Programming Redundant Backups on Digital Mixers

Redundant Backups on Digital Mixers

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Actors and Microphones

This scenario seems to occur time and time again in live theatre — the lead actor is so pivotal to the storyline he rarely leaves the stage.

This creates a technical challenge for the sound department.  If the actor experiences a microphone failure mid-performance, he will not have an opportunity to get the microphone replaced.  You can equip the actor with two microphone systems to alleviate this concern.  However, doing so creates a new complication when using digital consoles with programmable scenes.

Operating a digital sound mixer during a musical gives you the advantage over its analog counterpart.  It allows you to control several tasks with a single action.  We do this by merging multiple microphones into DCA Groups, and by programming mix levels and channel mutes into board scenes.  We program these scenes linearly, tracking changes from the start of the show to the end.

Computer programming in this manner always assumes the best-case scenario—a perfect performance with no human error and no technical failures.  Live theatre is anything but this perfect scenario.  Therefore, it is our responsibility as technicians to have contingencies in place, if and when things go wrong.

Redundant Backups

Let’s use Joe as an example.

Joe has been cast in the lead role in a new hit musical.  Joe never leaves the stage the entire performance, so we have equipped him with two microphone systems in the event of failure.

A redundant backup mic is simple to include on an analog sound mixer.  You would just use a second fader, placed next to Joe’s primary.  The analog mixer has no programmable scenes, so switching to Joe’s backup is as easy as muting one channel and opening the other.

But a digital console with multiple scenes creates a complication.  Here is the problem:

If Joe stays onstage through Scene 1 and Scene 2, we would program his primary microphone in an ON position to track through Scene 1 and Scene 2.  His backup mic (which is muted) would do likewise.

If Joe’s primary mic develops in issue in Scene 1, we would need to switch to the backup.  However, Joe’s backup is still programmed to be muted in Scene 2.  When we switch to Scene 2, Joe’s active mic will mute again and automate back to the malfunctioning primary.

Mute Groups

The way to resolve this programming dilemma is through the use of Mute Groups.

Mute groups operate independently and are unaffected by scene recalls.  They also override the programming of channel mutes within a scene.  If we assign each of Joe’s mics to its own Mute Group, we can either engage or disengage Mute Groups to choose which mic is active.  This means we have full control over which mic Joe is using regardless of the board scene.

A Programming Example

For ease of mixing, let’s assume that both Joe’s primary and backup mic are condensed down to a single DCA Group.

Since Joe never leaves the stage, we will assign both his primary and backup to an ON position for Scenes 1 and 2.  We will also assign Joe’s primary mic to Mute Group 1 and his backup to Mute Group 2.

Mute Group Assigns

In operation, Mute Group 2 will remain engaged so that audio can only pass through the primary microphone.  If the primary develops an issue, switching to the backup is as easy as engaging Mute Group 1, and disengaging Mute Group 2.

Backup Mic in Yamaha Studio Manager

There you have it.  We have outsmarted the computer by replicating an analog mixing technique into a modern digital console.  Now Joe’s performance can go off without a hitch, thanks to some clever programming and preparation.