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2.
Two Mono Audio Feeds
Mono
Feed 1
Mono
Feed 2
Switch
Notification 2
Forced
Switch 2
Forced
Switch 1
Backup
Audio Source
Backup
Audio Source
Transmiter
Transmiter
1 x XLR3
1 x XLR3
1 x XLR3
1 x XLR3
1 x XLR3
1 x XLR3
GPO
GPO
GPO
GPO
GPI MONO FEED 2
GPI MONO FEED 1
Switch
Notification 1
The SD1+ is effectively two single channel silence detectors. The example above shows the
operation of the unit when it is monitoring 2 separate mono signals, as a twin master fail
alarm. All functions are duplicated on both sides of the unit, and they can be set
independently. The info below is the same for mono feed 1 and selectable separately for
mono feed 2.
The mono feed audio from a mixer or link connects to the SD1+ as the primary audio source.
In normal operation, this audio passes straight through to output of the SD1+ which connects
to the transmitter.
An audio threshold needs to be set in order for the SD1+ to make a silence detection. This is
achieved by setting an audio level threshold, under which the SD1+ will start a timer. The
audio threshold is configurable from -60dB to -10dB and the timer is also configurable from 5
seconds to 5 minutes. These levels are often set at different points depending on the nature
of the source audio.
Once the primary audio source has been under the threshold for the preset amount of time,
the SD1+ will silently switch to the backup mono input. A remote start will also be triggered
to start playing the backup audio source, which is now connected directly to the primary
mono output. A further GPO is also triggered to notify an external system that the SD1+ is
now operating using the backup audio source. This will alert the engineers to investigate.
GPI control is always available by an external system to allow engineers to manually switch
between the primary and backup inputs. If the SD1+ is set in manual mode, then an external
GPI switch would be needed to switch back to the primary input.
In automatic mode, after the backup audio source has been selected, the primary audio
source is still being continuously monitored to check for the return of the audio. When the
primary source has been active again for a preset amount of time, the SD1+ will silently
switch back to the primary source. The recovery time to switch back to the primary input can
be set between 5-60 seconds.
