Project Description

Bel Digital Group BM-A2-4SHD MKII

High quality 4-channel broadcast audio monitor with SDI, AES3id and analogue audio sources plus SDI de-embedding in a 2U 19” unit.

  • Metering and monitoring of up to 4 channels of audio
  • 4-channel audio de-embedding of any SDI group
  • Auto-sensing SDI inputs (SD/HD/3G)
  • Additional 8-channel sources: AES3id x 2 and analogue x 4
  • AES3id outputs of channels 1 to 4 of the selected source
  • Very simple to use: all primary functions have individual controls
  • Display for input status and unit configuration
  • Any channel may be monitored on either speaker, including combinations and groups
  • High resolution 53-segment, tricolour LED meters with adjustable colour transition points and peak-hold facility
  • Four standard meter scales/ballistics, user selectable
  • Audio output levels are auto-adjusted for consistent volume when monitoring multiple channels
  • Compact 200 mm deep chassis, therefore ideal for OB and Flyaway applications

Bel Model BM-A1-4SHD provides similar facilities of the BM-A2-4SHD MKII, in a 1U chassis.


The Bel BM-A2-4SHD MKII is a high quality, 2U, 4-channel audio monitor/de-embedder suitable for operation in Master Control Rooms, OB vehicles and Flyaway systems where SDI is the standard video format. It is able to de-embed 4 channels of audio (1 group) from 3G/HD/SD SDI, display the levels on the front panel meters, and to provide stereo audio monitoring of any combination of the 4 channels.

The unit is very simple to use: all source selection and main monitoring setup is done from individual controls on the front panel without any necessity for menu navigation.

In addition to two auto-detecting 3G/HD/SD SDI inputs, the monitor has four balanced analogue inputs (XLR) and two AES3id BNCs. A re-clocked loop-through output is available for the selected SDI source providing a convenient and cost-effective method of switching SDI feeds to an external monitor. Channels 1 to 4 of the selected source are also routed to two AES3id outputs (providing de-embedding of any SDI audio group). In addition, the stereo audio monitor mix is available as a separate balanced feed at a pair of XLRs.

Audio levels are metered on four 53-segment tricolour LED bargraphs. User setup options allow a choice of four scales and ballistics (including BBC or DIN PPM, VU and AES/EBU), and also colour transition points and peak hold.

Users have full flexibility in assigning any channel to left, right or both speakers (or neither), and automatic level attenuation compensates for monitoring multiple channels. A ¼” jack headphone output socket is provided on the front panel. When in use, the internal speakers are muted. Audio level at the rear panel analogue outputs may be configured from a setup menu either to be fixed or to follow the main volume/mute control.

The BM-A2-4SHD MKII is fitted with a display screen, enabling easy device configuration and display of signal status information and volume.

The unit is built to a very high mechanical standard in a stainless steel 2U 19” enclosure that is only 200 mm deep. Warranty is for 3 years.


Bel Digital BM-A2-4SHD MKII Manual – PDF

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