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EXAMPLES OF USE
1.
Stereo Radio Station Transmitter Site
Mixer
Output
Backup
Audio Source
Switch
Notification
Forced
Switch
FM
Transmiter
2 x XLR3
2 x XLR3
2 x XLR3
GPO
GPO
GPI
This is the typical application for the SD1+ Silence Detector. It acts as a master fail alarm for
main programme audio for a radio station.
The main stereo programme audio from the mixer or the automation PC connects to the
SD1+ as the primary audio source. In normal operation, this audio passes straight through to
the stereo outputs of the SD1+ which connect 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 stereo input. A remote start will also be triggered
to start playing the backup audio source, which is now connected directly to the main stereo
outputs. 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 continually 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 automatically switch back to the
primary input can be set between 5-60 seconds.
