Objective measures of listener envelopment

This paper reports the results of subjective studies to determine objective predictors of perceived listener envelopment in concert halls. Subjects, seated in an anechoic room, were exposed to simulated sound fields that were expected to have varied listener envelopment. As independent variables: the reverberation time, the early-to-late sound ratio, the overall sound level, and the angular distribution of the late-arriving sound levels were varied. All of these factors had statistically significant effects on perceived listener envelopment. The results indicate, however, that the angular distribution of the late arriving sound and the overall level would have the largest effects in real concert halls. Thus listener envelopment depends on having strong lateral reflections arriving at the listener 80 ms or more after the direct sound. Several objective measures correlated significantly with listener envelopment. However, a new measure, the late lateral sound level, as measured using a figure-of-eight microphone, was found to be both conceptually simple and a very good predictor of the perceived listener envelopment of the sound fields in this experiment.