For some reason, when the "Pulseaudio" server is being used, the speakers on my laptop crackle loudly when muted. When not muted, they play sound as they should. When I switch to ALSA (Preferences -> Sound -> Music and Movies) this issue goes away.

Has anyone else experienced this issue? If so, it might help to post at this bug I have filed:

Dell Latitude D820, HDA-Intel Sound (of some kind, see bug)