The IDirectSound3DBuffer::GetMaxDistance method retrieves the current maximum distance for this sound buffer.
HRESULT GetMaxDistance(
LPD3DVALUE lpflMaxDistance
);
If the method succeeds, the return value is DS_OK.
If the method fails, the return value may be DSERR_INVALIDPARAM.
The default maximum distance, defined as DS3D_DEFAULTMAXDISTANCE, is effectively infinite.
IDirectSound3DBuffer::GetMinDistance, IDirectSound3DBuffer::SetMaxDistance