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Journal of the Acoustical Society of America

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Nov 1952

Volume 24, Issue 6, pp. 582-784

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A Phase Principle for Complex‐Frequency Analysis and Its Implications in Auditory Theory

W. H. Huggins

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 582-589 (1952); (8 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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A filtering scheme that utilizes the phase‐frequency characteristic of a filter is shown to have certain advantages for analyzing signals, such as speech, which are produced by shock or noise excitation of a physical system having one or more resonances. The phase principle is shown to be particularly well suited to neural mechanisms of inhibition and facilitation, and evidence is presented that such a principle may be used by the ear to achieve its analysis of the sound that it receives.

On the Process of Speech Perception

J. C. R. Licklider

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 590-594 (1952); (5 pages)

Online Publication Date: 29 Jun 2005

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The process of speech perception is analyzed into three main operations: (1) translation of the speech signal into form suitable for the nervous system, (2) identification of discrete speech elements, and (3) comprehension of meaning. The first operation appears to correspond roughly to the transformation made by the sound spectrograph. The second may be carried out by the neural equivalent of a set of matched filters. The third appears to involve a neural form of cross‐correlation that exhibits some of the properties of the analogous electronic process.

Control Tower Language

F. C. Frick and W. H. Sumby

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 595-596 (1952); (2 pages)

Online Publication Date: 29 Jun 2005

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Shannon and others have estimated that written English is about 60 percent redundant. These estimates are arrived at by considering linguistic constraints on our use of speech symbols; they do not consider additional restrictions imposed by the audience and the situation in which the speaker finds himself. In order to estimate the effects of such nonlinguistic constraints, an informational analysis has been made of the “sublanguage” used in the control of aircraft by Air Force control tower operators. When the situational, as well as linguistic, contexts are taken into account, the estimated redundancy is raised to 96 percent.

Some Experiments on the Perception of Synthetic Speech Sounds

Franklin S. Cooper, Pierre C. Delattre, Alvin M. Liberman, John M. Borst, and Louis J. Gerstman

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 597-606 (1952); (10 pages) | Cited 17 times

Online Publication Date: 29 Jun 2005

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Synthetic methods applied to isolated syllables have permitted a systematic exploration of the acoustic cues to the perception of some of the consonant sounds. Methods, results, and working hypotheses are discussed.

Phonemes and Allophones in Speech Analysis

W. F. Twaddell

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 607-611 (1952); (5 pages)

Online Publication Date: 29 Jun 2005

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Phonemes are quite abstract units. The criteria for establishing them are primarily distributional and articulatory, not acoustic. A unit intermediate between a single speech‐event‐segment and a phoneme is the allophone. An allophone is a statistical average, with constant, identifiable acoustic characterization. For many purposes of engineering, psychology, pedagogy, and information theory, the allophone may be a more suitable unit than the phoneme.

The Phonetic Basis for Identification of Phonemic Elements

Eli Fischer‐Jørgensen

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 611-617 (1952); (7 pages)

Online Publication Date: 29 Jun 2005

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Phonemic analysis must be based to a large extent on considerations of phonetic similarity and difference. For this purpose various stages of the speech event may be chosen, in particular the articulatory, the acoustic, and the auditory stage. It does not seem irrelevant which stage is chosen, for the analysis may give different results in each of the three stages. However, it is usually not possible to state general reasons for preferring one stage over another. In a given language functional reasons may in some cases decide the choice.

Operational Phonemics in Reference to Linguistic Relativity

Kenneth L. Pike

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 618-625 (1952); (8 pages)

Online Publication Date: 29 Jun 2005

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The phonemes of a language are neither absolutes nor bundles of absolute characteristics, but rather are fluctuating bundles of features identified (1) relative to each other in sequences, (2) relative to a system of fluctuating bundles of characteristics, and (3) relative to structural position in a sequence of such relative elements. Detection techniques, if paralleling phonemic analysis, would need to be able to work with fluctuating relative elements rather than with absolute physical characteristics only.

The Problem of Selective Voice Control

Winston E. Kock

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 625-628 (1952); (4 pages)

Online Publication Date: 29 Jun 2005

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The development of devices which can be operated automatically from the phonetic content of speech may be viewed in terms of the more general problem of the reduction of channel capacity in communications systems. Significance has been observed in formant positions and movements as regard the identification of speech sound. The basic problems in the derivation of phonemes from the formant patterns are reviewed.

The Information‐Bearing Elements of Speech

Gordon E. Peterson

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 629-637 (1952); (9 pages)

Online Publication Date: 29 Jun 2005

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This study deals with those aspects of speech which are phonetically significant. A technique has been developed with which phonetically equivalent speech samples may be obtained different phonetic contexts and from different speakers. Data on two front vowels by different types of speakers are presented. The technique has also been applied to the evaluation of words containing these two vowels.

Automatic Recognition of Spoken Digits

K. H. Davis, R. Biddulph, and S. Balashek

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 637-642 (1952); (6 pages)

Online Publication Date: 29 Jun 2005

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The recognizer discussed will automatically recognize telephone‐quality digits spoken at normal speech rates by a single individual, with an accuracy varying between 97 and 99 percent. After some preliminary analysis of the speech of any individual, the circuit can be adjusted to deliver a similar accuracy on the speech of that individual. The circuit is not, however, in its present configuration, capable of performing equally well on the speech of a series of talkers without recourse to such adjustment.
Circuitry involves division of the speech spectrum into two frequency bands, one below and the other above 900 cps. Axis‐crossing counts are then individually made of both band energies to determine the frequency of the maximum syllabic rate energy with each band. Simultaneous two‐dimensional frequency portrayal is found to possess recognition significance. Standards are then determined, one for each digit of the ten‐digit series, and are built into the recognizer as a form of elemental memory. By means of a series of calculations performed automatically on the spoken input digit, a best match type comparison is made with each of the ten standard digit patterns and the digit of best match selected.
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Duality in Mechanics

P. Le Corbeiller and Ying‐Wa Yeung

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 643-648 (1952); (6 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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Given an electric network Ev which has M meshes and P node‐pairs, its electric dual Ei will have P meshes and M node‐pairs and its classical mechanical analog Mf will have M+1 nodes, M independent node‐pairs, and P independent node cycles. A second mechanical system Mv, the classical analog of Ei, will have M cycles and P node‐pairs. If, for example, M = 2, P = 3, the systems Ev and Mv, analogs in the Firestone or “mobility” method, will be governed by two mesh equations, expressing that the algebraic sum of the voltages or velocities around any loop is zero; the systems Ei and Mf, also Firestone analogs, will satisfy two node equations, expressing that the algebraic sum of the currents or forces leaving any node is zero. These four sets of equations are identical, interchanging symbols suitably. The consideration of the four systems, Ev, Ei, Mv, Mf, forming a complete set, shows the advantages of the Firestone over the classical system of analogies and suggests a systematic use of duality in mechanical as well as in electrical systems.

Apparatus for Absolute Measurement of Analogous Impedance of Acoustic Elements

George B. Thurston

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 649-652 (1952); (4 pages) | Cited 2 times

Online Publication Date: 29 Jun 2005

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A hydrodynamical test system for absolute measurement of analogous impedance of acoustic elements is described. The test system is designed for use from dc to 700 cps, and in this frequency range it accurately measures pressure and volume flow.

Periodic Fluid Flow Through Circular Tubes

George B. Thurston

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 653-656 (1952); (4 pages) | Cited 5 times

Online Publication Date: 29 Jun 2005

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Some aspects of the periodic flow of an incompressible fluid through a circular tube of large length to diameter ratio have been studied. Expressions for the analogous acoustic resistance and inductance of the tube are presented. An experimental investigation of the resistance and inductance is described in which the tube dimensions, the viscosity of the fluid, and the frequency of the periodic motion are varied over a wide range. The experimental results are found to be in good agreement with the predictions of the hydro‐dynamical theory.

Theoretical Sensitivity of a Transversely Loaded, Circular Bimorph Transducer

Edward G. Thurston

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 656-659 (1952); (4 pages)

Online Publication Date: 29 Jun 2005

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With the advent of barium titanate as a piezoelectric material, the construction of transducers whose active elements can be in a wide variety of shapes became possible. The theoretical sensitivity of an interesting structure consisting of a transversely loaded, centrally supported, circular, barium titanate bimorph is calculated using the results of elasticity theory. Some experimental verification is presented.

The Use of Binaural Tape Recording in Automotive Noise Problems

David C. Apps

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 660-662 (1952); (3 pages)

Online Publication Date: 29 Jun 2005

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The record‐playback method of making noise comparison tests provides realistic answers with a minimum of equipment and sophistication. Such a method is especially attractive in problems handled by making experimental changes which, taken individually, usually produce very small changes in level and quality of noise.
In automotive work, playback of single‐channel recordings of interior car noise sensed by a single microphone sound unreal because of an emphasized bass, the cause of which is not known to the author. Directional effects also contribute to the lack of realism.
The use of a binaural magnetic tape recorder improves realism, which in turn enhances the resolution of smaller differences.

Axially Symmetric Vibrations of a Finite Isotropic Disk. II

Ram Ratan Aggarwal

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 663-666 (1952); (4 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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The calculations presented in Part I of this paper have been extended so as to include vibrations, which are antisymmetric with respect to the central plane of the disk. Curves showing the normal components of the displacements at the boundary surfaces are also drawn, to get the vibration patterns according to the theoretical assumptions made.

An Investigation of Sound Vibrations in a Tube Containing a Heat Source

Joseph L. Neuringer and George E. Hudson

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 667-674 (1952); (8 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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The aerothermodynamic process inside a tube in which is placed heat source and through which air is flowing is investigated theoretically. The formulation is based partly on the assumption that the average state of the medium inside may be approximated by a step distribution in the gas variables, simplifying hypothesis suggested by experimental observations by Lehmann (see reference 4). The zeroth‐order (mean hydrodynamic flow) and first‐order (acoustic) solutions inside the tube are first obtained using a heat transfer law for the heater which depends on some arbitrary function of the local values of the gas variables, velocity‐gradient, and source temperature. Upon the basis of a few hypotheses regarding turbulent flow and turbulent heat transfer, the possible existence of heaters whose heat transfer rate depends essentially on the negative of the velocity gradient of the flow through them is demonstrated. The solution is then specialized to those types of heaters, and it is shown that, in agreement with the so‐called Rijke effect, growth of the fundamental tone may occur with the heater almost anywhere in the first half of the tube from the blower end to the node, with decay almost everywhere else. The exact positions of the regions of growth and decay of sound inside the tube are then investigated.

Dependence of Pfeifenton (Pipe Tone) Frequency on Pipe Length, Orifice Diameter, and Gas Discharge Pressure

A. B. C. Anderson

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 675-681 (1952); (7 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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Measured dependences of the Pfeifenton frequency on static flow pressure, orifice diameter, and pipe length are presented, based upon studies of air flowing through pipes terminated various orifices. Frequency measurements were made of the vibrations inside the pipe. The Pfeifentöne are not a series of discrete single valued harmonics. Each covers a range of frequencies, any specific value of which is determined by the discharge flow‐velocity or pressure. When the orifice diameter approaches zero the behavior of the primary Pfeifenton frequencies is as if they were produced by an open‐closed organ pipe; when the orifice diameter approaches that of the pipe, the behavior is as if they were produced by an open‐open organ pipe. A mechanism for the excitation of the Pfeifentöne is proposed.

Vibrations of Evaporating Liquid Drops

Norman J. Holter and Wilford R. Glasscock

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 682-686 (1952); (5 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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An unusual type of vibration of flattened spheroidal liquid drops, occurring under certain conditions, is described and illustrated. Appropriate liquids placed on a sufficiently hot horizontal surface float on a film of their own vapor, which vapor insulates the drop so that it evaporates quite slowly, this phenomenon being known as the Leidenfrost effect. It is under these conditions that drops have been found capable of sustaining large amplitude regular radial vibrations whose driving force is probably related to the radial flow of vapor below the drops. The vibrating drops are approximately polygons which may have any of 2, 3, 4,…n sides, seen by the eye as drops with 4, 6, 8…(2n+2) regular lobes around the circumference. Methods of exciting and recording the effect are described.

Systematic Errors in Indirect Measurements of the Velocity of Sound

P. W. Smith, Jr.

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 687-695 (1952); (9 pages)

Online Publication Date: 29 Jun 2005

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An analysis is made of certain methods of measuring the velocity of sound. Specifically, attention is centered on those methods based upon measurements of the electrical driving‐point impedance of the transducer and the observation of some phenomenon of that impedance which is recurrent as the position of the reflector in the acoustic chamber is changed. Consideration is given to the influences of small losses in the propagation of sound in the chamber and of the existence of nonplane wave fronts. It is shown that such measurements can be subject to significant systematic errors arising from the method itself. The nature and magnitude of such errors are discussed.

Acoustic Propagation in Granular Media

R. W. Morse

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 696-700 (1952); (5 pages) | Cited 5 times

Online Publication Date: 29 Jun 2005

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A theory is developed for the sound velocity and attenuation in a medium composed of closely packed solid particles immersed in a fluid. The absorption mechanism considered is that of viscous motion of fluid between the particles, and the macroscopic point of view is taken. For high enough frequencies the attenuation is proportional to the square root of the product of frequency and static flow resistance of the medium. Comparisons are made with data reported previously by others, and the agreement with the theoretical results is good for cases involving particles of nearly uniform size. Still another frequency effect, dependent on the size distribution, is evident for unsorted granular substance.

Tube Method of Measuring Sound Absorption

Hawley O. Taylor

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 701-704 (1952); (4 pages) | Cited 1 time

Online Publication Date: 29 Jun 2005

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A description of a tube method of determining the sound absorbing power of materials in which no exploring device is introduced in the path of the sound wave in the tube. The method is an extension of a research by Kennelly and Kurokawa on “Acoustic Impedance and Its Measurement,” and makes use of the motional impedance of a telephone receiver which serves as both the source of the sound wave in the tube and as the means for determining the fraction of sound absorbed by the material, a sample of which is attached to the piston which slides in the tube. Sample calculations for sound absorption are included.

Attenuation of Sound Resulting from Ionic Relaxation

L. H. Hall

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 704-708 (1952); (5 pages) | Cited 4 times

Online Publication Date: 29 Jun 2005

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Slowness in the rearrangement of ion configuration under acoustic perturbation should cause sound absorption in ionic solutions. This mechanism investigated from the standpoint of the Debye‐Ḧckel theory of strong electrolytes. The electrostatic part of the free energy of the solution is formulated in terms of temperature, volume, and an ion configuration function. The partial derivative of this expression with respect to volume gives the electrostatic component of pressure. A rate equation for change of ion concentration at a point enables us to find the variation in the ion configuration function with a small harmonic fluctuation in volume. Since the pressure is expressed in terms of the configuration function, this leads readily to the relaxational bulk modulus connected with rearrangement. The rate equation involves a parameter which in interionic theory has been identified as the relaxation time of the ionic atmospheres and can be evaluated from conductivity data. A calculation made for MgSO4 solutions sets the relaxation frequencies for 0.001 and 0.01 molal concentrations at 21 and 143 mc, respectively, and shows the maxima in the wavelength absorption coefficients to be 20 and 660× 10−9 respectively. The recently reported much higher excess absorptions for MgSO4 at lower frequencies are thus due to processes other than ionic relaxation.

Electromechanical Properties of BaTiO3 Compositions Showing Substantial Shifts in Phase Transition Points

Don A. Berlincourt and Frank Kulcsar

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 709-713 (1952); (5 pages) | Cited 2 times

Online Publication Date: 29 Jun 2005

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Incorporation of CaTiO3 or Y2O3 into BaTiO3 ceramics causes a downward shift of the second transition point, resulting substantial improvement of temperature stability in the normal operating range.
Dielectric and electromechanical properties of BaTiO3 ceramics containing CaTiO3, Y2O3, and PbTiO3 are shown from −40° to +120°C. The composition containing 5 weight percent CaTiO3 combines high piezoelectric response with low temperature dependence of operating characteristics.

Acoustic Relaxation in a van der Waals Gas

Robert T. Beyer

J. Acoust. Soc. Am. Volume 24, Issue 6, pp. 714-715 (1952); (2 pages) | Cited 3 times

Online Publication Date: 29 Jun 2005

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Expressions are given for the sound velocity and the absorption coefficient per unit wavelength for a van der Waals gas. Numerical calculations have been carried out for several triatomic gases. In general, the velocity corrections, under standard conditions, average about 0.5 percent, while the absorption corrections are two or three times larger.
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