Comment 12 for bug 485488

I don't know if I've got the same problem. I've been having trouble with occasional sound glitches and generally poor sound quality since the upgrade to Karmic. The sound glitch is most noticeable when hearing the brief bit of music after logging in via gdm -- it's as if the music is tripping over itself. In general, the music sounds as if it's coming through cheap speakers, with bad mixing.

I tried adding tsched=0, as tomp suggested. I think it helped with the sound glitches, but not the decreased sound quality.