Concert Hall Acoustics—1991

Abstract

Acoustical design of concert halls began with Wallace C. Sabine who developed the reverberation equation and advised on Boston Symphony Hall (1900). Little additional information was learned in the next half-century. The use of reflecting panels in large spaces was introduced in halls with acoustically adverse shapes between 1953 and 1959. Next followed an understanding of sound absorption by audiences in different densities of seating, the initial-time-delay gap, and the value of lateral reflections. The London Royal Festival Hall and New York Philharmonic Hall confirmed the importance of those findings and revealed additional design requirements for reflective panels and sound diffusion. Extensive subjective studies, both in actual halls and in laboratories with electronically produced acoustical environments, were performed in Göttingen and Berlin (Germany), England, Denmark, Japan, and Canada. Those studies, when combined, revealed five orthogonal subjective attributes of concert hall quality: reverberance, loudness, envelopment, intimacy, and bass balance. These, in turn, are related to the objective quantities: initial and subsequent reverberation times (RT); cubic volume and audience area; lateral reflections and diffusion; initial-time-delay gap and subsequent reflections in the first 50 ms after arrival of the direct sound; and the slope of the initial RT versus frequency curve between 125 and 2000 Hz. An additional important subjective attribute is related to the physically measured ratio of the reflected energy in the sound field during the first 50 ms and that after 50 ms. Concert halls built since 1975, principally in Europe, United States, and Japan, constitute a “laboratory” for confirmation of those subjective attributes and related objective parameters.