Can you get a copy of the same song from a different source? I had that exact or extremely similar effect on a couple of individual tunes I bought on iTunes. I eventually found the original CD and the problem is now gone, even after doing my own ripping.

I couldn't hear the distortion in my lackluster truck stereo but my M60s play stuff for exactly what it is. Crap in = crap out. Luckily, the same formula applies for Awesome In.

With great power comes Awesome irresponsibility.