Reduced frequency selectivity and the preservation of spectral contrast in noise

1996 ◽  
Vol 100 (3) ◽  
pp. 1796-1806 ◽  
Author(s):  
Marjorie R. Leek ◽  
Van Summers
Keyword(s):  
Frequency Selectivity ◽  
Spectral Contrast ◽  
Reduced Frequency

Influence of Frequency Selectivity on Comodulation Masking Release in Normal-Hearing Listeners

1993 ◽  
Vol 36 (2) ◽  
pp. 410-423 ◽  
Author(s):  
Joseph W. Hall ◽  
John H. Grose ◽  
Brian C. J. Moore
Keyword(s):  
Normal Hearing ◽  
Frequency Selectivity ◽  
Frequency Separation ◽  
Signal Frequency ◽  
Noise Background ◽  
Masker Level ◽  
Reduced Frequency ◽  
Comodulation Masking Release ◽  
Comodulated Noise ◽  
Signal Band

Experiments 1 and 2 investigated the effect of frequency selectivity on comodulation masking release (CMR) in normal-hearing subjects, examining conditions where frequency selectivity was relatively good (low masker level at both low [500-Hz] and high [2500-Hz] signal frequency, and high masker level at low signal frequency) and where frequency selectivity was somewhat degraded (high masker level and high signal frequency). The first experiment investigated CMR in conditions where a narrow modulated noise band was centered on the signal frequency, and a wider comodulated noise band was located below the band centered on the signal frequency. Signal frequencies were 500 and 2000 Hz. The masker level and the frequency separation between the on-signal and comodulated flanking band were varied. In addition to conditions where the flanking band and on-signal band were presented at the same spectrum level, conditions were included where the spectrum level of the flanking band was 10-dB higher than that of the on-signal band, in order to accentuate effects of reduced frequency selectivity. Results indicated that CMR was reduced at the 2000-Hz region when masker level was high, when the frequency separation between on-signal and flanking band was small, and when a 10-dB level disparity existed between the on-signal and flanking band. In the second experiment, CMR was investigated for narrow comodulated noise bands, presented either without any additional sound or in the presence of a random noise background. CMR increased slightly as the masker level increased, except at 2500 Hz when the noise background was present. The decrease in CMR at 2500 Hz with the high masker level and with a noise background present could be explained in terms of reduced frequency selectivity. In a third experiment, we compared performance for equal absolute bandwidth maskers at a low (500-Hz) and a high (2000-Hz) stimulus frequency. Results here suggested that detection in modulated noise may be reduced due to a reduction in the number of quasi-independent auditory filters contributing temporal envelope information. The effects found in the present study using normal-hearing listeners under conditions of degraded frequency selectivity may be useful in understanding part of the reduction of CMR that occurs in cochlear-impaired listeners having reduced frequency selectivity.

scholarly journals The Assessment on the Sound Quality of Reduced Frequency Selectivity of Hearing Impaired People

2011 ◽  
Vol 60 (6) ◽  
pp. 1196-1203 ◽  
Author(s):  
Hong-Sub An ◽  
Gyu-Seok Park ◽  
Yu-Yong Jeon ◽  
Young-Rok Song ◽  
Sang-Min Lee
Keyword(s):  
Sound Quality ◽  
Frequency Selectivity ◽  
Hearing Impaired ◽  
Reduced Frequency ◽  
Impaired People

Evaluation of a method of simulating reduced frequency selectivity

1992 ◽  
Vol 91 (6) ◽  
pp. 3402-3423 ◽  
Author(s):  
Brian C. J. Moore ◽  
Brian R. Glasberg ◽  
Andrew Simpson
Keyword(s):  
Frequency Selectivity ◽  
Reduced Frequency

Frequency Selectivity in Normally-Hearing and Hearing-Impaired Observers

1980 ◽  
Vol 23 (3) ◽  
pp. 646-669 ◽  
Author(s):  
Mary Florentine ◽  
Søren Buus ◽  
Bertram Scharf ◽  
Eberhard Zwicker
Keyword(s):  
Hearing Loss ◽  
Narrow Band ◽  
Normal Hearing ◽  
Frequency Selectivity ◽  
Hearing Impaired ◽  
Tuning Curves ◽  
Reduced Frequency ◽  
Cochlear Hearing Loss ◽  
Test Level ◽  
Loudness Summation

This study compares frequency selectivity—as measured by four different methods—in observers with normal hearing and in observers with conductive (non-otosclerotic), otosclerotic, noise-induced, or degenerative hearing losses. Each category of loss was represented by a group of 7 to 10 observers, who were tested at center frequencies of 500 Hz and 4000 Hz. For each group, the following four measurements were made: psychoacoustical tuning curves, narrow-band masking, two-tone masking, and loudness summation. Results showed that (a) frequency selectivity was reduced at frequencies where a cochlear hearing loss was present, (b) frequency selectivity was reduced regardless of the test level at which normally-hearing observers and observers with cochlear impairment were compared, (c) all four measures of frequency selectivity were significantly correlated and (d) reduced frequency selectivity was positively correlated with the amount of cochlear hearing loss.

Accelerating Change

2018 ◽  
Author(s):  
Erin Stewart Mauldin
Keyword(s):  
Land Use ◽  
African Americans ◽  
Labor Relations ◽  
Cotton Production ◽  
Economic Independence ◽  
Contract Negotiations ◽  
Reduced Frequency ◽  
Ecological Event ◽  
Land Use Practices ◽  
Ecological Regime

Emancipation proved to be a far-reaching ecological event. Whereas the ecological regime of slavery had reinforced extensive land-use practices, the end of slavery weakened them. Freedpeople dedicated less time to erosion control and ditching and used contract negotiations and sharecropping arrangements to avoid working in a centrally directed gang. Understandably, freedpeople preferred to direct their own labor on an individual plot of land. The eventual proliferation of share-based or tenant contracts encouraged the physical reorganization of plantations. The combination of these two progressive alterations to labor relations tragically undermined African Americans’ efforts to achieve economic independence by tightening natural limits on cotton production and reducing blacks’ access to the South’s internal provisioning economy. The cessation, or even reduced frequency, of land maintenance on farms exacerbated erosion, flooding, and crops’ susceptibility to drought.

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