Further Assessment of the Effects of Intensity upon the Pitch of Pure Tones

Abstract

Typical methods for observing the effects of intensity upon the pitch of pure tones involve varying the frequency of one tone of fixed intensity (the comparison tone) so as to match the pitch of a second tone of fixed frequency (the tone under test) as the latter is set at different intensities. Differences between the frequency of the comparison and test-tones, when equated in pitch under these conditions, are attributed to their differences in intensity. These differences are used as a measure of the intensity induced pitch shift for the test tone. The comparison and test tones may differ in frequency, however, even when both tones are equated in pitch under equal intensity conditions. These frequency differences, reflective of pitch matching errors, conceivably may vary for different frequencies and intensities so as to nullify apparent pitch-intensity shifts or qualify the magnitude of those being observed. This possibility was studied in two experiments which were intended to reproduce Stevens' pitch-intensity relationship as well as explore new functions for tones of particularly low frequency, It was found that half of the “pitch-intensity” shifts noted for frequencies 50, 75, 100, 150, 200, 400, 700, 1500, and 6000 cps were not significantly different from pitch matching errors. The remaining shifts were in directions reported by Stevens but were typically small (2% or less). The lowest frequency tone to show a significant pitch change was 75 cps.