The DS3DLISTENER structure is defined as :-

struct DS3DLISTENER {
DWORD dwSize;
D3DVECTOR vPosition;
D3DVECTOR vVelocity;
D3DVECTOR vOrientFront;
D3DVECTOR vOrientTop;
D3DVALUE flDistanceFactor;
D3DVALUE flRolloffFactor;
D3DVALUE flDopplerFactor;
};