A Consideration of the Intensity-Loudness Function and Its Bearing upon the Judgment of “Tonal Range” and “Volume Level.”
Stephen E. Stuntz · The Journal of the Acoustical Society of America · 1950
Acoustical intensity not only affects the loudness of sounds, but also profoundly influences the listener's perception of certain ranges of frequencies. The data of Fletcher and Munson demonstrate that the effective frequency response of the ear varies with signal intensity-level. On the basis of this variation, it is possible to account for certain anomalies appearing in Eisenberg and Chinn's study of listeners' preference for frequency ranges and intensity levels in the reproduction of speech and music. It is also possible to explain the disparity between their results and those of Olson's investigation of preference for frequency ranges. For example, it can be shown that when frequency is plotted against loudness, raising the intensity level from 50 to 70 db will add more than one whole octave downward to the effective frequency response of the ear at 50 millisones loudness.