摘要:

This paper reports the results of a series of experiments on tone pulses designed to test certain predictions of the preliminary theory of intensity resolution (Durlach and Braida, 1969) relevant to one‐interval paradigms. Resolution was measured in identification and scaling experiments as a function of the range, number, and distribution of intensities, and the availability of feedback. Some of the results, such as those on the dependence of resolution on range and number of stimuli in absolute identification, support the theory. Other results, however, such as those comparing resolution in identification with resolution in magnitude estimation for a small common range, indicate that the theory is inadequate and needs to be revised.

ISSN:0001-4966    

DOI:10.1121/1.1912868

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

The intent of this study was to determine whether sound‐level measurements in dBAcould adequately depict harmfulness to hearing from exposures to noises differing widely in spectra. Each of 11 male listeners, ages 20–26 years, were exposed in separate sessions to each of three noises whose spectral slopes were −6, 0, and +6 dB per octave band and then re‐exposed to the same test noises in three additional retest sessions. All such noises were presented for 30 min via an earphone at 100 dBA. Analyses of variance of the temporary threshold shifts in hearing caused by these noise conditions [corrected to 2 min postexposure (TTS2)] showed insignificant differences, owing to the spectral variations for both test and retest conditions as averaged across audiometric frequencies 250–8000 Hz. Interactive effects between spectra and test frequencies were significant, the −6‐ and 0‐dB spectral conditions causing relatively more TTS2at frequencies below 3000 Hz, and the +6‐dB spectrum more TTS2at frequencies above 3000 Hz. Implications of these results for noise hazard rating schemes using dBAmeasures as contrasted with spectral determinations were noted.

ISSN:0001-4966    

DOI:10.1121/1.1912869

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

In a previous paper the author tried to show that hypothesized mechanical impact and mechanical fatigue processes in the cochlea are consistent with a range of psychophysical data on auditory fatigue and non‐linear effects (e.g., mechanical impact between the hair cells and tectorial membrane, and mechanical fatigue in terms of the viscoelastic or gel properties of the tectorial membrane). The present paper explores the extent to which mechanical processes of this type are also consistent with the recent findings of Goldstein [J. Acoust. Soc. Amer.41, 676–689 (1967)] regarding combination tones in the cochlea. We develop the idea of a hair vibrating in a pocket within the tectorial membrane, which is formed by the local movement of the hair. It is assumed that this pocket tends to close around the hair with some specified time constant. It is shown that impact between a single hair and the ends of the pocket generates the main features of the combination tone sequence found by Goldstein. Other combination tones are also generated, though it is argued that these might be discriminated against in a completely distributed impact model. The most important feature of this impact and fatigue mechanism is a dynamic change in pocket size that provides the normalization factor that the data demands, since the relative strength of the combination tones is found experimentally to be independent of input level.

ISSN:0001-4966    

DOI:10.1121/1.1912870

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Using standard operant conditioning techniques, a killer whale,Orcinus orcaLinnaeus, was trained to respond to pure‐tone auditory signals by pushing a response manipulandum. An audiogram was obtained for frequencies between 500 Hz and 31 kHz. Greatest sensitivity to the signal was observed at 15 kHz at a level of −70±5 dBre1 dyn/cm2. The observed upper limit of hearing was 32 kHz. At no time during training or testing did the animal respond to an undistorted signal above 32 kHz. Frequencies below 500 Hz were not tested, owing to high ambient tank noise levels.

ISSN:0001-4966    

DOI:10.1121/1.1912871

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

An old psychophysical test for degree of mechanical resonance in the cochlea was repeated, taking advantage of modern methods for controlling and reproducing audio signals. Unfortunately, the perception of a time separation pitch enters into the judgments and makes this particular method useless.

ISSN:0001-4966    

DOI:10.1121/1.1912872

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

The human auditory system's ability to recognize simple melodies that correspond to fundamental periods in sequences of periodic sounds devoid of fundamental energy was studied through musical interval identification experiments. Stimuli comprising two randomly chosen successive upper harmonics were presented both monotically (two harmonics to one ear) and dichotically (one harmonic to each ear). Subjects could recognize melodies equally well with both modes of stimulus presentation. The results imply that the pitch of these complex tones is mediated by a central processor operating on neural signals derived from those effective stimulus harmonics that are tonotopically resolved.

ISSN:0001-4966    

DOI:10.1121/1.1912873

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

A fresh water Amazon River dolphin,Inia geoffrensis, was conditioned to respond to pure tones by pushing a response lever. By using this method an audiogram was obtained for frequencies between 1.0 and 105 kHz. The animal was most sensitive to tones between 75 and 90 kHz. The sensitivity threshold in this area was −50 dBre1 dyn/cm2. The effective upper limit of hearing was 105 kHz. No reliable response was elicited above 105 kHz using a random presentation and undistorted signal.

ISSN:0001-4966    

DOI:10.1121/1.1912874

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

A tonal masking experiment of the sort pioneered by Wegel and Lane was conducted with both monotic and dichotic stimulation. The forms of the masking patterns under these two conditions of listening were markedly different. The monotic data were similar to the classical data—there was a local minimum in masking at the masker frequency, gradually more masking at adjacent frequencies, and then a gradual, and asymmetric, decline in masking at frequencies more distant from the masker. For the dichotic condition, however, masking wasgreatestat the masker frequency, and it showed two local minima at about ±10 Hz from the masker before declining gradually for more distant frequencies. These two minima are interpreted as reflecting a kind of time constant in the binaural system, an interpretation that receives support from research on binaural beats. Across signal frequencies, the masking‐level differences (MLDs) ranged from about 1 to 11 dB.Masker:400 Hz, 70 dB SPL, continuously present.Signal:100‐msec duration, 10‐msec rise‐decay time.Method:Two‐interval forced choice with feedback.Listening conditions:Nm‐Sm and N0‐Sπ.

ISSN:0001-4966    

DOI:10.1121/1.1912875

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Human observers performed two simultaneous increment detection tasks, one in each ear. This task, together with monaural and binaural control conditions, was used to investigate interaural time sharing, sensory inter‐actions, internal noise, and binaural decision spaces. When the signals were binaurally in phase, there was no evidence of cross‐channel facilitation or inhibition, and the observers were able to perform the task without performance decrements relative to single‐channel control conditions. For one observer, the derived estimate of the between‐channel correlation in the absence of an external masking noise was +0.40 and was consistent across different experimental conditions. Differences in the results for 180° phase‐shifted signals indicated probable changes in the nature of the processing mechanisms involved in the detection of the different types of signals. The paradigm and related analyses should be of value in the study of other kinds of perceptual phenomena.

ISSN:0001-4966    

DOI:10.1121/1.1912876

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Experiments were performed in which one ear of each of 36 cats was exposed to a 500‐Hz pure tone for periods totaling 80 min at one of four intensities while cochlear microphonic (CM) measurements were made. Exposure intensities were those necessary to produce a maximum in CM at 500 Hz, or 10 dB, 20 dB, or 30 dB higher than that. CM sensitivity before and after exposure was measured for frequencies from 100 Hz to 20 kHz. Losses were widespread and, at the highest intensity, were maximal at 500 Hz. Losses grew gradually with increasing intensity until somewhere between the two highest intensities the rate of loss became very rapid. The results of the present experiment were similar to those of a previous experiment in which a 5.0‐kHz exposure tone was used [G. R. Price, J. Acoust. Soc. Amer.44, 1541–1545 (1968)]. The implications of the data with respect to damage‐risk criteria were discussed.

ISSN:0001-4966    

DOI:10.1121/1.1912877

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP