Yamaha CL3 User Manual page 27

Yamaha Commercial Audio CL StageMix V3.0 User Guide
channels will be muted completely when the Mute Group Master is
activated. If the DIM indicator displays any other value, then channels
will be dimmed by that number of dB when the Mute Group Master is
active. In this case, the Mute Group Master button will display orange
when active to indicate that channels are not being completely muted.
Pressing any of the Dim Level buttons will open a popup screen that
allows the Dim Level parameter value to be set for each of the 8 Mute
Groups.
Tap anywhere outside this popup screen to close it.
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