In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 61, No. S1 ( 1977-06-01), p. S77-S78
Abstract:
It has been shown that TTS is smaller for shorter test signals [J. F. Jerger, J. Acoust. Soc. Am. 27, 121–124 (1955)]. However, shortening the test signal results in the scattering of of energy to adjacent frequencies. It is therefore possible that the threshold response to shorter signals is mediated by unfatigued neural elements near those elements that normally are maximally responsive to the test frequency. Ten subjects were exposed on separate occasions to one-third-octave bands of noise centered at 2500 and 630 Hz, respectively, in order to produce a localized TTS at 4000 Hz or at 1000 Hz. They were also exposed on separate occasions to magenta noise (a noise designed to produce equal TTS at all frequencies) and to white noise (as employed by Jerger). This hypothesis predicts that the difference between the indicated TTS employing short signals and that using long signals should be smaller after exposure to magenta noise than after exposure to either narrow-band or white noise. This prediction was confirmed: The difference in TTS indicated by 4- and 400-msec signal durations was 6 dB when the TTS was produced by the 2500-Hz narrow-band noise, but only 3 dB when it had been generated by the magenta noise. Apparently, then, part of the disparity in TTS can be attributed to energy scattering, but the “temporal summation” mechanism (assuming there is one) must also have been affected by the process that produces TTS. [Work supported by the National Institute for Occupational Safety and Health, Public Health Service.]
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
1977
detail.hit.zdb_id:
1461063-2
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