How can you disable KDE notification sounds in Ubuntu 14.04?

I installed Okular pdf viewer in my Ubuntu 14.04.

Okular is a KDE based software and it emits a KDE notification sound when I do some actions for example when I overwrite a file.

Is it possible that I disable these KDE notifications sounds and how do I do it?

I run Ubuntustudio 15.10, and have installed the KDE-app Kolourpaint. Wonderful app, but the sounds ... terrible.

1. Open File Manager and enable "View Hidden Files"
2. Go to FileSystem/usr/share
3. Open a terminal there and type
4. sudo chmod -R 777 sounds
5. Open FileSystem/usr/share/sounds in the File Manager
6. Delete every KDE*.ogg file.

Now no more KDE system sounds will disturb you.