Fluctuation Phenomena in Room Acoustics

Abstract

Two types of fluctuation phenomena are discussed theoretically, utilizing the concept of normal modes of aerial vibration in the room. The fluctuation noise due to the random motion of air molecules is found to be a property of air alone and independent of the room. On the other hand, the fluctuation during reverberation depends on both the room dimensions and its reverberation characteristics. Practical formulae of the magnitudes of the fluctuations are presented, which are in good agreement with the experimental data obtained previously. The astonishing gift of the blind in estimating the room size with surprising accuracy is explained, and further investigations on the problem of room liveness as related to fluctuation phenomena as well as its effect on the acoustical design of a room are suggested.