PulseAudio is a sound server, sitting above device drivers such as ALSA or OSS. It offers more capabilities than device drivers. PulseAudio is designed for consumer audio and makes it easy to use sound on desktops, laptops, and mobile devices. Multiple sources of sound can all play to the PulseAudio server, which will mix them together and play them. Low latency is not a design goal, so it is unsuitable for professional audio.
Here are some resources:
PulseAudio home page ( www.freedesktop.org/wiki/Software/PulseAudio )
“PulseAudio and Jack” ( http://0pointer.de/blog/projects/when-pa-and-when-not.html ...