You must encode your MP3's on a crap computer. I can hear a little difference sometimes in the quality between an mp3 file and a CD and mine are usually 128 bit. I think it depends on the encoder and what else might be running on your computer at the time and what CD you're listening to. And I'm picky about sound quality. I've downloaded some stuff off the internet that sounded crappy for some reason or the other even though it was at 128k.