Liveness of Rooms
R. L. Hanson · The Journal of the Acoustical Society of America · 1932
Experience has shown that the sense of liveness of reproduced sound cannot always be correlated with the reverberation period of the region in which the sound originates. A series of experiments have therefore been carried on which show that the liveness of reproduced sound is not a function of the reverberation period but is dependent upon the irregular fluctuation of the sound intensity at the microphone. This fluctuation which often appears during sustained as well as growing and decaying tones is a function of the size, shape, and abxorbing power of the room in which the microphone and sound source are located. It explains the effect of monaural pick-up, microphone distance, etc., on liveness. The conditions which give rise to a high degree of intensity fluctuation and hence liveness are often such that a long reverberation period results. It is pointed out in the paper that if there is an optimum reverberation period for listening in a room, that period should also be optimum for recording. The intensity fluctuation due to shifting interference patterns should, in the case of a monaural pick-up pe reduced to a degree comparable to that which is apparent to a two ear listener.