Acoustics of cinema auditoria

The paper records investigations made in an endeavour to discover the reasons for the difference of performance in the reproduction of sound by identical sound equipment in apparently similar cinemas. Details are given of frequency characteristics and reverberation times, and the requirements of good auditorium design are set out. The sound levels picked up by a microphone in an auditorium, and recorded on a high-speed level recorder, are shown by means of oscillograms.