System Idle Process is simply the title given to indicate available CPU resources, so the higher that percentage the better. It would help to know about the songs themselves (format and source), the media player used, and your sound card. The initial check, though, is usually to update the audio drivers, in this case downloaded from eMachines.
Let us know.
P.S. For other readers, Ronsin's specs are in his member profile.
recently ive noticed that music would randomly distort and slow down. i traced the problem to huge processor use jumps (from 0 to 50+ % for a second or 2) and i think theyr being caused by the "system idle precesses" that are taking up 80+ % of my cpu usage. is there anything i can do to make this stop?