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 input to monitor background noise
in a specific zone, then adjusts the overall
output level for that zone accordingly in order
to maximize intelligibility above the ambient
noise.
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 room
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
Ashly AquaControl™ Software
(output only)
unidirectional microphone pointed toward
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/Base 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 adjust 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.
Mixer Input Channel: This selects the input
channel to be used for the ambient noise
detecting microphone. The microphone signal
is taken after any input signal path processing.
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: The ratio of
dB increase in program audio 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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