And some update, previously I said that a new user doesn't help. That was false. I just removed .kde and that didn't help. When I created a new user all seems to be ok.

After some moving of directories I realized, that .pulse is the bad guy. I removed it and all is fine.

Tootai, did you also play around with pulseaudio? I bet no

Strike another thing aganist Pulseaudio... it is a total pain for KDE users. I completely disabled it on my system.