74TH MEETING ß ACOUSTICAL SOCIETY OF AMERICA

Carried out at about 175øC, where the relaxing vibrational specific heat of nitrogen becomes large enough to be readily measureable, both contaminants shift the Napier frequency upward by amounts simply proportional to their molar con- centrations: water vapor by 300 Hz per mole%, carbon dioxide by 250 Hz per mole%. However, preliminary work indicates that when both are present the shift is not the simple sum of the individual effects, but that there is considerable synergism. Such a synergistic effect is indeed to be expected on theoretical grounds. •This work was supported by the Office of Naval Research.]

Hl l. Measurement of Viscoelastic Properties of Polymers by Ultrasonic Methods. J. R. SMITHSON, United States Naval Academy, Annapolis, Maryland.--Yasaku Wada [_J. Phys. Soc. Japan 15, 2324 (1960)-! has proposed a method of calcu- lating the real and imaginary parts of the bulk modulus of a polymer from measurements of the sound velocity and ab- sorption coefficient of a water suspension of the polymer. An analysis of the propagation of measurement errors through the bulk modulus calculation, shows that errors in sound velocity are magnified in the calculation, but existing methods of velocity measurement are sufficiently accurate to allow worthwhile results. A feasibility study of the method has been made using some special suspensions of polybutadiene which were prepared by Goodrich Rubber. These suspensions were unique in that they contained very narrow bandwidths of

particle sizes. Studies have considered particle size, concen- tration, temperature, sound frequency, and effect of dissolved salts and soaps in the suspensions. Results indicate that the method has a considerable range of usefulness. [Supported by the Office of Naval Research.']

H12. Determination of Attenuation Constants for Air in

Tubes by Standing Wave Measurements. W. L. BEECH (nonmember) _aND J. V. SAND•.RS, Naval Postgraduate School, Monterey, California 93940.mAttenuation constants were precisely measured for air, at ambient conditions, contained in a rigid-walled tube. Standing waves were excited by a piston with the fundamental having a frequency of 93.8 Hz and a bandwidth of 1.12 Hz. Attenuation constants were determined both by the conventional technique of measuring the frequency difference between the half-power points on the resonance curve (Method A), and by measuring the microphone and accelerometer output voltages at resonance (Method B). The experimental results to the 40th harmonic were compared with the Rayleigh-Kirchoff theory that predicts a f• depend- ence. Both methods yield a frequency dependence of f0.•4*0.a. The attenuation at the fundamental frequency was (1.03 :t:0.03) X 10 -•' m -• by Method A and (1.10:t:0.04) X 100 •' m -• by Method B, approximately 10% and 15% higher than the theoretical value for a smooth tube without end losses. Method B which does not require accurate frequency determinations, has not been previously reported.

TUESDAY, 14 NOVEMBER 1967 SILVER CHIMES EAST, 2:00 P.M.

Session I. Speech I' Sound-Spectrum Analysis; Synthesis

JOHN C. LILLY, Chairman

Contributed Papers (10 minutes)

I1. Spectrographic Analyses of English Consonants. YUKIO TAK•.FUTA, The Ohio State University, Columbus, Ohio.--The purpose of this study was (1) to analyze the English conso- nants spectrographically and (2) to calculate the relative con- tribution of each acoustic correlate to the distinction of one

articulatory feature from another. Three male speakers of General American dialect recorded 24 English consonants five times in intervocalic positions of five different vowels, /a, e, i, o, u/. Three types of spectrographic display were made for all consonants: sonagram, section, and amplitude display. •uantitative measures were made for each of three aspects of acoustic analysis (intensity, duration, and frequency spec- trum). The acoustic features were interpreted in relation to the articulatory features of manner or place of articulation. Each correlate was also considered as a possible distinctive feature or an acoustic signal of the consonants, and the magni- tude of this signal was a measure of its strength. The index of signal detectability was calculated to quantify the relative contribution of the acoustic features.

12. Real-Time Colored Display of Sound Spectrogram. YASUAKI NAKANO (nonmember), TAKESHI NAKAYAMA (non- member), TSUNEJI KOSHIKAWA, AND TANETOSHI MIURA, Central Research Laboratory, Hitachi Ltd., Kokubunji, Tokyo, Japan.mlf signal spectrograms are displayed in real time, so-called brightness modulation display is used in general. Because of the limited dynamic range of brightness modula- tion of CRT, details of the spectrum are lost very often. In order to overcome such defects and be able to observe instan-

taneous spectrum patterns more clearly and easily, we con- structed new display apparatus in which effective use of visual function is considered. In this system, instantaneous spectrum

amplitude is quantized in 11 levels with the step of 4 dB, and each amplitude level is converted to predetermined hue re- sembled to contour map. Furthermore, these colored instanta- neous spectrograms are memorized in sky-sign like fashion in a certain time interval. As the results of displaying various acoustic signals, it is confirmed that color display of this type is more useful than monochromatic display for the visual dis- crimination of the characteristics corresponding to each signal differences.

13. Spectrum Analysis of Various Asian Dialects. S. JOSEPH CAMPANELLA, Communications Satellite Corporation, Washing- ton, D.C. AND R. C. I•OeF•.NST•.IN (nonmember), Melpar, Inc., Falls Church, Virginia.--It was the objective of the study reported here to analyze a variety of Asian dialects for the pur- pose of discovering spectrum distribution differences that may be correlated to the dialects. The dialects subjected to the analysis were North (10), Central (10), and South (10) Viet- namese; Cantonese (5), Mandarin (5), and Fukienese (4) Chinese; Cambodian (15) and the highland tribal dialects of Jari (3), Bahnar (3), Sedang (3), Rade (3), Cham (3), Koho (3), and Hre (11). The number of individuals sampled in each dialect is shown by the digit in the parentheses. Confidence in the results should be rated accordingly. All samples were taken from male talkers. Spectrum analysis was performed by means of a 31-channel 1/3-oct band filter bank over the frequency range from 20 to 20 000 Hz, scanned at a rate of 60 Hz. The speech source data were collected on high-quality portable tape recorders and these, after appropriate editing to remove unwanted background, were played into the 1/3-oct band spectrum analyzer. The spectra were then digitized and trans- ferred to an IBM 1410 computer for analysis for mean spec-

1162 Volume 42 Number 5 1967

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74TH MEETING ß ACOUSTICAL SOCIETY OF AMERICA

trum distribution for each dialect. Voiced and unvoiced events were segmented into separate groups and separate spectra for each of these classes thereby obtained. For the summary analysis, all spectrum scans of the voiced type and unvoiced type were individually averaged to produce an average voiced event spectrum and an average unvoiced event spectrum for each dialect. A tally of the number of spectra for each excita- tion class for each dialect also permitted the estimation of the ratio of voiced to unvoiced excitation that is characteristic of each dialect. The summary analysis showed that, generally, the voiced event mean spectrum differed only in minor detail as a function of dialect. The same was found true of the un- voiced event mean spectrum. The most variable parameter appeared to be the percentage of time occupied by voiced excitation. This parameter varied from 76% for Mandarin- Chinese to 90% for Cambodian, Jarl, and Hre. [-Dr. Cam- panella was employed at Melpar, Inc. at the time of perform- ance of the study reported in this paper. The work was per- formed under Contract Booze-Allen Corp. subcontract 5-66-1 ]

14. Coarticulation and the Locus Theory. PIERRE DELATTRE, University of California, Santa Barbara, Cahfornia.--The effects of coarticulation on formant transitions do not "... necessitate a re-evaluation of the locus theory..." [-S. E.G. Ohman, J. Acoust. Soc. Am. 39, 151 (1966)•. In fact, no acoustic data on human speech behavior could be used to alter this theory since it is essentially based, not on the production of human speech, but on the perception of controlled acoustic variables by human brains. The locus concept simply des- cribes the direction and extent that the second- and third-for- mant transitions of a consonant must take in order to contribute to the perception of place of articulation. It does not claim that the specifications of formant transitions defined by the locus are observed by all human speakers under all conditions. Earth speakers are only human. But it does assume that when, in human speech, a transition does not point to the appro- priate locus, that transition does not contribute to the perception of the appropriate place of articulation. Tables of VCV coarti- culation will be examined to find how the perception of place of articulation is possible when the interference of coarticula- tion prevents a transition from pointing to the appropriate locus. It will be shown that in every such case, other cues sub- stitute for the locus cue.

15. Pseudospeech Synthesis and the Phonette. H. M. TRUBY, Division of Newborn Infant and Phonetic Studies, Communi- cation Research Institute, Coconut Grove, Florida.--Direct programming intimacy, spanning 17 consecutive years, with, respectively, the Haskins Labs PB-2 and Octopus, the Swedish Royal Institute of Technology Ove I, LEA, Lucia, progres- sively developmental stages of Ove II, etc., and the IBM San Jose Terminal Analog Synthesizer, (both Mark I: manual patterns, and Mark II: computer-stored, diphone-nucleus nuclei) has led the author of this paper to consider strongly the term "speech" as applied to the products of electromechanical "synthesis" operations. The linguistics (sic) implications of the contrivance "pseudospeech" to these products seem highly apt to this investigator, who at one time proposed the acronym TAPS for the IBM device (and thus: Terminal Analog Pseudospeech Synthesizer) and presented a paper before the Xth Annual National Conference on Linguistics entitled, "A Phonetic Macro-matrix for Pseudo-speech Synthesis." The relevance of this iconoclastic, but perhaps useful, consideration to questions of listener judgment(s) and other psychological- testing procedure(s) is discussed, both in its own light and in light of a variable segmental unit, the phonette, proposed as a part of the Acta Radiol Logica Monograph Acoustico-Cine- radiographic Analysis Considerations (Truby, 1959), a 227- page publication including 1100 sound spectrograms of Ameri- can-English word utterances, each with correlated oscillogram, over-all-intensity record, pitch curve, and duplex oscillogram.

Synthesis and speech-transmission analysis have much to offer future communication research, provided they are not de- limited by misdefinition and equivocal evaluation criteria.

16. Digital Formant Synthesizer for Speech Synthesis Studies. LAWRENCE R. RABINER, Bell Telephone Laboratories, Inc., Murray Hill, New Jersey.--Recent work on speech synthesis by rule has led to the development and evalation of a novel digital formant synthesizer. The synthesizer was simulated on a computer at a 20-kHz sampling frequency. Among the novel points are an excitation source for the unvoiced component of voiced fricatives; a voicebar for the stop gap period of voiced stops; a novel source filter providing the voiced excitation for the synthesizer and the elimination of the higher pole correc- tion network for voiced sounds by exploiting the properties of sampled data systems. A comparison (in terms of the fre- quency response for vowels) between digital and analog syn- thesizers will be made. A brief discussion of the advantages and disadvantages of cascade and parallel synthesizers will be pre- sented. Examples of synthetic speech will be presented.

17. Control Rule of Vocal-Tract Configuration. AKIRA ICHI- KAWA (nonmember), YASUAKI NAKANO (nonmember), AND KAZUO NAKATA (nonmember), Central Research Laboratory, Hztachi Ltd., Tokyo, Japan.--Objectives of the research is to find out a simple but an effective rule for the control of vocal-tract configuration in the synthesis of speech. One of the following two alternatives is often selected as the control rule: (1) independent linear interpolation, (2) mathematical descriptions with several parameters. The former has an advantage of simplicity but also has suffered from over simplified deformation. The latter is hardly applicable to consonant. The proposed processes are as follows: (1) Define three key points for each target configuration' they are maxi- mum area points of front and back cavity V•, V,., and maximal constriction point P between these two. (2) Trace the trajec- tory of these key points between two target configurations in a certain time fashion. (3) Calculate the temporal change of each section by the interpolation from starting target value to ending target value with considering a restriction due to the pass of V•, V,., and P point. The proposed rule has two advan- tages: (1) applicable to any target configurations including consonants, (2) the restrictions avoid the results from over- simplified deformations. Some of the result will be shown with aids of our vocal tract pattern display.

18. Vocal-Tract Perturbation Functions. JoI•N M. HEINZ, Department of Otolaryngology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.--In recent years, Webster's horn equation has been widely used as the basis for an approximate description of the acoustic behavior of the human vocal tract. Starting from an assumption of the vali- dity of this equation, a procedure for determining for an arbitrary vocal-tract configuration those first-order changes in the configuration that will effect changes in one and only one formant frequency (or, alternatively, one and only one lip impedance pole or zero) is presented. Examples illustrating the iterative use of this procedure for determining vocal-tract con- figurations that correspond to specified impedance pole-zero patterns are given together with a discussion of some of the practical difficulties that arise in this application. [This work was supported in part by Special Fellowship from the National Institute of Neurological Diseases and Blindness, Public Health Service while the author was a guest at the Department of Speech Communication, The Royal Institute of Technology, Stockholm, Sweden.]

19. Control Rule of Voice Source to Improve the Naturalness of Synthetic Speech. TA•CESrfI NAtCAYAMA (nonmember), A•rIRA ICrImAWA (nonmember), AN•) KAZUO NA•rATA (non- member), Central Research Laboratory, Hitachi, Ltd., Tokyo,

The Journal of the Acoustical Society of America 1163

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