DirectSound

Output audio using the Direct Sound APIs.

DirectSound v2.0

Similar to Direct Sound 1.0, but allows fade out.

Kernel Streaming

Output sound using the more exotic Kernal Streaming API. This will bypass the standard Windows sound mixer. As a result, foobar volume will not be influenced by Wave volume in Windows. Requires driver support, and may be unstable for cards with poorly written drivers.

Note: No one has provided non-anecdotal proof that using Kernel Streaming instead of DirectSound or waveOut provides higher audio quality.