I can mute any of the 8 Parts in a Performance.
I can easily mute an Audio In Part by pressing the Audio In Button on the upper left.
Is there a way to quickly mute the Digital Part in a Performance from the Montage?
Can the Super Knob be used to do this?
If your goal is to change the digital IN (USB audio IN) volume, then I believe the soon-to-be-released Firmware v1.50 will address this:
Monitor Volume for USB Input - OS v1.5 adds USB audio monitor control. This is useful for quickly adjusting the incoming audio level from a DAW or iOS device. It’s also handy when listening to music on the computer from iTunes™, YouTube™ or other source.
I'm not sure that this will be exposed to superknob control or not. At this point, I would say probably not - but the information is limited.
This may not work for you for other reasons, but you can mute digital audio by using the sledge-hammer technique: change MIDI mode from USB to MIDI. This will disconnect everything else from USB as well.
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R