XM weirdness

I suddenly have a weird problem with my XM radio.  I thought it was no longer working, so I refreshed the radio signal, then I went out to mess around with it and it still wasn't working.  Although the Wx displays fine and the AUX page on my G600 says signal strength is excellent, I can't hear the music audio. Then I turned up the volume by adjusting it on the G600 to max volume, and I could hear it but at max volume it was still very low. Even weirder, it would play even during transmissions. It used to be that whenever I or ATC spoke it would cut out. It also used to be loud. Either I have some fault going on or am I a total dolt and missing some obvious setting... I'm going to try to figure it out tomorrow on my flight down to LA and back.