To enable the audio levels display on the layout, use the "Audio for Video" command from the layout editing mode context menu:
Faders are available for the audio tracks of each configured video device:
The faders allow changing the volume level on playout by moving the slider with the mouse. Unused faders are disabled.
On top of each fader the video device it is controlling is indicated.
The "Mute all" button mutes all the available video device controls simultaneously.
To mute a certain video device control individually, press the "Mute" button below the corresponding fader.
The muted device is indicated with the corresponding icon.