98' A4. My Cd player Freezes so i assume it's half knackered but i also suffer the rear speakers dropping out and the fronts loose the base or for some reason just sound "tinny" Also when you turn off Concern (non Bose) head unit when this happens and back on all is fine for 5 seconds before the rears cut out again. you have to turn the engine off before it works fine again. This has happened to me 3 times in the last 2 days. sooooo Currently i'm booked into a Audi centre on Friday so they can have a look. DO i put up with the CD changer errors and hope they fix the sound issues. Or Do i change the head unit for something that accepts MP3 cd's and get the garage to check the wiring and rear amps over for problems?