Restart Ubuntu sound processes via command line

As suggested by mikewhatever in his answer to this question on Ask Ubuntu:

pulseaudio -k && sudo alsa force-reload

PulseAudio is a user service, so run systemctl with the --user flag.

systemctl --user restart pulseaudio

If Ubuntu is still using Alsa for its sound engine (I'm not sure as its been awhile since I've used it), you can restart by typing sudo /etc/init.d/alsa-utils restart into the terminal.

Since it doesn't seem to be working, you might need to make sure that nothing is trying to use it. (example shamelessly stolen from the Ubuntu forums)

name@comp:~$ lsof | grep pcm
sh 5079 name 70u CHR 116,6 13639 /dev/snd/pcmC0D0p

name@comp:~$ kill -9 5079