Comment # 4 on bug 1198727 from Florian Bauer

(In reply to Takashi Iwai from comment #1)
> Is PulseAudio being used, or is it pipewire?
> Since speaker-test works, it's rather a problem of the sound daemon.
> 
> In anyway, please give the output alsa-info.sh, too; run the script with
> --no-upload option and attach the output to Bugzilla.

Honestly I've to say that I've some problems to understand Linux sound servers.
However, Pipewire is installed but I also tried to remove everything related to
Pipewire and using PulseAudio again. But it didn't change anything:
Under KDE settings still no sound from audio test if I click "subwoofer".

output from alsa-info.sh attached.

Thanks for your help! :-)