DirectOut Technologies EXBOX.BLDS

Automatic, Seamless MADI Changeover Switch for Fail-safe Applications

DirectOut Technologies EXBOX.BLDS2018-10-04T17:00:40+00:00

Project Description

DirectOut Technologies EXBOX.BLDS

Automatic, seamless MADI changeover switch for fail-safe applications

  • 2-in/2-out MADI changeover switch for critical audio playback or broadcast routing applications
  • Automatically selects secondary MADI source if primary source fails
  • Alternative manual source selection from either front panel or via GPIs
  • Available with dual fibre or coaxial and fibre I/O
  • Uses proprietary BLDS (Buffer Loop Detection Signal) as trace tone to confirm presence/validity of incoming MADI data
  • Software application (supplied) records low-level BLDS on spare DAW track
  • Can be configured to switch on loss of BLDS or MADI frames
  • Switches within 2 samples (0.02 ms) of failure detection
  • MADI data is reclocked
  • Second (parallel) output for monitoring purposes
  • 48/96 kHz-compatible
  • Seamless, inaudible changeover when sources are wordclock-synced
  • Transparent to other MADI formats (AES10)
  • LEDs confirm MADI and/or BLDS statuses
  • User-definable priority operation
  • USB port for remote control and firmware updates
  • 4 x GPI port, 4 x GPO port for signalling and control
  • Dual power supply inputs for redundancy
  • Compact free-standing unit

The EXBOX.BLDS is a development of the EXBOX.64, which provides MADI reclocking, optical/coaxial format conversion and can act as a MADI extender.


The EXBOX.BLDS has been developed to provide an automatic, inaudible changeover between two identical, synchronised MADI sources in the event of the failure of one of them. Typical applications would be the use of two DAWs for multitrack audio playback at large-scale musical events, or two (differently-routed) MADI feeds at a large OB site.

DirectOut Technologies has developed the Buffer Loop Detection System (BLDS) as part of the solution to fail-safe, dual-redundant MADI operation. A specially-developed data pattern  is transmitted on one channel of each MADI stream (usually Ch 56, or Ch 28 if 96 kHZ sample rate is in use) at low level (-66 dBFS). This can be generated by a simple Windows application (available as a freeware download) and recorded as a continuously recurring loop of varying lengths on one DAW track.

The EXBOX.BLDS constantly monitors the data channel on the primary input and in the event of a data discontinuity, automatically re-routes the output MADI datastream to be sourced from the secondary input. Changeover typically occurs within 2 samples, and provided the source audio is identical and the DAWs (or other MADI sources) externally synchronised via a common timecode source, the output audio will be seamless and the changeover inaudible.

Manual operation is also available, with a front panel button “forcing” selection of one MADI input; source selection may also be controlled remotely via the GPI port.

The EXBOX.BLDS is available with one MADI port (input and output) on BNC co-axial connectors and the other on SC dual-fibre conectors; alternatively, SC fibre connectors can be supplied for both MADI ports.

MADI Out 2 always provides a buffered and reclocked copy of the data at MADI Out 1; this is useful for local monitoring/checking of the output datastream.

A comprehensive set of front panel LEDs confirms status of incoming MADI and BLDS signal on each port, priority settings and clock status. Separate 9-pin GPI and GPO ports allow remote set-up and monitoring. The 4-input GPI port permits manual selection of one input and priority set-up, while the 4-output GPO port provides unit status tallies for remote signalisation use.

The EXBOX.BLDS is built in a compact metal enclosure (140 x 140 x 42 mm) and is supplied with two external DC PSUs, which connect via separate, locking rear panel HiRose connectors.


DirectOut EXBOX.BLDS Brochure – PDF


DirectOut EXBOX.BLDS Manual – PDF
DirectOut USB Driver Install and firmware update Manual – PDF

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