sonifex rb sd1 iso

The Sonifex RB-SD1 silence detection unit is a 1U rack-mount device used to monitor an unattended stereo studio feed and in the event of the signal going “quiet” after a given period the unit will switch through an alternative stereo audio signal. This signal could be a recorded message (e.g. “normal service will be resumed”, etc), a feed from a CD player or minidisc machine, or an alternative recorded programme. Controls are provided to start external equipment and to provide a remote status indication.

It has 2 balanced stereo audio inputs with the maximum input level being +28dBu. 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. 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 -60dBu and -15dBu in 3dB steps via a 16-position rotary switch on the rear panel. The silence interval can be adjusted between 2 seconds to 30 seconds in 2-second steps, or, alternatively, set to 2 minutes 5 seconds also via a 16-position rotary switch on the rear panel. The audio outputs use stereo professional balanced XLR-3 male connectors.

The unit can operate in 2 modes – automatic or manual. In both modes, it will automatically switch over to the auxiliary source on detecting silence. When the main signal is again detected it will either return to the main signal automatically or manually depending on the mode chosen. The RB-SD1 has a number of remote operational features. Remote outputs provide separate relay contact closures for the failure of the main and auxiliary inputs. You can also control remotely all of the front panel switches for source selection, mode selection and signal Restore. You can remotely start and stop another piece of equipment on alarm failure and the main signal Restore respectively. Also, the longest silence time (2min 5sec) can be set remotely, which is useful if you are expecting to broadcast a long silence.

The unit can be configured to alarm when either the left or right channel of the main input source fails, or if the whole stereo signal fails. There are also options to set the remote start output as momentary or latched, to disable switching to the auxiliary input on alarming and to increase the gain on the auxiliary input so that an unbalanced input can be used, for example, from a domestic minidisc player.

Front panel LED indicators show individually left and right programme and alarm conditions for both the main and auxiliary inputs. The status of the source, mode and alarm state is also shown on the front panel with LED indicators.

Additionally, the RB-SD1 can be programmed for specific applications which can be defined on the power-up of the unit. Contact Sonifex for further information if you have a particular requirement. (Refer to the handbook on the website for information on current configurations).

The RB-SD1 has been designed to have a passive signal path through the main input, so if power to the unit fails, the signal input will still be routed through to the output. This is essential for applications such as installation at transmitter sites, where a power failure to the unit should not prevent the audio input signal from being output to the transmitter.

RB-SD1IP Silence Detection Unit With Ethernet & USB

The RB-SD1IP Silence detection unit is an upgraded version of the RB-SD1. The unit is a 1U rack mount device used to monitor an unattended stereo studio feed and in the event of the signal going “quiet” after a given period the unit will switch through an alternative stereo audio signal. This signal could be a recorded message (e.g. “Normal service will be resumed”, etc), a feed from a flashcard player, audio from a connected USB flash drive or an alternative recorded program. Controls are provided to start external equipment and to provide remote status indications.

New Features:

The RB-SD1IP offers all of the functionality of the standard RB-SD1 with several extra capabilities. Ethernet connectivity provides the ability to set up and control the unit via a browser-based GUI. The network capabilities allow the user to more finely control silence level (-60dBu to 0dBu in 3dBu steps) and silence duration (1 second to 24 hours). You can also remotely lock/unlock the front panel controls on the unit and opt to use either the hardware configured settings or web-based settings. In addition to the front panel LEDs, the GUI home page offers a real-time view of signal levels and alarm statuses.

Using the new browser GUI, left and right channels can be treated independently and remote relay triggers can be configured as one of many events including the new GPIO pins. You can also choose to lock/unlock the use of the remote pins to control the unit and firmware updates can also be performed using the web GUI.
SNMP V1 is implemented so that the unit can be controlled by existing network management systems. The addition of 6 extra GPIO pins to the rear panel allows customisable functionality, including the use of the RB-SD1IP network interface to generate SNMP Traps on behalf of other, non-networked, hardware.

The RB-SD1IP has been fitted with a USB interface on the front panel and can act as a host in two ways. Firstly the USB port can be used to upgrade the firmware on the unit from a USB flash drive. Secondly, such a drive can hold a pre-recorded message which the unit can play out in the event that both main and auxiliary signals fall silent.

  • Adjustable silence detect threshold level
  • Adjustable silence duration
  • Adjustable passive signal path
  • Switching of external equipment on silence detection
  • Automatic or manual operation
  • Mono or stereo operation
  • Front panel LED indications of alarm status
Key Features of the RB-SD1IP
  • IP Enabled with Web Browser control interface.
  • SNMP V1 Compatible.
  • Trap generation for non-networked hardware via GPIO port.
  • USB Functionality.

Audio Specification

Maximum Input Level:+28dBu
Maximum Output Level:+28dBu
Frequency Response:20Hz - 20kHz ±0.1dB
Gain:+8dB (for unbal input B - optional)
Distortion:As input for balanced input, <0.05% ref +8dBu output for unbalanced input
Input Impedance:>100kΩ balanced
Output Impedance:As input, except when using unbalanced auxiliary input where output impedance <50Ω
Noise:<-87dB, unity gain, ref +8dBu output for unbal input

Rear Panel Connections and Controls

Inputs (Main & Auxiliary):4 x XLR 3 pin female (balanced, auxiliary can be unbalanced)
Output:2 x XLR 3 pin male (balanced)
Remotes:15 way D-type plug
Alarm Threshold:-15dBu to -60dBu in 3dB steps via rotary switch
Silence Detect Duration:2 - 30 seconds in 2 second intervals & 125 second option via rotary switch
Detection Type:Mono or stereo, via DIP switch
Silence Switch Defeat:Disable/enable silence switching, via DIP switch
Remote Start:Latched or momentary, via DIP switch
Mains Input:Filtered IEC, switchable 110-120V, or 220-240V, fused, 9W max
Fuse Rating:Anti-surge fuse 100mA 20 x 5mm (230VAC) Anti-surge fuse 250mA 20 x 5mm(115VAC)

Front Panel Controls and Indicators

Controls (with indicators):Source select, mode select and restore
Indicator:Program and alarm indicators for left and right source for both main and auxiliary channels

Equipment Type

RB-SD1:Silence detection unit

Physical Specification

Dimensions (Raw):48cm (W) x 10.8cm (D) x 4.2cm (H) (1U) 19” (W) x 4.3” (D) x 1.7” (H) (1U)
Dimensions (Boxed):58.5cm (W) x 22.5cm (D) x 7cm (H) 23” (W) x 8.9” (D) x 2.8” (H)
Weight:Nett: 1.4kg  Gross: 2.0kg Nett: 3.1lbs Gross: 4.4lbs


    There are no reviews yet.

    Be the first to review “Sonifex RB-SD1”

    Your email address will not be published.

    BW Price Guarantee

    (Subject to conditions)


    Tech Support

    2-Year Warranty


    Related products
    STUDIO Sonifex RB-SD1