Abstract

In 1900 Wallace Sabine, a physicist at Harvard University, published a mathematical formula for calculating the reverberation time in a room, a measure of how quickly or slowly sound energy dies away in an enclosed space. In 1930 Carl Eyring, a physicist working in the Sound Motion Picture Studio at Bell Telephone Laboratories, revised Sabine's equation. This essay examines material changes in the practice of architectural acoustics in order to explain how and why Eyring was motivated to reformulate the Sabine equation. Sabine's equation was the product of experimentation in highly reverberant rooms. Eyring worked in a world increasingly constructed of sound-absorbing building materials--a world of acoustically "dead" rooms in which Sabine's original assumptions were no longer valid. Further, Eyring's world was filled with electroacoustic devices that had not existed in 1900. "Live" wires powered new tools for producing, measuring, and controlling sound, and the new electroacoustic technologies additionally provided a new conceptual framework for thinking about the behavior of sound. Eyring's equation is shown to be a direct product of these new material conditions of the science and practice of architectural acoustics.