The IDirectSound3DListener::GetRolloffFactor method retrieves the current rolloff factor.
HRESULT GetRolloffFactor(
LPD3DVALUE lpflRolloffFactor
);
If the method succeeds, the return value is DS_OK.
If the method fails, the return value may be DSERR_INVALIDPARAM.
The rolloff factor has a range of DS3D_MINROLLOFFFACTOR (no rolloff) to DS3D_MAXROLLOFFFACTOR (as currently defined, 10 times the rolloff found in the real world). The default value is DS3D_DEFAULTROLLOFFFACTOR (1.0). For additional information, see Rolloff Factor.