Got in last night and passenger door speaker screamed at me. Almost sounded like feedback but was clearly coming from the stereo/Bose system as it went away as soon as I turned off the stereo. I put in a new head unit in January and it has been working great. The noise went away as soon as I turned off the head unit. There was no output to the speakers at the time it was howling, I turned it off before the unit found anything to output.

I still have my original Symphony unit and I will throw that back in to isolate the problem between the new headunit and the Bose system amp.

Anyone ever heard of something like this?

2003 A4

 

More info: I swapped back the old headunit and I get the same howl.

Is the speaker shot? Something grounded out? Or is the amp shot? Feedback from something?

Any thoughts?