Are you talking about ATC instructions to you? There is a certain amount of random changes in sound quality to reflect real world radio coms but the volume is never reduced to a point where is is inaudible. Perhaps you should reduce your SIM volume to balance things out and then turn the overall master volume up
Yes. The ATC instructions. They start off loud and at normal volume, then at some stage during the flight reduce to a barely audible volume without me having modified anything in the sim. The simconnect message still shows up. Just the volume reduces.