I've noticed a month ago that sound while playing several mp3 songs in Ubuntu Linux has deteriorated. The sound was fine and more than perfect while using Windows XP, and I couldn't remember changing anything.
Then it struck me and I almost yelled "Eureka". I'm using Rhythmbox in Ubuntu so I thought of checking the volume, because I remembered that too high values could cause a bad output!
So I went to Applications > Sound & Video > Volume Control:
I set it to about 90% and the sound was better already, then I went to alter Rhythmbox's internal volume bar:
There, all done! Who said Linux can't be a breeze? It needs some substantia grisea to work though.