Audio System Level
Setting System Levels
In audio systems that employ separate mixers and amplifiers, there are quite a few controls that affect the volume
of a signal. Knowing how to set these different volume controls is instrumental to proper system operation. In gen-
eral, the closer the control is to the signal source, the higher that control should be set.
For example, an audio system contains a microphone, a CAM2, and a power amplifier.There are 3 controls that affect
the volume of the microphone through the audio system speakers; the MIC input control, the CAM2 MASTER con-
trol and the volume control on the amplifier. How should these be set for best operation? Since the MIC control
is the closest (electrically), the microphone should be turned up the highest while still allowing enough “headroom”
to increase the microphone volume if necessary.The MASTER control should then be adjusted to produce an out-
put signal that lights up the red output meter indicator only on loud peaks and the volume control of the amplifier
should be set so that the volume of the speakers are as loud as could possibly be needed. By setting the volume
controls this way, the amount of undesirable hiss noise, which is produced in all audio equipment, is minimized.
This is the correct theory in setting up system gains (volume levels). However, there are some other factors that
ought to be considered. For instance, the individual input control should not be set so high that it requires the MAS-
TER control to be set near zero to keep the output signal level out of the red.There has to be a reasonable amount
of “control range” to the MASTER control to make it useful. In this case it is a good idea to reduce the level of the
individual input control so that the MASTER control can be rotated over a wider range to provide some overall
level control. During normal operation of a well set up audio system, the MASTER control is used to increase or
decrease the overall system level as the noise and audience increases and decreases. However, large changes in the
necessary volume level should be adjusted at the power amplifier. If the signal output level of the CAM2 is near its
maximum (as indicated by the output level meter) and the desired speaker level cannot be achieved, even with the
power amplifier volume at full, it indicates that the power amplifier or the size/quantity of the speaker is not ade-
quate to cover the desired area.This type of problem cannot be corrected by system volume control settings.Trying
to get more volume out of a system under these circumstance can only lead to distorted sound since the audio
equipment will be pushed beyond their designed maximum operating conditions. Correct the problem by getting
more suitable equipment for the job.
It is typically desirable to get as much signal level from the output of the CAM2 without making it so large that the
output circuit cannot maintain the signal level and begins to distort the signal.
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