[KDE] Popping sound on volume change not working

I’m having problems with the popping sound on volume change - system is opensuse 13.1 on a Thinkpad T400 laptop.
On my desktop machine it works - I get a nice popping sound when I press the volume up / down key.
This was tested in kde 4.11.x and 4.12.x (PC and laptop).

Observing the PC there is an application that shows up in kmix - “audio-volume-change” when pressing volume keys, the same doesn’t happen on my laptop.
What could be the cause?

I further tested this on live opensuse GNOME cd and Ubuntu 13.10 - the popping sound works there, it’s just an issue with KDE somehow, as it doesn’t work in Kubuntu 13.10 either.
Must be something with KDE and thinkpad key mappings? xev says they are registered properly.