Sound distortion

[tomw at videotron.ca]

My wife has noticed a big difference in the sound quality (when playing mp3's)
between the xfce and kde environments.

This distortion is most noticable  when she plays  pop or rock music with lots of bass.
The best description is perhaps a old hand held transistor radio with the volume on
max.  (Or perhaps a speaker with it's fabric cone damaged.)

This distortion is present when using xfmedia or kaffeine in xfce but is
not "as bad" in the kde environment.

Any ideas as to what the problem might be...?
Perhaps it be possible to use the kde sound server (arts?) with xfce?
BTW this basically a Ubuntu (MEPIS) system so no ALSA.

Thanks for any help offered.