Comment 13 for bug 1931902

@ppq

I've actually been able to determine what the issue was. The speech-dispatcher package is the one causing issues. It is possible to uninstall it from any Ubuntu installation (or Ubuntu-based distros). But to make sure that indeed this is what is causing the issue in your case, try to run this command on your Terminal:

speech-dispatcher -K

And check if the crackling noise will go away. If it does, uninstall it using apt:

sudo apt remove speech-dispatcher (or replace remove with autoremove if you want to also uninstall any packages related to speech-dispatcher).

It seems that this package will stop behaving correctly after some time with the system running, and will interfere with everything that pulseaudio will output.