List of some random Wireplumber / Pipewire issues I've ran into and some kind of solutions for them.
One issue I ran into while trying things is that at some point WirePlumber decided to set the "default sink" to incorrect ALSA device. I am not sure how that happened, but it felt difficult to find out where it got/stored the setting .. trying to fix it with 'pactl set-default-sink' was not possible because Pipewire was not seeing any other sinks.
Eventually I found that $HOME/.local/state/wireplumber/default-profile contains the device profile. You can try deleting that file and restarting wireplumber. You might also want to delete $HOME/.local/state/wireplumber/default-routes
If you get trouble with Wireplumber not starting properly, e.g. something like:
wireplumber: Error acquiring session bus address: Cannot autolaunch D-Bus without X11 $DISPLAY
in user journal, you may have to restart session (log out/login) several times. Or reboot completely.
In Debian, Fluidsynth daemon can block the audio device causing PW not to work. I ran into this and decided to just disable the daemon. "systemctl --global disable fluidsynth.service". Not a perfect solution, but I don't personally need Fluidsynth as a separate service.
Around August 2026 I noticed that the volume in Youtube in Firefox suddenly seemed to be oddly low, even when having hardware device volume at maximum (e.g. changing volumes via alsamixer). After chasing my tail around Googling for "low volume youtube firefox" etc, I eventually noticed via "pw-dump | grep -i volume" that Firefox and few other applications had their "volume" property at 1.0 (e.g. the maximum) but "channelVolumes" were something lower, such as [0.259993, 0.259993] for Firefox.
I could not find any in-application way of adjusting those "channelVolumes" values, so I tried (first making a backup copy) deleting
$HOME/.local/state/wireplumber/stream-propertiesfile and restarting PW + WP via "systemctl --user restart pipewire wireplumber". This seems to have fixed the problem for now. I have no idea how the settings got like that, however.