Stereo buzzing issue

[superchargedman]

So, I unlocked the car tonight when the car was outside in -15c, and I open the door. I immediately hear this high frequency buzzing coming from all the speakers, but predominantly in the rears. I turn on the car. Everything's running fine, but the buzzing continues and get progressively higher in frequency. It was loud. I drove home, and even after turning the car off, the noise persisted. When I locked the car, it stopped. I unlocked it a few mins later, and the problem vanished. Has anyone experienced this? I have the premium stereo, not hk. Thanks.

[Satalite]

Sounds like a problem I have in my 128 all the time, but it doesn't stop like yours... What you are hearing is the AMP feedback through the speakers. Whenever you engage in opening the car door it will automatically turn on and usually turn off after 15 minutes of inactivity when the car is stopped...

http://www.1addicts.com/forums/showthread.php?t=519483

Apparently people have had luck replacing head units... but that didn't work for mine. Also people say there is now an SW update, but my dealer says it doesn't exist.

[rapter]

One BMW tech once told me that this problem is a result of customers complaining that the overall volume in the car was not high enough for active listening- as a result the engineers uped the volume in all cars and this problem started coming up in a few customer vehicles.

Solutions varied from new amps to new head units

Dealer visit!

[superchargedman]

Thanks guys!