Change of Pitch with Loudness at Low Frequencies

Abstract

The changes in pitch which result from changes in the loudness of low frequency tones were investigated for several frequencies between 75 and 1000 c.p.s. with a crew of 9 observers. The loudness levels covered the range 20 to 120, and both telephone receivers and a loudspeaker were used as sound sources. Fletcher's pitch standard, a pure tone of loudness level 40, was employed. All consistent judgments gave pitch shifts downward with increasing loudness, but large differences between individuals were found. Two observers perceived no shifts at any frequency or loudness while three others experienced changes greater than 35 percent at the highest intensity. Appreciable changes with time in individual judgments were found. There appeared insignificant difference between data obtained with telephone receivers or with the loudspeaker. A set of contours of equal loudness level, plotted on coordinates frequency and pitch change in percent, is given. These curves show a pitch change small at 1000 cycles, increasing to maximum at a low frequency and decreasing for still lower frequencies. The frequency of greatest shift increased from about 100 cycles at small loudness to about 200 at loudness level 120. The Appendix describes automatic test equipment that greatly simplified the testing routine and improved its accuracy.

The Doppler effect is not what you think it is: Dramatic pitch change due to dynamic intensity change

“…Thus, perception of the lower frequency tone was influenced slightly less by continuous intensity change than was perception of the higher frequency tone. This much smaller effect is consistent in size and direction with the previously known findings in which discrete increases in intensity of lower frequencies produce lower pitch (Snow, 1936;Stevens, 1935;Terhardt, 1974;Verschuure & van Meeteren, 1975). In other words, the nonlinearities in the frequency-encoding mechanisms responsible for the discrete influence of intensity on pitch (i.e., increasing the intensity of lower frequency tones makes them sound lower in pitch) may have moderated the continuous influence of intensity on pitch for the low-frequency tone used here.…”

“…Tones that discretely increase in intensity in this frequency range are experienced as to falling in pitch. The magnitude of the pitch change for discrete increases is typically less than 3% (Gulick, 1971;Scharf & Houtsma, 1986;Snow, 1936;Stevens, 1935;Terhardt, 1974;Verschuure & van Meeteren, 1975). …”

“…Although frequency is a primary determinant of pitch, it is well known that pitch depends in part on intensity. The general findings are that for frequencies lower than about 3 kHz, discrete increases in intensity lower pitch (Snow, 1936;Stevens, 1935;Terhardt, 1974;Verschuure & van Meeteren, 1975). This may be due to subtle nonlinearitiesin the physiological frequency-encoding mechanisms (Helmholtz, 1954;Scharf & Houtsma, 1986).…”

The sense of pitch and local increase in threshold

“…From the distribution of judgements a frequency of the second tone was found which had the same pitch as the standard tone. A similar method was used to that of Snow (1936).…”

“…Hitherto, in work on the modifying influence of intensity (e.g. Stevens, 1935;Snow, 1936;Morgan, Garner & Galambos, 1951) the subjects have been chosen for their normality of hearing. It is reported by Morgan et al (1951) that it is typical for such subjects to find pitch almost independent of intensity.…”