Study of Methods for Estimating Loudness

Abstract

The methods for computing loudness developed by K. E. Zwicker and S. S. Stevens were applied to several complex sounds encountered in our work on architectural acoustics. The loudnesses computed on the basis of Stevens' method did not agree closely with the loudnesses computed by Zwicker's method, and the results obtained by using the two methods were not related to one another in any consistent way. Further, studies with subjects showed that both sets of computations gave results at variance with the responses of the subjects. Investigation of the loudness vs frequency contours for our subjects showed closer conformity to the Fletcher and Munson data than to the more recent equal-loudness contours reported by the National Physical Laboratory, the functions reported by Zwicker, or the band-pressure levels that form the basis for the loudness weighting Stevens' method. However, this feature does not suffice to account for the discrepancies observed.