bluuebunny/crossref_metadata_2025 huggingface dataset:
The ability to vary stress in a subject with apraxia of speech
Authors: Gelfer Carole E.
Published: October 2005

The ability of one subject with aphasia and apraxia of speech to vary syllabic stress was investigated. The subject repeated the nonsense utterances /əpapipə/ and /əpipapə/, where stress was alternated between /a/ and /i/ in both utterance types. Acoustic analyses were performed for those parameters known to vary in the speech of normal talker when conveying lexical stress; that is, vowel duration, fundamental frequency, amplitude, and first and second formant frequencies. Judgments of perceived stress were obtained for 31 listeners. Tokens were then grouped according to whether more or less than 85% of the listeners judged stress as intended by the subject. Acoustic analyses revealed that fundamental frequency and vowel duration contributed significantly to listener perceptions. For those tokens judged as intended, fundamental frequency and duration were varied in a manner resembling the strategies adopted by normal speakers. For those tokens judged less accurately, differences in fundamental frequency and duration for stressed and unstressed vowel pairs was less marked, and, in fact, often reversed. [Work supported by NINCDS and BSRG.]
Preliminary data on the relationship between oral morphology and jaw movement patterns during speech
Authors: Garber S. R. , Speidel T. M. , Burzynski C. M.
Published: October 2005

The purpose of the present study is to compare jaw movement patterns during speech in persons with varying occlusion and to describe the changes in patterns which occur following surgical repositioning of the jaws (orthognathic surgery). Subjects are placed in a cephalostat and tape recorded using a videofluoroscopic procedure. Selected portions of the tapes are photographed with a 35-mm camera and enlarged to life size. Cephalometric measurements of lip, tongue and jaw position are made from each photograph. At present, data on sustained phonation of /s/ and /∫/ have been obtained from persons with varying occlusion. In addition, two subjects have been tested before and after orthognathic surgery. Preliminary data indicate that speakers tend to compensate for their malocclusion. Persons with excessive overjet move their mandibles forward and persons with deep overbite rotate their mandibles open during speech. Following surgery, these patterns are altered. [Work supported by a University of Minnesota Graduate School Grant and an NIDR fellowship.]
Further results on the Tadoma method of speech communication
Authors: Reed C. M. , Conway-Fithian S. , Braida L. D. , Durlach N. I. , Schultz M. C.
Published: October 2005

Results on the perception of speech through the Tadoma method (in which the “listener” monitors the articulatory process by placing a hand on the talker's face) have been obtained on seven adult deaf-blind, experienced Tadoma users. Six of the subjects became deaf and blind as a result of meningitis between the ages of one and seven; the seventh became deaf from a progressive hearing loss and blind from retrolental fibroplasia suffered in infancy. Performance was measured on various word and sentence tests (W-22 words, SPIN sentences, and CID sentences), syllable tests (identification of sets of consonants and vowels), and a test of language (Quigley et al., 1978). The results of these tests provide us with information concerning the comparative abilities of a relatively large sample of experienced Tadoma users to communicate through Tadoma. [Work supported by NIH.]
Cochlear combination tones and basilar membrane linearity
Authors: Johnstone J. R.
Published: October 2005

The existence of combination tones which mimic real sounds is often taken to mean that additional propagated disturbances must be present in the cochlea. This is not so. For example, consider the two pure tones of frequency f1 = 15 and f2 = 16 kHz which generate the distortion product 2f1 − f2 = 14 kHz. The maxima of the two primary traveling waves will be located at the 15 and 16 kHz points on the basilar membrane, 0.1 and 0.2 octaves from the 14-kHz point. But at the 14-kHz point the amplitudes of the primaries are lower by only 10 and 20 dB. If, as is widely accepted, there exists a second local filter with 500 dB/oct high-frequency slope, a neurone at the 14-kHz point should reject each of the primaries. However, any nonlinearity at that location will generate a family of distortion products, one of which (2f 1 − f2) will pass through the second filter and may cause nerve impulses to be generated. This neural activity will be in most respects like that generated by an external sine wave, e.g., it may be phase locked and may be cancelled by an external tone. In the same way neural difference tones (e.g., f2 − f1 can be accounted for but it is necessary to remember that the initial 100 dB/oct high-frequency roll-off of the traveling wave continues for only 30 riB. More apically than that the slope drops to 20 dB/oct. For example, primaries at 12 and 14 kHz will cause traveling wave displacements at the f2 − f1 = 2 kHz location which are both about 50 dB lower than at the peak of the traveling wave. [Work supported by NHMRC.]
Contribution of pure tones to the loudness, annoyance, and noisiness of white noise
Authors: Hellman Rhona P. , Aylward Noelle
Published: October 2005

Single tones at frequencies of 250, 1000, and 3000 Hz were added to white noise to determine the effect of tonal components on judgments of overall loudness, noisiness, and annoyance. Binaural measurements were obtained by magnitude estimation without designated standards. To obtain a reference function for the group of ten normal-hearing listeners, the loudness of the noise was judged both with and without tonal components. When tonal components were added, the SPLs of the tone and noise were independently varied over a 30-dB range between 70 and 100 dB SPL. Within this range, tone-to-noise ratios of +5, +10, +15, +20, +25, and +30 dB relative to the appropriate one-third octave-band pressure level were produced and evaluated. Tentative data analysis indicates that in order to adequately assess the perceived magnitude of noise-tone complexes, the effects of mutual interaction between noise and tone need to be considered. Such interaction seems to depend on frequency, tone-to-noise ratio, and overall SPL of the noise. [Work supported by NASA-Langley Research Center.]
An initial performance test of the systematic effects of context on noise annoyance
Authors: Weiler E. M. , Fraley-Cohen M. , Kagan S. , Jhaveri J. , Davis J. M.
Published: October 2005

Previously, it was reported [Weiler, Pavlakos, and Davis, J. Acoust. Soc. Am. Suppl. 1 64, S126(A) (1978)] that paper and pencil ratings of noise annoyance are affected by systematic manipulation of described noise-in-context situations. The present study is a two-dimensional performance task consisting of teacher versus student roles combined with facilitating, neutral, or interfering effects of disco music on different dance tasks. Significant differences in noise annoyance ratings were found between the differing roles of raters as well as between interference/neutral/facilitation effects of music on the tasks. Systematic variation of contexts can serve as a useful empirical tool for studying noise annoyance. Studies in environmental applications are suggested.
Coarticulation during oro-sensory anesthetization
Authors: Daniloff R. , Wilcox K.
Published: October 2005

Two normal adults spoke the full inventory of VCV-type utterances used by Ohman in his spectrographic study of coarticulation. Subjects then underwent mandibular and maxillary nerve blocks after which they repeated the full set of VCV utterances. Spectrographic analyses of the data show that labial and apical coarticulation are reduced and made more variable, whereas there was lesser reduction of dorsal coarticulation.
Analysis-by-synthesis of speech spectra from /s/ defective and normal children
Authors: Wilcox K. A. , Hasegawa A. , Stephens I. M. , Daniloff R. G.
Published: October 2005

Utilizing an analysis-by-synthesis scheme, the /s/ spectra of a normal child and three children with varying types of /s/-misarticulation were investigated. Analysis was based on the repetition of sentences which included /s/ in a wide variety of consonant and vowel contexts, with varying stress and juncture. Inspection of the data indicate that the spectra of most normal and defective /s/ productions can be closely approximated by a model consisting of two poles and one zero. Furthermore, each articulatory type (normal, lateral, dental, and other) exhibited different, yet fairly consistent parameter values for the model. Normal and deviant articulatory patterns, as well as possible contextual effects, are discussed. [This project was supported by David Ross Fellowship ♯0314.]
Bearing errors in aeroacoustic pointing and tracking systems
Authors: Church E. L.
Published: October 2005

Advances in microprocessors have focused interest on the development of simple aeroacoustic target-location systems consisting of a small, few-element sensor array followed by FFT analysis, which provide the acoustic bearing θ(t) and the apparent target frequency f(t) as functions of time. This paper discusses factors which may limit the practical applications of such systems: (i) Signal-to-noise effects lead to bearing fluctuations δθ(rms) ≈ [(1 − ρ)N/S]1/2/kd, where ρ = the noise correlation between the two detectors and d = their separation. (2) Subsonic target motion leads to a bearing bias of δθ ∼ M relative to line of sight. For a constant-velocity trajectory, δθ = Arctan (ḟ/fθ̇); an exact expression involving only measured quantities and their first derivatives. Expressions for other target/trajectory parameters involve higher derivatives as well. (3) Multipath/multitarget signals which overlap in frequency lead to bias errors when analyzed as a single target. For example, two such signals analyzed by a two-sensor system lead to an apparent target bearing which can fall either inside or outside the directions of the individual targets, depending on the relative amplitudes and phases of the two signals.
Composite signals for simultaneous estimation of target range and bearing
Authors: Skinner D. P.
Published: October 2005

In a previous paper [J. Acoust. Soc. Am. Suppl. 1 65, S62(A) (1979)] the design of large time-bandwidth product signals for simultaneous estimation of the range and bearing of stationary point targets from a moving platform was discussed. Examination of the range-bearing ambiguity functions produced by a number of simple FM signals indicated marginal gains in terms of interference suppression even for relatively large TW products. In this paper the performance of a class of composite (multicarrier) FM signals which have desirable ambiguity, and interference suppression properties, will be discussed and compared with the previous results. [Work supported by NAVMAT.]
Comparisons of Streit's array optimization technique with other methods
Authors: Buehler Barry G. , Streit Roy L.
Published: October 2005

A general array optimization technique developed by Streit [“Optimization of Discrete Arrays of Arbitrary Geometry,” J. Acoust. Soc. Am. (to be published)] is reviewed briefly. Several examples which have been studied in the literature by a variety of other methods are re-examined using this new and more general technique. In each of these examples, the earlier results are shown to be nearly optimum in the sense defined by Streit. Therefore, this new optimization technique not only yields results comparable to earlier methods, but is applicable in many situations where earlier methods do not apply. Arrays with nearly 500 directional elements have been successfully treated using this technique.
Sound absorption characteristics of theater seats and reverberation time in unoccupied concert halls
Authors: Schultz Theodore J.
Published: October 2005

One of the most important elements determining the reverberation time in an unoccupied concert hall is the sound absorption contributed by the expanse of empty seats. Good design practice is to select the seats so that their own (unoccupied) sound absorption matches as nearly as possible the sound absorption of a seated occupant. To the extent that this goal is achieved, the acoustical conditions in the unoccupied hall, for rehearsals, will be similar to those in the occupied hall, for performances. Such acoustical stability in the sound of a hall eases the performers' rehearsal problems, because questions of musical balance can be adjusted in rehearsal without the need for readjustment in performance. In practice, such stability is very rarely achieved. Usually, there has been only limited flexibility in the choice of seat absorption characteristics, partly because there exists very little technical information as a basis for varying seat absorption to match specific requirements. This paper considers the desirable shape for the curve of reverberation time versus frequency in unoccupied concert halls, then deduces the corresponding form of seat absorption curve, and, finally, proposes a scheme for specifying the upholstery of theater seats to achieve the desired seat absorption.
Sound absorption of acoustical draperies used to provide variable reverberation time in concert halls
Authors: Schultz Theodore J.
Published: October 2005

For many years acoustical draperies have been used in concert halls to provide control over the reverberation time; the draperies are removed from the hall into storage places when a long reverberation time is desired, and introduced into the hall in various amounts to achieve shorter reverberation times. Unfortunately, the design of variable absorption in halls has rested on a poor technical footing, so far. Not only was the theory of sound absorption for free-hanging draperies (whether against a wall or out in space) not developed in readily usable terms, but also the relevant properties of the fabric were usually not known. Moreover, laboratory measurements of drapery absorption are poor guides for drapery absorption in halls. This paper presents a design scheme and design curves that permit the selection of drapery fabric to conform to the desired sound absorption characteristics. It also discusses differences between the absorption of acoustical draperies as measured in laboratory reverberation rooms and in concert halls.
Studies on the variation of absorption coefficient with absorber geometry
Authors: Bartel Thomas W.
Published: October 2005

The effective absorption coefficients, in the one-third-octave frequency bands from 125 to 10 000 Hz, obtained from measurements on three different materials in a reverberation room were studied as a function of the geometry of the test sample. The measurements were designed to isolate the effects of the sample area, perimeter, and shape, making use of the precision available at the NBS reverberation room facility [T. W. Bartel and E. B. Magrab, J. Acoust. Soc. Am. 63, 1841–1850 (1978)]. Measurements made with the sample edges exposed and with the edges covered with reflecting material were compared. The measured absorption coefficients, which increase approximately linearly with the ratio of the sample perimeter to the sample area, were compared with a theoretical model [T. D. Northwood, J. Acoust. Soc. Am. 35, 1173–1177 (1963)] using values of the acoustical admittance obtained from impedance tube measurements performed on the same material. The agreement was within the order of 15%. It was found that if the area and the perimeter of the sample were held constant, the shape of the sample had a small effect on the measured absorption coefficients, which decreased by a few percent as the number of corners in the sample configuration increased.
The acoustical benefits of increased thickness of building insulation on sound attenuation in residential construction
Authors: Sundberg D. G.
Published: October 2005

Controlled field tests were conducted on three houses that have identical floor plans, orientation, doors, and windows, but have different amounts of building insulation. Steady-state transmission loss tests were conducted to determine the sound insulation of the exterior shells as a function of increased thickness of building insulation. The results show a gradual improvement in transmission loss. In addition, flyover tests were conducted with a jet aircraft at altitudes of 1000, 500, and 250 feet. Sound levels were measured both inside and outside of each home. The results of this series of tests were compared to determine the acoustical benefits provided by increased thicknesses of insulation in residential construction. Test results and comparisons of the two test procedures are presented.
Protecting Harvard University buildings from construction noise
Authors: Tocci Gregory C. , Cavanaugh William J. , Burbank Robert C.
Published: October 2005

The reconstruction of the Harvard Square (Cambridge, Massachusetts) rapid transit station and its associated tunnel work, scheduled for completion in 1983, will have resulted in sustained construction activity over a five-year period. A number of Harvard University dormitory, classroom, and other academic buildings directly abut work sites and a great many more buildings have shielded or partially shielded exposure to construction noise. The potential problems of long term activity interference, occupant annoyance, and sleep disturbance were recognized and addressed early in the planning phases of the project. Extensive noise monitoring both before and after the construction commenced was carried out in dormitory rooms, classrooms, and faculty offices with open and closed windows. On the basis of analysis of the existing noise environments and the proposed construction activity scenarios, a program of sound attenuation measures for most severely affected buildings was developed and implemented. This paper reviews the development of criteria for permissable interior noise levels produced by construction noise sources, the noise monitoring program, the design and implementation of building noise attenuation features, and general results observed to date.
Recent developments in the acoustic spectroscopy of violins
Authors: Weinreich Gabriel , Arnold Eric B.
Published: October 2005

Between the oscillation of the bowed violin string and its final acoustic output stands the intricate dynamical system of the violin body and air cavity. The behavior of this (linear) system is under all circumstances completely characterized by its normal modes, or “resonances,” provided they are analyzed not only as to frequency but also as to complex eigenfunctions. By assembling such information we are in a position to compute the coupling of each mode to the driving points at the bridge and to all acoustic-field variables. The approach will be illustrated by data on several violins and by the way the corresponding transfer functions change with change in parameters such as soundpost placement. [Work supported by NSF.]
Trumpet spectrum transformation systematics
Authors: Benade A. H. , Hoekje P. L.
Published: October 2005

The spectrum transformation function Tmr(f) converts the mouthpiece spectrum into the spectrum averaged over the room's sound field, Tmr is extremely irregular, and is best represented as the product of other functions. Tmc transforms from the mouthpiece to the standing wave amplitude in the cylindrical main bore. Tcb converts this to the on-axis spectrum just outside the bell. Tbr modifies the latter to give the room average spectrum. Tcr = Tcb ⋅Tbr = [1 + (1343/f)9.9]−0.25, and Tbr = [1 − (f/104)] for f ⩽ 4000 Hz. For a tonal component whose frequency coincides with an input impedance peak, Tmc ≃ 1 at low frequencies, ≃ 0.3 at 800 Hz (near the mouthpiece popping frequency Fp), and climbs past 1.0 at 2000 Hz. At high frequencies Tmc → (arim/acyl), the ratio of mouthpiece radius to that of the cylindrical bore. Harmonics of a played tone may not coincide with the input impedance peaks. If the harmonic moves above such a peak, Tmc rises overall and its dip smoothly changes into a peak. If the harmonic lies below an air column resonance, Tmc is below the resonance Tmc for f < fp increasing to very large values above fp. [Work supported by NSF.]
The temperament of Lambert Chaumont
Authors: Lawson Dewey T.
Published: October 2005

A tempering method for harpsichord published in a 1695 Belgian organ book has been cited recently by a major organ-building firm. An examination of this prescription reveals (1) a novel pedagogical framework for discussion of scales and temperament in both theoretical and practical terms and (2) an intriguing opportunity to apply computer techniques to a problem combining elements of acoustics and musicology.
Key design, material properties, and temperature factors in frequency variation of Sisaala jengsi (xylophone) keys
Authors: Seavoy Mary H. , Klement William
Published: October 2005

Dimensions, mass, volume, and density are used to describe the complex geometries and concomitant frequencies of keys on a pair of 17-keyed jengsi (from northwestern Ghana). Frequency variations, with keys in free and bound states, are analyzed at equilibrium under selected temperature and relative humidity conditions, and in a diurnal cycle simulated for the West African dry season. Frequency, length, nodal, and central thickness are accurately interrelated with the irregular geometries. It was discovered that key width/length, an important aesthetic factor, is nearly constant. Under climatic change, material properties of the wood are much more critical factors in frequency variation than key geometry. Jengsi keys (missanda wood) showed decreases of about 0.96 cents per 1.0°C increase in temperature in the range 10° to 38°C, with greater decrease at 44°C.
The ontogenesis of auditory pattern perception
Authors: Brady S. L. , Gilliom J. D. , Berry D. T. R.
Published: October 2005

The effect of duration on the perception of part tones within the context of a musical chord was measured using a yes-no signal detection task. The experimental paradigm required an observer to perform a monaural detection task of a tonal signal within Gaussian noise. The signal frequency was randomly chosen on each trial from a set of six frequencies. A contralateral frequency cue, randomly chosen from a set of six different durations, was provided prior to the detection interval. This cue, placed within the context of a three element musical chord, was provided to reduce the deleterious effects of the signal frequency uncertainty. Discussion will cover the effectiveness of the cue in raising detection performance and the implications of this study in the search for the organizational principles important to the perception of part tones within musical chords.
Psychophysical tuning curves: Narrow-band noise versus sinusoidal maskera
Authors: Johnson-Davies David , Patterson Roy D.
Published: October 2005

Psychophysical tuning curves were produced using a narrow-band noise masker (0.1 kHz wide) and compared with curves produced by the more traditional sinusoidal masker. The signal was a 2.0-kHz sinusold 0.5 s in duration, and it was presented simultaneously with the masker. The curves were obtained for five subjects at three signal levels (approximately 10, 20, and 30 dB SL for each subject). The noise-masker curves fall below their sinusoidal counterparts in the region 1.6 to 2.1 kHz. Beating between the signal and the sinusoidal masker could account for part of this difference, but it could not explain why the difference is asymmetric about the signal frequency. The curves produced by the noise masker are basically symmetric and independent of signal level, whereas those associated with the sinusoidal masker are asymmetric, with the lower brauch flatter, and the asymmetry increases with signal level. [Author David Johnson-Davies are supported by an SRC studentship.]
A model of binaural interaction
Authors: Sujaku Y. , Kuwada S. , Yin T. C. T.
Published: October 2005

We present here a model which simulates some recent findings [S. Kuwada et al., Science 206, 586–588 (1979); S. Kuwada et al., Neurosci. Abstr. 76 (1979)] in which the interaural phase sensitivity of inferior colliculus neurons has been studied using interaural delays or binaural beats. The cyclic response patterns of some neurons are altered systematically as a function of stimulus off-time and interaural intensity differences. In addition, the response to binaural beat stimuli indicates that some cells are sensitive to the direction of interaural phase change. The model is comprised of two inputs (one from each ear), each with crossed collateral inhibition. The two inputs synapse on a third cell, resulting in four synaptic connections; two inputs are presynaptic inhibitory and two are direct excitatory. At each junction, simple rules about transmitter release, transmitter supply, and changes in membrane potential are made. Manipulation of these parameters allows for simulation of the commonly seen cyclic response pattern as well as some of the unique effects of off-time, interaural intensity differences, and sensitivity to a particular direction of interaural phase change. [Supported by NIH grant NS12732.
Pharynx measurement—a new method
Authors: Javkin Hector R. , Pearson Steven , Carlson Ronald
Published: October 2005

A new method has been developed for the measurement of the cross-sectional area of the pharynx during speech. A tube is inserted into the pharynx through the nose. The tip of the tube contains four distance sensors each consisting of a focused light-emitting diode (LED) and a photocell. Each sensor is oriented at a 90° angle to its two neighboring sensors. Each LED is pulsed in turn. The light reflected by each pharyngeal wall is collected by an accompanying photocell. The amount of light (which varies with distance according to the inverse square law) is converted to a distance measure by a small computer. The lateral and sagittal dimensions of the pharynx are calculated by adding the distances measured by the two pairs of opposing sensors and the tube diameter. Preliminary tests show that the instrument can provide good accuracy with some indeterminacy at very short distances due to parallax error between the LED's and the photocells. [Work supported by NIH.]
Mechanisms of stop-consonant release for different places of articulation
Authors: Keating P. A. , Westbury J. R. , Stevens K. N.
Published: October 2005

The burst interval (i.e., VOT) following release of a voiceless unaspirated stop consonant has a duration that is somewhat longer for alveolars than for labials, and substantially longer for velars than for either. In the case of velars, the burst often consists of a sequence of two or more pulses. These facts may be explained in terms of a model which describes the effects of constriction geometry and articulatory kinematics, specific to different places of articulation, on aerodynamic events immediately following stop release. Calculations derived from this model suggest that Bernoulli forces may act on the surface of a compliant occluding articulator as closure is released. Presumably these forces cause a delay in the opening movement of the articulator, and a tendency for its surface to vibrate, that is greater for velars than for alveolars and labials. Measurements of VOT for stop consonants in different languages are described, with detailed data on the incidence of two or more release bursts and the temporal characteristics of those bursts. [Research supported by grants from NINCDS.]
Lip and jaw movements during altered speaking rates
Authors: Linville Raymond N.
Published: October 2005

Previous research has shown that lip and jaw movements can vary dramatically with speaking rate. However, few studies have explored lip and jaw movements over a range of contrived speaking rates. The purpose of this investigation was to examine kinematically movement parameters associated with six different rates of speaking (1–6 s). The upper lip, lower lip, and jaw vertical amplitudes of a naive male speaker were transduced via a strain gauge system and recorded concurrent with the speaker's utterances. Consonant-vowel syllables composed of /m, p, k, w/ in combination with the vowels /i/ and /æ/ served as the speech sample. Desired rates of production were obtained by training the subject to synchronize his productions with an audiovisual timing device. The results demonstrated generally increased upper lip amplitudes and reduced jaw amplitudes as the rate of speaking increased. More importantly, lower lip velocity was observed to increase systematically from 1 to 3 s but decreased precipitously at 4 s, and thereafter increased in a pattern similar to that found for the slowest rates. This apparent reorganization at a consistent rate corresponded to voicing and movement variability also associated with an utterance rate of four syllables per second. Discussion will focus upon these variables.
Effects of palatal morphology on /s,z/ articulation
Authors: McCutcheon Martin J. , Hasegawa Akira , Fletcher Samuel G.
Published: October 2005

Dynamic palatographic techniques were used to measure the palatal boundaries of the medial groove during production of /s/ and /z/ by normal speakers. Test words were embedded in the carrier sentence “Say haCVC again,” with V = /æ/ or /i/ and presented randomly. Palatal morphology information was obtained from measurements on stone dental models of the speakers' hard palates. Results indicate that palatal morphology influences /s/ and /z/ medial groove location and accounts for some laterality effects. Medial groove parameters were essentially the same for /s/ as for /z/. [Work supported by NIH grant NS-11852-04.]
Some distributional characteristics of amplitude levels of nasal accelerometric signals during connected speech
Authors: Horii Yoshiyuki
Published: October 2005

Amplitude distribution characteristics of nasal tissue vibration during oral reading were investigated using a miniature accelerometer placed on the external surface of the talker's nose. Six male and six female adults read the “Zoo” passage (Fletcher, 1978) which was devoid of nasal consonants, and the “Rainbow” passage (Fairbanks, 1960) which contained a number of nasal consonants, at a low, comfortable, and high vocal intensity level. Nasal accelerometer signals were rectified, smoothed, and quantized at a rate of 200 times per second. The distributions of the sampled nasal amplitude levels showed clear differences between the two passages, particularly for the male subjects. Effects of the vocal intensity levels and fundamental frequency levels upon the nasal amplitude levels, and two methods of normalizing the nasal accelerometric data regarding to the intensity differences were discussed. [Work supported in part by National Institute of Aging.]
Towards modeling of speaker characteristics
Authors: Millar J. B. , Oasa-Stoychef H. , Wagner M.
Published: October 2005

The results of two related studies in the description of speaker characteristics will be presented. In one study narrow phonetic transcription of four speakers uttering 14 sentences were produced by several independent transcribers. Transcriptions were reduced to a common notation and analyzed for evidence of reliability of detection of speaker characteristics. Results indicating the interaction of transcriber strategy, reliability of variants indicative of speaker differences, and narrowness of the transcription are presented. A second study analyzes the speech of several speakers in terms of acoustic features and the statistical variation that exists between the production of these features by groups of speakers. Significant variations between representative groups of Australian and North American English were found for the production of certain stop consonants. Other variations observed agreed well with observations already reported in the literature.
Contributions to VLF noise by merchant ships
Authors: Cybulski John , Wright E. B.
Published: October 2005

Modified SQS-57A (XN-5) Sohobuoys with hydrophone sensors at 305 m depth were deployed in line array patterns to obtain estimates of the sound pressure levels corresponding to 22 assorted merchant ships in the frequency band 1–128 Hz. These were ships of opportunity enroute over the deep ocean basins of the Northeast Atlantic and the Mediterranean Sea. The data was taken on two field trips, August 1975 and January 1977. The ships ranged in size from 326 down to 12 thousand dead weight tons. These procedures yield an adequate representation of the contribution of merchant ships to the lower-frequency spectra whenever the sea state was three or less, and the range to the closest point of approach was less than 600 m. Besides the line components that can be identified with the shaft and blade rate lines, and an associated sideband structure that is easily discernible, there is a broadband infrasonic structure attributable to the ship. The source of this broadband noise has as yet not been ascertained. Possible mechanisms are discussed in terms of measured horizontal and vertical directionality patterns. [Work supported by Naval Material Command.]
Underwater sound from surface waves according to the Lighthill theory
Authors: Lloyd Stuart P.
Published: October 2005

The acoustic source density given by Ribner's version of the Lighthill theory is calculated for a stochastic surface gravity wave field. A Green function gives the acoustic farfield, as a volume integral. For a homogeneous ocean the mean-square pressure in the farfield agrees below ripple frequencies with a result of Brekhovskikh. The method eliminates some of the complications involving the moving ocean surface. [Work supported in part by ONR, Code 480.]
A simple analytical directional ambient noise model
Authors: Cornyn John J.
Published: October 2005

A sampling problem resulting in slow convergence of noise levels predicted by a Monte Carlo type low-frequency underwater acoustics noise model, SIAM II, led to the development of a simple analytical ambient noise model, called CNOISE. The inputs to the model are azimuthal sector geometry about a receiver, ship counts in range-sector bins, transmission loss curves for each sector, and ship source levels. The outputs available from the model include horizontally directional and omnidirectional ambient noise levels. The major advantages of this model include: Significantly increased speed relative to Monte Carlo noise models, and analytical solution that lends itself to straightforward analysis and implementation, and the avoidance of the sampling problems which appear to plague Monte Carlo models. Comparisons of noise levels predicted by other models (BEAMPL, SIAM II, and FANM) have shown very good agreement.
The laryngograph in singing. II. The “ring” in the professional voice
Authors: Brown Oren , Fraterrigo Noël , Gates Linda , Potter Charles , Reed William , Reynolds Evelyn , Teaney Dale
Published: October 2005

For a given vowel, sung or intoned at constant pitch and subjective loudness, the trained male or female voice user has control over an additional timberal feature, namely the “ring” in the voice. The ring is manifest as an additional 10 or 20 dB in the voice sound power spectrum |Ac| in the band near 3 kHz. Production of the ring is associated with maintaining a lowered larynx and open pharyngeal spaces. [J. Sundberg, J. Acoust. Soc. Am. 55, 838 (1975)]. We report here that an additional correlate of the ring is the relative extension of the closure phase of the laryngeal cycle [Fry, private communication, (1978)]. We have measured the power spectra of both the laryngeal acoustic source |Lx′| and the voiced sound; the larynx and the vocal tract are both significantly involved in the effect. The cross spectrum, |Vt| = |Lx′* Ac|/|Lx|2, yields the magnitude of the vocal tract transfer function directly. Two-channel precision is not required to reinforce the kinesthetic cues of the ring: The lx waveform shows an easily discernable increase in the relative duration of the closure phase for increased ring along with other waveform features associated with the target laryngeal behavior. Waveforms, spectra, and cross spectra will be shown for several voices.
Constraints imposed on phonetic processing by syntax
Authors: Dechovitz David R.
Published: October 2005

The fricative-affricate contrast is signalled by a set of diverse acoustic features [L. Gerstman, Ph.D. thesis, New York University (1957)]. A previous study suggests that major syntactic boundaries constrain the stretch of speech over which these features are integrated in perception [D. R. Dechovitz, “Speech Communication Papers,” J. Acoust. Soc. Am. Suppl. 1, 66, S79 (1979)]. In the present research, the role of silence in distinguishing fricative from affricate is assessed at a major syntactic boundary which is not marked with obligatory acoustic changes, and in sentence positions occurring before syntactic structure has unfolded. The present results confirm that the influence of syntax need not be mediated by prosodic variables and indicate that listeners' expectations about constituent structure can determine syntactic effects. [Research supported by NICHD.]
Measures of auditory frequency selectivity using forward masking: Effects of masker-probe time delay and masker duration
Authors: Kidd Gerald , Feth Lawrence L. , Goodman Alison , Mason Christine R. , Corban Mark
Published: October 2005

Psychophysical tuning curves and masking patterns have been obtained under a variety of conditions using a forward masking paradigm. In one experiment 300-ms tonal maskers preceded 20-ms tonal probes by time intervals from 5 to 40 ms. In a second experiment musket-probe time delay was held constant at 5 ms while masker duration was varied from 500 to 35 ms. It was found that increasing masker-prob time delay or decreasing masker duration reduced the “residual masking” effect and resulted in concommitant changes in the observed frequency selectivity. [Work supported by a David Ross Fellowship from Purdue University and grants from N.I.H.]
Method for predicting the development of vibration-induced white finger
Authors: Brammer A. J.
Published: October 2005

Habitually exposing the hands to vibrations may lead to recurring episodes of finger blanching and numbness, with reduction in manual dexterity, tactile sensitivity, and damage to soft tissue occurring in severe cases. By systematically analysing retrospective studies of workers occupationally exposed to vibration, it can be shown that the duration of employment (and hence exposure) determines, on the average, both the appearance of the initial vascular symptoms, and the transition from reversible to irreversible disorders in groups using similar tools. A power law relating vibration amplitude and duration of exposure can then be deduced for occupations involving near-daily exposure, provided an equinoxious contour is selected to frequency-weight vibration spectra. In this way both the appearance and progression of subjectivity reported symptoms can be related to the vibration experienced by the hands. If it is then assumed that an individual's susceptibility remains unchanged during the course of the disorders, tolerable vibration exposures for the whole population can be predicted. The vibration limits so derived compare favorably with those proposed for day-long exposure by the ISO.
Nearfield of a large acoustic transducer, Part II: Parametric radiation
Authors: Tjøtta J. Naze , Tjøtta S. , Garett G. S.
Published: October 2005

The transducer is the same as the one considered in an accompanying paper by Garrett, Naze Tjøtta and Tjøtta. It has a diameter of 182 cm, and is composed of 364 elements of size 4.8 × 6.4 cm, which are distributed in 13 equally spaced rings. It is used to generate difference frequency sound at 0.5–5 kHz in water. Amplitude and phase of the generated sound are measured at various distances in the nearfield of the transducer. The results are compared with calculations based on Westervelt's equation [J. Acoust. Soc. Am. 35, 535–537 (1963)]. Simplifications are obtained by utilizing the parabolic approximations [J. Naze Tjøtta and S. Tjøtta, J. Acoust. Soc. Am. 67, 484–490 (1980)]. This also makes it possible to use a realistic model for the primaries (see the accompanying paper) when evaluating the nonlinear source term, such that all effects of the nearfield oscillates in the amplitude and the phase are fully accounted for. [Work supported by the Office of Naval Research.]
A compound isolation system for T-AGOS I class 600-kW diesel generators
Authors: DeWoody R. T.
Published: October 2005

The T-AGOS 1 class ocean surveillance ships are to tow a sonar array known as the Surveillance Towed Array Sensor (SURTASS). In order for the towed array to operate in a quiet environment, the underwater radiated noise level of the towing ship must be low. This paper presents a design for the installation of four 600-kW diesel generator units. The radiated noise, due to two operating units, is estimated for a frequency range from 10 to 400 Hz by assuming that the hull acted as 16 simple pistons. Verification of the compound isolation system performance was made by conducting a land-based test and measuring vibration throughout the system and the force transmitted to the foundation. The estimated radiated noise levels based on test data are compared with those based on mathematical analysis of the isolation system and found to be quite similar.
Correction for a class of approximate diffraction solutions
Authors: Richarz W. G. , Wong R.
Published: October 2005

It is well-known that the Kirchhoff Theory of diffraction does not accurately predict the diffracted sound field. A development of this approximate theory, the Maggi-Rubinowicz line integral, suffers from similar deficiencies. The line integral approach is rather attractive, as only the outline of the diffracting object need be considered. Thus the shielding effectiveness of irregular shapes can be estimated without undue analytical effort. For the special case of thin barriers, the errors incurred in such computations appear to be systematic. Consequently, an empirical correction factor has been derived. It is based on comparison with exact solutions. The correction factor requires but a single parameter, the Fresnel number. The applicability of the scheme is tested in a series of laboratory measurements. On the whole, good agreement is found. [Work supported by NSERC and University of Toronto.]
The use of an array receiver in baffle performance measurements
Authors: Maple R. , Sachs D. A.
Published: October 2005

The use of an array receiver in place of the omniphone traditionally employed in baffle performance measurements can reduce panel edge diffraction interference as well as provide a measurement which averages over any field nonuniformities caused by panel inhomogeneities (e.g., tile edges and vacuum channels). In addition, boundary reflections and ambient noise can be suppressed. In this paper, data obtained from some recent experiments employing a planar array as a receiver is discussed. The predictions of theoretical models for baffle performance and panel edge diffraction are compared with the experimental results. [Work supported by NUSC, New London, CT.]
Acoustic nearfield of an axisymmetric jet
Authors: Richarz W. G. , Kun C.
Published: October 2005

An analytical model of the unsteady pressure field of subsonic and moderately supersonic jets has been derived. It is valid in the nearfield as well as the farfield of the jet flow and based on Lighthill's theory of aerodynamic noise. Instead of the usual farfield approximations, the full solution incorporating the nonradiating pseudosound field is used. The equivalent sources of sound are quadrupoles of random strength and orientation. Their statistics are described by a locally homogeneous isotropic turbulence model with realistic length and time scales. The formalism “predicts” realistic power spectral densities as well as intensities of the unsteady pressure. The nearfield is dominated by intense low-frequency “pseudosound,” the propagating acoustic waves making negligible contribution. If the observation point is moved away from the flow, the predicted power spectral densities approach the asymptotic farfield solution. This allows one to deduce the least separation at which “farfield measurements” are possible. [Work supported by NSERC and University of Toronto.]
Measurement of particle velocity in a hydroacoustic field by hot-film anemometry
Authors: Dubbelday Pieter S.
Published: October 2005

Most underwater acoustic detectors measure pressure fluctuations. Velocity hydrophones are usually based on determination of pressure gradient. A more direct measurement of particle velocity would be useful to describe an acoustic field in cases of complicated geometry, e.g., in the nearfield of a projector. The technique of hot-film anemometry may accomplish this. It is based on the cooling effect of fluid flow on an electrically heated film. The sensor is also affected by temperature fluctuations, but by proper choice of instrument parameters the velocity effect dominates. Preliminary measurements made in the acoustic field of an NRL/USRD G-19 calibrator at 100 Hz gave an anemometer output of 22 mV for a calibrated particle velocity of 2.7 mm/s, at a temperature difference between sensor and water of 28°C. The sensitivity was found to decrease with increasing frequency. This effect is tentatively ascribed to the influence of particle displacement on the cooling process. A sizable directional sensitivity was observed at 100 Hz, but practically none at 200 Hz.
Auditory distortion products as predictors of TTS: A final look
Authors: Erdreich John
Published: October 2005

There is a long history suggesting a relation between the nonlinear amplitude response of the auditory system, physical overload, and the development of threshold shift. In a previous report, I showed a relation in three subjects between TTS2 and the amplitude of the distortion product ∫1 + ∫2 measured behaviorally. This relation has been examined more fully in a population of 20 listeners. Complete data were obtained in 13 of these listeners. The relation between TTS2 and the amplitude of the ∫1 + ∫2 and 2∫1 + ∫2 was examined at ∫1 = 500, 1000, and 2000 Hz. Distortion product amplitudes were measured for ∫1 and ∫2 = 1.2∫1, each at 70 dB SPL. TTS2 was measured at 1.5∫1 for pure tones at ∫1, either at 90 or 100 dB SPL. Results are mixed. For a 1-kHz fatiguer, a relation exists between distortion product amplitude and TTS2. The relation is TTS2 = 0.25 ADP-1.2 with r = 0.52. This may not be meaningful. At 500 Hz, no TTS was produced by the exposures although there was variability in the level of ∫1 + ∫2 between subjects. At 2 kHz, there was extreme variability in TTS exhibited by the listeners which was unrelated to distortion product level. The relation exhibited at 1 kHz may be a manifestation of a secondary phenomenon not related to the primary mechanism of auditory fatigue.
Newborn responses to acoustic stimuli
Authors: Franklin Barbara
Published: October 2005

A comparison was made of the responses of 20 neonates, 12–48 h old, to 3 acoustic stimuli—a 3 kHz warbled pure tone, a 2–4 kHz noise band, and a 2–4 kHz speech band—at three intensity levels—65, 75, and 85 dB SPL. The stimuli were presented free field through a speaker, and the newborns' responses were video taped. These tapes were subsequently viewed by three trained observers, and two of them had to agree on a response for it to be recorded. There was a total of 57 responses for the noise band, 56 for the warbled pure tone, and 61 for the speech band. There was a high number of responses to the stimuli at the 75-dB intensity level. It was found that responses could be determined by viewing subtle movements of the face, particularly the eyes and mouth. Future studies will vary the properties of the acoustic stimuli, and will also focus on the establishment of a standardized procedure for observing and recording responses which could be used for newborn hearing screening. [Work supported by BRSG/NIH.]