P Evjen, John S Bradley, and S.G. Norcross (2001)
The effect of late reflections from above and behind on listener envelopment
Applied Acoustics, 62(2):Pages 137–153.
New experiments have investigated the effect on perceived listener envelopment of late-arriving sound from above and behind the listener using simulated sound fields. In all cases, the listener envelopment was found to be principally related to the cosine-squared weighted late-arriving sound energy. The late lateral sound level measure, that incorporates a cosine-squared weighting, was concluded to be a practical indicator of the amount of listener envelopment in concert halls for sound arriving from all directions.