Installation guide

VAR4 / VAR12 / VAR20 - Product Description
The ANS system can be set to act on different audio sources in different units. For normal audio sources the
ANS level is frozen and does not change during each announcement into a zone. This so that the broadcast
itself is not ‘heard’ by the ANS sensors as an increase in the ambient noise level. Without this function the
ANS system would cause the broadcast volume to increase during each broadcast. However some input
sources can be set to not have the ANS level frozen during broadcast, such as background music. These
sources must be set so that their maximum volume is below the maximum ANS threshold (in dBA).
It is possible to disable the ANS function per output channel for system test purposes.
The diagram in Figure 11 illustrates the ANS operation.
Figure 11 ANS Operation
AMBIENT NOISE
LEVEL
Min
ANS=+70dBA
Max
ANS=+90dBA
ANNOUNCEMENT
IN PROGRESS
T
MAX CONTROL RANGE
(+20dB)
B
A A
AREA
AMBIENT NOISE BELOW MIN ANS THRESHOLD,
THEREFORE MINiMUM GAIN IS USED.
AREA
AMBIENT NOISE ABOVE MAX ANS THRESHOLD,
THEREFORE MAXIMUM GAIN IS USED.
A
B
PA
SYSTEM GAIN
0dB
-25dB
ANNOUNCEMENT
IN PROGRESS
(FROZEN ANS LEVEL)
MAX CONTROL RANGE
(+20dB)
T
-5dB
OUTPUT GAIN SETTING:
MAXIMUM GAIN (WITHOUT ANS) =-5 dB
ANS SETTINGS:
MIN ANS THRESHOLD = +70 dBA
MAX ANS THRESHOLD = +90 dBA
Issue: 03 complete, approved
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