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At least 19 recordsLinked to original sources
PubMedDate not supplied

A multivariate strategy for prediction of psychoacoustic performance from electroacoustic characteristics of hearing aids.

Sentence length psychoacoustic material was processed through 16 hearing aids and presented to 220 listeners. Twenty-nine indices of electroacoustic performance were abstracted from a testing program under laboratory conditions. Through a multivariate statistical strategy, psychoacoustic achievement was shown to be positively correlated to and could be predicted by a knowledge of white noise gain, bandwidth below and above 1 kHz, frequency response regularity, and transiet distortion (multiple R = 0.77; F = 2.04; df = 5,10). It was concluded that a multivariate statistical tactic, when used with discretion, can be a useful and powerful tool to predict psychoacoustic performance from a knowledge of hearing aid electroacoustic characteristics.

Amplifiers, Electronic↗
PubMed1979

Automatic speech recognition using psychoacoustic models.

An approach to automatic speech recognition is described, which, in a straightforward way, follows the concept of (1) preprocessing in terms of auditory parameters and (2) subsequent classification and recognition. The preprocessing system has been realized in analog hardware, while recognition is carried out on a digital computer. In the preprocessing system, the essential psychoacoustic principles of the perception of loudness, pitch, roughness, and subjective duration are implemented with some approximation. The system essentially consists of 24 bandpass filters, nonlinear transformation of each filter output into specific loudness and specific roughness, and final transformation of these parameters into total loudness, total roughness, and three spectral momenta. As a means to further reduce the information flow, continuous selection of dominant parameters is also considered on the basis of psychoacoustic data. The subsequent recognition process is mainly characterized by (1) discrimination between speech and silent periods, (2) detection of syllable peaks and classification of syllable nuclei, and (3) assumption of syllable boundaries and classification of consonant clusters. Though the entire system as yet is far from being complete and perfect, the present results indicate that the concept provides a systematic and promising way towards automatic recognition of continuous speech.

Computers↗
PubMed1977

Comparative psychoacoustics: perspectives of peripheral sound analysis in mammals.

Psychophysical data on hearing in mammals are summarized. The data are then correlated to the anatomy and physiology of the ear. Common mechanisms of sound transfer and analysis in the acoustic system, with stress on the auditory periphery, are discussed. In this paper an attempt is made to bring basic psychoacoustic data from man and mammals in a logical line with the anatomy, physiology, and biophysics of the ear. This comparative approach is based on man and those five mammals, including bat and dolphin, for which sufficient data are available.

Animals↗
PubMedDate not supplied

Psychoacoustical tuning curves in audiology.

The correlation between classic masking patterns and psychoacoustical tuning curves is discussed quantitatively. A simplified method to measure such tuning curves in clinical use is described. They are shown to be insensitive to the frequency dependence of the hearing loss. Tuning curve data of six different groups including normal and hard-or-hearing observers are given: normal hearing, conductive hearing loss, degenerative hearing loss, noise-induced hearing loss, otosclerosis and Menière's disease. The resulting tuning curve data indicate that the frequency resolving power of the four groups mentioned last is greatley reduced but not completely absent, especially in the range of greater hearing loss. The correspondence between the frequency-resolving power measured by the tuning curve method and the result of speech discrimination tests is demonstrated. The measured data indicate that more than 50% of the patients with otosclerosis show reduced frequency selectivity although otosclerosis is commonly regarded as a conductive hearing loss.

Acoustic Stimulation↗
PubMed1977

[Determination of the impaired ear's frequency selectivity using psychoacoustical tuning curves (author's transl)].

An apparatus for clinical use is described by which simplified psychoacoustical tuning curves can be measured near 500 Hz and near 4 kHz. Data produced by four groups (normal hearing, conductive hearing loss, noise induced hearing loss and degenerative hearing loss) are separately averaged and compared. The first mentioned two groups as well as the third in the low frequency range show good frequency resolution, the others, however, show largely decreased frequency resolution.

Audiometry↗
PubMedDate not supplied

Psychoacoustic evaluation of present prostheses.

A battery of psychoacoustic tests, designed to specify auditory discriminations possible with present, single-channel auditory prostheses, was administered successfully to 12 of the 13 subjects. While no subject was able to perform all discriminations required by this battery of tests, there was no discrimination that at least one subject did not perform successfully. The typical subject could 1) discriminate intensity differences within normal limits for frequencies below 1000 Hz; 2) discriminate frequency differences quite normally at 125 and 250 Hz, but not at all at 1000 or 2000 Hz; 3) discriminate differences in signal duration, temporal patterning (rhythm), and spectrum (e.g., tone vs narrow-band noise); and 4) discriminate between pairs of synthesized vowel-like sounds. The results of masking experiments could only be interpreted in terms of intensity discrimination. Several subjects were able to relate stimulus intensity to loudness for low-frequency sounds; and they could relate stimulus frequency to pitch for signals below 25 Hz. The intelligibility of the subjects' speech was found to improve when their prostheses were activated.

Auditory Threshold↗
PubMed1992

[Psychoacoustic tests: effects of atropine].

The efferent pathways exert a control action on the function of the cochlear nucleus and hair cells. Acetylcholine is the neurotransmitter of the centrifugal system and its action can be blocked by atropine. In order to give a contribution to the knowledge of the function of the efferent bundle and of the cochlea efficiency we examined 10 young normal subjects before and after infusion of 1 mg of atropine i.v. a battery of three psychoacoustical tests (Remote Masking, Critical Ratio and Brief Tone Audiometry). After infusion of atropine we have shown an increase of 0.25 Hz hearing threshold, an increase of RC values and a decrease of RM values. It can be concluded that the pharmacological block of the olivo-cochlear bundle determines a stiffness of outer hair cells and basilar membrane; this finding means that the atropine can inhibit the facilitating activity of the efferent system on the cochlear performance.

Adolescent↗
PubMed1978

Psychoacoustical aspects of synthesized vertical locale cues.

A new method of studying vertical localization is described whereby the high-frequency response of the external ear is synthesized by a computer program incorporating two variable latency delay and add processes. The resulting sounds were evaluated by presentation to subjects via headphones which bypass the external ear. Vertical movement of the sound source was perceived when the latency of one echo was changed dynamically between 100 and 300 microsecond and this effect required the presence of high-frequency signal components (about around 4 kHz). In further experiments, the variation of perceived elevation with echo delay was measured, and it is shown that the vertical locale of the apparent source is a monotonic function of echo latency in the 160-260 microsecond region. It is proposed that locale is decoded by a form of spectral pattern recognition, whereby the locale of the source is represented as a peak on an autocorrelation function. The time-axis values (between 160 and 260 microsecond) corresponding to these peaks are considered to correspond to vertical locale for elevations between roughly, 60 degrees above horizontal and 40 degree below.

Auditory Perception↗
PubMedDate not supplied

Filter effect of earmold venting: comparison of electroacoustic and psychoacoustic methods of evaluation.

The filter effect of venting an earmold was evaluated by measuring the coupler-acoustic and threshold responses to open versus closed earmolds. In the coupler-acoustic technique the effect of venting was determined by measuring the output of the experimental earmolds seated on a modified 2-cc coupler with a specified signal impressed upon the earphone. The real ear threshold technique called for the determination of threshold by five listeners for the same earphone-earmold system. The data indicated that the difference between the coupler and threshold measures were of the same order of magnitude as the difference seen by other investigators reporting coupler and real ear-probe tube microphone measures. It was concluded that the threshold technique provides the same general description of the effects of venting an earmold as does the probe tube technique and should thus provide a useful method for determination of the filter effects produced by the venting of an earmold.

Auditory Threshold↗
PubMedDate not supplied

Problems with earphone calibration using a manikin.

The response of a single TDH-39 receiver mounted in a MX-41/AR and an Auraldome cushion was measured psychoacoustically and electroacoustically using standard couplers and the Zwislocki coupler mounted in KEMAR (Knowles Electronic Manikin for Acoustic Research). Although the psychoacoustic data were similar for both cushions, electroacoustic responses differed across cushions and across couplers. It was concluded that an accurate method for evaluating circumaural earphones has not yet been developed and the manikin, in its present form, is unsuitable for supra-aural or circumaural earphone calibration.

Acoustics↗
PubMedDate not supplied

Vowel categorization and the critical band.

Using the concept formation paradigm, two series of experiments were conducted to test the hypothesis that the critical band (CB) was a factor in learning to make absolute discriminations of vowels. The specific hypothesis being examined was that the CB is a psychoacoustic boundary in learning to make vowel categorizations, and that learning absolute discriminations of pairs of vowels that differ in one of their formants by one bark or more is significantly easier than learning absolute discriminations of vowels that differ by less than one bark. Subjects were given the task of learning to identify paired sets of synthesized vowels that differed in either F1 or F2 by 0.4, 0.6, 0.8, 1.0, or 1.2 bark. The results of these experiments suggest that the critical bandwidth is not a natural psychoacoustic boundary in the learning of vowel categories, and also that subjects seem better able to learn distinctions involving differences in F1 than distinctions involving differences in F2. The discussion raises the possibility that vowels that differ by less than one bark may not be perceptually viable because of such factors as ambient noise, articulatory constraints, and coarticulatory influences. Some evidence from Dutch and French is presented in support of this conjecture.

Auditory Perception↗