Comment # 10 on bug 922401 from Wolfgang Bauer

(In reply to Christian Bachmaier from comment #9)
> As a work-around I have now set flat-volumes = no. Then the master is not
> changed without user interaction any more. However, the system sound slider
> in KMix is set automatically to 66% every time a system sound is played
> destroying the balance to other sound sources.
> 
> > But flat-volumes=false, which is the source of this problem, is set by default.
> 
> flat-volumes = yes was commented out, and yes is the default and not false.
> I have never changed the file daemon.conf before.

Yes, that was a typo, sorry.

flat-volumes = yes is the default, and causes this behaviour, that
notifications are even able to change the overall volume.

> > Maybe you raised the volume for notifications in PulseAudio itself?
> 
> No. pavucontrol was not installed on my system until now.

But you may have changed it in KMix, knowingly or unknowingly.

> > PulseAudio basically allows a separate volume setting for each application.
> > You should be able to set the volume for notifications in KMix or pavucontrol.
> 
> Changeing the loudness of system sounds in pavucontrol to 25% does not
> change anything.

As I don't use PulseAudio myself, I have no idea whether "system sounds" would
be the correct thing here for KDE I have to admit.

> > But actual notifications should be played at the correct (lower) volume.
> 
> No, I don't see that. It is rather hard to find/trigger an automatic sound
> without using the control center despite logoff. Any suggestions?

Well, depends on your notification config of course.
An easy way might be to open more than one tab in Konqueror or Dolphin and
close the window. A dialog should appear asking you whether you want to close
the current tab, the whole application, or cancel, and also a notification
sound should be played (with the default settings at least).

> The old behavior with a slider in control center was better.  In my opionion
> the system sound level should not be changed automatically.

This slider is removed by openSUSE's patches. And it's that slider (or rather
the option to configure the notification volume at all) that actually causes
the problem with PulseAudio/flat-volumes=true.

KDE 15.04 disables this volume control by default, but allows the user to
enable it if (s)he wants to.
I haven't tried that patch myself either though, so cannot tell if that would
fix all problems, or the same problems would remain.

> So once has
> changed in KMix (or with the slider in the control center since in KMix is
> is only shortly during playing the notification sound) the level should be
> left as is. pavucontrol should not be needed, since a KDE user has KMix and
> pavucontrol is not installed in a default installation.

Yes, but in my experience the right volume slider in KMix does exactly this.
It is available permanently, and sets the volume for notifications to a fixed
value.
You don't have to use pavucontrol.

But I have to say again, personally I find this whole flat-volumes behaviour
irritating at best. E.g. if you raise the notification volume (and probably the
volume for any other application), the general volume gets raised as well when
this plays a sound. But lowering the notification volume does not do any change
to the general volume...
Again, IMHO this is a design issue in PulseAudio and/or a bad default, or maybe
the problem lies in KDE's PulseAudio support.