Ashly mXa-1502 Operating Manual page 20

mXa-1502 • Operating Manual
Ambient Noise Compensation - ANC
Ambient noise compensation (ANC) is an
automatic output level control that uses a
microphone monitoring a zone's ambient
background noise to adjust overall output
level for that zone, automatically maintaining
intelligibility above the ambient noise.
Note: The ambient sensing microphone input
can not be routed to the zone's mixer.
The ambient noise sensing mic is processed
similar to a slow-responding SPL meter, which
is then used as the control signal for the
automatic level control of the program audio.
The ambient sensing microphone doesn't need
to be a high-quality microphone. It is only used
to detect the overall noise level in the zone
and is not used for the direct program audio or
paging.
The placement location of the noise-detecting
microphone is very important for the ambient
noise compensation function to work well. A
unidirectional microphone pointed toward
Ashly AquaControl™ Software
(output channels only)
the noise sources but away from any speakers
works best.
ANC Parameters:
Max Gain: This sets the maximum gain the
ANC can apply to the program audio. A typical
starting value is 10 dB.
Min Gain: This sets the base level of the
program audio before any ANC action affects
it. When the noise detecting mic exceeds
the noise threshold, ANC applies gain above
the minimum gain setting according to the
Program/Ambient Gain Ratio setting. A typical
starting value for minimum gain is -20 dB.
Gain Change Rate: This is the rate at which
the ANC will increase the gain, measured in
seconds per dB. A typical starting value is 2
seconds/dB.
Input Level Meter: This indicates the level
of the program audio before any ANC gain or
attenuation is applied.
ANC Gain Meter: This shows the current gain
or attenuation being applied to the program
audio by the ANC function.
ANC Mixer Input Channel: This selects the
mic input channel used for ambient noise
sensing. The mic signal is taken post-input DSP.
The mic must not be routed to the ANC zone.
Noise Threshold: This sets the ambient noise
mic level above which the ANC will begin
increasing the program audio gain above the
minimum gain setting. A typical starting value
is -30 dBu. Keep in mind that any changes to
the noise-sensing microphone gain will affect
the action of the noise threshold control.
Program/Ambient Gain Ratio: This sets the
ratio of dB increase in program level for every
1 dB increase in ambient noise level. A typical
starting value is 1.0 which means that for
every 1 dB increase in ambient noise above the
threshold, the ANC will increase the gain of the
program audio by 1 dB.
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