sound. I think most is related to the DSP. I get no sound from mine often. I have settings for the DSP in Memory 1. When no soound is coming out, the Memory 1 that is in the center display with the radio station is not there. When the Memory 1 reappears after turning radio and/or car off several times, sound comes out again. I would be interested if you have the same experiences with your problem. I am on my 3rd amp, so I don' think that is the problem. I have also had blown speakers and clicking and popping sounds. More BMW electrical glitches!