Suddenly some apps (I think those that use Alsa directly?) became very quiet, such as Skype. I think it happened after pairing via Bluetooth with an iPhone (to use the PC headphones/mic there). But it’s unpaired now.
Using latest Pipewire, Wireplumber.
As suggested in the Arch wiki I checked volume in alsamixer → F6, but if I increase from 37 to 100 Skype becomes better but other apps/sounds become too loud, the volume in KDE becomes 100%.
Skype volume in KDE and pavucontrol is 100%.
Any ideas how to debug this or how to reset things that may cause this?
Still the same, so far I reproduced this issue in two apps:
- Skype: call (or “make a free test call” in settings). The ringtone work fine.
- Bluetooth audio from my Android phone (Pixel 6a). At least the microphone recorder and calls. Youtube seems to work fine somehow, even though in both cases I see the same
bluez_input in PulseAudio Volume Control and EasyEffects.
Looks like I fixed it by deleting some Wireplumber cache. 
$ systemctl --user stop wireplumber
$ rm -rf ~/.local/state/wireplumber
$ systemctl --user start wireplumber
I have looked into this dir before, but thought that it cannot be related to the issue because in the restore-stream file all volumes were 1.0 and Skype is missing there (I guess Audio:media.role:Communication may be used for it).