Leo L. Beranek
975 Memorial Dr., Ste. 804, Cambridge, MA 02138-5755
An overall computational scheme for estimating from modern acoustical measurements the acoustical quality of concert halls is explored in this study. The method showing promise is based on Ando [Concert Hall Acoustics (Springer-Verlag, Berlin, 1985)]. Identified are the most important acoustical attributes to the rating scheme: RT, G, ITDG, IACC(E), and BR. Preferred values for each of these acoustical attributes is estimated from the results presented in a companion paper [Beranek, ``Correlations between categories of acoustical quality and modern physical quantities'']. Formulas are borrowed from the Ando study and constants are chosen that express the relative importance, and the degree of falloff in contribution to quality with deviations from optimum, of each of these acoustical attributes. By process of adjustment of the constants, the best fit between the measured physical quantities and the subjective determination of acoustical quality of concert halls is determined. Excellent correlation between the final result and the rank-orderings is obtained. It must be emphasized, however, that other factors are important in concert hall design which are not included in this rating scheme, for example, the degree to which musicians can hear each other and hear themselves on stage and balance among the sections of an orchestra. There may be other unknown acoustical factors that contribute to acoustical quality.