This is probably not your problem, Dusty, but I experienced a similar problem with another airplane recently. The radio was almost unintelligible... it sounded like the squelch was on (or off?) all the time. Changing headsets didn’t help. Switching to the other set of jacks was the same. We pulled the radio and took it to the radio shop to be bench tested. It was fine. Started looking at wiring, etc. and finally noticed that there was a little portable Lithium Ion battery pack in the airplane that was used for charging or powering other devices, and it was connected to a portable Garmin ADS-B unit to power it. Turns out that battery pack/power supply was like a miniature radio station, and it was broadcasting an unbelievable amount of noise. I unplugged it from the Garmin unit and the noise instantly stopped. Further testing with another battery power supply created no noise... it was just that particular unit.