I think the problem is the following: 1) You mute Master 2) Pulseaudio picks the change up, thinks you want to mute and mutes itself, as well as the other ones just to ensure you're really really muted everywhere. 3) You unmute Master 4) Pulseaudio does pick up that change, but at the same time, since other mixer controls are now muted, PulseAudio does nothing.
Btw, by controlling PulseAudio instead of amixer, your keyboard shortcuts will work correctly. ** Package changed: alsa-utils (Ubuntu) => pulseaudio (Ubuntu) ** Changed in: pulseaudio (Ubuntu) Status: Confirmed => Triaged -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/878986 Title: amixer -q sset Master toggle does mute, but does not unmute! To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/878986/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs