Comment 4 for bug 587185

May be it'll helps:
from /var/log/messages
 Jun 6 11:42:18 lucid kernel: [ 4.037493] hda_codec: ALC889A: BIOS auto-probing.
Jun 6 11:42:18 lucid kernel: [ 4.038881] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:14.2/input/input5
Jun 6 11:42:18 lucid kernel: [ 4.051677] HDA Intel 0000:01:05.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19
Jun 6 11:42:18 lucid kernel: [ 4.075714] Console: switching to colour frame buffer device 240x67
Jun 7 01:11:59 lucid kernel: [ 6.458063] hda-intel: IRQ timing workaround is activated for card #1. Suggest a bigger bdl_pos_adj.
Jun 7 01:12:24 lucid pulseaudio[1446]: ratelimit.c: 11 events suppressed
Jun 7 01:16:40 lucid kernel: [ 286.680101] CE: hpet increasing min_delta_ns to 15000 nsec
Jun 7 01:26:20 lucid pulseaudio[1446]: ratelimit.c: 19 events suppressed
Jun 7 01:32:28 lucid pulseaudio[1446]: ratelimit.c: 36 events suppressed
Jun 7 01:33:11 lucid pulseaudio[1446]: ratelimit.c: 12 events suppressed

" pulseaudio ratelimit.c: events suppressed" - continue collecting in messages while music playing.

also i found this bug https://bugs.launchpad.net/ubuntu/+bug/479296
"the music got stuck on two notes repeated for two or three seconds at short distance intervals, then everything gets back to normal." - i have same problem.