Normally I'm pretty good at accessing problems and fixing them without resorting to help from others but this one has me stumped. I bought a 27" iMac this past summer and have a pair of Harmon-Kardon Soundstick IIIs hooked up to an Airport Express so I can use Airplay to stream music to the speakers from the iMac as well as from my iPad and iPhone. Now, everything was working great until the past couple of weeks when, while playing certain mp3s, I can hear a loud chirping sound occasionally going with the beat (no birds stuck in my iMac ). It doesn't happen with all mp3s, just certain ones. There are no Apple Stores here in Sweden and the closest Apple Authorized Repair Center is a good 75 minutes away by subway as well as by foot. I really don't want to lug this puppy all the way there. My guess would be mp3 file corruption normally but deleting the file and redownloading it from iTunes doesn't fix the problem and neither does ripping a new copy from a cd. I'm stumped!