|Microsoft DirectX 9.0|
Sound buffers have three processing modes: normal, head-relative, and disabled.
In normal mode, the sound source is positioned and oriented absolutely in world space. This is the default mode, and is used for sound sources that do not move and turn with the listener.
In head-relative mode, the 3-D properties of the sound source are all relative to the current position, velocity, and orientation of the listener. As the listener moves and turns, the buffer is automatically repositioned in world space. Head-relative mode can be used for sounds such as a fly buzzing around the listener's head. However, most sounds that travel with the listener don't have to be 3-D sounds at all.
In disabled mode, 3-D sound processing is disabled and the sound seems to originate from the center of the listener's head.