I am running Ubuntu 12.04 on a HP Pavilion dv6. About a week after setting up my dual-boot Win7/Ubuntu, my laptop speakers began a soft popping sound on roughly 5 second intervals. It's the damnedest thing; the popping will occur at the same volume regardless of the system volume (even when muted). The fix is to play any sound, and the popping goes away (again even if the system is muted and the music/video/etc. is playing). Maybe I erroneously updated the wrong HP sound card drivers, but I haven't the slightest idea otherwise..