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.
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.