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The Sonifex RB-DSD1 Digital Silence Detection Unit works in a similar way to the Sonifex RB-SD1 analogue silence detection unit, but has AES/EBU, S/PDIF and TOSlink inputs and outputs instead of analogue inputs and output respectively. Designed to switch from one input to another in the event of loss of audio, the unit is ideal at transmitter sites, or after the master output of a studio, to switch in another audio source, or simultaneous broadcast, should a master source fail.


The unit can switch:

  • On loss of level of the main input.
  • On loss of level on one channel of the main input.
  • On loss of synchronisation lock of the main input.


The RB-DSD1 has 2 x digital stereo audio inputs, each one selectable via front panel MAIN and AUX push buttons, from either AES/EBU balanced XLRs, S/PDIF unbalanced phonos or TOSlink unbalanced optical inputs. Sample rate converters on each input mean that sources of different sample rates can be used with the output sample rate being defined independently. Each input is user-defined as either the main source or auxiliary source and both sources are monitored for failure, each having a remote failure alarm. The colour of the MAIN and AUX push-buttons indicate which input is the main (green) and auxiliary (red) input, with a flashing LED indicating loss of synchronisation.


In the event of the main source dropping below a pre-set level for a pre-determined amount of time, the unit will automatically switch through to the auxiliary signal. The silence detect level is adjustable between -39dBfs and -84dBfs in 3dBfs steps via front panel DIP switches. The silence interval can be adjusted between 0 seconds and 252 seconds in 2 second steps via another front panel DIP switch block. A small cover panel can be screwed in place to obscure the DIP switches to prevent tampering of the settings.


There are 2 stereo outputs to allow for distribution of the selected input to multiple outputs. Each output is available as simultaneous AES/EBU balanced XLRs, S/PDIF unbalanced phonos or TOSlink unbalanced optical outputs. The output sample rates are selectable via rear panel DIP switches from one of 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz.


The unit has TTL wordclock BNC and AES/EBU XLR synchronising inputs as standard and optionally, the RB-SYA and RB-SYD synchronisation boards can be fitted to synchronise the unit to analogue or digital video signals. A front panel DIP switch block is used to decide whether the unit is synchronised to Input 1, Input 2, the AES/EBU sync input, the wordclock sync input or an optional video sync board. A front panel SYNC button selects the synchronisation mode of the unit and the button flashes whenever the unit is not synchronised to an incoming sync