I recently installed Ubuntu GNOME 13.04 on my new Haswell desktop build which has an Asus Xonar XD sound card. Everything seemed to run smoothly until I noticed issues with sound on Google Chrome. Audio from various sources (Flash and HTML5) sounded faster than normal and had a weird pitch. I could also hear some crackling and popping.
Upgrading to chrome-beta fixed the issue with audio being sped up (bug report: PulseAudio doesn’t always use the sample rate reported by the server), but I could still hear some cracks and pops. I tried changing some PulseAudio settings but no luck.
Finally, I bumped into this old post on the Linux Mint forums which mentions how the timer-based scheduler behavior in PulseAudio can conflict with some Alsa drivers. The Asus Xonar XD card uses the snd_virtuoso driver. Immediately after disabling PulseAudio’s timer-based scheduling all my audio problems were gone.
Edit /etc/pulse/default.pa as root with your favorite editor:
sudo subl /etc/pulse/default.pa
Look for these lines:
load-module module-udev-detect use_ucm=0 load-module module-detect
Change them to this:
load-module module-udev-detect use_ucm=0 tsched=0 load-module module-detect tsched=0
Kill PulseAudio (it will automatically restart):
That’s it, haven’t had any issues since. If you have any comments reach me on twitter @oscrperez.