1.5 seconds. The reverberation time is an important acoustic characteristic of concert halls, theaters, auditoriums and other buildings. In terms of sound waveform, in university theater, when the waveforms of original sound and echo basically coincide, the loudness of sound increases; When the waveforms of the original sound and echo do not coincide, the reverberation effect is heard, and the reverberation effect is the best when the time is just set at1.5s. Reverberation is an acoustic phenomenon that the sound continues to exist and rebound after the sound source stops sounding in a certain space.