BEL DIGITAL AUDIO
BMA2-4SHD
Operation
2006 BEL (Digital Audio) Ltd
4
Version 0.8
BMA2-4SHD can provide warnings of several input signal conditions:
Signal condition
Notes
Alarm indication
Audio loss
The currently selected four audio
channels are monitored for
persistent under-level. An alarm is
generated when an input is < -30dB
(-50dB for AES meter) for more than
15 seconds.
Audio tone
Bottom bargraph
segment flashes amber
TTL/serial alarm
Audio-over-level
The currently selected four audio
channels are monitored for transient
over-level. An alarm is generated
immediately when the first red
segment of the relevant bargraph is
illuminated.
Audio tone
Bottom bargraph
segment flashes red
TTL/serial alarm
Audio anti-phase
Audio pairs 1&2 and pairs 3&4 are
monitored for sustained anti-phase.
Audio tone
Appropriate phase LED
illuminates
TTL/serial alarm
Button functions
Note:
The over-level alarm threshold can be adjusted by moving the red bar transition point.
To prevent the anti-phase detector from generating intermittent alarms, only persistent
anti-phase conditions are used to raise an external alarm or generate an audio tone.
An alarm is generated when an anti-phase condition exists for more than 10 seconds.
Alarm arming
No alarms are generated unless alarm functions have been ‘armed’.
The front panel alarm toggle switch has four functions:
1. Upper position held – ALARM RESET - any armed input alarms are cleared
2. Upper position momentary – resets bargraph peak-level indicators
3. Middle position – OFF/MUTE - the internal audible alarm is muted
4. Lower position – SET - alarm functions are selectively armed
The switch must be held in the upper ALARM RESET position for more than 3 seconds for a
reset to occur.
In the lower SET position the inputs currently active are automatically detected and the
appropriate alarms are selectively enabled. The unit is then set to monitor only the active
inputs. The SET function can be disabled using a serial command.