Effects of Distribution of Directional Late Sound Energy on Listener Envelopment

The purpose of this study is to clarify the effect of late arriving sound on listener envelopment(LEV). In our previous work, it was shown that late sounds from above and behind the listener as well as lateral, which had a single directional component, significantly affected LEV when the ratio of early-to-late sound energy(C80) was constant. Furthermore, shown was the relation between C80 and directional late energy ratios(DLR), and perceived LEV. In this paper, two kinds of psychological experiments are performed with simulated sound fields in order to examine the relation between DLR and perceived LEV. In the first experiment, late sounds which consist of plural directional components are used. The previous findings about the contribution of DLR to LEV are confirmed also when late sounds come from arbitrary directions. In the second experiment, the effect of DLR on LEV is examined when the reverberation time is set to 2.5 s. The result shows that the contribution of overhead and back late energy ratios grows larger when reverberation time is longer