After rebooting I had no sound at all. So I deleted /etc/pulse/default.pa entirely and tried another reboot. I did not backup the file (stupid, I know).
How to come back to working config?
sudo apt-get remove pulseaudio
sudo apt-get install pulseaudio
It's still not working. The file /etc/pulse/default.pa is missing.
Here's what pulseaudio and pacmd commands show:
$ pulseaudio E: [pulseaudio] main.c: Daemon startup without any loaded modules, refusing to work. $ pacmd No PulseAudio daemon running, or not running as session daemon.