I have this sttrange behavior in KDE. Sometimes when starting I get a message about sound devices that must be removed. When this happens, I have no sound on skype, clementine and any other sound application. But if I close KDE and start X with MATE, everything works fine.
I am using Fedora 19, but this behavior was the same in previous versions of Fedora and KDE. mys lsmod reports an hda_intel sound device.
Probably must be some simple trick, but it is really annoying. Despite loving KDE, I am foreced to use MATE.
Some help would be appreciated.
J.G.

Which Phonon backend are you using? This can be determined in System Settings > Multimedia > Phonon > Backends. Usually GStreamer or VLC are used.
Also, does your system use Pulseaudio?

The Phonon backend reported is Gstreamer, and Pulseaudio comes in Fedora by default.
Thanks.

When this happens, do KMix or "pavucontrol" detect any playback devices?
You may also want to try removing /var/tmp/kdecache-$USER/libphonon/hardwaredatabase outside KDE.