I use the pulse audio equalizer (qpaeq) and after update i had no sound, when i was restarting i didnt start qpaeq and sound was back. Seems the problem lies in pulse audio:
I think they changed the audio driver with the last update so it has to do with new libcanberra driver (warning popped up with dependancies to pulse audio) and that the new driver somehow includes pulse, but deletes the previous settings??
( wiki . archlinux . org/title/Libcanberra )
libcanberra no longer requires any backends for ALSA, pulseaudio or gstreamer, as they are now built in to the libcanberra package.
I dont know if I’m right with this, dont have enough knowlage to solve this, but this might bring some light into the case?!