I've heard so much nice things about this, but just can't figure out how to get it to work.
AUR has packages for replacing PA and jack with pipewire, but when I tired this I ended up with a dead ardour and not even timeshift could get me back to a working system.
You might also need to reconfigure your audio settings, but that is unfortunately desktop session specific. (E.G. KDE has it in one place, gnome desktops another, etc)
Restarting your whole session is enough but you must restart every connections between the sound server and applications. Restarting is just often the easiest way to do that because it shutdowns everything and rebooting is extremely fast nowadays but it is not required.
You've always had to basically reboot your computer for big system component changes to be applied, otherwise you'll have some applications running the old system, and some running the new system. Yes, you could close those applications, but that's practically every process in your session, and getting the order right is tricky.
Both PulseAudio and PipeWire work best when running the underlying kernel drivers in "exclusive" mode, which means only one sound server can be running at a time. In order to ensure that works correctly, you need to:
1. Close all applications
2. Shut down PulseAudio and prevent it from auto-restarting
3. Start up PipeWire, and then restart your desktop environment if you want any hope of the volume applet working (or figure out which of the processes to kill if your volume applet in another process)
4. Start up your applications again.
5. There might be some applications that have tried to play audio that you were unaware of! Like your file manager, which can play a custom "bell" for mandatory audio alerts when trying to type in a place that doesn't accept characters. Oops! Better close that down too and start 1-4 over again.
Restarting the computer is an easy and safe way to apply these changes. That people didn't follow all these steps in this exact way meant the computer started to break in strange and unobvious ways, not that it was ever supported.
If you want to help out designing smoother ways to change out core system components without reboots, feel free to do that. The people involved might not find it worth the trouble to fix, though. I think it's just sensible to restart the system.
If we're lucky, it will take them ages to polish this turd, so effectively you're still good "just" using pulse.
Which also broke on my laptop after the last dist-upgrade, and after half an hour of debugging and fiddling I gave up. Found "apulse" which is a small library you can LD_PRELOAD that implements the pulse api but simply translates everything to ALSA. Doesn't support the more advanced stuff from pulse obviously, but works for normal things like Firefox etc.
AUR has packages for replacing PA and jack with pipewire, but when I tired this I ended up with a dead ardour and not even timeshift could get me back to a working system.