Removing Pulseaudio worked for me too. Follow next explanation and reboot. http://ubuntuforums.org/showthread.php?t=973637
-- noise when muting PCM volume and audio is playing https://bugs.launchpad.net/bugs/272321 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
