ABSTRACT

Evidence for a power function with a slope of 0.3 for loudness is provided by direct measurements of sensory magnitudes and by loudness matching. Figure 15.1 summarizes the results obtained from a broad cross section of studies in which a variety of ratio scaling procedures were used. Plotted are the relations between the logarithms of the loudness ratios and intensity ratios with the slope for loudness as the parameter. Each function shows the combinations of intensity ratios and loudness ratios possible for a loudness function with a fixed slope . The intermittent line with a slope of 0.3 is the mean of a distribution of slopes from 78 different experiments, and the solid lines give values of the slope out to ± 3 standard deviations from the mean . Seventy-one of the slope values used to compute the mean are from 27 studies reported by Marks (1974); the additional 7 values are from 6 more recent studies of loudness (Algom & Marks , 1984; Canevet, Hellman, & Scharf, 1986; Collins & Gescheider , 1989; Hellman , 1976; Hellman & Meiselman , 1988; Zwislocki , 1983) .