QtMultimedia is you way

But you must know that one thing is audio playback (a simple thing) and another whole thing is audio processing (a complex thing)

Here the qt blog talks about the concept and an example of qtmultimedia for audio processing.

http://labs.trolltech.com/blogs/2010...-qtmultimedia/

http://labs.trolltech.com/blogs/2010...trum-analyser/

The 2nd one has a video!

Hope this helps