摘要:

By using the parameters for the ear and the equations for a ’’communication theory’’ model of the behavior of the ear, a family of masking curves can be drawn up which one can apply to the conditions prevalent in automotive vehicles. From the behavior of the ear and its ability to resolve sounds in noise, estimates can be made of the conditions under which sirens and speech communications will be audible within motor vehicles moving in traffic, and some estimate can also be made as to their potential for attracting notice. These quantities can be read off by graphic techniques. Examples of their use are given.Subject Classification: [43]65.50, [43]65.75, [43]65.58 [43]50.70.

ISSN:0001-4966    

DOI:10.1121/1.381213

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

In electrococholegraphy, compound action potentials (AP) are recorded from the human promontory and the guinea pig round window. High‐pass noise masking and subtraction of AP responses at various high‐pass cutoff frequencies give the narrow‐band contributions to the whole nerve AP. Although the narrow‐band contributions recorded from human and guinea pig ears differ essentially, this narrow‐band concept makes it possible to derive a response area for a given type of stimulus, e.g., tone bursts. Within the response area, any combination of stimulus intensity and site on the cochlear partition evokes a detectable narrow‐band response contributing to the whole‐nerve AP. The main part of this contribution shifts basally the higher the stimulus intensity. Latency differences between responses from the various narrow bands are used to calcuate the traveling‐wave velocity for the human cochlea, which ranges from about 20 m/sec at 10 kHz to 1 m/sec at 500 Hz. The amplitude and width of the narrow‐band responses are closely related to the traveling‐wave velocity in the narrow band. It is argued that the response area and the narrow‐band‐response concept offer a means to relate electrocochleography in the human subject to the results obtained from single‐fiber studies in the normal and pathological animal cochlea.Subject Classification: [43]65.26, [43]65.20, [43]65.22, [43]65.40.

ISSN:0001-4966    

DOI:10.1121/1.381214

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

An experiment conducted to compare the discomfort produced by whole‐body sinusoidal vibration with that produced by one‐third‐, one‐, and three‐octave vibration spectra is described. Seated subjects were required to adjust the level of a variable test vibration such that it produced a degree of discomfort similar to that caused by a 10‐Hz sinusoidal vertical whole‐body vibration at 0.75 m/sec2rms. The test stimuli were nine sinusoidal vibrations (at 3.15, 4.00, 5.00, 6.30, 8.00, 10.00, 12.50, 16.00, and 20 Hz); nine one‐ third‐octave bands of random vibration centered at the above frequencies, three single‐octave bands (centered at 4.00, 8.00, and 16.00 Hz) and a three‐octave band (centered at 8.00 Hz). The results obtained by this method indicate that the mean equivalent discomfort produced by all the random motions employed in the experiment may be predicted by weighting the vibration spectra with a filter network. A suitable filter response is that determined from a contour of equal comfort for sinusoidal or one‐third‐octave random vibration.Subject Classification: [43]65.70.

ISSN:0001-4966    

DOI:10.1121/1.381215

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Psychophysical tuning curves were obtained on normal chinchillas using a shock‐avoidance technique. Curves were measured at several levels and frequencies of the signal, and both simultaneous and forward masking were employed. The chinchilla curves were found to be similar to those obtained with human subjects by other researchers. Also, a comparison of the chinchilla psychophysical tuning curves with cat physiological tuning curves shows that the two are similar in shape and sharpness of tuning.Subject Classification: [43]65.58, [43]65.68, [43]65.35, [43]65.75; [43]80.50.

ISSN:0001-4966    

DOI:10.1121/1.381216

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The effective bandwidths of cat auditory‐nerve fibers were estimated electrophysiologically from the masked thresholds of tones at the nerve fibers’ characteristic frequency. The masking noise was of variable bandwidth but constant total power and was geometrically centered on the characteristic frequency. It was presented at an intensity which, for the narrowest masker bandwidth used, raised the tone threshold by about 20 dB. The point at which the masked tone threshold began to decline as the masker bandwidth was increased provided an estimate of the fiber’s effective bandwidth. A similar method had been used in earlier psychophysical estimates of the cat’s critical band. The auditory‐nerve‐fiber bandwidths were on average 6 dB less than the critical bandwidth at the same frequency. Two of the cats had been tested both psychophysically and electrophysiologically; in these cats the difference was 6.8 dB. Most fibers, moreover, had critical ratios less than that observed psychophysically. The results suggest that the critical band is not a simple correlate of the tuning curves of auditory‐nerve fibers.Subject Classification: [43]65.42, [43]65.58.

ISSN:0001-4966    

DOI:10.1121/1.381217

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

A model relating discharge rate in single auditory‐nerve fibers to parameters of a two‐tone stimulus is presented. We consider cases where one tone is at fiber characteristic frequenfcy (CF) and the other tone produces two‐tone suppression. The last stage in the model is a saturating nonlinearity. For the CF tone presented alone, the input to this nonlinearity is the CF amplitude; in the two‐tone case, the CF amplitude is attenuated by a factor which depends only on the suppressor‐tone amplitude and frequency. The model serves to relate a number of two‐tone studies. In particular, it predicts our recently reported differences in two‐tone suppression for the cases of suppressor frequencies above and below fiber CF.Subject Classification: [43]65.35, [43]65.42.

ISSN:0001-4966    

DOI:10.1121/1.381218

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

A mathematical model based on statistical decision theory has been devised to represent the human auditory localization task. The known localization cues have been represented as Gaussian random variables, so that their interaction in a given experiment can be analyzed (and predicted) along the lines of classical detection/estimation theory. We have applied this technique to most of the horizontal and vertical localization experiments reported in the literature during the past ten years, encompassing over 200 subjects and 20 000 trials. Using a nonlinear regression program we have been able to estimate the standard deviations of four of the auditory localization cues, allowing objective comparison of their relative accuracy. The resulting model provides a relatively good fit to the published results on 40 localization experiments.Subject Classification: [43]65.62, [43]65.58, [43]65.35.

ISSN:0001-4966    

DOI:10.1121/1.381219

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

This is the second in a series of articles in human listeners’ abilities to discriminate between word‐length tonal sequences, or ’’patterns.’’ The first article reported that frequency resolution, by highly trained listeners, is four to five times more accurate for high‐frequency, late‐occurring components of such sequences than for low−frequency early components [Watson, Kelly, and Benbasset, J. Acoust. Soc. Am. 57, 1175–1185 (l975)]. These effects, which are similar to described as ’’recognition masking’’ or ’’informational masking’’ by other authors, have now been shown to be strongly dependent on the degree of trial‐to‐trial stimulus uncertainty of the psychophysical procedure in which they are measured. When stimulus uncertainty is reduced to its psychophysical minimum, frequency resolution for any component of a tonal sequence is only slightly less accurate than for isolated tones. Previous reports of recognition masking this may reflect limitations imposed by those more dynamic parts of the sensory process concerned with memory and attention, rather than information loss in the more static peripheral auditory system.Subject Classification: [43]65.22, [43]65.75, [43]65.64, [43]65.58.

ISSN:0001-4966    

DOI:10.1121/1.381220

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise‐burst duration (on time), interburst interval (off time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increase in stimulus duration and therefore loudness resulted in a systematic increse in latency, probably due to response recovery processes, as this effect was eliminated with increases in stimulus off time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on time produced smaller amplitude responses only for sufficiently short off times. It is concluded that wave V of the human auditory brainstem‐evoked response is solely an onset response.Subject Classification :[43]65.59.[43].65.75.

ISSN:0001-4966    

DOI:10.1121/1.381194

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

A dynamic model of the vocal cords, namely, a bilaterally symmetric two‐mass model, is extended to a bilaterally asymmetric two‐mass model to simulate pathological conditions of the vocal cords. Asymmetric behavior of the computer model is investigated for various conditions of imbalance in bilateral tension. The computer model is found to behave in three basic vibratory modes that are similar to those observed in physiological experiments on larynges under tension imbalance. The three distinctive modes are (1) a vibratory pattern with differences in phase and amplitude of cord vibration; (2) a nearly periodic motion without glottal closure; and (3) an unsteady, dicrotic or tricrotic motion. The three modes are found to be a strong function of the subglottal pressure and the glottal rest area, as well as the imbalance conditions of the cord parameters. The asymmetric vocal‐cord model is incorporated into a dynamic vocal‐tract synthesizer to simulate speech with a hoarse voice.Subject Classification: [43]70.20, [43]70.50.

ISSN:0001-4966    

DOI:10.1121/1.381221

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP