bluuebunny/crossref_metadata_2025 huggingface dataset:
Viscothermal theory for sound wave propagation in a multicomponent reactive mixture of nondiffusive fluids
Authors: Marguiles T. , Schwarz W. H.
Published: October 2005

A formal theoretical analysis has been made for the attenuation and dispersion of a forced, plane, small-amplitude sound (compressional) wave in a multicomponent reactive mixture of nondiffusive fluids according to the linearized equations of classical hydrodynamics including dissipative transport processes. The treatment considers the general class of reaction mechanisms represented by an arbitrary number of independent, elementary reaction steps of any order. The result is a complex, biquadratic characteristic equation for the propagation variable (x/k0). This is a modified form of the Kirchoff-Langevin equation applicable to reacting systems. The theory is complete to the same extent as the classical viscothermal theory for a single component fluid [Truesdell, J. Rat. Mech. Anal. 2, 643 (1953)]. It is shown that special cases and approximations of this analysis are in agreement with the work of other investigators and that the classical viscothermal and chemical contributions to the absorption and dispersion are additive only to first order. [Acknowledgment is made to the donors of the Petroleum Research Fund, administered by the American Chemical Society, for support of this research.]
Acoustic diffraction: Malyuzhinets, Sommerfeld, and Kirchoff
Authors: Skudrzyk E. J.
Published: October 2005

The plane Kirchoff diffractor is ideally absorbent, and the diffraction phenomenon depends only on the shadow boundary. The Kirchoff theory can be generalized for reflecting and partially reflecting diffractors. A comparison of the results with the Sommerfeld theory then is very instructive. Malyuzhinets generalized the Sommerfeld theory for impedance and elastic Wedging by using powerful new methods of analysis. The diffraction at an ideally absorbent (impedance matched) semi-infinite plane then leads to a solution that differs from the Kirchoff solution only in the proximity of the plane and differs also from it by a small scattering term that is practically angle independent. The Malyuzhinets theory uncovers very interesting and hitherto unknown features of the diffraction that is connected with absorbent or partially absorbent surfaces. [Supported by the Naval Ordnance Systems Command.]
Comparison of remote extracochlear versus intracochlear recordings in guinea pig
Authors: Durrant John D.
Published: October 2005

Current techniques in human electrocochleography often rely upon recordings at sites quite remote from the origins of the recorded responses. There is presently little detailed information concerning the extent to which the appearance of the cochlear electrical responses are altered by volume conduction to remote sites such as the ear canal. A comparative study was made of the whole-nerve action potential (AP) recorded from a wire electrode placed on the eardrum (TM) in the guinea pig [analogous to the technique used in humans by Cullen et al., Acta-Otolaryngal. 74, 15–22 (1972)] and an intracochlear electrode placed in scala tympani of the first turn (ST1). For purposes of comparison, an additional electrode was often placed in scala tympani of the third turn (ST3). Cochlear microphonics (CM) and summating potentials (SP) were also studied. It was consistently observed that in the TM recording the N2 of the AP is proportionally larger in relation to the N1 magnitude than in the ST1 recording. However, N2 was proportionally less in the ST3 recording. The expected decreased sensitivity at the TM site was observed in all responses, typically on the order of 40 dB. While the TM-recorded CM and SP behaved similar to the ST1-recorded responses, the former did not mimick the latter in every respect. Thus, significant volume conduction effects are operant in remote extracochlear recordings. For the AP significant volume conduction effects appear even within the small dimensions of the cochlea.
Morphological changes in the ears of noise-exposed parakeets
Authors: Bohne Barbara A. , Dooling Robert J.
Published: October 2005

Parakeets exposed to 13-octave bands of noise for 12 or more hours sustain asymptotic threshold shifts (Dooling and Saunders). The ears of three parakeets from the Dooling and Saunders study were prepared for phase-contrast microscopic examination as embedded whole mounts after final audiograms had been obtained. Findings in these ears were then compared to ears of other parakeets exposed for 12 hours to a 13-octave band of noise centered at 2 kHz with a sound pressure level of 76, 86, or 106 dB. The ears of half the parakeets were prepared for microscopic examination 30 minutes following exposure, while the rest were prepared after the birds had recovered from their ATS. Preliminary findings in parakeet ears with ATS include: no sensory cell loss, no tectorial membrane displacement, no reticular lamina breakage, and no abnormalities in the stereocilia. In addition, the cytoplasm of some tall hair cells bulged from the surface of the basilar papilla, thus separating nerve endings from the hair cell bases. This latter feature was not present in parakeet ears which had recovered from ATS.
Selective lesioning of the guinea pig organ of Corti with the use of high-frequency current
Authors: Ferraro John A. , Dallos Peter
Published: October 2005

When experimenting with the electrophysiology of the inner ear there often arises a need, for a variety of reasons, to selectively destroy certain components, or portions of the organ of Corti. Common methods of creating cochlear lesions are the use of ototoxic drugs, such as kanamycin, and exposure to intense sounds for prolonged periods of time. A procedure developed in our laboratory for selective destruction involves the use of high-frequency current (1–3 mA) at approximately 5 MHz) that is passed, for a controlled amount of time, between two electrodes located in the scalae vestibuli and tympani of a particular cochlear turn. A localized region of destruction of elements of the cochlear partition located between the electrode tips, progressing from outer to inner hair cells and to supporting structures, results. Electrophysiological and corresponding histological data from the first, second, and third turns of the guinea pig cochlea are presented and discussed.
Vibration patterns of excised larynxes
Authors: Baer Thomas
Published: October 2005

Excised dog larynxes are used to simulate normal steady phonation. The frontal-plane trajectories of small particles on the vocal folds are measured using microscopic observation from the supraglottal and subglottal aspects under stroboscopic illumination, as previously described [J. Acoust. Soc. Am. 54, 318(A) (1973)]. Measurements have been made for three particles at eight uniform phase increments throughout a glottal cycle. These data, along with qualitative observations, are used to construct sketches representing the instantaneous frontal sections at the eight phase increments. The sketches show a wave propagating up the medial surface onto the superior surface, leading to a “vertical phase difference.” A particle near the edge may be on the superior surface at one phase and on the medial (or inferior) surface at a subsequent phase in the cycle. A movie showing vibrations of a preparation itself and an animation of the frontal sections will be shown. The frontal sections, along with other measurements (such as subglottal pressure, glottal volume velocity, and mechanical properties of the tissues), provide data to test and evaluate laryngeal models or guide the development of improved models. [This work was supported by NIH grants.]
Electromyographic study of velar movements during speech
Authors: Ushijima atsujiro , Hirose Hajime
Published: October 2005

Electromyographic recording of the levator palatini was performed to investigate the relationship between velar movements and the motor command. Two Japanese subjects read a list of meaningful disyllabic test words. There was no systematic difference in EMG level between either voiced and voiceless or stop and fricative consonants. Rather, the activity level for a certain non-nasal consonant appeared to vary according to the phonetic environment. Our EMG data seemed to be consistent with our previous fiberoptic findings on the difference in the degree of nasalization between syllable-initial and syllable-final nasals [Ushijima and Sawashima, Annual Bull. RILP Univ. Tokyo 6, 25 (1972)]. Electromyographically, the right-to-left effect of nasalization followed the so-called look-ahead mechanism, although in some examples there seemed to be a restriction of anticipatory coarticulation effect. On the other hand, the left-to-right effect manifested itself as increasing levator activity for postnasal vowel segments. The findings suggest that there exists a different mechanism between the right-to-left and left-to-right effects of coarticulation at the level of motor command. [Supported by NIDR Grant DE-1774.]
Time-domain acoustic characteristics of allophones and phonological phenomena
Authors: Baker Janet M.
Published: October 2005

Time-domain up-crossing analysis is useful for deriving acoustic characteristics of certain allophones as well as acoustical correlates of certain phonological phenomena. Parameters used singly and in combination in this analysis include, among others, measures of the period of each cycle, amplitude, and the microstructure of each cycle in the waveform. Allophones of the fricatives and stop consonants have been extensively studied using this technique. Since the phones of connected speech often occur in reduced form, time-domain methods are especially appropriate for both detecting and characterizing these transients.
Influence of pitch on formant frequencies and bandwidths obtained by linear prediction analysis
Authors: Atal B. S.
Published: October 2005

As is well known, the predictor coefficients are obtained by minimizing the mean-squared prediction error over a speech segment typically 10 to 20 msec long. For periodic signals, such as voiced speech, the prediction error is large at least once during a pitch period. It is shown that the inclusion of speech samples with large prediction error in the analysis interval introduces errors in the predictor coefficients and in the formant frequencies and bandwidths derived from them. However, these errors are small if the vocal-tract resonances die out effectively within a pitch period. This is often not the case, particularly for the first formant. The errors can be significantly reduced by either confining the analysis to the closed-glottis part of the pitch period or by eliminating those samples from the analysis which have large prediction error. Methods for determining predictor parameters accurately from the autocorrelation function of a periodic signal are also presented.
Residual excited linear predictive coder
Authors: Magill D. T. , Un C. K.
Published: October 2005

We describe a linear predictive vocoder excited by the speech residual with the transmission bit rate below 8k bits/sec. The features of the residual excited linear predictive (RELP) vocoder system are as follows: (1) no pitch extraction is needed; (2) the bit rate is relatively low; and (3) the system is simple for hardware implementation. The RELP vocoder combines all the attractive concepts of linear predictive coding (LPC), voice excited vocoder (VEV), and adaptive delta modulation (ADM); that is, the system employs LPC for a better spectral representation of the vocal tract, the concept of VEV for bandwidth compression of excitation signal, and ADM for its simplicity of implementation and ability of accurate coding of a low-frequency signal. The LPC residual is generated by a feed-forward LPC analyzer, is low-pass filtered at cutoff frequency 800 Hz, and then is coded by ADM. At the synthesizer the decoded residual is passed through a spectral flattener and its output is finally fed as an excitation signal to the LPC synthesizer to obtain synthesized speech. The quality of synthesized speech is, in our opinion, reasonably good compared with those of other vocoders with the same bit rate. [The study was supported by the Defense Communications Agency.]
Experimental comparison of stationary and nonstationary formulations of linear prediction applied to voiced speech analysis
Authors: Lin Wen C. , Chandra Satish
Published: October 2005

There are basically two formulations of linear prediction: (1) stationary, and (2) nonstationary. This paper presents the theoretical differences between the two formulations and gives the results of experimental comparison of the two formulations when applied to voiced speech analysis. In this experimental study three criteria are used for comparison purposes: (1) total minimum normalized squared error (η) [Makhoul, “Spectral Analysis of Speech by Linear Prediction,” IEEE Trans. Audio Electroacoust. (June 1973)], (2) accuracy in estimating speech spectrum, and (3) accuracy in estimating formant parameters. This paper presents the results of linear prediction pitch synchronous as well as pitch asynchronous analysis of synthetic and natural speech. Influence of analysis segment size and its position on the estimated formant parameters and η have been investigated. Nonstationary formulation performs better in case of pitch synchronous analysis than pitch asynchronous analysis. We have found that, for pitch synchronous analysis, nonstationarity is a better assumption than stationarity, but for pitch asynchronous analysis and large analysis segment size (20–25 msec) the performance of both formulations in representing the speech waveform is practically the same.
Edge-mode radiation from fluid-loaded semi-infinite membranes
Authors: Davies Huw G.
Published: October 2005

The vibrational response of and the associated acoustic radiation from a semi-infinite membrane in contact with a compressible fluid is considered. The plane of the membrane is extended by a rigid baffle. A pressure field with sinusoidal time and space dependence acts on the membrane. The pressure field is such that far from the edge of the membrane only acoustically slow waves are excited. The acoustic radiation into the fluid thus is generated in the vicinity of the edge of the membrane. A closed-form solution is obtained by using the Wiener-Hopf technique. The effect of arbitrary fluid loading on the membrane response and on the acoustic farfield is evaluated. It is shown that the usual edge-mode approximation of neglecting fluid-loading in determining the membrane response and subsequently estimating the radiation is a reasonable one even for quite high fluid loading.
Scattering of sound from layered elastic spheres
Authors: Flax Lawrence , Davis Charles M.
Published: October 2005

The scattering of plane waves by a layered elastic sphere is investigated theoretically. The sphere is composed of a solid core surrounded by a shell of different material. The composite sphere is immersed in water. Both the core and shell are composed of isotropic linearly elastic material. The form function is calculated for a nondimensional frequency range as a function of the thickness of the shell and the elastic constant of the material. Comparative analysis of the resulting form function suggests that the ratio of the shear modulus of the shell to that of the core is of significant importance.
Reflection from an absorbing sphere—theory and experiment
Authors: Vogt Richard H. , Flax Lawrence , Dragonette Louis R. , Neubauer Werner G.
Published: October 2005

Measurements of the monostatically reflected pressure vs ka, for lucite spheres in water, were found to differ greatly from elastic theory based on classical harmonic wave series analysis. Excellent agreement, between this theory and experiment, was previously found and presented for metal spheres in water. These previous elastic calculations had not included the absorption of shear and compressional waves in the material. Calculations, which include the effects of absorption as well as elastic properties, have been made for lucite spheres and good agreement between theory and experiment was obtained.
Scattering of a plane wave by spheres with nonuniform surface impedance distribution
Authors: Brungart D. L. , Oestreicher H. L.
Published: October 2005

A general mathematical solution of this problem involving the solution of an infinite set of equations in infinitely many unknowns by a truncated approximation was developed for computing sound pressure distributions in the near- and far-field regions around a sphere with an arbitrary, nonuniform surface impedance distribution in the presence of a plane acoustic wave. The solution procedure, which is easily programmed for a digital computer, is shown to be convergent in the general case for restricted values of ka (the product of wavenumber and sphere radius) and for all ka values for cases in which the impedance distribution is symmetric about the normal of the plane wave, as well as for some specific non-symmetric cases. Numerical solutions were computed for several symmetric cases and one nonsymmetric case consisting of a wave approaching a sphere with one rigid hemisphere and one kapok-covered hemisphere. Experimental data obtained using wood and kapok models in an anechoic chamber are in good agreement with theoretical computations.
Evidence for mechanical origin of peripheral inhibition in the anuran inner ear
Authors: Capranica R. R. , Moffat A. J. M.
Published: October 2005

The auditory fibers in the eighth nerve of the American toad (Bufo americanus) that have their best excitatory frequencies in the range 100–600 Hz can be totally inhibited by the addition of a second tone of appropriate frequency and intensity. Each of these fibers can also be excited by a pair of tones if their frequency difference is approximately equal to the unit's best excitatory frequency, even though neither tone by itself has any excitatory effect on the unit. The intensities of the two “difference tones” in many cases need only be 10–20 dB greater than the intensity of the best excitatory tone to evoke comparable spike rates. The excitation of these low-frequency fibers by difference tones seems to reside in nonlinear mechanical events in the inner ear. Midfrequency-sensitive units, having their best frequencies in the range 500–1000 Hz, and the high-frequency-sensitive units, with their best frequencies in the range 1100–1700 Hz, cannot be inhibited by tones nor can they be excited by pairs of difference tones. Similar results in other anuran species provide evidence that inhibition in the peripheral auditory system of frogs and toads is of mechanical origin. [Supported by NSF Grant GB-18836 and NIH Grant NS-09244.]
Role of the caudal medial geniculate nucleus and its cortical projection in the discrimination of temporally organized visual and auditory patterns
Authors: Wegener J. G.
Published: October 2005

Four monkeys were used to study the retrograde degeneration of the caudal portion of the medial geniculate nucleus resulting from ablation of the cortex of the supratemporal plane anterior to the primary auditory cortex. Four additional monkeys were trained to perform auditory frequency and temporal pattern discriminations prior to bilateral ablation of the cortex of the anterior supratemporal plane. Three more monkeys were trained to perform both visual and auditory pattern discriminations prior to ablation of the anterior supratemporal plane cortex. The results indicate that the anterior supratemporal plane cortex gets its primary neural input from the caudal 20%–25% of the parvocellular division of the medial geniculate nucleus. Bilateral ablation of the anterior supratemporal plane cortex results in severe initial deficits in the performance of both visual and auditory pattern discriminations, but not in the performance of auditory frequency or visual color discriminations. All monkeys reacquired the ability to perform the preoperatively learned visual and auditory pattern discriminations. The visual pattern discrimination performance was reacquired more rapidly than the auditory discrimination. These findings require the modification of the current interpretation of the role of these structures in discrimination behavior. [Supported by PHS NS 06587.]
Orderly representation of the cochlea within primary auditory cortex in the cat
Authors: Merzenich M. M. , Knight P. L. , Roth G. L.
Published: October 2005

Microelectrode mapping experiments have been conducted in the auditory cortex of 21 cats, using conventional microelectrode recording and sound stimulation techniques. Cats were anesthetized with urethane or ketamine. Best frequencies (frequencies with lowest response thresholds) were determined for neuron clusters isolated within a large number of penetrations from individual cats. Among the results were the following: (1) Best frequency was remarkably constant within penetrations directed normal to the cortical surface in the primary field (AI). The range of best frequency was less then 0.1 octave in 95% of 169 vertical penetrations into AI in which best frequency was determined at each of several depths within individual penetrations; it did not exceed 0.3 octave in any of these penetrations. (2) There is a highly ordered representation of the cochlea within the primary field. (3) Any given frequency band or any given sector of the basilar partition is represented by a band or strip of cortex that crosses the primary field. These frequency-band strips are oriented dorsoventrally, approximately parallel to the ectosylvian sulci. (4) There is evidence of a columnar organization of AI expressed in the fine detail of its frequency organization. (5) The relation of the primary field to the cortical surface landmarks was highly variable. The location of AI cannot be defined on the basis of surface landmarks alone. (6) Auditory responses were seen within the belt of cortex surrounding the primary field. There is an orderly representation of the cochlea within a field rostral to AI. (7) In individual animals, the cytoarchitectonic boundaries of AI appear to coincide with physiologically defined boundaries. [Supported by NIH Grant NS 10414.]
Some speech and auditory discrimination measurements in poor-reading children
Authors: Lenhardt M. L.
Published: October 2005

It has been suggested that children who are unable to make simple and complex auditory discriminations or who are unable to perceive phoneme blending in words will have difficulty in phonics reading programs [NINDS Mongr. No. 9 (1969)]. Forty normal-hearing reading-impaired children with normal SRTs were given phonetically balanced words monaurally at 60 dB HL. Words were next presented to one ear at 10 dB SL and to the other at 40 dB SL. The later was altered so that all energy above 1.5 kHz was effectively attenuated. Intelligibility was determined for temporarily distorted speech (as in words “sounded out” and words with one or more missing phonemes.) JNDs for pitch and loudness were obtained with a reference tone of 1 kHz at 60 dB HL. The perception of binaural beats at 0.5 kHz was also noted. It was observed that reading-impaired children yielded normal speech discrimination scores but typically poor binaural scores. Difficulty in perceiving the temporarily altered and/or phonetically deleted speech was also significant for the poor readers. Pitch, intensity, and beat perception were found to be unimpaired. Errors found in listening were primarily restricted to the consonants, while errors in oral reading tended to be chiefly vowels. That is, vowels were usually heard correctly but read incorrectly. Types of errors and relation to orthography are discussed.
Prompted intelligibility of words in sentences
Authors: Nelson T. R. , Wheeler K. E. , Jarvella R. J.
Published: October 2005

The intelligibility of particular words in sentences was studied in a paradigm where subjects were asked a wh— question before or after they heard a statement masked by white noise. The answer to the question was always a single word from the accompanying statement. The statements and questions used each contained two noun phrases, whose position, emphasis, function, and redundancy were varied. The results obtained suggest that both syntactic and semantic factors influenced intelligibility of the nouns in these phrases.
Transcription of unfamiliar language material
Authors: Shockey L. , Reddy D. R.
Published: October 2005

This paper presents results of an experiment designed to quantify the type and nature of perceptual differences among listeners when they are deprived of nonphonetic cues in a continuous speech perception task. It also examines the relationship between a phonetic transcription done using the standard aural technique and other transcriptions of the same material from spectrographic and oscillographic displays. Fifty short recorded utterances from 11 languages were used. Four experts were asked to transcribe this corpus by ear, two from spectrograms, and one from oscillograms. Preliminary results indicate that impressionistic transcription yields an average “correct” score (as determined from native speaker reports and careful analysis of spectral displays) of approximately 70% in cases where an identification was attempted. Spectrogram and oscillogram reading both yield “correct” scores of approximately 30%. However, it is found that responses considered correct very frequently fall in the same class as the supposedly correct element: allowing the categories stop, nasal, glide, flap or trill, fricative, and vowel, about 90% of the responses fall in the proper category in the aural transcription task, and about 80% in both the spectrogram and oscillogram reading tasks.
Dichotic backward masking, the “lag effect,” and processing phonetic features
Authors: McNabb S. D. , Pisoni D. B.
Published: October 2005

The “lag effect” has been used to support the argument that speech perception engages distinctive processes that differ from those of nonspeech auditory perception. However, a number of recent experiments have shown that the effect may not be peculiar to speech, since it may be obtained with non-speech timbres, vowels, and other stimuli. In fact, the effect appears to be a variation of a more general result obtained in backward masking experiments: a second stimulus may impede the processing of a preceding stimulus. The present study sought to determine the locus of this effect. Under dichotic presentation, one of four syllable targets (/ba/,/da/,/pa/,/ta/) was followed by one of six possible syllable masks (/ga/,/ka/,/gæ/,/kæ/,/gɛ/,/kɛ/), each 300 msec in duration. The onset time of the mask relative to that of the target was varied over the range 0 to − 150 msec. Subjects identified only the target sound in an ear monitoring task. Two findings were obtained which argue that the lag effect has an auditory basis. First, when the target and mask differed on voicing it. e., b-k, p-g), performance improved with increases in the onset time of the mask; no inteference was obtained when the target and mask shared voicing. Secondly, performance varied inversely with the similarity of the vowels in the mask: performance was lowest with /a/ and highest with /ε/. Since the interference occurred only for trials that differ on voicing and since these trials were also affected by vowel context, we conclude that the locus of the lag effect lies before phonetic analysis and therefore must have an auditory rather than phonetic basis.
Ambient noise field edge effects in product array processing
Authors: Autrey S. W.
Published: October 2005

Product array processing, also called split beam correlation, is often the favored process for both detection and tracking because it has higher spatial resolution than sum and square processing and because it has been thought to yield a near zero mean output for either independent or isotropic noise inputs. Numerical evaluation, however, shows that when steered near endfire a product line array embedded in isotropic noise will yield a substantially nonzero mean, e.g., 15% correlation. This effect is studied in terms of both interelement correlation and directional response patterns for both split arrays and element pairs. It is shown to be a consequence of the discontinuity in the isotropic noise field when considered in the total interelement delay space that the array is capable of being steered to. It is thus seen to apply to product arrays of arbitrary configuration whenever the product steering delays are nearly equal to the maximum possible delays in the medium, e.g., near endfire for any element pairs. This effect is also shown to apply to ambient noise fields that are highly nonisotropic. Finally, it is shown that this effect can be greatly reduced by the addition of noise at each of the array elements, the noise being correlated in such a manner as to extend the isotropic noise field further into the delay space covered by the array.
Acoustic tracking of subsonic objects
Authors: Reid Walter P.
Published: October 2005

This paper presents a method for tracking an object moving at subsonic speed by using observations of the direction at which sound arrives at a cluster of microphones. Sound is assumed to travel at constant speed in a straight line from the object to each microphone. Sample calculations are given.
Relative measurements of pulse component source energies of the USN explosive sound signal MK61 detonated at 60 ft
Authors: Buck Beaumont M.
Published: October 2005

While conducting propagation experiments in a shallow water area using the MK61 SUS (Sound, Underwater Signal) at 60-ft detonation depth and at ranges of 5 to 20 nautical miles, it was noted that the shock wave and the first and second bubble pulses arrived as separate and distinct arrivals in the signal. The limited multipaths in this particular area allowed separate energy analyses of each of the pulses. These energy analyses are compared with Weston's theoretical predictions of source energy flux density. The first bubble pulse energy relative to the shock wave was less, and the second bubble pulse energy was greater, than that predicted by Weston. Sixty feet is considerably above his “critical depth” for a 2-lb TNT charge and, therefore, in a zone where bubble migration effects reduce the energy of the bubble pulses. Weston cautions that his source level predictions at such shallow depth are inaccurate. A “best estimate” of MK61 SUS at 60-ft energy source level was derived from a summation of Weston's shock wave energy, which should be independent of depth, and relative measurements of first and second bubble pulse energies.
Pure-tone thresholds of the squirrel monkey (Saimiri sciureus)
Authors: Beecher M. D.
Published: October 2005

The audibility function of the squirrel monkey was measured with particular interest in determining the high-frequency cutoff. The animals were trained to lick a tube to produce a tone burst. This response served to fix the animal's head in the sound field. A barpress within 3 sec of tone onset produced food and was counted as a detection. The squirrel monkey audibility function obtained had a low-frequency slope of approximately 10 dB/octave, the typical notch at 4 kHz and maximum sensitivity in the 8–10-kHz region. The high-frequency side was complex, consisting of a decrease of sensitivity to 16 kHz, a flat portion from 16 to 32 kHz, and a sharp cutoff commencing between 32 and 40 kHz. The 70-dB-SPL point occurred at 46 kHz.
Correlation of Fluctuating Forces on Enclosed Flow Spoilers with Sound Radiation
Authors: Heller Hanno H. , Widnall Sheila E.
Published: October 2005

Interaction of flow with rigid “obstructions,” such as blades or struts, constitutes an important source of noise in aircraft engines. This paper presents the results of a theoretical and experimental study of the relation between radiated sound and the fluctuating aerodynamic forces that act on fixed flow spoilers enclosed in a hard-walled duct. The theory considers the effects of the duct wall and of the duct end reflection on the radiated sound power and on the transmission characteristics of aerodynamic dipole sources, using Curle's dipole-source free-field predictions. The experiments were carried out with a specially developed system of transducers, capable of measuring simultaneously the drag and lift components of the fluctuating aerodynamic forces acting on variously shaped flow spoilers. A theoretically predicted increase in the dipole sound power by a factor of 3 (above the free-field case) for frequencies below the duct cutoff frequency was verified experimentally. [The research reported in this paper was supported by the National Aeronautics and Space Administration under contract.]
Effect of a Transverse Resonant Acoustic Field upon Viscous Fluid in a Cylindrical Enclosure
Authors: Hribar A. E. , Purdy K. R.
Published: October 2005

An analytical and experimental study was conducted to examine the interaction between a standing transverse resonant acoustic field and viscous fluid. The objective was to obtain flow-behavior information related to combustion instability phenomena. Reduced governing equations were obtained in a form that separated the time-dependent motion from the time-mean motion through the use of a rigorous order-of-magnitude analysis. Solutions of these equations predict the existence of standing vortices (acoustic streaming) in the cross section of the cylindrical enclosure. The number of vortices and their circulation velocities are proportional to the resonant mode. The results extend and lend greater clarity to work of other authors. Pressure measurements confirmed that the experimental system satisfied the constraints of the mathematical analysis. Photographs of the streaming flow, using tobacco smoke as a tracer, substaniated the mathematical results. [Research supported by NASA.]
Acoustic and Magnetic Ultralow Frequencies Generated by the SATURN F-1 Engine
Authors: Fehr Uri
Published: October 2005

The source characteristics both in the infrasonic region (110–20 cps) and the magnetic fluctuations (4–16 cps) have been determined. The acoustic signals have shown a characteristic ignition and cutoff pulse. The first shows an explosion (N-type) behavior, while the latter produces a bubble-pulse-type effect that might have resulted from an implosion structure. The engine run produces a steady-state signal. However, its acoustic energy peak in the ultralow frequencies is a function of duration of engine run. The power spectrum shows energy distribution in two regions, with maxima at 4–8 cps and about 1.4 cps, with energy extending to almost 0.1 cps. The lower-frequency peak becomes more significant with growth of time of engine run. The magnetic signals have shown narrow-band signal between 8 and 12 cps during engine run, and a high-intensity cutoff signal of wider band. The cutoff signal resembles a pulse. The downward exhaust of a static firing of a rocket is a source for ultralow-frequency acoustic and magnetic waves. Similar conclusions are drawn for the behavior of an ATLAS vehicle during the first few kilometers of flight.
Empirical Studies of Linguistic Universals in Very Young Children
Authors: Bever Thomas G.
Published: October 2005

Recent studies of the acquisition of discriminative and productive speech capacities raise the possibility that certain aspects of human language are specifically innate. (1) In 1–3-month olds, the relative amount of orientation to vowel-vowel transitions suggest that /a/ is the most basic vowel, /u/ the next most basic, and /i/ the least basic. (2) In 1–2-year olds, the notion of actor-action-object is present. There is no obvious explanation for the development of these universal features of adult language to be found either in the child's nonlinguistic behavior or in his experience.
Certain Aspects of the Development of Speech Production and Perception in Children
Authors: Preston Malcolm S. , Yeni-Komshian Grace H. , Stark Rachel E. , Port Diane K.
Published: October 2005

This paper reviews the results of several research projects that have examined the developing capabilities in children for producing and perceiving speech sounds. Most of this work has been carried out with children between the ages of 1 and 5. Particular attention has been directed toward the development of stop consonants as they occur in syllable initial position. Such sounds occur early in the vocalization of infants and are characterized by easily identifiable acoustic features critical for differentiating stops along the dimensions of voicing (voice-onset time). The projects to be reported in detail include a longitudinal study of productive capabilities in normal and hearing-impaired children, and a cross-language study (English and Arabic) of perceptual capabilities in normal-hearing children. [Research supported in part by the National Institute of Child Health and Human Development.]
Predetection Integration Applied to the Detection of Passive Acoustic Signals
Authors: Schutzer Daniel
Published: October 2005

The use of the fast Fourier transform algorithm for filtering a narrow-band signal of unknown frequency and phase prior to detection is most conveniently achieved by representation of the sampled signal in its analytic (complex) form. This automatically results in an output spectrum that preserves both amplitude and phase information, which in turn suggests a summation of successive spectral outputs prior to envelope detection. The resultant processing gains are examined as a function of the signal-phase instability. The three distinct processes are used to model this phase instability. They are: average phase drift, narrow-band Gaussian process, and sinusoidal signal of known phase in the presence of additive narrow-band Gaussian noise. It is demonstrated that, given the appropriate conditions (large signal-to-noise ratio preceding filtering and relatively long coherence times), predetection-integration techniques may be employed either to increase greatly processing gains at equal sample rates or to produce equivalent processing gains for greatly reduced sampling rates. The application of these results to the detection of passive acoustic signals is then briefly discussed.
Acoustic Navigation Utilizing Group Phase
Authors: Caldwell Walter H.
Published: October 2005

Underwater navigation by acoustic methods has been the subject of study and development in industry and at ITT Avionics. The ITT approach was to use the difference in phase between acoustic signals traveling three different paths. These paths were between one local point and a set of three other distant points. The study included calculations, abetted by the ubiquitous computer, together with experiments in water. One problem was to have a set of three transducers that could be efficient, and yet much smaller than a wavelength. The solution to this difficulty lay in the use of a high-frequency carrier of short wavelength, permitting an efficient transducer several wavelengths in size, but to separate three transducers a distance that was a fraction of the wavelength of a modulation signal. The relationship between the group phases of modulation signals traveling three paths and the angle between the line joining the point to the triangle and a reference axis of the triangle was the subject of analysis and experiment.
Comments on the Theory of the Composite Resonator
Authors: Bleustein Jeffrey L.
Published: October 2005

A brief review of simple resonator theory is given leading to a discussion of the motivation for the thin-film composite resonator. A simplified analysis of a CdS-quartz composite resonator is presented and the complications associated with a more exact analysis are indicated.
Theoretical and Experimental Study of Modes of Vibration in Contoured, AT-Cut Quartz Resonator Plates
Authors: Lee P. C. Y. , Pearman G. T.
Published: October 2005

Thickness-shear and flexural modes of vibrations and their anharmonic overtones in rectangular AT-cut quartz plates of varying thickness are considered. Mathematical solutions are obtained analytically for plates with partial electrode platings and four free-edge conditions. The plated portion of the plate is of uniform thickness while in the unplated portion, the thickness varies as an exponential function of the length coordinate of the plate. A study is made of the effects on the resonant frequencies and mode shapes due to changes of plate parameters, such as the rate of decrease of the thickness of the plate and the ratio of the length of the plate to the length of the plating. The measured frequencies are compared with the computed values.
Temperature Dependence of the Electroacoustical Constants of Li-Doped ZnO Single Crystals
Authors: Smith R. T. , Stubblefield V. E.
Published: October 2005

A combination of ultrasonic velocity and piezoelectric resonator techniques has been used to determine the room-temperature electroacoustical constants and also their temperature derivatives for a hydrothermally grown, Li-doped single crystal of ZnO in the temperature range 10°–110°C. The crystal as initially grown had a bulk electrical resistivity of about 2×104Ω cm, which was low enough such that the ultrasonic velocity measurements were effectively made under zero electric-field conditions. The measured ultrasonic velocities and associated elastic moduli were in excellent agreement with Bateman's 25°C results for similar, low-resistivity material [(J. Appl. Phys. 33, 3309–12 (1962)]. The material was subsequently thermally annealed at several temperatures up to 800°C to increase the electrical resistivity (final value >1011Ω cm), and the electroacoustical constants and their temperature derivatives were remeasured. The electromechanical coupling coefficients calculated from the room-temperature data agree more closely with those of Jaffe and Berlincourt [Proc. IEEE 53, 1372–86 (1965)] than those of Chrisler et el. [Proc. IEEE 56, 225–6 (1968)]. The first-order temperature derivatives are negative for all five independent elastic and all three independent piezoelectric stress constants, but positive for the two independent dielectric constants. The relevance of these results to the design of piezoelectric resonator devices is briefly discussed.
Vibratory Patterns Observed in Real Time by Interferometric Holography
Authors: Tonndorf Juergen , Khanna Shyam M. , Janecka Ivo
Published: October 2005

Interferometric holography [K. Stetson, J. Acoust. Soc. Amer. 39, 1215 (1966)] provided detailed photographic records of the vibrational modes of given structures at known amplitudes ranging from approximately 10−5 to 10−4 cm. This method is currently being adapted for a study of the vibrational modes of the tympanic membrane. However, the approach is handicapped by the fact that nothing can be observed until the exposed holographic plate has been processed, and that each plate records only the response to one given frequency/amplitude combination. In an effort to alleviate these shortcomings, a real-time technique was developed. Although of lesser quality than Stetson's original method, it facilitates viewing the complex dynamics of vibratory events directly as they occur with changes in signal parameters. Interesting mode patterns may then be selected for later registration in the standard manner and for more detailed analysis. A motion picture is presented showing real-time interferometric holography of the vibrating diaphragm of an earphone with mode patterns changing continuously as signal parameters are being varied. [This work was supported by NIH grants.]
Responses of Single Auditory-Nerve Fibers in Cochleas Damaged by Ototoxic Drugs
Authors: Levine R. A. , Moxon E. C. , Kiang N. Y. S.
Published: October 2005

Electrophysiological recordings from single auditory-nerve fibers of cats were made two to 75 days after subcutaneous injections of neomycin or kanamycin. For units that responded to acoustic stimuli, characteristic frequency (CF) and threshold at CF were determined. For individual cats, distributions of CF and threshold usually differed from those of normal animals. In some cats, one particular pattern has been noted: The highest CF found is significantly lower than in normal animals, and units with CF immediately below the highest CF are abnormally distributed in threshold. Histological examination showed hair-cell losses that extend from the basal end of the cochlea toward the apex. According to Schuknecht's map, the frequency range associated with the apical limit of the damage corresponds to the highest CF obtained in each animal. These findings will be interpreted in terms of the innervation patterns of the cochlea. [Supported by NIH grants and the Joint Services Electronics Program.]
Development of Auditory Function in the Mongolian Gerbil
Authors: Finck Alfred , Schneck Carson D. , Hartman Albert F.
Published: October 2005

The gerbil ear is not mature at birth. The sound-conducting apparatus as well as inner-ear structures continue to develop over a period of at least 16 to 20 days postparturition. This circumstance allows a unique opportunity to examine relationships between morphology and function in the auditory apparatus. Mongolian gerbils were vitally perfused at various ages ranging from 20 min to more than 23 days. Serial sections were done and observations made on the developmental status of the external, middle, and inner parts of the ear. Cochlear potentials were recorded from some animals. The presence of reflex activity to sound was noted. Our observations indicate that the earliest reflex response to sound (whole body) occurred at 16 days. Electrical activity could be recorded from the round window niche by day 14. Maturation of the organ of Corti was questionable by day 10, and the limbus and spiral sulci were not well differentiated. By day 16, all parts of the organ of Corti appeared well developed. Ossicular ossification was almost complete by day 16, but mesenchyme was still present in the region of the incudomalleolar joint. [Work supported by NIH.]
Physiological and Histopathological Comparison of Deaf and Normal-Hearing White Cats
Authors: Hattler Karl W. , Suga Fumiro
Published: October 2005

A group of pure white cats, three profoundly deaf, were subjected to behavioral tests and seven neurophysiological measures of auditory function. Response levels for behavioral, cochlear microphonic, and averaged evoked potential tests were in good agreement especially for the deaf animals. The action potential, summating potential, and positive dc endolympathic resting potential were absent in the deaf cats, but clearly present among the normal-hearing animals. The negative dc potential was observed in all animals. Histological examination of the deaf cat temporal bones revealed a marked lack of melanin pigment in the stria vascularis and pathological changes similar to the cochlear-saccule degeneration of Scheibe. The results of behavioral and neurophysiological measurements are discussed in light of histological findings.
Irreversible Statistical Mechanics and the Structure of Anisotropic Turbulent Stress Tensor
Authors: Yildiz M.
Published: October 2005

Turbulence structures of most practical flows are little understood, and involved calculations of their sound field are prohibited by our severely restricted knowledge of a complicated turbulence stress tensor. Proudman [Proc. Roy. Soc. (London) A211, 564 (1952)] computed the noise radiated by decaying isotropic turbulence on the basis of the theory developed by Lighthill [Proc. Roy. Soc. (London) A214, 119 (1952)], but this work is probably the only detailed quantitative application of noise theory that is feasible with our present limited understanding of turbulence. Recent developments in statistical mechanics may lead to better understanding of the complicated structure of the turbulence stress tensor in an anisotropic turbulence. It is shown how spectral and correlation tensors are evaluated with the aid of various irreversible thermodynamic derivatives and the sum formulas recently discussed by Onsager, Kubo, and others, in connection with transport phenomena in many body theory and in irreversible statistical mechanics.