the desired settings.

Next , using the ML-800RACK or Room Control Panel, set Room One to Local Mixer on, Mics On.

The Mic volume bar graph should illuminate the third led from the top. If not, consult the dip switch

setting section of this manual to reset the factory settings. Check the output level of Room One to

confirm unity gain through the ML-800 system. Proceed to the output of each successive audio compo-

nent in Room One’s audio chain, adjusting as necessary to achieve 0 dBm. Stop at the power amplifier

input.

Move the signal source to the first mic input of the next mixer, and repeat the procedure for Room Two.

Continue in this manner until all rooms are complete.

BACKGROUND MUSIC SET-UP

Continue by setting Room One’s wallplate to Music On, Mic and Local Mixer Off. Select music source

one. The Music volume bar graph should illuminate the third led from the top. Inject the anticipated

nominal music level into Music Input Source 1. Adjust the associated gain trim pot ( just below the input

connector) to yield 0 dBm at the ML-800 audio output connector. Select the next music source and

repeat this procedure until all four outputs are calibrated.

If the paging feature of the system is to be used, inject the anticipated level page signal into the page

input connector. Connect the P (priority page) terminal to ground on the page control terminal block

Adjust the page gain trim pot to obtain 0 dBm at the output of the ML-800 audio card.