PulseAudio

PulseAudio

The purpose of pulseaudio is to handle multiple incoming streams, so that if you receive an incoming message, for instance, your media player doesn't have to stop to let it through. When it works, it works well, but there are times when it might need a little more understanding to solve a problem. These references should help:

Phonon Problems
GPU-Performance/External_Sound_Cards
The PulseAudio wiki
The Perfect Setup
Setting up your speakers