MP3 playback from my RH10 seems alot more "muddy" than compared to playback on my PC and my pocket PC. For example, the drumbeats from a pop song would sound less distinct on my RH10. The problem would seem to be worse if your music is encoded at a lower bit rate. However, if your music collection are high bitrate MP3's, this "muddiness" should reduce significantly. The equalizer on the RH10 would not totally solve the "muddy" playback for me, however, as I listen to MP3's using the RH10, I got used to the sound, so to me it's not a big problem. Sorry if my reply does not seem to be too technical, but this is what I feel as an average layman listener.