Biamp A4 - Manual (Page 142)

Audia-Manual-A4
ANC Setup Procedure
Connections
 Feed the "program" signal into the Program Input (top left) of the ANC block. Setup of the
ANC block is best done with a relatively constant program source. This can be the actual
program source or a pink noise approximation, but its level should represent the highest
program material level you expect will be fed to the ANC block.
 Feed the "ambient" signal into the Ambient Input (bottom left, marked with an "A") of the
ANC block. This signal should be derived from either a single dedicated sensing
microphone, or from a dedicated array of sensing microphones feeding a common Mixer
block. Setup of the ANC block is best done when the ambient noise in the room(s) is
minimal, but the Ambient Meter should read at least -60dBu.
 Connect the output of the ANC block to its destination. Keep in mind that the ANC should
be the last block in the program signal path, with no form of level control provided at the
outputs, amplifiers, or speakers.
Setting Min and Max Gain
 Adjust the Min Gain and Max Gain settings for the desired amounts of minimum and
maximum gain to be applied to the program signal. Remember that Min Gain is the
constant gain that the ANC block will apply while the Ambient Input signal level is below
the Ambient Threshold. Remember that Max Gain is the maximum amount of gain that
the ANC block will ever apply to the program input.
If Min Gain and Max Gain are not known, these settings may be determined by listening to
the ANC output, as follows:
 Set the Ambient Threshold to its maximum setting (+24dBu) to ensure the Ambient Input
level is below threshold. This ramps the ANC to the Min Gain setting. Keep in mind that
the speed of this ramping is determined by the Gain Time setting.
 Adjust Min Gain until you have the desired minimum program level comining out of the
ANC block. Note this value for later.
 Adjust Min Gain until you have the desired maximum program level coming out of the ANC
block. Set Max Gain to this value. Set Min Gain to the value determined in the previous
step.
Setting Response Times
 Adjust the Gain Time to determine how quickly the ANC gain changes. Gain Time is the
amount of time it takes for the ANC block to ramp from Gain Min to Gain Max, or vice
versa.
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