Project Description

Bel Digital Group BM-A2-64MADI

The BM-A2-64MADI provides comprehensive in-rack metering and audio monitoring of MADI data. It displays signal level for all 32 stereo pairs, with any pair routable to stereo speakers, hi-resolution bargraphs and analogue outputs. Metadata including MADI frame data, AES Status and User bits for any channel pair may also be displayed. All AES3 channels are available at the rear panel in balanced and unbalanced formats.

  • Coaxial and optical (SC multi or single-mode) MADI inputs
  • Loop-throughs of both inputs with full Dolby E/Dolby Digital transparency
  • Simultaneous metering of all 32 AES pairs
  • Audio Present LED for each AES pair – confirms valid audio data
  • Any channel pair may be selected for audio monitoring on integral loudspeakers or via headphones
  • Selected channels displayed on 52-segment tri-colour L&R bargraphs
  • Analogue outputs (balanced) of selected channels
  • MADI channel data analysis – MADI frame data, AES Channel Status and User bits can be displayed for all channel pairs
  • All channels simultaneously available as 32 x AES3 and 32 x AES3-id outputs
  • On-board sample rate converters (SRCs), switchable
  • Comprehensive sync options (wordclock, AES, Black and Burst, MADI)
  • Wordclock and AES sync outputs
  • Ethernet interface
  • Dual power supplies, with separate IEC mains connectors (with cable clamps)
  • 2U, 19” rack-mounting enclosure
  • Designed and built in the UK


Intended for professional broadcast, production and live sound use, the BM-A2-64MADI is a 2U rack-mounting unit allowing immediate monitoring, audition and status checking of all 64 audio channels in a MADI bitstream.

Both 75 ohm coaxial and SC multi-mode optical MADI inputs (AES 10d-2008 compliant) are provided; a single-mode option is available for the optical input. Loopthrough outputs are provided in both cases, allowing the BM-A2-64MADI to be installed “in-line” in the system infrastructure.

The front panel display includes 32 bargraph meters, each permanently showing the (L+R) signal level in each channel pair. A further pre-channel ‘Audio Present’ LED is included to confirm the presence of valid audio data in the AES word (including the correct implementation of ‘digital silence’).  Any channel pair may be selected via a rotary control for closer analysis, which comprises: audio monitoring via an integral pair of loudspeakers; accurate level display on a pair of hi-resolution LED bargraph meters; selectable display of MADI frame and AES channel metadata: MADI frame status, AES Status and User bits. The selected channel is also available as pair of balanced analogue line level outputs at the rear, and at a ¼” stereo headphone jack socket on the front panel.

In addition to its monitoring functions, the BM-A2-64MADI also converts the MADI data to both 32 AES3 balanced pairs and 32 AES3-id unbalanced pairs. Sample Rate Conversion may be selected for all channels if required. The balanced audio outputs are in the form of four 25-pin Dsub connectors wired to the familiar “Tascam” standard; unbalanced outputs are on a 37-pin hi-density Dsub connector. 1U break-out panels for both formats are available as accessories: the BOB/O-32 makes the AES3 balanced outputs available on 16 XLR connectors (two required), while the ASBO makes the AES3-id unbalanced outputs available on 32 BNC sockets.

The synchronisation source may be selected from word clock, AES3, black-and-burst video or the MADI input. Sync outputs are available in word clock and AES3 formats. And Ethernet interface is included to facilitate firmware updates.

Broadcast-standard reliability is achieved with dual power supplies (with separate IEC inlets) for full redundancy, careful choice of components and extensive test and QC procedures.


Bel Digital BM-A2-64MADI Manual – PDF

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