Loud Static and Popping Sound from Speakers

[Gilta]

My X5 has had a few issues with the stereo system.

It started out with just a few occasions where the sound would fade in and out for a while then just clear up.

A few days later, while listening to Sirrius, there was a loud pop and then extremely loud static. I tried turning the sound down and even off and it still continued. That stopped then each of the speakers, in rotation, had a popping sound from each one. This happened 3 cycles and then the stereo just stopped. 5 minutes later everything came back on with no problems.

I have had my X5 into the dealers but they cannot find the problem.

Anyone hear of this or know what the problem is?

Thanks!