Arch Linux

I'm not able to reproduce, so here are a few things to check:

When you go to "System Settings" -> "Application and System Notification" -> "Manage Notifications", can you play the event sounds manually?

How about if you open the folder containing the event sound files (/usr/share/sounds) in Amarok or Dolphin (using the preview button), do they play?

If not, then you probably lack the correct gstreamer plugin. Could you install all gstreamer related packages and try again?

Otherwise, could you give a specific example of an event that does not play a sound and what the sound file is called. Furthermore, could you verify that the event is actually triggered by adding more actions in addition to playing the sound (e.g. "Show a message in a popup").

I cant' believe this... I was using the gstreamer backend, i switched to vlc backend in order to use it the next time i logged in, but since i read your comment i decided to test it again, so i switched back to gstreamer and then i relogged in. Theme sounds play fine, but the strange part is they didn't play before with gstreamer. I had made a clear log in the last time o chose gstreamer, but didn't play any sounds. And now this... This is really weird behaviour.

Also i want to mention, i didn't change a single thing, instead of selecting vlc and then again gstreamer before relogging in...

It seems it works fine now. It seems it has something to do with configuration files KDE automatically generates. There is no other possible explanation, since i didn't change a single thing package-wise. Anyway, i believe this should be closed now.

No, it seems it is not it. I still have the issue, after a reboot. After selecting gstreamer as my backend, i rebooted. Now i have no theme sounds, and i cannot play them even in notification settings...

Since KDE themes are all ogg files, maybe it is a bug of ogg support with gstreamer?

Nope, i can play ogg audio files in Amarok using gstreamer backend fine. It is a problem of KDE notifications only.

After a while, i can play the notifications sound while still using gstreamer as a default. Maybe KDE switches to the next backend in the list after some time?

This sounds extremely weird.
If I understand correctly, this is the scenario:
Immediately after a reboot you observe:
1) Event sounds are not played
2) Except for the missing sounds, the notification events are triggered
3) The ogg files corresponding to the notification can manually be played in e.g. Amarok (what about playing them manually in the kcm, does that work?)
4) After some time, suddenly notification sounds start playing again.

Couple of more questions: if you keep an eye on the "Event sounds" volume slider in KMix, does this change when all of this is going on? How about non-phonon event sounds (e.g. Skype)?

FWIW: I don't think the backend is changed after a timeout, if the problem had been purely with the phonon backend you should not have been able to play files in amarok. My guess is that somehow PA mutes all event sounds. It would be interesting to know
1) are non-kde event sounds affected the same
2) is the problem reproducible in the absence of kmix? in the absence of a kde session?
3) what triggers the system to fix itself...

I found the problem. After installing paprefs pavumeter and pavucontrol, i noticed that the system sounds slider was set to zero. I will experiment with it a bit.

I don't know why this is set to 0 only with gstreamer backend.

No, still no solution. Adjusting the volume at pavucontrol provided me with sounds in the notification configuration screen, but still when a notification happens, i hear no event sound. Strangely, i hear a sound like a click, like the noise speakers do sometime when suddenly pluggin the audio cable while on power...

This is strange.

I have been having the same problem with my KDE notifications for the last few days, but using phonon-xine.

Following along with this bug I checked that pulseaudio hadn't got installed on my system as pulseaudio will not work on my Asus D1 audio card!

To my dismay I found pulseaudio had snuck under my radar & had been installed (via an upgrade? I guess).

Removed pulseaudio & I now have full audio back including KDE notifications.

I hope this helps you out.

@TemplarGR: I'm trying (still unsuccessfully) to reproduce this. What is the most reliable way for you to reproduce? Do you observe the bug if you play the event sounds using the test button in System Settings?

Can you elaborate on how/when it starts working again? Is it always after the same amount of time?

For me to reproduce this bug (using phonon-xine) I just need to install pulseaudio & KDE notifications go silent.

I have not had sound in KDE notifications (with pulseaudio installed) start working after a period of time.

With pulseaudio installed there was no sound when using the test button in System Settings > System Notifications (first thing I checked).

Pulseaudio has never worked on my Asus D1 sound. The main complaint of pulseaudio from what I have read is that pulseaudio is very hit & miss on hardware. I have pulseaudio working on my girlfriends HP laptop & daughters desktop but it will not work on my Asus D1 sound card. To the credit of the developers of pulseaudio I am at least now getting some sound.

This bug will be difficult to reproduce on hardware that pulseaudio works on.

I suspect that this is a pulseaudio bug not a KDE bug.

Seems that this isn't a packaging bug, so I'd like to close this. Please ask for support on the forums or MLs.

@BaSh: I agree, it is almost certainly an upstream problem.