bluuebunny/crossref_metadata_2025 huggingface dataset:
Features of Coarticulation in VCV Utterances
Authors: Öhman S. E. G.
Published: November 2005

Spectrographic and cinéradiographic data on voiced stops in V-V context are presented. The data suggest that (1) the neural signals controlling the activity of the vocal structures during V-stop-V utterances do not occur as a discrete time sequence corresponding to the graphic sequence of phoneme symbols; (2) the articulatory response to the neural instruction for the stop is superimposed on the initial portion of the response to the instruction for the following vowel; (3) the vocal-tract-shape target for the stop is not unique and depends on the V-V context as a whole; and (4) the formant loci of a stop+vowel (vowel+stop) syllable may be shifted along the frequency scale by a preceding (following) vowel. Interpretation of the data in relation to a dynamical model of speech production are discussed.
Electromyographic Study of Timing in Vowels
Authors: MacNeilage Peter F. , Sholes George N.
Published: November 2005

Patterns of electrical activity in the tongue musculature can be matched with the component features of a phonetic description of the vowels. When an English vowel is short and simple, e.g., /ɪ/, activity patterns are observed to occur more or less simultaneously. When a vowel is longer and more complex, e.g., /i, ɑɪ/, a particular activity pattern will occur earlier or later, depending on the vowel. But we find that some longer vowels, e.g., /e/, occupy a middle ground between vowels that are clearly simple, such as /i/, and those that are clearly diphthongs, such as /ɑɪ/. Theoretical commitments will determine whether these intermediate cases fall into one category or the other, or whether they illustrate yet a third category of diphthongizing vowels. We briefly explore some of the considerations that would lead to the last interpretation. [This investigation was supported in part by Public Health Service research grant DE-01774, National Institute of Dental Research, National Institutes of Health, U. S. Department of Health, Education, and Welfare.]
Crosslanguage Study of Voicing in Initial Stops
Authors: Lisker Leigh , Abramson Arthur S.
Published: November 2005

In describing the phonemes of a language, phoneticians often find it useful to divide them into “voiced” and “voiceless” categories. For stop consonants, some languages are said to utilize aspiration in conjunction with voicing to yield two, three, or four categories, while in some few languages categories are said to be distinguished solely by differences in aspiration. Some phoneticians, moreover, speak of strongly articulated (fortis) and weakly articulated (lenis) categories. Earlier work has shown that the two English categories /ptk/ and /bdg/ can, in initial positions, be distinguished acoustically by a difference in the time interval between the burst that marks stop release and the onset of periodicity that reflects laryngeal vibration. This measure of voice-onset time was applied to eleven languages that vary in the number and phonetic description of their initial-stop categories. In all these languages, this measure was found to be highly effective as a means of separating phoneme categories; the languages vary in where along the continuum of voice-onset time they put the boundaries between stops. Speech synthesis is being used to test the perceptual relevance of this dimension, and physiological data are being collected on underlying articulatory mechanisms. [This work was supported in part by the National Science Foundation under grant G-23633.]
Transitions in Fricative Noise
Authors: Uldall Elizabeth T.
Published: November 2005

The terminal-analog speech synthesizer at the Phonetics Department of Edinburgh University is used for work on the specification of speech sounds by means of acoustic parameters. Problems arising during the synthesis of passages of connected speech frequently lead to experiments in acoustic-phonetic detail. In one of these, the cues to the place of articulation of stops in clusters of the type fricative-stop-fricative, as in e.g., “clasps,” have been studied. It appears that transitional movements in the frequency position of the energy peak in the hiss spectrum used for the fricatives may be a cue for the place of articulation of the stop, parallelling formant movements in vowels as cues to the places of articulation of neighboring stops.
Technique for Measurement of Axle-Gear Dynamic Tooth Stiffness
Authors: Nimmo Philip E.
Published: November 2005

This paper describes a program aimed at obtaining correlation between axle-noise levels and variations in stiffness of gear-teeth pairs during meshing and loading in an operating-gear set. The work described involves only the technique developed to measure the effective dynamic gear-tooth stiffness for each combination of pinion and gear teeth. In principle, this was done by measuring the change in time for passage of reference locations on the drive and driven shafts (due to tooth bending under load) relative to the unloaded time interval. The incremental time is related to incremental deflection angle by a precise measurement of average shaft speed. An optical-triggering system was used for the electronic timers, which had a resolution of ±1 μsec. This system was capable of resolving 1% variations in tooth stiffness. The data-acquisition procedure included a technique for averaging ten consecutive deflection measurements for each of the 645 tooth-mesh combinations involved. A Fourier analysis was performed on the 645 data points from two axles, thereby giving some indication of the noise spectra that might be expected from the gear sets.
Frequency Conversion and Whirl Modes
Authors: Bonvallet Duane J.
Published: November 2005

Two interesting vibration phenomena, frequency conversion and whirl modes, occur frequently in practice and are discussed in this paper. The frequency-conversion phenomenon occurs when a rotating member, having a resonant mode within an exciting frequency range, is driven at its resonant frequency fn by excitation frequency fe = fn ± f, where f is the rotational speed in rev/sec. The “lift” in the vibration and noise, as viewed from a stationary reference frame, occurs at, say, fn + f, so that a search for a resonant mechanical system at this frequency is fruitless. A practical example of frequency conversion dealt with in the paper is an automotive fan excited by engine-firing frequency. The whirl-mode phenomenon may occur at the resonant flexural frequency or critical speed of a rotating shaft. This characteristic is a bending mode of the shaft as it rotates about the shaft static centerline. Whirl may occur either in the direction of rotation of the shaft itself or in the reverse direction (reverse whirl). Specific examples of whirl that are discussed are a fan that was causing shaft failure and a propeller shaft where whirl produced an objectionable noise.
Transducer for the Dynamic Measurement of Forces and Moments Produced at the Front Wheel of an Automobile
Authors: Edwards Sonny G.
Published: November 2005

This paper covers the development of a transducer for the measurement of three forces and two moments at the front-wheel spindle of an automobile. The transducer is capable of independent, continuous measurement of the vertical force, fore and aft force, lateral force, camber moment, and steer moment. A major problem was the reduction of crosstalk or interaction between channels. This problem was solved by unique mechanical design of the transducer strain-sensing beams and by the employment of sophisticated strain-gauge techniques. The transducer design is also unique in that it can be used in conjunction with any automobile, with any tire or suspension, over any roads, and under any driving conditions without modification of the vehicle geometry or wheel, tire, and suspension relationships. The instrument has been employed mainly for basic vibration studies in the frequency range below 20 cps, and has exbihited considerable merit toward use for basic investigation of road noise in the frequency range up to 300 cps.
Mathematical Model of the Uniform Beam for Linear Vibration Analysis
Authors: Staffeld S. E.
Published: November 2005

For a beam with uniformly distributed mass and stiffness, a linear mathematical model is derived that closely duplicates dynamic behavior through the two rigid-body modes and the first of two bending modes. The model has four terminals, transverse and angular displacement at each end, permitting it to be connected into assembly on a fixed-end basis. Eight degrees of freedom are used. It is shown that the response is superior to that obtained with the normal mode or lumped parameter approaches when a comparable number of degrees of freedom are used. Application of the results to a specific case involves only arithmetic operations.
Response of a Linear Oscillator to a Train of Forcing Functions
Authors: Harris Thomas A.
Published: November 2005

A noteworthy observation was made during an analog-computer investigation of the response of a vehicle suspension to a repetitive train of symmetrical forcing functions with differing time intervals between these impulses. It was found that a plot of the suspension displacement vs vehicle velocity of this single-degree-of-freedom system was dependent upon the direction of the vehicle velocity, i.e., the chronology of the train of the forcing functions. An inspection of the forcing function by the usual frequency analysis does not reflect this dependence on the chronology. This paper conveys the results of two analytical approaches to the problem of explaining the observation. For a linear system, the principle of superposition applies. The application of this principle in the frequency domain and in the time domain precipitates the characteristics of the forcing function on which the response is dependent.
Acoustic Scattering from Spheroidal Inhomogeneities
Authors: Knollman G. C.
Published: November 2005

An acoustic wave propagating under water experiences fluctuations in phase and amplitude attributable, in the main, to scattering from inhomogeneities arising from variations in the temperature field. Since “patches of thermal inhomogeneity” in the sea are generally regarded as lenticular in shape, it is the purpose of this paper to extend, for both plane and spherical sound waves, contemporary wavefluctuation theory to include the circumstance of spheroidal inhomogeneities. Mean-square amplitude and phase fluctuations are considered for acoustic waves propagating in a statistically uniform medium in which random deviations of the refractive index are small. Large-scale inhomogeneities of arbitrary spheroidal shape are treated, and the influence of transmitter-to-receiver range, acoustic wavelength, and “patch” dimensions on variations in waveamplitude and phase is derived for this general case. Particular attention is given the high-frequency ray limit (Bergmann region) and the low-frequency (Fraunhofer diffraction) region. The significant effects on wavefluctuations of nonspherical inhomogeneities are compared for plane and spherical acoustic waves. [This work was supported by the LMSC Independent Research Program.]
Scattering from the Volume of an Inhomogeneous Half-Space
Authors: Stockhausen J. H.
Published: November 2005

An expression is developed for the sound returned to a pulsed acoustic source in the ocean after first-order scattering in the volume of an inhomogeneous semiinfinite bottom. The material of the bottom is assumed to have uniform volume-scattering strength, proportional to f4, and to have an absorption coefficient proportional to fn. At low frequencies and for small source-bottom distances, the reverberation rises to a rounded peak and decays slowly. At higher frequencies and greater source-bottom distances, the reverberation peaks sharply and decays approximately as t−4, corresponding to an equivalent bottom-interface scattering strength proportional to the cosine of the angle of incidence.
Experimental Study of Acoustic Scattering from Solid, Elastic, Hemispherically Capped Cylinders
Authors: Goldsberry T. G. , Diercks K. J.
Published: November 2005

Experimental measurements are presented of backward and general scattering from the beam and end aspects of solid, aluminum, hemispherically capped cylinders in water. Cylinder lengths from 0 (two hemispheres only) to 10 in. (twice the target diameter) are considered. The ka range investigated is from 2 to 22. For the beam aspect, it is shown that, with regard to the backscattering (target strength) and general scattering patterns and echo-pulse forms, for even the shortest cylinders used (18 in.), the cylindrical portion of the target dominates in determining the targets' scattering behavior (which, with the exception of magnitude, parallels that of the cylinders alone). At the end aspect, for the backscattering case, the conclusions that one obtains are dependent upon the portion of the echoes that one observes. The echoes from all the targets display onsets characteristic of the hemispherical cap, and one could, using this portion of the echoes, arrive at target-strength functions characteristic of a sphere. Otherwise, there is a pronounced effect of cylinder length upon the functions and pulse forms obtained. The general-scattering patterns, as would be expected, exhibit changes consistent with the addition of increasingly long cylindrical sections. [This work was supported by the U. S. Office of Naval Research.]
Acoustic Field of Plane Piston
Authors: Williams A. O.
Published: November 2005

King's exact integral for the velocity potential φ of a plane piston [radius a, in an infinite rigid wall, imparting particle velocity v0 exp(−iωt) to a fluid] is φ(r,z) = v0a ∫ 0∞ exp[−(κ2 − k2)12z]J0(rκ)J1(aκ) (κ2 − k2)−12dκ; k is ω/c; r, z are cylindrical coordinates—z along beam axis. For 0 ⩽ κ ⩽ k, replace κ by (−ik cos θ); for k ⩽ κ ⩽ ∞, by (k cosh χ). A standard “multiplication theorem” extracts θ or χ from the argument of J. Integration yields a result expressible as a differential operator acting on a simple function. Reversing the multiplication theorem produces a rigorous formulation, seemingly new: φ(r,z) = (−iv0 ka2/2) Λ0(kr Γ) Λ1(ka Γ) [w−1 exp (−w)]. The modified Bessel functions Λ0(s) and Λ1(s) are, respectively, J0(s) and (2/s)J1(s); w is (−ikz), Γ2 the operator (1 − d2/dw2). These Bessel-function operators Λ0 and Λ1 commute and obey some of the familiar recursion rules. Various known approximations for φ are derivable. The Λ operators are themselves interesting: Λ0(kr Γ) converts the amplitude at (0,z) of a wave to its value at (r,z); Λ1(ka Γ) converts the amplitude at (r,z) of a spherical wave originating at (0,0) to the plane-piston value at (r,z). [Supported in part by U. S. Office of Naval Research.]
Measurements of the Second-Harmonic Component of a Plane, Finite-Amplitude Wave
Authors: Lester William W.
Published: November 2005

A method for the measurement of the second-harmonic component of a plane, finite-amplitude wave as a function of the distance has been devised that makes use of fixed-distance measurements in a two-transducer pulsed system. The fixed-distance method eliminates problems of transducer alignment and traversal. The technique is similar to a method previously used for obtaining the fundamental-frequency component as a function of the distance from fixed-distance measurements [J. Acoust. Soc. Am. 34, 1991(A) (1962)]. Measurements have been made in water at 5 mc/sec at distances up to 80 cm, and are compared with theory [J. Acoust. Soc. Am. 33, 1196 (1961)] over a range of the initial-value parameter αL. Optical methods are used to calibrate the sending transducer and to measure the harmonic content of a known wave, which allows one to calibrate a tuned receiving transducer. [This work was supported by the U. S. Office of Naval Research.]
Radiation from Subsonic Surface Waves
Authors: Cook Richard K. , Young Jessie M.
Published: November 2005

Gravity waves on the surface of water travel at subsonic speeds, but nonetheless can radiate sound power into the atmosphere. The radiation occurs when long trains of surface waves come to a stop, as, for example, on a beach. Computations of both the near and far sound-pressure fields in the atmosphere have been made for water waves approaching a beach under various conditions, including oblique incidence, the formation of standing waves, and gradual attenuation as they approach the beach. The radiation computations are compared with observations on microbarom sound waves at infrasonic frequencies in the Washington, D. C., area. These come mainly from the east, travel parallel to the earth's surface, and occasionally have sound pressures as great as 6 dyn/cm2, with predominant periods between 5 and 7 sec.
Approximate Ray Tracing in Inhomogeneous Media
Authors: Salenius Aimo
Published: November 2005

A method of approximate ray tracing is developed that can be applied to media that are inhomogeneous in two or three dimensions. The medium is subdivided into regions in each of which the velocity is approximated by a linear function of the space coordinates. The approximation results in a constant-velocity gradient in each region and a continuous velocity across the boundary between any two regions. A ray trace through the regions consists of a sequence of circular arcs that are tangent to one another at each boundary between regions. The technique may be applied to study the effects of inhomogeneity in more than one dimension in the construction of soundfield models, using geometric acoustics.
X-Ray Diffraction Topographs of Acoustic Modes in Rectangular AT Quartz Plates
Authors: Spencer W. J. , Frymoyer E. M. , Hunt R. M.
Published: November 2005

An x-ray-diffraction technique developed for the direct observation of defects in crystalline material has been used to study standing acoustic waves in rectangular and circular AT quartz plates [W. J. Spencer, Appl. Phys. Letters 2, 133 (1963)]. The lattice curvature associated with the elastic standing wave in the crystalline lattice produces an enhancement in the intensity of the diffracted x-rays. The transverse waves near the fundamental thickness shear mode of rectangular AT quartz plates have been observed as one dimension of the plate is reduced. The results generally correspond with the empirical results obtained earlier, with the exception of the anharmonic thickness shear modes. The phase reversals of these modes occur along the z′ axis rather than along the x axis, as had been previously assumed.
Auditory Memory
Authors: Julesz Bela , Guttman Newman
Published: November 2005

Memory for acoustic events was investigated by determining the duration threshold for three canonic patterns surrounding temporally by noise. The patterns were iterated and the computer-generated acoustic stimuli were f(t) = NN1NN2NN3 …, SN1SN2SN3 …, and GN1GN2GN3 …, where the N1 were segments of unrepeated random noise, N was an iterated segment from the same random process as Ni, S, and G were segments of sinusoid and gap (silence), respectively. The pattern recurred at intervals of T sec and had the duration d. One criterion of pattern-duration threshold was perception of periodicity; thresholds of N, S, and G were studied as a function of T. It was found that minimum perceptible durations dN, dS, and dG are a relatively constant percentage (less than 10%) of T for T−1 higher than about 10 cps. For lower T−1, dS and dG are less than 10 msec, whereas dN increases rapidly. These results suggest that above 10 cps detection of patterns in noise is independent of pattern shape; below 10 cps, it is not. Evidently and reasonably, in the low-frequency region, memory for N is far weaker than memory for S and G, and the obtained data for N provide a basis for estimating the extent of auditory memory for the least-distinguished pattern shapes.
Further Experiments on Learning to Identify Nonverbal Sounds
Authors: Swets John A. , Harris Judith R. , McElroy Linda S. , Rudloe Harry
Published: November 2005

Earlier experiments on computer-aided teaching of the identification of nonverbal sounds showed an extremely simple procedure to be more effective than the procedures of automated or programmed instruction. Specifically, a procedure in which the sound-label pairs are just presented and observed, in random order, was superior to procedures that employed various configurations of continual interrogation, overt response, immediate knowledge of results, presentation of items in a developmental order, and presentation of successive items conditional upon previous performance. Two additional experiments have now been conducted in which the subject was able to choose freely, at any time, among the various instructional procedures, and to regulate the introduction of new materials. Granting such control to the subject led to no better final performance than that observed when the experimenter determined the course of the lesson. The results provide detailed support of the earlier conclusions: for example, success was highly correlated with the proportion of time spent on simple exposure, and negatively correlated with the proportion of time spent in active responding, receiving feedback, and making second tries. Three variables related to streamlining of the task and temporal contiguity of sound and label account for nearly 100% of the variance. [This research was supported by the U. S. Naval Training Device Center.]
Effect of False Information on Responses in a Signal-Detection Task
Authors: Carterette E. C. , Friedman M. P. , Wyman M. J.
Published: November 2005

In a 2-alternative, temporal, forced-choice signal-detection task, observers received degrees of correct information as to the interval in which the signal had occurred. Groups π(100), π(75), and π(50) received correct feedback following every trial in the proportions 1.00, 0.75, and 0.50, respectively. Group π(0) received no information on any trial. 18 observers were run for 400 trials under each combination of 2 E/N0's and the 4 information conditions. Results were (a) detection rate was greatest for π(100) and π(0) within both E/N0's; but (b) rate of Group π(100)>π(0) for low E/N0 and π(0)>π(100) for high E/N0, in agreement with an earlier result obtained in a Yes-No experiment. Are S1EjAk states on trial n independent of S1EjAk states on trial n−1 (where i, j, k=1, 2 and Si=stimulus interval, Ej=experimenter feedback to observer, Ak=response of observer)? That is, are transition probabilities stationary? For both E/N0's: (1) all states for π(0) were stationary; (2) a single state (S2E2Ak) was nonstationary for π(100) groups; (3) half the states (all S2) were nonstationary for π(75); while (4) more than half of the states (S1 and S2 randomly) were stationary for the π(50) groups. (7) First-order sequential effects clearly were strongest under feedback. (8) Detection rates were higher and false-alarm rates lower on trials following EjAk agreements (i.e., j=k) than on disagreement trials (j≠k).
Primary Measures of Cochlear Pattern Shapes in Hearing
Authors: Stewart John L.
Published: November 2005

A sound results in a spatial pattern of vibratory activity along the basilar membrane of the inner ear. This activity is converted to neural form so as to give a relatively smooth spatial pattern that changes with time for a time-varying stimulus. A pattern of this kind may be produced on an electronic-analog ear. The question is: What set of measures for the space-time pattern of analog neural activity are important to the human for interpreting connected speech? A group of measures is proposed that may be ordered into a set whose members show decreasing importance. The most important single measure appears to be a gross localization of the pattern along the basilar membrane. Additional measures of importance are one giving total pattern intensity, and one that specifies pattern width. Primary significance of these measures is demonstrated in two ways: graphical recognition of speech sounds and use of measures for synthesis of speech having moderate intelligibility.
Mechanical Hysteresis
Authors: Benson Robert W.
Published: November 2005

Hysteresis loops have been obtained on metallic samples vibrated at large-strain amplitudes at rates of several kilocycles per second. The mechanical-hysteresis loop is of the form of an asymmetrical “figure 8” pattern. The cause of the asymmetry is discussed relative to transducer design and also its effect upon fatigue life. Related experiments have been performed that indicate the importance of lateral motions of transducing elements in determining loss characteristics of vibrating solids. The study has led to methods for the prediction of the onset of a marked increase in loss with strain amplitude and also the onset of a catastrophic increase in loss leading to failure by fatigue. [This work was conducted under sponsorship of the U. S. Office of Naval Research.]
Green's-Function Technique in the Dynamics of a Finite Cylindrical Shell
Authors: Cottis Milt G.
Published: November 2005

The Reissner linearized equations of motion, including hysteretic and viscous-type damping terms, are adopted in the study of the dynamics of a finite, thin, elastic, cylindrical shell of circular cross section. The integral representation of the displacement solution is obtained for an arbitrary, three-dimensional, time-dependent pressure field and the associated Green's-function solution is calculated; it is shown to be of identical form to the Green's function for other elastic systems. In particular, the shell response to a moving shock wave (step-function discontinuity), impinging upon the shell at an arbitrary angle of incidence, is calculated. In the special case of axial symmetry, two additional waveforms are considered, that of a moving exponentially decaying shock wave and a ramp step-function wave. Typical numerical results are given in the form of displacement time curves and the effects of the various parameters are discussed.
Speech Monitoring
Authors: Miller James D. , Hartman Carol V.
Published: November 2005

One aspect of speech monitoring is the prediction of the intelligibility of speech. In experiments, which were designed for the analysis of speech communication from deaf talkers to normally hearing listeners, three types of subjects made word-by-word intelligibility predictions during intelligibility tests. These subjects were the deaf talkers themselves, normally hearing listeners (judges) who knew which word was to be spoken, and normally hearing listeners (identifiers) who only knew the message set but not the particular word to be spoken. Such predictions were analyzed by using operating characteristics that yield a single measure (dr) of the accuracy of these predictions. Typical values of (dr) for large message sets (100 words) would be 0.3 for deaf talkers and 1.3 for hearing identifiers, while for normally hearing judges and very large message sets (all English monosyllabic words) a typical value of (dr) would be 0.9.
Identification and Discrimination of Rounded and Unrounded Vowels
Authors: Stevens K. N. , Öhman S. E. G. , Liberman A. M.
Published: November 2005

The aim of this experiment was to examine the identification and discrimination of a series of rounded and unrounded vowels by a group of listeners (Swedish) who were familiar with both types of vowels. The following groups of stimuli were assembled using the Stockholm OVE II speech synthesizer, and were arranged in the form of identification tests and ABX discrimination tests: (1) a series of thirteen vowels in which the first three formants varied in approximately equal logarithmic steps through three unrounded vowels (roughly /i/, /ɪ/, and /ɛ/); (2) a similar series in which the second and third formants varied in approximately equal logarithmic steps from the unrounded /i/ through the rounded /y/ to the rounded /u/; and (3) a series of thirteen vowels constructed by taking /i/ as a center and then including the first six steps along the unrounded continuum and the first six steps along the rounded continuum. The discrimination functions showed small peaks near the phoneme boundaries; i.e., discrimination between adjacent stimuli on the vowel continuum was better when the stimuli were near phoneme boundaries. Discrimination was at least as good for the rounded series as for the unrounded series, and seemed to be especially sharp in the region where rounding first became apparent.
Intelligibility of Frequency-Shifted Speech
Authors: Darnall W. H. , Birch J. N.
Published: November 2005

An electronic system has been developed that allows a speech spectrum, initially confined to a band of frequencies from 300 to 3300 cps, to be deviated from its normal spectral location. The perturbation is sinusoidal in nature and controls both the amount of deviation and the rate of deviation of the spectrum about its normal position. This system, in conjunction with an appropriate psycho-acoustical test, provides a functional relationship between intelligibility and the independent variables, deviation and rate of deviation.
Physical Basis of Woodwind-Recorder Voicing
Authors: Elder Samuel A.
Published: November 2005

Ease of playing, loudness, and clarity of tone of a woodwind recorder are determined by the manufacturer's skill in the art of “voicing.” Recent advances in edgetone theory have now made it possible to approach the voicing problem from the point of view of the underlying physical mechanisms involved. When edgetone modes and pipe-resonance modes are simultaneously plotted in terms of the Strouhal number S=fh/U0 and Reynolds number Re=U0h/ν, where U0 is orifice velocity, h is lip height, ν is kinematic viscosity, and f is frequency, a universal-mode diagram results that relates recorders of all sizes and makes. Well-known pecularities with respect to the playing of certain notes on the recorder can be accounted for by reference to the mode diagram. When correctly played, all notes of the recorder scale are driven by the first edgetone mode. Scaling laws for large and small instruments, loudness and clarity considerations are also found to be affected by the requirements of the mode relationships. In addition to giving a fresh insight into the basic physical limitations that guided the evolution of the historical instrument, the theory provides a frame of reference from which to explore new design concepts.
System for Measuring the Effective Length of Wind Instruments or Portions of Instruments
Authors: Kent Earle L.
Published: November 2005

In musical-instrument design, it is desirable to be able to accurately determine the resonance frequencies of an instrument. These measurements are expressed in terms of the length of a cylinder that will resonate at the same frequency. Portions of an instrument can be measured, as well as complete instruments. The system reported upon here is a refinement of a system reported upon earlier by John Webster. It produces accurate measurements that correlate well with the average results obtained when musicians play the instruments. It is especially helpful where subjective evaluations for research, design, and production purposes are confusing and time consuming.
Comparison of a Mathematically Derived Effective Length of a Cornet Bell with Experimental Data
Authors: Kent Earle L.
Published: November 2005

In working with the intonation aspects of wind instruments, it is convenient to use the term “effective length.” The effective length is said to be the length of cylinder that will resonate at the same frequency as the instrument or the portion of the instrument under consideration. The mathematical treatment of the effective lengths of the shapes used in wind instruments becomes quite involved. Simplifications are often made to make the mathematics less cumbersome, but these factors may not be negligible in music where a 1% change in frequency is 17% of a half-step in the equally tempered scale. Mathematically neat horn shapes do not seem to be useful in simple form in practical wind-instrument design, and it is difficult to correlate mathematical predictions with the practical results obtained when a musician plays the instrument. This paper gives the results obtained in a mathematical and experimental study of a particular cornet bell that is successful in practice.
Analysis of the Resonance Patterns Obtained with Mouthpieces of Varying Dimensions
Authors: Hall Jody C.
Published: November 2005

It is agreed by nearly all musicians who play cup-mouthpiece instruments that a mouthpiece can greatly change the playing characteristics of an instrument. Measurements made with an electronic-response apparatus show that musicians' judgments correlate with measured resonance curves. The resonance patterns not only differentiate between mouthpieces, but also provide a measure of the effect of the size of the cup, the orifice, and the backbore.
Implosions as Sources of Underwater Sound
Authors: Urick R. J.
Published: November 2005

When a gas-filled cavity suddenly implodes under hydrostatic pressure, a series of short transient pulses is generated by the collapse and subsequent oscillation of the cavity. Such “bubble pulses” are well-known in connection with explosions in water. They are also generated by the fracture and collapse under pressure of rigid air-filled containers. In experimental work at sea, weighted ordinary glass bottles of various sizes between four fluid ounces and one gallon were dropped from a surface vessel, and the sound of the implosion was recorded by a shallow hydrophone. Recordings were also made in a large pressure chamber in the laboratory. Peak pressures, pulsation times, and energy spectra have been determined, and estimates made of the maximum listening range against ambient sea noise. Implosions of this kind have uses as safe, inexpensive, and portable sources of underwater sound.
Representation of Acoustical Space-Time Signals
Authors: Parvulescu Antares
Published: November 2005

An acoustic field is fully described if it is specified at all points and at all times within a specified space. Such a situation may exist in some careful laboratory experiments, if the properties of the space are all known and if all sources of sound are under our control. The above case is theoretically trivial; the case of interest arises when the field is imperfectly known and we wish to arrive at an estimate of the “real” field. The function of four variables describing the field can be called a four-dimensional signal that we wish to “receive” with an imperfect receiver: there are certain advantages to the analogy with the theory of communication. The signal may be known only within a sub-space of the total four-dimensional space, be it a small geometric region, a short time interval, or a combination of such bounds; or it may be known only at a finite or denumerable collection of four-dimensional points—i.e., it is a sampled signal. Sources of unknown positions and waveforms usually exist outside the “receiving region,” and the properties of the medium and its boundaries are usually known as sampled data. The estimation of signal parameters at the inaccessible points involves an extrapolation; we discuss here several ways to do this, and their deficiencies. We reach the conclusion that the problem cannot have a unique solution, but that the use of representations for the signal that are orthogonal in four dimensions is at least necessary to prevent gross divergence in our estimate. We finally discuss the problem when the sources, medium, or boundaries are in unspecified motion.
Extraction of Linearly Ranging Signals with a Scanning Correlator
Authors: Tack D. H. , Ziemer R. E. , Lambert R. F.
Published: November 2005

When a correlation receiver is used to extract signals emanating from moving sources from additive noise backgrounds, a time-varying correlation function results. An extension of the analysis of Davenport, Johnson, and Middleton [J. Appl. Phys. 23, 377–388 (1952)] for correlators with fixed delay and finite averaging time is made to the case of linearly time-varying delays to enable the calculation of the mean and variance of the output as a function of observation time. It is shown, in the case of a scanning correlator, that proper choice of the scan rate k minimizes the error in the extraction of the correlation function of the ranging signal. Some experimental measurements of the output mean of a scanning correlator are presented and compared with theoretical results. The output variance of the correlator also is discussed. In the case of coherent extraction, the variance can be shown to be of the form of the product of the variances of the input noise and signal divided by a Nyquist sample size. This Nyquist sample size is given by 2WSN Ta, where WSN is the noise-equivalent bandwidth of the spectrum formed by the convolution of the signal and noise spectra and Ta is an equivalent integration time of the averaging filter. [This research was supported by grants from the National Science Foundation.]
Acoustic Transponder Buoy for the Atlantic Missile Range Shipborne Navigation System
Authors: Jackson Donald E.
Published: November 2005

An ocean-bottom-mounted acoustic transponder was developed to provide earth-referenced navigational data for the ARIS tracking ships. This paper develops the basic sonar-operating requirements for the system and briefly describes the resulting instrumentation.
Underwater Acoustic Tank Facility for Nearfield Measurements
Authors: Lubell Alan H.
Published: November 2005

This paper describes a large tank facility that has been in operation since the first of the year at the Fullerton site of the Hughes Aircraft Company. This facility was designed primarily for making nearfield measurements of large underwater acoustic radiators. (The 30-ft-diam by 20-in.-high redwood tank is completely enclosed in a corrugated-metal building.) Unique features and capabilities of this installation are described. These include provisions for the reduction of both airborne and ground-transmitted acoustic noise; a truck entry from which large transducers can be lifted directly to the tank top level; a movable bridge for mounting transducer fixtures that may be positioned anywhere above the water surface or rolled clear of the tank for special test purposes; a complete complement of electronic instruments, including a Hughes-designed pulsing and gating unit, for making precise measurements of pressure amplitude and phase. Acknowledgment is made of the helpful and continuing encouragement and advice of Dr. Elias Klein of the Defense Research Laboratory, Austin, Texas.
Rectified Diffusion during Nonlinear Pulsations of Cavitation Bubbles
Authors: Eller Anthony , Flynn H. G.
Published: November 2005

A gas-filled bubble in a liquid will generally dissolve because of diffusion of gas out of the bubble into the surrounding liquid. However, when set into motion by an acoustic field, a bubble may grow by a process called rectified diffusion. This process can counteract the effect of diffusion for values of the acoustic-pressure amplitude greater than some threshold value. This threshold has been determined by a theory that uses computed radius-time curves for bubbles pulsating nonlinearly rather than assumed infinitesimal, sinusoidal motions. For radius-time curves calculated by a digital computer, this threshold has been computed for a sequence of values of gas concentration, bubble radius, and acoustic frequency. [This work was supported by the U. S. Office of Naval Research (Code 468).]
Evaluation of a New Artificial Mastoid as an Instrument for the Calibration of Audiometer Bone-Conduction Systems
Authors: Olsen Wayne O. , Sanders Jay W.
Published: November 2005

A basic problem in obtaining dependable bone-conduction thresholds in pure-tone audiometry has been the attainment of an objective measure of the vibrational output of the system. In the past, several different artificial-mastoid designs have been reported, but none has proved entirely satisfactory as a standard calibration instrument, largely because of the problems involved in devising a stable and reproducible method of terminating the bone vibrator with a mechanical impedance that simulates that of the average human mastoid. In the present study, a new artificial mastoid, Beltone model 4, was analyzed for stability of response and for its potential use as a calibration instrument. Two bone vibrators were used for repeated measurements over a period of time to establish the reliability and linearity of the measuring instrument. Normative data were then derived from a suitable sample of normal-hearing subjects for one of the vibrators. These data were then transferred to other vibrators of the same type via the artificial mastoid, and bone-conduction thresholds were measured for the criterion sample of normal-hearing subjects and for subjects with sensorineural hearing impairments. Results suggest that the new artificial mastoid has good stability and that it shows excellent promise as an instrument for the calibration of bone-conduction audiometers.
Estimates of Auditory-Frequency-Response Limits as a Function of Mammalian Ossicular Density
Authors: Parnell John E.
Published: November 2005

An apparent rank-order relationship between the density of mammalian ossicular components and the upper-frequency-response limit for the mammal in question has been observed. Measurements of ossicular density showed Hominidaen and Cetacean (Odontocete) specimens to represent the lowest and highest values, respectively, for mammals included in this investigation. The best available estimates of upper-frequency-response limits also place Hominidae and Cetacea (Odontocete) as extremes for upper-frequency threshold measures. Density determinations performed on other mammalian orders continued to approximate this density-frequency-response relationship. Density measurements could not be performed on ossicular specimens from small mammals, using conventional methods. A “flotation” technique was developed for obtaining density values for specimens weighing as little as 0.0004 g (Cavia spp.), providing accuracy within 0.2%. Two applications for the data from this type of investigation are apparent. First, this would conceivably provide an index for taxonomic classification of mammalia according to auditory capacity. Second, the technique for making accurate density determinations on ossicular specimens provides a precise value for computations based on mathematical models of middle-ear function.
Vowel Discrimination by Cats: Acquisition and Disruption
Authors: Dewson James H.
Published: November 2005

Five cats have been trained in a three-lever operant situation that allows differential response to three auditory stimuli. The animals were initially taught to discriminate among pure tones that were varied in frequency and/or intensity (approximately 2000 trials). Next, the vowels [u], [i], and [a] were delivered at equal fundamental frequency and over-all intensity until stable discrimination performances were attained (approximately 3000 trials). Transfer took place rapidly (less than 50 trials) between vowels spoken by male and female speakers. Following bilateral removal of the ventral insular and temporal cortex, the cats failed to discriminate the vowel sounds and relearning was not achieved in 10 000 trials, despite complete retention of the pure-tone discrimination problems. Insular and temporal cortex is thus found important in mediating the spectral, as well as the sequential, complexities of auditory signals.
Influence of Irregular Patterns in the Inharmonicity of Piano-Tone Partials upon Tuning Practice
Authors: Kent Earle L.
Published: November 2005

It has been shown that it is characteristic of piano tones to have partials that are slightly higher in frequency than harmonics would be. The departure from a harmonic relationship is termed inharmonicity of the partials. It has been shown also that the inharmonic relationships of the partials influence the tuning of the octaves of the piano. The result is a departure from the equally tempered scale with the treble strings tuned sharp and the bass strings tuned flat. The octaves are thus stretched from the true-octave relationship. This paper discusses the influence of the string-to-string patterns of inharmonicity upon piano tuning within the octave. It is the goal of the piano tuner to tune each string so as to produce smoothly increasing progressions of beat rates between two tones in a given musical interval as the tones move up the scale. This goal can be achieved in practice if the partial-inharmonicity pattern is essentially the same for each string or if there is a smooth change in the pattern from one string group to the next. The departure from “ideal,” especially in spinets, is discussed and demonstrated.
Dispersive Properties of Sound Propagation in Gases
Authors: Maidanik Gideon , Fox Herbert L. , Heckl Manfred A.
Published: November 2005

A model of sound propagation in gases is proposed that attempts to explain the mechanism that controls the dispersive properties of sound propagation. The model is based on the concept that loss of coherence is related to “phase mixing” that occurs during the free molecular flight between collisions. We present some representative experimental data of the dispersion of sound in a gas where molecular-surface interactions dominate the molecular collisions. The data are explained by using the proposed model. It is suggested that the model may also explain the dispersive properties of sound in gases where intermolecular collisions dominate. [This research has been supported by the U. S. Office of Naval Research.]
Ultrasonic Absorption in Single Crystals of p-dichlorbenzene and naphthalene
Authors: Yun Seung-Soo , Beyer Robert T.
Published: November 2005

Acoustic absorption in p-dichlorbenzene and naphthalene single crystals was measured from room temperature to −70°C in the frequency range 5–95 MHz. A frequency-squared dependence of the absorption values was observed in both crystals, and comparisons are given with the values calculated by the resonance absorption theory suggested by Liebermann [Phys. Rev. 113, 1052 (1959)] for a benzene single crystal. The temperature dependence of the absorption coefficient α is similar in the two crystals, with α decreasing slightly as the temperature increases above −40°. This dependence is similar to that observed by Rasmussen for a cyclohexane single crystal [SIO Ref. 61-1, Scripps Inst. Oceanog. Marine Physical Lab. (April 1961)]. The value of α measured in the two cases was about two orders of magnitude smaller than those obtained by Liebermann and Rasmussen, and was approximately the same size as those observed for some metal single crystals at room temperature. However, other absorption processes, such as thermal conduction and dislocation damping, were ruled out as possible sources of the attenuation by experimental tests. [Supported by U. S. Office of Naval Research.]
Backward Wavetransmission of Stress Pulses in Elastic Cylinders and Plates
Authors: Meitzler Allen H.
Published: November 2005

The propagation characteristics of longitudinal modes are described by the Pochhammer frequency equation, in the case of elastic cylinders, and the Rayleigh-Lamb frequency equation, in the case of elastic plates. The longitudinal modes in both geometries are closely analogous. In both cases, the second branch of the mode spectrum determined by the roots of the applicable frequency equation shows a region in which phase and group velocities have opposite signs. Wavemotions having phase and group velocities of opposite sign occur in certain guided, electromagnetic wavemotions and are often referred to as backward wavemotions. This paper reports experimental observations of stress pulses traveling in backward, elastic wavemotions in cylinders and plates. Also included in the paper is a detailed description of how the distribution of the energy-flux density changes as the wavemotion corresponding to the second branch of roots goes from the region of forward wavemotion to the region of backward wavemotion.