To obtain a pointer to an IDirectSound3DListener interface, you must first create a primary 3-D sound buffer. Do this by using the IDirectSound::CreateSoundBuffer method, specifying the DSBCAPS_CTRL3D and DSBCAPS_PRIMARYBUFFER flags in the dwFlags member of the accompanying DSBUFFERDESC structure. Then, use the IDirectSoundBuffer::QueryInterface method on the resulting buffer to obtain a pointer to an IDirectSound3DListener interface for that buffer, as shown in the following example with C++ syntax:
// LPDIRECTSOUNDBUFFER lpDsbPrimary;
// The buffer has been created with DSBCAPS_CTRL3D.
LPDIRECTSOUND3DLISTENER lpDs3dListener;
HRESULT hr = lpDsbPrimary->QueryInterface(IID_IDirectSound3DListener,
&lpDs3dListener);
if (SUCCEEDED(hr))
{
// Perform 3-D operations.
.
.
.
}