Comment 57 for bug 66483

Still no solution for this problem, however there -is- now a viable workaround.

In Hardy, the "standard sound server" is meant to be PulseAudio, and so far from my experience it isn't bad. I say "meant to be", if you've upgraded from Gutsy you probably have to follow these instructions - https://wiki.ubuntu.com/PulseAudio .

The key is the package libsdl1.2debian-pulseaudio, which replaces libsdl1.2debian-alsa. Set up PulseAudio according to the instructions, get this SDL package, and there's no more crackling. Even if you fiddle with the volume.

Of course, this doesn't address the issue for people who don't want a hulking great sound server and just want the bare-bones ALSA plugin to work as it should. Still it's worth a mention.