PulseAudio is a network-capable sound server hosted at freedesktop.org. Supported operating systems include Linux, the BSDs, Solaris as well as Microsoft Windows.
I experienced some weird behaviour with my Logitech: Z10 speakers. Sometimes the volume set on the device differed from my pulseaudio setting. Sometimes they just muted. After playing around with alsamixer I noticed when modifying the PCM channel directly in alsa the volume display updated.
I just modified the path file for my sink: /usr/share/pulseaudio/alsa-mixer/paths/iec958-stereo-output.conf:
[Element IEC958] switch = mute
and added a Master element. After merging the PCM element with the Master element everything seemes to work now.
[Element Master] switch = mute volume = ignore [Element PCM] switch = mute volume = merge [Element IEC958] switch = mute
Note: Master and PCM must be before the actual output element!