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Nov 1987

Volume 82, Issue S1, pp. S1-S124

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back to top Session K. Psychological and Physiological Acoustics II: Loudness and Auditory Fatigue
Contributed Papers
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Absolute magnitude estimation of loudness by adults and children (A)

George A. Gescheider and Amy A. Collins

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S25-S25 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Twenty‐three subjects performed absolute magnitude estimation of the lengths of a series of lines and the loudness of a series of tones as well as cross‐modality matching between loudness and perceived line length. The results support the hypothesis that subjects judge stimuli on an absolute scale. Specifically, for 9 out of 12 adults and 9 out of 11 children, lines and tones assigned the same number in magnitude estimation were judged to be subjectively equal in cross‐modality matching. A correction procedure was employed to eliminate the effects of idiosyncratic number usage from the magnitude estimations of loudness. This correction procedure, consisting of dividing the loudness exponent by the line length exponent, produced power function exponents for loudness that were virtually identical for magnitude estimation and cross‐modality matching. Implications of the results for clinical measurement of loudness are discussed.
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Deviations from a power‐function near miss and their relation to loudness functions (A)

William S. Hellman and Rhona P. Hellman

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S25-S25 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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In a previous paper [W. S. Hellman and R. P. Hellman, J. Acoust. Soc. Am. Suppl. 1 81, S53–S54 (1987)], the neural‐count function N(I) was derived from the intensity‐jnd function J(I) through the relation N(I)1/2 = (h/2)∫dI/[IJ(I)] + a. Loudness functions were then generated by the prescription L = k[N(I) − N]. Using a power‐function near miss for J(I), good agreement between the measured and calculated loudness values for pure tones was obtained. While a power function yields a simple evaluation of the integral for N(I)1/2, the results of many recent jnd studies do not easily conform to a power‐function fit. In order to determine how the departures from a power‐function near miss affect the form of the loudness function within the model, the integration was performed over the segmented intensity jnd functions observed for gated and continuous tones. The calculated loudness functions and their respective input intensity jnd functions are shown for frequencies of 250 and 1000 Hz. In spite of the segmented, and in some instances, nonmonotonic intensity jnd functions, the results reveal that the smoothing action of the integration over J(I) produces loudness functions consistent with experimental results. [Partially supported by the Rehabilitation Research and Development Service of the VA.]
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Overall loudness of tone‐noise complexes: Measured and calculated (A)

Rhona Hellman and Eberhard Zwicker

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S25-S25 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Loudness measured for single‐tone‐noise complexes [R. P. Hellman, J. Acoust. Soc. Am. 72, 62–73 (1982)] is compared to loudness calculated in accordance with a loudness‐calculation program based on ISO 532 B [E. Zwicker, H. Fast, and C. Dallmayr, Acustica 55, 63–67 (1984)]. Data are given for single tones centered within the spectrum of broadband‐flat, low‐pass, and high‐pass noises. The measured and calculated loudness functions exhibit a similar pattern of loudness growth. Both measured and calculated loudness of the tone‐noise complexes are nonmonotonic functions of the overall SPL of the complex. Thus two tone‐noise combinations at nearly the same overall SPL can produce markedly different loudness values. These results hold over a 30‐dB range from about 73–103 dB. The results also show that the magnitude of loudness depends on the spectral shape of the noise and the frequency of the added tone. The close agreement between the measured and calculated loudness‐growth patterns means that basic psychoacoustical principles governing loudness and masking can account for the observed effects. [Supported by the Rehabilitation Research and Development Service of the VA and by the Deutsche Forschungsmeinschaft.]
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Psychometric functions for level discrimination (A)

Søren Buus, Christine R. Mason, and Mary Florentine

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S25-S25 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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To determine the form of psychometric functions for 2I, 2AFC level discrimination, ten increment levels were presented in random order within blocks of 100 trials. Stimuli were chosen to encompass a wide range of conditions and difference limens: eight 10‐ms tones had frequencies of 0.25, 1,8, or 14 kHz and levels of 30, 60, or 90 dB SPL; two 500‐ms stimuli also were tested: a 1‐kHz tone at 90 dB SPL and a white noise at 63 dB SPL. For each condition, at least 20 blocks were presented in mixed order. Results for three normal listeners show that the sensitivity d′ is nearly proportional to ΔL{= 20 log[(p + Δp)/p], where p is pressure} over the entire range of difference limens. When d′ is plotted against Weber fractions for pressure Δp/p or intensity ΔI/I exponents of the best‐fitting power functions decrease with increasing difference limens and are less than one for large difference limens. These results indicate that the transformation from stimulus intensity to decision variable may be approximately logarithmic and that ΔL—plotted on a logarithmic scale—is an appropriate representation of level discrimination performance. [Work supported by NIH.]
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Investigation of a model of loudness (A)

P. S. Chien and J. L. Hall

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S25-S26 (1987); (2 pages)

Online Publication Date: 13 Aug 2005

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A model of loudness summation by Schroeder et al. [J. Acoust. Soc. Am. 66, 1647–1652 (1979)], which was used by them to provide an objective quality measure of digital speech coding, is being investigated. (1) Iso‐loudness contours generated by the model are compared to iso‐loudness contours generated by human subjects. (2) The spreading function used in the model to calculate excitation levels is converted from the critical‐band domain to the frequency domain for various center frequencies. The resulting curves are compared to tuning curves measured in the cat. (3) The effect of partial masking on the relative loudness of pairs of pure tones is examined. (4) The model is used to predict the loudness of broad bands of noise from the loudness of narrow bands of noise centered at several frequencies. Studies (1)–(4) have revealed strengths and short‐comings of the model.
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Loudness adaptation in musicians and nonmusicians (A)

C. Baruch and M.‐C. Botte

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S26-S26 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Measurements of simple and induced loudness adaptation were made on 10–12 musicians and 10–12 nonmusicians by the method of successive magnitude estimations. Simple adaptation (SA) was measured for a 500‐, 1000‐, or 4000‐Hz tone presented monaurally for 3 min at 10 dB SL. Induced adaptation was measured for a continuous 1000‐Hz, 60‐dB SPL right‐ear tone; loudness was judged before, during, and after each occurrence of an intermittent inducer tone set to five frequencies from 500–3260 Hz and presented every 30 s for 10 s to the same ear (ipsilaterally induced adaptation, IIA) or to the left ear (contralaterally induced adaptation, CIA). We also measured CIA with a rapid intermittency of every 1 s for 0.5 s. The level of the inducer was 60 dB for CIA and 75 dB for IIA. Musicians showed less adaptation than nonmusicians whatever the type of adaptation: For the musicians, the maximum loudness decrease was 44% under SA, 30% under CIA, 30% under IIA; for the nonmusicians, this maximum was 70% under SA, 70% under CIA, 41% under IIA, but differences were statistically significant only for SA and for CIA with the rapid intermittency. Moreover, musicians showed significant adaptation over a less extended range of frequencies than nonmusicians.
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A pure‐tone‐induced temporary threshold shift on normal hearing and noise‐induced permanent threshold shift (A)

I. M. Young and L. D. Lowry

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S26-S26 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Temporary threshold shift after an exposure to a pure tone was measured by automatic audiometry on three subjects with normal hearing and three subjects with noise‐induced permanent threshold shift. Subjects were exposed to a stimulating pure tone with a frequency 1500 Hz through an earphone at an intensity of 110 dB SPL for a duration of 10 min. Temporary threshold shift was measured beginning at 5 s after the cessation of the stimulation. In normal hearing subjects, the greatest shift was observed at the frequency area of 2000 Hz as demonstrated previously. In subjects with noise‐induced permanent threshold shift, temporary threshold shift was demonstrated not only at the frequency region of 2000 Hz, but also at higher frequencies with permanent threshold shift. Post‐exposure effects at higher frequencies showed the greater threshold shift for the steady tone resulting in increased separation between normal amplitude pulsed tone tracings and markedly reduced amplitude steady tone tracings. Similar post‐exposure findings were observed on a subject with congenital nonprogressive bilateral symmetrical sensorineural loss of high frequencies similar to noise‐induced permanent threshold shift. Spread of temporary threshold shift at the higher frequencies was discussed and compared with the greater spread of masking effect at the higher frequencies.
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Auditory fatigue and induced loudness adaptation (A)

S. Charron, M. C. Botte, S. Mönikheim, and B. Schaff

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S26-S26 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Measurements of induced loudness adaptation and temporary threshold shift (TTS) were made on 48 young subjects. Loudness adapatation of a continuous 60‐dB test tone was induced in the right ear by an intermittent 1000‐Hz inducer tone at 90 dB, presented every 30 s for 20 s. The loudness of a 1000‐Hz or 1160‐Hz test tone at 60 dB was measured after each occurrence of the inducer by the method of successive magnitude estimations. Induced adaptation caused the loudness of the continuous tone to decrease on the average by 38% (the equivalent of 14 dB) after 120 s. In a separate session, the subject's right ear was exposed for 45 min to a 1000‐Hz tone at 90 dB SPL. One minute after exposure, thresholds were measured by Békésy tracking for 4 min. The maximum TTS, averaged across subjects, was 20.4 dB at a mean frequency of 1635 Hz. The correlation between maximum TTS and the amount of induced adaptation was 0.83. Thus ipsilaterally induced adaptation (IIA), which is akin to temporary loudness shift, may stem from cochlear mechanisms just as TTS does. Also, IIA could become the basis for an audiological test to identify those individuals most susceptible to auditory fatigue. [Work supported by Ministère de l'Environnement and NIH.]
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Reduction of auditory damage due to intermittence (A)

W. Dixon Ward

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S26-S26 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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Two groups of chinchillas were given daily exposures, 5 days/week for 9 weeks, to 700–2800‐Hz noise at 110 dB SPL. Each day, one group received a single 48‐min exposure, the other group a series of 40 1.2‐min bursts spaced at 12‐min intervals. Whereas the continuous single exposures produced a median permanent threshold shift (PTS) of 16 dB at 1, 2, and 4 kHz and destruction of 33% of the outer hair cells (OHCs), the intermittent exposures resulted in a PTS of only 6 dB and less than 5% destroyed OHCs. Inasmuch as the latter group suffered about the same cochlear damage as (and less PTS than) a group given 45 daily 48‐min exposures at 102 dB SPL, one can infer that an 8‐dB “correction for intermittence” of a 110‐dB exposure is approximately correct, in accordance with present OSHA regulations governing industrial noise exposure. [Research supported by NIH Grant 12125.]
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Threshold recovery functions following impulse noise trauma (A)

Roger P. Hamernik, William A. Ahroon, and James H. Patterson

J. Acoust. Soc. Am. Volume 82, Issue S1, pp. S26-S26 (1987); (1 page)

Online Publication Date: 13 Aug 2005

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An analysis of the pure‐tone threshold recovery functions obtained from 118 chinchillas exposed to high‐level impulse noise showed that there are at least three distinctly different types of threshold recovery functions. Type I: the classical recovery function that declines monotonically with increasing postexposure time; type II: a delayed recovery, i.e., for a period as long as 6 h following removal from noise, the pure‐tone threshold remains elevated and stable before a monotonically declining recovery process sets in; and type III: the growth function, i.e., over a period of at least 6 h following removal from the noise, pure‐tone thresholds continue to get worse before a stable monotonically declining recovery process begins. Frequencies characterized by a type III recovery process show more PTS and sensory cell loss than do those characterized by the type I recovery process. The existence of three distinctly different audiometric recovery functions implies the existence of different mechanisms of cochlear trauma.
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