I had this go out on my 05 HAH this week and was VERY glad I read this thread here because I was the first one to hit my dealer with this problem.

Fortuntaely (I guess) in addition to replacing the faulty noise supression unit, they also replace the radio speakers because the chances are pretty good you've blown the bass in your speakers. (the only way I can describe the sound is like driving over those "barking strips" on the freeway, only 10x louder.

If anybody needs to go to their dealer about this, the service bulletin number is: 06-005