The XAudio2 output is Microsofts latest API for sound output and designed to supersede DirectSound. The plguin I've written works well with my Audigy 2 ZS, Realtek ALC889A OnBoard sound and my brand new X-Fi Elite Pro. I set the buffer size to be always 4 frames, no chance to edit (yet).

The OpenAL plugin is also my creation. The API was documented way too short so I had to find out some stuff for myself, but I think it is stable now. While OpenAL works with an incredible buffer size of just 2 frames smoothly with my X-Fi, the Realek OnBoard required a minimum of 5 frames.