Mackie DL806 Reference Manual page 124

Mackie DL806 and DL1608 Reference Guide
Mute groups are also great for muting all inputs during song breaks or as a break switch in between sets.
In fact, this is similar to the iconic break switch found on many classic Mackie consoles...but with the
DL Series mixers, you can actually set up the break switch how you want. Here's how:
A classic break switch is muting all inputs and outputs, except the iPad channel and LR, as seen below.
When the mute group 4 button is engaged everything will be muted except for the house music over
the PA. Just unmute group 4 when the next band's gear has been set up and they're ready to rock!
It is still possible to mute channels, even if mute groups are engaged. Not only that,
but the color differs, so you know which muted channels belong to a mute group
[oxblood red] or just a regular 'ol mute [red]. See below.
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