Comparison of magnitude estimation and interval scaling of loudness.

To identify whether equal-appearing interval or magnitude estimation scaling resulted in a data set with a closer correlation to the physical stimuli involved 20 young adults completing two tasks. In Task 1 subjects used a 7-point equal-appearing interval loudness of 18 10-sec. samples of babble speech, presented randomly at intensities of 5 to 90 dB SPL. In Task 2 subjects used magnitude estimation scaling to rate these stimuli, presented in a randomized order. Analysis showed significantly high correlations for both scaling methods and the stimuli (Spearman rho = 1.00 and .99, respectively). Subjects can use either form of scaling to rate changes in loudness.