Mitsubishi Eclipse GS 2000 with the 7-speaker factory audio. When I play radio or use my iPod FM transmitter, I hear irritating buzzing/static from the front door-window tweeters during playback of certain frequencies and sounds in the music (especially heavy, driving guitar riffs).

Radio or iPod-broadcast songs from the band Evanescence, for example, sound REALLY BAD, but if I put in the CD, no problem, sounds great. I don't think it's a busted tweeter, as that would sound bad no matter what the music source was, right?

Any ideas on what this could be and how to fix?

 

I would assume that it is just the FM Transmitter your using. There never going to be CD quality compared to an actuall CD.