System information
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Bypass disables the Ambient Noise Compensator without changing settings.
Right-clicking over certain settings will provide a menu of additional options. Control Dialog Boxes for Ambient
Noise Compensators can be minimized to create user control surfaces (see Customizing Component Objects).
see Ambient Noise Compensator setup procedure.
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.
• Adjust the Ambient Response time to determine how quickly the Ambient Input detector responds to changes in the
Ambient Input signal. Ambient Response should be set fast enough to track important ambient level changes (e.g. an
approaching train in a depot), but slow enough to ignore unimportant ambient level changes (e.g. someone popping
their bubble gum).