Abnormal acoustic phenomena in a cinema hall with a dolby surround-recording system

Abstract

The maximum sound energy in a reconstructed cinema hall increaes by 5 - 7 dB at the frequencies of 125 - 500 Hz. This occurs only in the time interval from 0 to 140 ms. At 1000 - 4000 Hz, the energy increase amounts to 4-8 dB and takes place in the time interval of 0 - 100 ms. This means that abnormal phenomena occurs only under the balcony and only in the initial period of the sound energy decay.