GAI-Tronics 13363 Addressable Amplified Speakers Installation and Operation Manual - Manual (Page 19)

Pub. 43004-034F
Model 13353, 13363, and 13373 Addressable Amplified Speakers Page 14 of 52
e:\radio products-current release\43004\43004-034f\43004-034f.doc
03/15
With Automatic Level Adjustment Enabled
The Automatic Level Adjustment (ALA) allows the speaker to automatically adjust its output to broadcast
at a pre-programmed level above the average ambient noise. Usually an offset of 10 dB is appropriate.
The speaker calculates the average ambient noise level every 5 seconds while it is not broadcasting. The
output level is then adjusted to compensate for the background noise. The first update to the calculated
ambient level will be at most 10 seconds after the standby time expires at the end of a broadcast.
Four settings are available for the ALA feature; Disabled, 5 dB Offset, 10 dB Offset, and 15 dB Offset.
To activate the ALA feature, select one of the three offset levels. The Offset Level is the level of audio
(in dB SPL) above the average ambient noise level, at which the speaker will broadcast.
With ALA enabled, the speaker will adjust its output, based on the steady background noise level in the
vicinity of the speaker, to some level between its maximum output (8 watts) and a programmed minimum
output level. To set this minimum output level, use CARD Suite or adjust the level remotely as described
in the previous section (ALA Disabled). As the background noise level decreases, the speaker output will
also decrease, but the speaker output will not drop below this minimum programmed setting, even when
the background noise drops to a very low level. This setting in CARD Suite is labeled as “Min. Volume
Level.”
Local Volume Adjustment
Local Volume Adjustment is achievable through the use of an L-pad volume control connected to the
speaker assembly (Model 12506-001). No test tone is generated during this adjustment as the user must
generate audio for this test while adjusting the L-pad.
This is a passive adjustment. The maximum output level is defined by the CARD Suite program. Since
the Local Volume Adjustment can only adjust the output level lower than the maximum programmed
level, it is recommended that the Addressable Amplified Speaker is programmed for maximum volume
level (8 watts).
Do not connect an L-pad if the Automatic Level Adjustment is enabled as the automatic adjustment
may be ineffective.
Acoustic Feedback
An audio broadcast command originating too close to an installed speaker (such as from telephones or
portable radios) may create acoustic feedback, depending on the volume level setting of the speaker. To
prevent feedback from occurring, originating distance from the speaker and orientation to the speaker (do
not position in front of the speaker) should be considered.
If the originating position with respect to the speaker’s location requires close proximity, the speaker can
be muted via a “shutdown” closure input. The shutdown closure input could be from a handset
hookswitch, relay, or other similar device.