An application sets or retrieves the angles that define sound cones by using the IDirectSound3DBuffer::SetConeAngles and IDirectSound3DBuffer::GetConeAngles methods. To set or retrieve the orientation of sound cones, an application can use the IDirectSound3DBuffer::SetConeOrientation and IDirectSound3DBuffer::GetConeOrientation methods.
By default, cone angles are 360 degrees, meaning the object projects sound at the same volume in all directions. A smaller value means that the object projects sound at a lower volume outside the defined angle. The outside cone angle must always be equal to or greater than the inside cone angle.
The outside cone volume represents the additional volume attenuation of the sound when the listener is outside the buffer's sound cone. This factor is expressed in hundredths of decibels. By default the outside volume is zero, meaning the sound cone will have no perceptible effect.
An application sets and retrieves the outside cone volume by using the IDirectSound3DBuffer::SetConeOutsideVolume and IDirectSound3DBuffer::GetConeOutsideVolume methods. Keep in mind that an audible outside cone volume is still subject to attenuation, due to distance from the sound source.
When the listener is within the sound cone, the normal buffer volume (returned by the IDirectSoundBuffer::GetVolume method) is used.
For a conceptual overview, see Sound Cones.