Buzzing From Rear Speaker

[Diver]

Last night I opened the driver side door and then the trunk. The speaker on the passenger side of the shelf behind the back seat started making a buzzing noise. The radio was off. The noise did not stop until I drove home, got out and locked the car.

Has anyone experienced this or know what is going on?

[Dackelone]

Bad head unit or you need new SW flash/level. That is what members have reported before.

[Diver]

Dackel to the rescue. Car is going in Monday for other problems, so I can add this to the list. There has been way too much trouble with this car. I am looking for the exit.

[bimmerfile]

I had the same issue last Sunday.
My wife and I just finished lunch at a local restaurant and when we got back to the car, there was a load buzzing coming from the rear speakers as soon as we opened the doors. The buzzing continued regardless of what I did. Engine on or off, radio on or off. Nothing would stop it.
It was loud and irritating.
We had to stop by my son's place 20 minutes later and it was still buzzing as we got out of the car.
By the time we got back to the car with my grandson in tow, the buzzing had stopped.
I've had the 1er for just shy of 4 years, 32K Kms and this is the first time that happened.
Coincidentally, the next day the driver and passenger windows started acting up - bouncing back down half way when I tried raising them.
I took the 1er in for service and they fixed the windows, did the annual service and maintenance (oil, etc), but they could not find anything which would cause the speakers to buzz - I told them not to bother as I had "searched" this forum and learned that most people waste a lot of time without getting anything resolved for that particular issue.
Anyway, if it only happens every 4 years, then I don't have much to worry about.
Let me know if they find the source of the problem..