An application can set and retrieve a 3D sound buffer's position in 3D space by using the IDirectSound3DBuffer::SetPosition and IDirectSound3DBuffer::GetPosition methods.
To set or retrieve the velocity value that DirectSound uses to calculate Doppler-shift effects for a listener, use the IDirectSound3DBuffer::SetVelocity and IDirectSound3DBuffer::GetVelocity methods. A buffer's position is not affected by its velocity. For more information about the relationship between position and velocity, see Position Versus Velocity.