I think it's a bug in Phonon, Qt or the backend, because it not only happens in my app, but also in the demo "qmediaplayer" found in the "QtSDK/Demos" folder.
I'm looking for a workaround now...
These steps are required to see it happen:
1. Build the demo qmediaplayer and install it on the phone (i have a N8)
2. Open and play a MP3 file
3. Choose an audio effect like the equalizer, configure and apply it
4. You should hear a difference because the equalizer works now; so far so good
5. Open and play another MP3 -> The app hangs forever, even closing it with the task manager isn't possible
Does anybody knows of a workaround or fix for this?