Pitch Shifts of Tones in Wide-Band Noise

Abstract

Pitch shifts of pure tones occuring in wide-band noise were measured for five frequencies (250, 500, 1000, 3000, and 6000 Hz) at four levels (5, 15, 25, and 35 Db] above quiet and masked thresholds for each of 11 subjects. Amount of noise employed was sufficient to shift threshold of a 1000-Hz tone by 35 dB. Alternate monaural presentation of 500 msec standard and variable signals was employed. The amount of pitch shift expressed in Hertz was found to increase with frequency. Relative pitch shift (absolute shift/standard frequency) increased with frequency between 250 and 3000 Hz but was less for 6000 than for 3000 Hz. The data suggested that the relative amount of pitch shift may decrease with signal level for frequencies less than 3600 Hz, increase with signal level for 6000 Hz, and be independent of signal level for 3000 Hz. All observed pitch shifts were in all upward direction, except for the two lowest frequencies.