|Microsoft DirectX 9.0|
When you create a secondary buffer with the DSBCAPS_CTRL3D control flag, you can also specify an algorithm to be used in spatializing the sound if the buffer is in software. By default, no head-related transfer function (HRTF) processing is performed, and the location of the sound relative to the listener is indicated by panning and volume only. You can request two levels of HRTF for the buffer.
For more information, see DSBUFFERDESC.