摘要:

This paper is concerned with the effect of morphological and syntactic boundaries on the temporal structure of spoken utterances. Two speakers produced 20 tokens each of four sets of words consisting of a mono‐syllabic base form, disyllabic and trisyllabic words derived from the base by the addition of suffixes, and three short sentences in which the base form was followed by a syntactic boundary; this in turn was followed by a stressed syllable, one unstressed syllable, and two unstressed syllables. The sentences thus reproduced the syllabic sequences of the derived words. The duration of words and segments was measured from oscillograms. The manifestation of morphological and syntactic boundaries is discussed, and some implications of the findings relative to the temporal programming of spoken utterances are considered.

ISSN:0001-4966    

DOI:10.1121/1.1913062

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

A study was made of the duration of bilabial closures for /p/, /b/, and /m/ under voiced and whispered speaking conditions. The results, obtained from 12 normal‐speaking young adult males, indicated significantly greater whisper durations for /p/ and /b/ but not /m/. An explanation for this finding is offered in terms of the hypothesis that individuals conserve air when whispering by prolonging air‐arresting articulatory gestures.

ISSN:0001-4966    

DOI:10.1121/1.1913063

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

A two‐year experiment on voice identification through visual inspection of spectrograms was performed with the twofold goal of checking Kersta's claims in this matter [Nature196, 1253–1257 (1962)] and testing models including variables related to forensic tasks. The 250 speakers used in this experiment were randomly selected from a homogeneous population of 25 000 males speaking general American English, all students at Michigan State University. A total of 34 996 experimental trials of identification were performed by 29 trained examiners. Each trial involved up to 40 known voices, in various conditions: with closed and open trials, contemporary and noncontemporary spectrograms, nine or six clue words spoken in isolation, in a fixed context and in a random context, etc. The examiners were forced to reach a positive decision (identification or elimination) in each instance, taking an average time of 15 minutes. Their decisions were based solely on inspection of spectrograms; listening to the identification by voices was excluded from this experiment. The examiners graded their self‐confidence in their judgments on a 4‐point scale (1 and 2, uncertain; 3 and 4, certain). Results of this experiment confirmed Kersta's experimental data, which involved only closed trials of contemporary spectrograms and clue words spoken in isolation. Experimental trials of this study, correlated with forensic models (open trials, fixed and random contexts, noncontemporary spectrograms), yielded an error of approximately 6% false identifications and approximately 13% false eliminations. The examiners judged approximately 60% of their wrong answers and 20% of their right answers as “uncertain.” This suggests that if the examiners had been able to express no opinion when in doubt, only 74% of the total number of tasks would have had a positive answer, with approximately 2% errors of false identification and 5% errors of false elimination. The different conditions existing between experimental trials of identification or elimination performed by the examiners of this study and the tasks performed by a professional examiner in real cases are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1913064

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

In a scheme for the mechanical recognition of speakers, it is desirable to use acoustic parameters that are closely related to voice characteristics that distinguish speakers. This paper describes an investigation of an efficient approach to selecting such parameters, which are movitated by known relations between the voice signal and vocal‐tract shapes and gestures. Rather than general measurements over the extent of an utterance, only significant features of selected segments are used. A simulation of a speaker recognition system was performed by manually locating speech events within utterances and using parameters measured at these locations to classify the speakers. Useful parameters were found in fundamental frequency, features of vowel and nasal consonant spectra, estimation of glottal source spectrum slope, word duration, and voice onset time. These parameters were tested in speaker recognition paradigms using simple linear classification procedures. When only 17 such parameters were used, no errors were made in speaker identification from a set of 21 adult male speakers. Under the same conditions, speaker verification errors of the order of 2% were also obtained.

ISSN:0001-4966    

DOI:10.1121/1.1913065

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Resistance measurements of the cochlear membranes are analyzed regarding the effective length of the cochlea actually sensed. It is shown that only short segments are represented by the measurements, as confirmed by experimental results. It is asserted that both the longitudinal and transverse dimensions must be considered simultaneously in cochlear modeling, as facilitated by a transmission line or core conductor approach.

ISSN:0001-4966    

DOI:10.1121/1.1913066

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

It is argued that the approximately constant relationship of cochlear microphonic output to stapes velocity noted by Weiss, Peake, and Sohmer [J. Acoust. Soc. Amer.50, 602–615 (1971)[ is probably a function of a bias introduced by the choice of electrode location, i.e., the bone near the round window. Based on recordings from the round window, cochlear microphonic output rises about 20 dB between 100 Hz and 10 kHz if stapes velocity is held constant.

ISSN:0001-4966    

DOI:10.1121/1.1913067

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Three types of zero‐crossing measurements—(i) average zero‐crossing rate, (2) density of time intervals between zero‐crossings, and (3) excess‐threshold duration—are related theoretically. It is shown that measurement types 1 and 3 can be derived from the type 2 measurement. Measurement types 1 and 3 cannot be directly related, but it is shown that the type 2 measurement can be derived from the type 3 measurement.

ISSN:0001-4966    

DOI:10.1121/1.1913068

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

摘要:

Echolocating bats were trained to discriminate between two small, spherical targets, each separated by a different angle from a third spherical target fixed in one location between the other targets. The targets were all in the horizontal plane. The angle from the fixed target to one of the movable targets was kept constant at 19° of arc, while the angle from the fixed target to the other movable target was varied from 37° to 19° in small decrements. The acuity with which the bat could use sonar to discriminate the larger angle from the smaller, constant angle of 19° was experimentally determined to be 6° to 8° forEptesicus fuscusand 4° to 6° forPhyllostomus hastatus.Phyllostomushas a nose‐leaf through which it broadcasts its sonar cries, using a beamwidth (6 dB down) of 40° to 50° in this experimental setting.Eptesicusemits cries through its open mouth and, in the apparatus for angular discrimination, used a beamwidth of 55° to 65°. There are many other differences between these species in echolocation, but the data suggest that at least the width of a bat's beam of sound may be related to acuity of angular resolution.

ISSN:0001-4966    

DOI:10.1121/1.1913069

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1913070

出版商:Acoustical Society of America    

年代:1972

数据来源: AIP