Comment 9 for bug 477423

For those who are curious about why the 01PulseAudio script even exists, it's because there were some buggy ALSA drivers in the kernel that didn't get resumed properly if PulseAudio was still accessing them when the kernel suspended. The result was that if there were applications playing sound (and hence, PulseAudio accessing the soundcard), PulseAudio and all applications attempting to play sound would hang upon resuming.

The script does not mute/unmute, but rather suspends PulseAudio, hence forcing it to release the sound card prior to suspending the kernel, and unsuspends PulseAudio after resuming.