For quite some time, I have been trying to get the konversation IRC client to play sounds when certain events happen in IRC. KDE has a slick, unified notifications system but for some reason, I couldn't ever get the sound notifications to work.
Well, I finally found the answer. This follow-up to a bug report about failing KDE audio notifications provides the solution. In brief,
That's it. When you try your next audio notification through knotify, everything should work.