Generation and Propagation of Finite‐Amplitude Waves in Flexible Tubes

L. Bjørnø
<span title="">1972</span> <i title="Acoustical Society of America (ASA)"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/hwn3tbm3t5cpnjcflcmmwnprc4" style="color: black;">Journal of the Acoustical Society of America</a> </i> &nbsp;
94305.--The effects of changing stimulus durations were examined for speech and nonspeech signals. The aperiodic initial portion of the syllable [•n] was cut by progressive 7-msec decrements thus generating stimuli perceived as progressing, as expected, through several categories lrom unvoiced sibilant to voiced stop. These stimuli were presented in reversed sequential orders to listeners for identification. Two similar sets from a second talker were randomized and presented to 36 judges for
more &raquo; ... ntification and for discrimination. Additional stimuli of similar time course prepared from square gated white noise followed by a pulse train were judged for discriminability. Analyses showed that context effects in the sequential identification tasks were small. Discrimination scores reflected response preferences involving order of presentation for both speech and noise stimuli. Comparison of identifications and discriminations shows increasing evidence of categorical perception as category size diminishes or duration decreases. Discrimination and detection curves for speech and noise stimuli show marked constrasts. [-We gratefully acknowledge the assistance of Earl D. Schubert.-] AZ. A Cross-Language Study of Perceptual Asymmetry. T. F. Britain.--Recent findings that the speechdominant hemisphere is specialized at the level of distinctive feature analysis entail a prediction that the processing of acoustic cues embodying a feature distinction in a particular language is asymmetric for "native" listeners, but not asymmetric for nonspeakers of the language if their own language does not employ the contrast. Russian-and English-speaking listeners were presented dichotic sequences of syllables for identification of the consonants, i.e., the stops, categorized in Russian, but not in English, as palatalized or nonpalatalized. The results are discussed in the context of a recognition model equipped with a "filter" for feature selection. *Now at Bolt Bernrick and Newman, Inc., Cambridge, Mass. 02138. A3. Perceptual Features of Nine English Consonants Determined by Choice Reaction Time. FRaOERlC•t WEINoeR AND SADANAND SINGH, Ohio University, Athens, Ohio.--Nine English consonants were presented in pairs for the judgments of same/different to 10 subjects. Subject's choice reaction time (CRT), in making the above judgment, was considered to represent the interpoint distance of the criterion phoneme in subjects' perceptual space. A multidimensional analysis (IND-SCAL) showed that the magnitude of subjects' CRT for determining the sameness or differentness of a phoneme pair was governed by the distinctive features of these sounds. The features retrieved from a three-dimensional analysis were (1) sibilant, (2) voicing, and (3) place. It was further shown that phoneme pairs distinct by zero, one, two, or three feature differences had significantly different CRTs. Pairs having a "zero" feature difference had significantly greater CRTs than pairs different by one-three features. Similarfly, pairs with a one-feature difference had significantly greater CRTs than those with a three-feature difference. Within one-feature comparisons, CRT associated with sibilant was shortest following by the features place and voicing. This indicated greater distinctiveness of sibilant than place and voicing. Voicing showed the longest CRT, thus indicating minimal perceptual distinctivehess. A4. A Search for the Perceptual Features of the 29 Prevocalic I-Umdi Consonants. SADANAND S1NGH AblD •LA SIblGH, School of Hearing and Speech Sciences, Ohio University, Athens, Ohio 45701.--The 29 consonants of Hindi were recorded prevocalically with the vowel [a[. Each consonant was included in proportion to its statistical probability in Hindi. Thus, while /p/was included five times, /k/ 14 times. Ten native speakers of Hindi listened the stimuli in each ear separately in five S/N ratio conditions. Listeners responded in an openchoice manner. The responses were written in Devn•gri script. The tallies were made for all the errors which were then averaged for each stimulus consonant across the 10 subjects. The analysis of the 10 matrices (five S/N ratio X Ears) by IND-gCAL method provided beat interpretation in fivedimensional space. The perceptual features obtained were best described in articulatory terms. The first two dimensions were interpreted as voicing, aspiration, and sonarant with further interpretation of sonarant as: retrofiection, nasality, laterality, and semivowel. A subset of 22 consonants, for which place of articulation was phonogically distinctive, was further analyzed. The analysis yielded perceptual features (with articulatory nomenclature) front/back and palatal. [This work was partially supported by a grant from NIH.] AS. Perception of Segments of Spoken (Hindi) Vowel-Consonant-Vowel Syllables. $. S. AaPO, WAL, Central P. lecironies Engineering Research Institute, Pilani, India, ]12 ¾olume r•2 Number ! (Part I) 1972 83RD MEETING ß ACOUSTICAL SOCIETY OF AMERICA S. K. GUV?A AND RAIS AmaaD, Department of Physics, A. M. U. Aligarh, India.--This study presents some results of an experiment conducted to determine the effect on perception of deleting different numbers of 10-msec segments from the initial and final parts of VCV syllables. Eight stop consonants /p,t,•,k,b,.d,d,g/ and two affricates /ts,dz/ were combined with three pure vowels /i,a,u/to produce 30 VCV stimulus words. An electronic gating apparatus was developed to present sequential segments of initial and final portions of these syllables. The VC and CV stimuli so obtained were used for two separate listening tests and the responses were analyzed for individual consonants as a function of time. Perceptual phoneme boundaries were found from the response curves and compared with the acoustical phoneme boundaries obtained from sonagrams. The results indicate that the transitions of initial and final vowels terminating in the consonant are of maximal importance for the recognition of intervocalic consonants. The data indicate that the plosive burst plays a more important part in the recognition of unvoiced stops than in the case of voiced stops. The plosive gap was found to play a greater role in the recognition of voiced stops. The affricates were found to utilize all the acoustic events for their recognition. The study of errors showed that for intervocalic consonants, the voicing feature was not recognized in the early part of the initial transition and in the end part of final transition. B T7 INN, Northern Ireland.--Voice onset time (VOT) has proved in many languages to be a useful descriptive variable with which stop consonants may be classified in respect of the distinction voiced/nnvoiced. The question arises as to whether this variable also has fundamental perceptual relevance. Experimental evidence suggests that if VOT as such is registered in preception, then it must be registered in a fashion relative to other ongoing temporal events; for example, we have shown that perception of voicing depends on over-all syllabic rate. However, a separate effect of the rate of transition of the first formant from the onset of voicing to the steady state in the vowel is also evident. Stevens and Klatt (1971) proposed that the presence of a significant and rapid spectral change in the F1 region at the onset of voicing was the positive cue for voicedness. It is possible to go further and attempt to separate the effects of the extent, duration, and rate of the first formant transition. In such a synthesis experiment where VOTs were held constant, we obtained differences in voiced/unvoiced responses that supported Stevens and Klatt's suggestion that VOT is not the real perceptual cue, only appearing so because of the tied variables mentioned. Our results further indicate that there is little or no effect of the extent or duration of the transition, but that a critical rate of transition for perception as optimally voiced may be operating: The implications of these findings for feature detecting mechanisms in speech perception are discussed. [Work supported by J.S.R.U.--U.K.] A7. Some Perceptual Mechanisms in Speech Processing. MARK P. HAGGARD AND A. QUENTIN SUMMERFIELD, Department of Psychology, The Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland.--Enough is known about the acoustical cues in speech to enable highly intelligible synthesis from simple algorithms, but, in most cases, the most valid expressions of cues from the point of view of perception and the mechanism of detection, weighting, and decision are not known. Experiments that manipulate several cues and the phonetic context offer some hope of charting information flow through the human perceptual process and providing detailed block diagram models. Several examples are given. Perception of voicing in initial stops depends upon the place of articulation as well as the traditional voicing cues such as VOT--i.e., the boundary VOT value differs with place. Two separate experiments show that this effect is carried not by acoustical place information but by a perceptual decision about place, logically prior to the: voicing decision. But, in another context effect, dependence of consonant place upon the adjacent vowel, the effect appears conditioned by the acoustical vowel information and not by the decision as to linguistic identity. Implications for perceptual theory and speech recognition are pointed out. [-Work supported by .--The suggestion has often been made that stress serves an organizing function in speech perception. The present study attempts to investigate this idea by examining the relationship between stress patterns and the frequency of occurrence of substitution errors and order errors in the perception of obstruent clusters. Eighteen disyllabic CVCCVC nonsense words were selected to serve as stimuli. Only the medial consonant cluster was varied so that all combinations of p, t, and k with s were presented under three different stress patterns: stressed first syllable, stressed second syllable, and equal stress on both syllbales. Preliminary results indicate that, although the number of correct responses is the same under all conditions of stress, the ratio of ordering errors and substitution errors is different for the three stress conditions. A9. Consonant Confusions in Patients with Sensorineural Hearing Loss. R. Confusion matrices were obtained l!or 22 patients on four sets of nonsense syllables, using a forced-choice procedure. Each syllable set considered of 16 consonants in combination with the vowels /i,a,u/ either in CV or VC form. Syllables were presented at a comfortable listening level approximately 40 dB above the audiologic SRT. Over-all performance varied as a function of syllable set, vowel, and hearing loss. The confusions were analyzed by two multidimensional scaling procedures, MDSCAL and IND-SCAL. In addition, an iterative feature analysis of transmitted information was performed, in which the feature system of Mille. 15213.--Perceptual confusions were obtained at six speech-to-noise ratios ranging from --10 to +IS dB, at over-all noise levels of 50, 65, 80, and 95 dB SPL. Stimuli were four sets of CV and VC nonsense syllables formed by combining all English consonants with the vowels /i,a,u/. Noise levels of 80 and 95 dB resulted in poorer discrimination, particularly at moderate speech-to-noise ratios. Performance also varied as a function of vowel, syllables with /u/ being consistently better discriminated than others. An iterative feature analysis of transmitted information revealed that in both the Miller and Nicely [J. Acoust. Soc. Amer. 27, 338-352 (1955)-] and Chomsky and Halle [Sound Pattern of English (Harper & Row, New York, 1968)] feature systems, voicing accounted for the greatest relative transmitted information. [Research supported by a grant from SRS].
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