Used for normal sounds, not expected to pass to AK::SoundEngine::SetMultiplePosition() (if done, only the first position will be used).
Simulate multiple sources in one sound playing, adding volumes. For instance, all the torches on your level emitting using only one sound.
Simulate one sound coming from multiple directions. Useful for repositionning sounds based on wall openings or to simulate areas like forest or rivers ( in combination with spreading in the attenuation of the sounds ).