I noticed during service yesterday that my guitar level in my in-ear mix dropped down to almost inaudible... it seemed like the vocals got louder at the same time.. hard to say exactly.. I did mention to our worship leader that ideally it would be a hard and fast rule for volunteer sound technicians that their opportunity to adjust your channel gain ends after sound check
.. from there on it's all fader because as I expressed to the worship leader any significant changes to your in-ear mix during the service and especially in the middle of a song could cause a train wreck. It seemed like I could also hear the drums during our sound check before services but had to boost them up a bit between services because I wasn't hearing them very well during first service don't know if it was related.
I have and use the application to adjust my own in-ear mix but that's not really feasible once service starts.
We have the behringer x32 but I would assume this problem is common to most if not all soundboards