VAR4 / VAR12 / VAR20 - Operation Manual
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12.3
Ambient Noise Sensor (ANS) Configuration
An Ambient Noise Sensor (ANS), or multiple ANS sensors, may be used to adjust the output gain of any
zone based on a measure of the ambient noise in the target zone, see Section “
16.2.5 Configuring an
Analogue Input as Ambient Noise Sensor (ANS)
”. With the ANS sensors acting to reduce the output gain of
the zone from the maximum configured value when the ambient noise in the zone is below a set maximum
threshold value. This is useful to ensure that the broadcast is set to a level above the ambient noise, and
therefore is always loud enough to be clearly audible, yet is as quiet as possible to minimise noise nuisance,
and unnecessary or uncomfortably loud broadcasts when the target zone is quiet.
If a zone is large then up to twelve ANS sensor can be used for any one zone. However in this use it may be
better to split the zone into separate sub-zones, each configured by one or two ANS sensors. Additionally an
ANS can be positioned at the junction of two zones, and can then be used to control the volume of broadcast
in both zones.
Where multiple ANS sensors are assigned to a single VAR Router output, the highest of the received ANS
values is used, i.e. the zone volume is increased to the required level in the worst case area.
The ANS function may be enabled or disabled per output, and the following ANS parameters are
configurable per output:
•
Min ANS:
This is the minimum threshold value of the ambient noise in the zone (in dBA). This is used to limit the
range over which the gain may be reduced. When the ambient noise reaches or is below this value, the
VAR Router applies the maximum reduction to the output gain. Therefore this has the minimum gain,
and a lower ambient noise will not reduce the broadcast volume further.
•
Max ANS:
This is the maximum threshold value of ambient noise in the zone (in dBA). When the ambient noise
reaches or exceeds this value, the VAR Router applies the full configured output gain for the zone.
•
Attack:
The Attack Time controls the rate at which the VAR Router can increase the gain when the ambient
noise rises. This is to stop the ANS system from suddenly increasing the broadcast volume in response
to any short-term increases in ambient noise.
The diagram in
Figure 9
illustrates the ANS operation, and the following sections describe the ANS
configuration.
A monitoring function is provided which allows the user to view the current ANS readings. Please see
Section “
18.2.2 ANS Monitoring
”.
L
It is possible to exclude an input from ANS compensation for instance to force emergency
broadcast to always be made at the full zone volume; see Section “
7.2.11 Input Ambient Noise
Sensor (ANS) Configuration
”.
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