Hi,
first step: assign an input to a surface strip, set it up (assign local input, Slink etc) and set fader to any value so audio is send to master
Second step: Remove input from surface strip.
In this way signal keeps going to output(s) but is not controllable.
Result was when all layers are muted, still a keyboardsignal was send to master (and mix busses) without being visable and controllable on mixer.
I added another input to surface strip, and ‘luckily’ this input was connected to the same audio source as keyboard, and it was this signal what was send to master.
I muted this channelstrip and deleted it from surface.
I had this issue a few weeks ago but didn’t understand what happened.
Now I found out and wanted it to share with you, because I’m sure I’m not the only one.
Maybe I expected (unconsciously) that if you remove a channel from surface strip it’s audio is also deleted from audio flow.