$ alsamixer
For restart alsa:
$ sudo alsa reload
or
$ sudo alsa force-reload
Else sometimes can be useful reinstall pulseaudio:
sudo apt-get install --reinstall pulseaudio
or
sudo apt-get purge pulseaudio
sudo apt-get install pulseaudio
sudo apt-get install indicator-sound libcanberra-pulse pulseaudio-module-gconf pulseaudio-module-bluetooth pulseaudio-module-compat
Path of also configuration file:
/usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf
