Answer by Dr. Cool for No sound on wake, Dummy Output always takes over. 'pulseaudio -k' the fix

I tried the solution by @WinEunuuchs2Unix but it didn't work with my Ubuntu 20.04.2 on a Lenovo Ideapad Y910. This is what I had to do to make it work with my setup:

Add a file (let's call it "pulseaudio-fix") to the directory /usr/lib/systemd/system-sleep and give it execution permission:

chmod a+x pulseaudio-fix

Include the following content in the file:

#!/bin/shcase $1 in  post)    su user-name -c "    killall pulseeffects;    killall pulseaudio;    sleep 1;    DISPLAY=:0 /usr/bin/pulseeffects --gapplication-service &"    ;;esac

Where "user-name" is the name of your user account. In my case commands wouldn't run under the system account. Additionally, killing pulseaudio would mess with pulseeffects, so it needed to be killed before pulseaudio and restarted after it autostarts. If you don't need pulseeffects, just delete the two lines from the code above.

This made the random "dummy output" after sleep problem go away for good in my case.