Foobar2000:Preferences:Output
DirectSound
Output audio using the DirectSound API provided by DirectX.
DirectSound v2.0
Similar to DirectSound, but allows fade out. Recommended for maximum compatibility.
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.
waveOut
Use the waveOut functions of the standard Win32 API to output sound.