bluuebunny/crossref_metadata_2025 huggingface dataset:
The stability of phonational frequency range when elicited by two different methods
Authors: Cook Spencer Connie , Pausewang Gelfer Marylou
Published: October 2005

Previous investigations of phonational frequency range suggest that the method of elicitation can affect the stability of this range. The method of matching tones [R. Colton and H. Hollien, J. Speech Hear. Res. 15, 708–713 (1972)] appeared to yield more stable data than did spontaneously produced scales [X. Geller, J. Acoust. Soc. Am. Suppl. I 79, S82 (1986)]. In the present study, subjects matched descending and ascending semitones and spontaneously sang down and up the scale to the lower and upper limits of their range. These data were collected three times in one day, and three times on a second day 10–12 weeks later. The elicited frequency productions were converted to semitones (ST), and lowest and highest production and total range were calculated. For both elicitation methods, within-day and between-day variability were examined for all measures. Results indicate that similar frequency range values are obtained regardless of elicitation method. However, for both lower and upper limit of range, the matching procedure yielded somewhat more extreme values (0.2 ST, 0.4 ST). Within-day and between-day variation were similar to what has previously been reported (±2 ST).
Perception of onset bursts in /ba da ga/ syllables by good and poor readers
Authors: Parker Judith A.
Published: October 2005

In identification and discrimination tasks, good and poor readers listened to tapes of synthesized stimuli consisting of 350-ms full (burst + formant transition) and partial (formant transition only) acoustic signals for voiced stop CV syllables. A free identification procedure was used to elicit percepts and an oral response method was used to avoid possible reading/writing confounds. The ANOVA, probit analysis, and signal detection analysis were used to evaluate findings. As a group, poor readers demonstrated significantly weaker categorical perception for the /da ga/ boundary in stimuli lacking bursts. Burstless signals produced severe problems for some poor readers; others performed similarly to the higher averaged performances of the good readers. Individual differences were noted: impaired perception regarding place, manner, or boundaries occurred in the full-stimulus condition, and more often for the partial condition. The data are relevant to theories that propose a hierarchy of acoustic cues for the perception of linguistic contrasts and also suggest a possible perceptual deficit that may be involved in some forms of dyslexia.
Laboratory calibration of acoustical calibrators and noise dosimeters
Authors: Crivaro Michael A. , Giardino Dennis A.
Published: October 2005

The Mine Safety and Health Administration (MSHA) maintains a laboratory to calibrate noise dosimeters and acoustical calibrators. Dosimeters and calibrators are used by Federal mine inspectors to determine compliance with occupational noise regulations. Topics covered include reasons for creating the laboratory, test system design philosophy, test procedures, and estimates of uncertainties.
Scattering of acoustic waves in a waveguide
Authors: Sen Rahul , Thompson Charles
Published: October 2005

The problem of scattering from boundary discontinuity in a waveguide is discussed. The relationship between the static and dynamic representations of the scattered pressure field will be investigated for those frequencies falling below the first cross mode of the duct. Special attention is paid to the influence of cutoff cross modes to the solution of the pressure field. It is shown that the method of matched asymptotic expansions can be successfully used to determine globally valid pressure field junction conditions near a boundary discontinuity. The matching of exponentially decaying terms of the inner solution is shown to, in turn, contribute to the junction impedance and extend the frequency range of the solution's validity.
Experiments on junction inertance
Authors: Li Zili , Benade A. H.
Published: October 2005

The concept of junction inertance at the joint between two axisymmetric waveguides of different tapers arises from the nonaxial rearrangement flow and may be understood in terms of the imaginary wave impedance of the locally excited evanescent modes. The cases considered consist of cylindrical pipes with infinitely long conical terminations of different angles. In these cases, the terminal impedance of the pipe can be written as Zt = jwMj + Zcone, where Mj is the junction inertance and Zcone is the parallel combination of Mc, conicity inertance of the cone, and R0, the characteristic impedance of the pipe. Experiments were performed over a frequency range of 150 Hz–15 kHz and reflection coefficients were measured for cones with half-angle 10, 32, and 90 deg. The results showed that at high frequencies (above 8 kHz for pipe radius a = 10 mm), the effect is negligible for all cases. For 10 deg, Mj is 0.03(a/c)R0 in a range of 4–6 kHz, where c is the speed of sound. At low frequencies (below 3 kHz), Zt has the form of jw(Mj + Mc); to separate Mj and Mc becomes more complicated. Several cases will be discussed. [Work supported by NSF.]
Modal propagation in ducts lined with elastic porous materials
Authors: Bolton J. S. , Shiau N. M.
Published: October 2005

The characteristics of sound propagation in ducts lined with either locally or bulk reacting material are well known. The latter material is generally assumed to be homogeneous and capable of supporting only a single longitudinal wave and is usually modeled as a rigid-framed porous material. It has recently been demonstrated both experimentally and theoretically that elastic porous materials of the type used in noise control (i.e., relatively stiff, partially reticulated foam) can support two longitudinal waves: the frame wave and the airborne wave. In this paper, Scott's treatment of extended reaction duct linings is modified to allow for this observation. Equations governing the three-dimensional propagation of each wave type within the material are presented along with the appropriate boundary conditions at the duct/lining interface. The effects of finite frame elasticity are demonstrated by a comparison of the attenuation and phase speed of the first several duct modes for elastic porous linings and the equivalent rigid porous linings.
Ultrasonic Bragg imaging of flaws
Authors: Na Jeong Kwan , Breazeale M. A. , Leroy Oswald
Published: October 2005

A superficial crack on an aluminum plate becomes an internal flaw when covered by a second plate. Ultrasonic waves are caused to resonate between the external surfaces of the plates and produce transmission maxima characteristic of Lamb modes in the plates. The transmitted wave fronts in a liquid, modified by the presence of the flaw, are now used to diffract light at the Bragg angle. The Bragg diffraction orders contain images of the ultrasonic wave fronts and, hence, can be used to image the internal flaws. Characteristic flaws are shown and resolution limits are discussed. [Research supported by the U.S. Office of Naval Research and by the UT-ORNL Science Alliance.]
Accurate and precise assessment of pulsatile volume blood flow by time domain correlation
Authors: Hein Ilmar A. , O'Brien William D.
Published: October 2005

An ultrasonic flow velocity measurement technique using time domain correlation has been developed to accurately and precisely measure the axial flow velocity of liquid in a circular vessel. This technique can be used to estimate the volume flow in a circular vessel without any previous knowledge of the vessel size, flow velocity profile, or transducer measurement angle. Continuous flow has been measured with an overall uncertainty of less than 15%. Pulsatile flow has been estimated by measuring flow velocity at the center of the vessel. Results indicate that the accurate and precise measurement of pulsatile flow of human blood by time domain correlation is possible, and the application of this technique in the diagnosis of various thrombosis in the lower limbs is being studied.
Comparison of two multichannel tactile aids for the hearing-impaired
Authors: Potts Susan M. , Weisenberger Janet M.
Published: October 2005

Two multichannel tactile devices for the hearing-impaired were compared in tasks using acoustic stimuli of varying levels of complexity. One device was a 16-element linear vibratory array worn on the forearm, which displayed activity in 16 overlapping frequency channels. The other device utilized 16 channels in a similar stimulus processing strategy, but delivered the tactile stimulation to a linear electrocutaneous array worn on the abdomen. Subjects were tested in tasks including phoneme discrimination in pairs of rhyming syllables, phoneme identification in larger sets of rhyming syllables, learning of a list of words, and connected discourse tracking. All stimuli were presented live-voice by a female talker, and lipreading was permitted only in the tracking task. Results showed both devices to be good transmitters of manner and voicing features of articulation, but poor transmitters of place features. Differences between the two devices were found only at the level of connected discourse tracking. Results are discussed in terms of differences between the two devices in processing strategy, location of stimulator array, and type of transducer. [Work supported by NSF and NIH.]
Lingual vibrotactile magnitude estimation and cross-modality matching: Aging effects
Authors: Randolph-Tyler Elizabeth , Fucci Donald , Petrosino Linda , Harris Daniel
Published: October 2005

Lingual vibrotactile suprathreshold sensation magnitudes were investigated across four age groups (mean ages = 7.8, 19.3, 45.2, and 57.0 years) by employing the psychophysical methods of magnitude estimation and cross-modality matching. Lingual vibrotactile stimuli were presented in combination with auditory stimuli for the cross-modality matching task. For lingual vibrotactile magnitude estimation, both the upper and lower power functions were steeper for the oldest age group. The power functions for cross-modality matching in which the vibratory stimulus was the standard showed asymptotic growth at about 25-dB sensation level for the three older age groups, but not for the youngest age group. Straight-line power functions were obtained for all age groups on the cross-modality matching task when the auditory stimulus was the standard, with the older aged subjects making larger lingual vibrotactile magnitude adjustments to the lower level auditory stimuli than the younger aged subjects. In summary, age-related response differences did occur at suprathreshold levels of vibrotactile stimulation, and the psychophysical techniques employed appeared to be a noninvasive way to make judgments about suprathreshold functioning of the human tactile system as it changes with age.
Tactile sensation in hands exposed to vibration: A pilot study
Authors: Brammer A. J. , Piercy J. E. , Auger P. L. , Nohara S.
Published: October 2005

Three methods are compared for assessing impaired tactile sensation in vibration-exposed workers: a medical examination including traditional neurological tests, and refined measures of vibrotactile and gap perception. Of 28 subjects, 21 were judged free of confounding factors (13 forestry workers exposed to chain saw vibration, aged 28 years ± 4 s.d., and 8 laboratory workers not exposed to vibration, for comparison, aged 34 ± 3 years). The measurements of vibrotactile perception were performed over a wide frequency range (2–400 Hz) to permit separate assessment of the three different types of mechanoreceptors—Pacinian corpuscles, Meissner corpuscles, and Merkel disks. The gap perception was measured with a newly improved aesthesiometer. Preliminary analysis of the results indicates that measurements of vibrotactile perception particularly can detect sensory changes in the fingers not consistently found by conventional clinical tests.
Response time to a sentence verification task as a function of LPC narrow-band processing and bit error rate
Authors: chmidt-Nielsen A. , Kallman Howard J.
Published: October 2005

The comprehension of narrow-band digital speech with bit errors was tested using a sentence verification task. The difficulty of the verification task was varied by using predicates that were either strongly or weakly related to the subjects. (A toad has warts./A toad has eyes.) In addition, half of the sentences were about category relationships, and half were about property relationships. (A salmon is a bird./A camel has horns.) The test conditions included unprocessed speech and speech processed using a 2400 bit/s linear predictive coding (LPC) voice processing algorithm with random bit error rates of 0%, 2%, and 5%. In general, response accuracy decreased and reaction time increased with LPC processing and with increasing bit error rates. False sentences took longer to verify than did true sentences, but there were fewer errors for the false sentences. Weakly related true sentences and strongly related false sentences were more difficult than their counterparts. Interactions between sentence type and processing conditions will be discussed.
Perception of natural and vocoded sentences among English monolinguals and German-English bilinguals
Authors: Mack Molly
Published: October 2005

In the present study, the perceptual performance of 24 English monolinguals and 24 German-dominant German-English bilinguals was subjected to detailed analysis. Stimuli consisted of 57 semantically anomalous natural and vocoded English sentences. Results revealed that the monolinguals made an average of 5.92 errors and the bilinguals 66.58 errors in the natural condition, while the monolinguals made an average of 30.58 errors and the bilinguals 83.17 errors in the vocoded condition. For both groups, phonemic errors predominated, although approximately 30%–40% of the errors were morphosyntactic and/or lexicosemantic. {These latter results were essentially in agreement with previous findings [M. Mack and B. Gold, MIT Lincoln Laboratory Tech. Rep. 703 (1985) and J. Acoust. Soc. Am. Suppl. I 77, S10–S11 0985)].} Further, the bilinguals' responses to the vocoded stimuli suggested that they were employing a theory-driven rather than a data-driven response strategy, presumably due to the difficulty of the task. [Work sponsored by the Department of the Air Force.]
Listener-talker interaction: Is there an “autophonetic” effect?
Authors: Hawks John W. , Miller James D.
Published: October 2005

Based on recent physiological evidence for neural selectivity to self-produced song in the auditory system of the White-Crowned Sparrow, a hypothesis stating that the human perceptual mechanism for speech may be most acute for self-produced speech sounds was tested. A test of the ability to identify monosyllabic words was presented in a noise background. The same subjects served as both talkers and listeners. A small, but statistically nonsignificant, advantage is found when listener and talker are the same person. Additionally, while variation between talkers was nearly twice the variation between listeners, the performance of a particular talker-listener pair could be predicted by a simple equation. This equation gives equal weight to the talker's and listener's average performance, and thus the talkers, by virtue of their greater variance, tend to have a greater influence. [Work supported by NIH.]
The acoustics of “black smoker” hydrothermal plumes
Authors: Palmer David R. , Rona Peter A.
Published: October 2005

High-temperature “black smoker” hydrothermal plumes occur when seawater that has penetrated into the oceanic crust and assimilated heat from magma is discharged from vents located at the axis of a mid-ocean ridge. The acidic, metal-rich, discharge mixes with alkaline, oxidizing seawater, and a fine suspension of sulfide particles is precipitated and convected by the flow. Vents fields have now been found at both fast and slow seafloor spreading centers and may be a ubiquitous feature of mid-ocean ridges. A review of the progress made in using underwater acoustics to study black smoker plumes is presented. Both active and passive techniques are being investigated. Active techniques involve a high-frequency monostatic sonar mounted on a submersible. Analysis of the amplitude and phase of the signal backscattered from the plume provides information about the three-dimensional shape of the plume as well as estimates of the flow-velocity field of the discharging fluid. Passive techniques use bottom-mounted hydrophones to listen to the very low-frequency, hydrodynamic noise generated by a plume. These noise signatures have potential use in locating, characterizing, and monitoring plume sites and in determining the contribution plume noise makes to the overall ambient noise field in the ocean.
Aerosol agglomeration in high-intensity acoustic fields
Authors: Shaw David T. , Patel Sushil
Published: October 2005

The operational conditions for the application of acoustic agglomeration (AA) as a preconditioner for the control of particulate matter under high temperature and pressure are discussed based on recent data on the acoustically induced turbulence. The AA kernels in various regimes are evaluated for various performance parameters, including acoustic intensity, frequency, residence time, gas temperature, and pressure. The turbulent interaction is found to be the dominant process for particle agglomeration. Since AA is not particle-size dependent, it is ideally suited for preconditioning, and subsequent removal of the submicron particles. A computer model for the prediction of AA has been developed and good agreements have been found between the theory and experimental data. Based on a comprehensive evaluation of the techniques for the generation of high-intensity sonic field and problems in their applications, a dirty-air chopper has been built and tested with very favorable results.
Early lateral reflections in modern concert halls
Authors: Cremer Lothar
Published: October 2005

It is agreed that part of the acoustical qualities of the “shoe box” halls of the 19th century results from their nearly parallel sidewalls and from “cue ball” reflections below the soffits of their balconies. This arrangement conflicts with the enlargement of the stage and audience capacity and with the modern expectation of comfortable seating and full view of the stage from each location. Three possibilities for overcoming these difficulties, based on the author's recent consulting work, are discussed: (a) Placement of a large part of the audience behind the stage but not lateral to it (Madrid. under construction). This solution is unsatisfactory for visual performances; (b) providing strong early reflections from proscenium towers which focus the sound in the vertical plane but diffuse it in the horizontal. This solution, proved by echograms, can be used in even a very broad (26-m) stage, such as the Salle Apollon, Nice, opened in 1985. Subdivision of the audience by “vineyard” steps produces early lateral reflections; (c) the use of vineyard steps, allowing an optimal and simple “trapezium terrace” system (Las Palmas, Gran Canaria, planned). Here, the visually preferred diverging fan-shaped plan is compensated acoustically by the converging steps of the trapezium terraces, which could easily be inclined so that they provide early lateral reflections to the middle of the terraces. The limits of this geometrical behavior are quantitatively investigated according to Fresnel's formula. The more diffuse reflections at lower frequencies are profitable for the late reverberant sound.
Roving level tone in noise masking
Authors: Kidd Gerald , Mason Christine R. , Brantley Merry A. , Owen Grace A.
Published: October 2005

The results of tone in noise detection experiments have long formed an empirical basis for the notion of the “critical band” and have led to the development of the “energy detection” model. In this study, the detectability of tones in bands of random noise was measured for conditions in which the overall level of the noise was roved randomly from interval to interval of each experimental trial. The functions relating masked tone threshold to noise bandwidth for the roved conditions were identical to those obtained when no rove was employed at “supracritical” bandwidths. At “subcritical” bandwidths, the detection thresholds were higher for the roved conditions, but were still lower than would be predicted from arguments based purely on energy detection. These results suggest that the traditional critical band and energy detection models should be modified to account for discrimination based on spectral shape or waveshape. [Work supported by NIH and NMRDC.]
Exact jnd functions for a generalized McGill-Goldberg counting model
Authors: Hellman William S. , Hellman Rhona P.
Published: October 2005

In an earlier work [W. S. Hellman and R. P. Hellman, J. Acoust. Soc. Am. Suppl. 1 79, S34 (1986)], a generalization of the McGill-Goldberg counting model was presented. It was demonstrated that loudness functions, consistent with experiments, could be determined from intensity jnd functions that obeyed both the power-function near miss and Weber's law. The central formula for the model is the integral relation N(I)1/2 = (h/2)∫dI /[IJ(I)] + a, where h and a are constants, and N(I) and J(I) are the neural count and input jnd functions, respectively. Following McGill and Goldberg, the model was developed using a first-order approximation for the jnd induced change ΔN. To determine just how appropriate the first-order approximation might be, the results of boot-strapping the model are shown. That is, given the derived neural-count functions, the “exact” associated jnd functions are generated. For a power-function near miss as original input, an “exact” jnd function that exhibits a low-intensity deviation from power-function behavior is obtained. When the input jnd function obeys Weber's law, it is found that the boot-strapped jnd function is constant over a wide range of intensities. These results are compatible with psychophysical data. [Work partially supported by the Rehabilitation Research and Development Service of the VA.]
Comodulation masking release (CMR) as a function of signal frequency, flanking-band frequency, masker bandwidth, and flanking-band level
Authors: Schooneveldt Gregory P. , Moore Brian C. J.
Published: October 2005

Thresholds for 400-ms signals were measured in the presence of a continuous narrow-band noise centered at signal frequencies (fs) ranging from 250–4000 Hz in 1-oct steps. The masker was presented either alone or together with a second band of noise (the flanking band) whose envelope was either correlated with that of the on-frequency band or was uncorrelated; its frequency ranged from 0.5 to 1.5 fs. CMR was defined as the difference between thresholds for the correlated and uncorrelated conditions. The CMR showed two components: a broadly tuned component occurring at all signal frequencies and all flanking-band frequencies, and a component restricted to flanking-band frequencies close to fs, which increased in magnitude with increasing fs. The second component was probably not a true CMR, but resulted from “beating” between the carrier frequencies of the two masker hands. Additional experiments, in which the bandwidth of the masker and the level of the flanking band were varied, support this interpretation. The first component, which is probably a “true” CMR, was only about 3 dB. [Work supported by the MRC, U.K.]
A multichannel tactile aid reduces articulation errors during spontaneous and imitative speech
Authors: Gavin William J. , Mathay Melinda K. , Harr Debra
Published: October 2005

Five tactually experienced, hearing-impaired children were tested in two sessions wearing the tactile aid during both sessions but activated during only one session. Subjects received auditory and visual information throughout. Each session consisted of a spontaneous and an imitative speech task, each eliciting six productions of four monosyllable and four bisyllabic words. Recorded responses were transcribed using broad IPA techniques. Four of the five children produced fewer errors with the aid active compared to the nonactive condition during both the spontaneous and imitative tasks. The mean percent of errors in nonactive and active conditions for spontaneous task was 27% and 26%; for imitative task, 19% and 17%. A 2×2 randomized block analysis-of-variance test showed a significant main effect for task (p <0.001). The tactile aid condition approached but did not reach significance (p <0.10). The data are extremely encouraging. While the act of producing speech is largely a habitual motor response, removal of the tactile information resulted in a measurable increase in articulation errors.
Development of a unique passive level-dependent hearing protector
Authors: Allen C. H. , Berger E. H.
Published: October 2005

The need for protection of hearing against intermittent high-level sounds and the opposite need for retaining hearing sensitivity during low-level intervals, have led to the development of level-dependent, commonly called “nonlinear,” hearing protectors. This paper deals with the design and refinement of passive means for automatically and instantaneously altering the amount of attenuation, provided at the ear, in response to the incident sound level. The early successful development of a nonlinear earplug for protection against gunfire is followed through laboratory and field tests, and the advantages and limitations of such an earplug are discussed. The more recent application of a nonlinear orifice to earmuffs, for various applications, introduces several new difficulties. Their identification and the means that have been found suitable for use in practical level-dependent earmuffs are discussed. Test data are presented showing acoustic characteristics over a range of incident sound levels from 100 dB, or lower, to 160 dB, or higher. Results obtained with steady state, broadband, and narrow-band noise are compared and are shown to be similar to results obtained with impulse noise, such as experienced, for example, from gunshots or forging hammers.
History and development of active noise reduction hearing protection
Authors: McKinley Richard L.
Published: October 2005

Ever since Lueg's 1936 patent, the application of active noise reduction technology to hearing protection has been a goal of numerous research groups. This paper will describe the various efforts to apply active noise reduction technology to earcups over the time span from 1936 through the present. Each of the various efforts will be described in terms of basic cancellation technique, hardware realization, and both laboratory and field performance when available. In addition, a working model of the current active noise reduction headset developed jointly by the Air Force and Bose Corporation, similar to the unit used on the around the world flight of the Voyager, will be presented.
Separation of simultaneous voices
Authors: Stubbs Richard J. , Summerfield Quentin
Published: October 2005

People with sensorineural hearing impairments find the task of separating speech from interfering noises particularly difficult. For this reason, the ideal hearing aid would selectively amplify a target voice while attenuating competing voices and other background noises. In exploring possible noise-reduction strategies for future aids, two algorithms for separating the voices of talkers who are speaking simultaneously, with periodic excitation at similar overall intensities, are evaluated. Both approaches are pitch based and exploit the regularity in the harmonic structure of voiced speech. The first involves attenuating the harmonics of the competing voice via a cepstrumlike representation. The second method is derived from the procedure for harmonic selection [T. W. Parsons, J. Acoust. Soc. Am. 60, 911–918 (1976)]. Perceptual evaluation of the two processing methods, in a test involving the separation of concurrent vowel pairs synthesized on fixed fundamental frequencies, has demonstrated an increase in performance for both normal-hearing and hearing-impaired subjects. The results of experiments involving the separation of simultaneous sentences containing a high proportion of voiced excitation and varying fundamental frequencies will also be discussed.
Input impedance and sound radiation of the piano sound board
Authors: Wogram Klaus
Published: October 2005

The soundboard of the piano acts as the signal converter from the string vibration to the airborne sound. The type of mounting of the soundboard on the back, as well as the ribs, influences both the sound radiation and the input impedance that acts as a load for the strings as vibration generators. Furthermore, the iron plate affects the effectiveness of the soundboard. Extensive measurements have shown that mass loading by the ribs is in general too large to compensate for the unisotropism in its modulus of elasticity. This causes an additional damping and sometimes an increase of the decay rate of the piano sound.
Vibrations of a piano soundboard: Modal analysis and finite element analysis
Authors: Kindel Joseph , Wang I-Chih
Published: October 2005

Modal analysis measurements have been made on two concert grand piano soundboards and a finite element model to describe the vibrational characteristics of these soundboards has been developed in order to explore the possibility of using both of these techniques in the designing of new soundboards. To provide an experimental basis for the model, modal analysis measurements were made on two piano soundboards, each mounted in a rim. Then a finite element model of the soundboard was constructed. The resonant frequencies and mode shapes of the first few modes of the finite element model match very well with those found experimentally using modal analysis. The correspondence between the modal analysis and finite element analysis results is very good and these techniques will be of value in designing new piano soundboards. [Work supported in part by Baldwin Piano and Organ Co., Cincinnati, Ohio.]
Absolute pitch: A methodological fallacy
Authors: Rasch Rudolf A.
Published: October 2005

The research on absolute pitch (AP) has already celebrated its first centenary. So far, researchers (and the public) have divided listeners into AP possessors and non-AP possessors. Analyses of the tasks included in AP performances show that it is unsuitable to speak about AP or RP (relative pitch) without qualification. Certainly there are large individual differences in the capacity of naming the pitch of a tonal sound presented without prior reference. But responses are bound to be (more or less) normally divided, with the standard deviation as measure of performance. In such a view, the decision of whether or not a person is an AP possessor depends on the category width of the labels, which means that the distinction between AP and non-AP is relative, not absolute.
Use of matched fields and other methods to locate sound sources or reflectors in the ocean
Authors: Bucker Homer P. , Schey Philip W.
Published: October 2005

A fundamental difference in locating a sound source underwater and a visual source in our everyday experience is that the sound waves are strongly bent by the variation of sound speed as a function of depth and range in the ocean. With the advent of inexpensive computing machines, it is now possible to begin to unscramble the refraction and reflection effects of underwater sound propagation to “see” the location of underwater sources and reflectors of sound. This paper reviews earlier theoretical and experimental work in matched field processing where the typical problem has been to determine the range and depth of an underwater source using narrow-band signals received at a vertical line array. In future years, it is clear that these methods will be expanded to cover wideband signals and reflective as well as active sources. A method will be discussed where correlations are made between calculated and measured plots of sound pressure as a function of frequency and time. [Work supported by NOSC IR Program.]
Matched field processing: A detection and estimation theory overview
Authors: Baggeroer A. B. , Kuperman W. A. , Schmidt H.
Published: October 2005

Matched field processing in weak signal/noise situations requires maximum exploitation of the physics of both the signal and noise structure as well as optimum methods for the signal processing. In recent years, numerical models for the physics have advanced to the point where many of the detection and estimation theory results available in the signal processing literature can now be used for many acoustic environments. Fundamentally, matched field processing is known as the detection/estimation in colored, or correlated, noise problem in the signal processing literature. As such, ambiguity functions, Cramer-Rao bounds, and spectral measures of performance can be derived from a basic, well-known theory. Generalizations to high-resolution algorithms and environments with partial coherence are also suggested. Finally, results for the less studied problem of matched field processing performance using estimated covariance matrices can be addressed.
Linguolabials
Authors: Maddieson Ian
Published: October 2005

A number of Austronesian languages spoken in Vanuatu have a series of linguolabial consonants (i.e., stops, nasals, and fricatives produced by articulation of the tongue blade with the upper lip). This paper presents the first detailed study of the production and acoustic nature of linguolabials based on data from three of these languages. These sounds may be produced with varying degrees of retraction of the upper lip and protrusion of the tongue, but all involve a vocal tract configuration with a narrow cross-sectional area in the front region. In linguolabial continuants the second resonance of the vocal tract is higher than it is in labials, and the burst of the linguolabial stop has greater energy at high frequency than a labial stop. These segments thus have some similarities with dental segments. Linguolabials are perceptually difficult to distinguish from dental or labial sounds, depending on phonetic context. The occurrence of contrast between labials, linguolabials, and dentals in these languages indicates that quite subtle details in the spectrum must be adequate to signal differences in place of articulation. [Work sponsored by NSF.]
The relationship between vowel variation and vowel-to-vowel coarticulation across languages
Authors: McAdams Brian
Published: October 2005

The amount of coarticulatory vowel variation within a language may be dependent on the size and distribution of the vowel inventory within the vowel formant space [P. A. Keating and M. K. Huffman, Phonetica 41, 191–207 (1984)]. Similarly, it has been suggested that the extent of vowel-to-vowel coarticulation in a language varies in proportion to the degree of vowel variation within the language [S. Y. Manuel and R. A. Krakow, Haskins Status Report No. 77/78, 69–78 (1984)]. Manuel and Krakow supported this idea with evidence comparing Swahili and Shona (5-vowel systems) to English (12-vowel system). The present study compares vowel-to-vowel anticipatory and carryover coarticulation in Japanese and Hausa (10-vowel systems, with different vowel distributions) to German (14-vowel system). Three speakers of each language read bVbV “words” in lists and in frame sentences. The effects of phonemic vowel length and phrasal context on coarticulatory vowel distribution are also considered.
Perception of Persian uvular and velar stop consonants by speakers of American English
Authors: Polka Linda
Published: October 2005

Recent cross-language studies by Werker and Tees [J. Acoust. Soc. Am. 75, 1866–1878 (1984)] describe difficulties in English speakers' perception of a Thompson glottalized uvular-velar stop contrast. However, the acoustic information that differentiated the contrasting phones was difficult to specify. The present study extends the examination of non-English place contrasts by investigating native English speakers' ability to perceive a nonglottalized uvular-velar contrast in Persian (Farsi). Multiple instances of velar and uvular stop consonants produced in several VCV contexts by a native speaker of Farsi were presented. Correct identification of the medial consonant varied systematically as a function of vowel context from very few errors to near change performance. Acoustic analysis revealed systematic F2 and F3 formant transition differences between uvular and velar consonants produced in the same vowel context. Variations in voicing offset (murmur) were also observed in several vowel contexts. These results further our understanding of the role of linguistic experience in the perception of phonetic categories. [Research supported by NINCDS.]
Acoustic study of Russian vowel allophones
Authors: Keating Patricia A.
Published: October 2005

The five Russian vowels vary in auditory quality depending on their consonant contexts; one traditional reference gives several major and minor impressionistic allophones for each stressed vowel. The consonants are reported to be relatively unaffected by their vowel contexts, and to block vowel-to-vowel interactions. This paper presents a study of Russian vowels in CV, VC, and CVC syllables for three speakers. Preliminary results for vowels /i/ and /a/ across a wide variety of contexts suggest that the allophonic variation is of three kinds. First, there is target variation: Each of these vowels has one target in some contexts, and a second target in other contexts. Second, some additional vowel variation is due to undershoot of those targets after extensive F2 and F3 transitions. Finally, however, in many contexts the formants do reach their targets, despite the extensive transitions. In these cases, the perceived vowel quality variations seem to arise from differences in the transitions alone. [Work supported by NSF.]
Coarticulation in VCV sequences in Arabic
Authors: Hussein Lutfi
Published: October 2005

Vowel-to-vowel coarticulation in VCV utterances has been the subject of several studies. Ohman [J. Acoust. Soc. Am. 39, 151–168 (1966)] found that vowels in VCV utterances in English and Swedish have some transconsonantal effect on one another. He also found some evidence suggesting that secondary articulation features, like palatalization in Russian, block coarticulation. Action theorists, such as Fowler [J. Exp. Phon. Gen. 112, 386–412 (1983)], explain V-to-V coarticulation in terms of timing; that is, they claim that vowels in speech production are underlyingly overlapping and consonants ride on top of the vowels. This suggestion implies that intervocalic consonants, whether they have secondary features or not, do not block coarticulation. Keating [UCLA WPP 62, 1–13 (1985)], on the other hand, explains it in terms of autosegmental phonology. She places the features for vowels and consonants on two separate tiers, and leaves consonants unspecified for vowel features, so that V-to-V coarticulation affects an interpolation between vowel targets. Keating's model implies that consonants that have secondary articulation (i.e., vowel features) must block coarticulation. A preliminary analysis of VCV utterances in Arabic shows that pharyngealized consonants indeed tend to block coarticulation, a finding which supports Keating's prediction over Fowler's.
Glottal source-vocal tract acoustic interaction
Authors: Fant Gunnar , Lin Qi-guang
Published: October 2005

Earlier work reported in the STL-QPSR (Speech Transmission Laboratory, Quarterly Progress and Status Report, KTH, Stockholm) each year since 1979 has been extended to the modeling of the supraglottal impedance to include five formants and a time span of analysis to embrace several successive glottal periods. The acoustic interaction is highly nonlinear and may give rise to spectral peaks between formants. This is largely due to nonlinear superposition ripple originating from previous excitations. At a high F0, coinciding with F1, the air consumption is minimized as previously shown experimentally by Rothenberg. One aspect of the interaction is intraglottal variations in formant bandwidths and frequencies. The modeling of superposition at increasing F0 and constant articulation shows how the formant amplitude range at in-phase and out-of-phase superposition decreases due to intraglottal losses. In addition, there appear nonlinear deviations such as a weak tendency of synchrony between the second and first formant amplitude dependency of F0. A constant leak added to the normal glottal area function has been modeled as a first step toward the study of leaky voices. Here, the apparent linear-type formant ripple in the maximally closed phase is a memento for inverse-filtering criteria. Implications for female and child phonations are discussed.
A multidimensional scaling study of normal voice quality in females
Authors: Gelfer Marylou Pausewang
Published: October 2005

Little is currently known about the perceptual dimensions listeners use in discriminating female voices and how these dimensions relate to perceptual rating-scale judgements. The purpose of this study was to examine these issues for normal female voices. In addition, the judgments of 20 naive listeners and 20 experienced listeners (speech pathologists) were compared. Listeners provided dissimilarity judgments of sentences produced by 20 females (24–25 years). The listeners also rated each voice on 17 perceptual rating scales (e.g., high pitch-low pitch, clear-hoarse). Results of the multidimensional scaling (MDS) analysis produced a five-dimensional solution (RSQ = 0.509). A stepwise linear regression related the perceptual attributes of pitch, age, loudness, “liveliness,” and pitch variability/quality to the five MDS dimensions. When listener groups were compared, the experienced listeners relied on pitch somewhat more than the naive listeners, while the naive listeners utilized the pitch variability/quality dimension to a greater degree. This study demonstrates that listeners' perceptual ratings can be significantly correlated with perceptual dimensions derived from MDS analysis. [Research supported by BRSG Grant S07 RR07031, DRR, NIH.]
Cross-language study of children's prosodic development—IV: Comparison of 4- and 5-year-old French-, German-, and Swedish-speaking children's TAKI productions
Authors: Luczycki Denise , Allen George D.
Published: October 2005

Six 4-year-old and six 5-year-old French-, (Austrian) German-, and Swedish-speaking children were engaged in an experimental task requiring them to first learn and then produce the names of toys. Each pair of toys was associated with a pair of names, which differed in prosodic contour, one pair being phonologically simple (/'taki/ versus /ta'ki/), one slightly more complex (/'smopfi/ versus /smop'fi/), the third much more complex (/'gluvistrap/ versus /gluvi'strap/). The children's spontaneous productions of these names were tape recorded and analyzed auditorily and spectrographically for their prosodic features (F0, duration, and intensity). Productions of the prosodically simpler forms were more likely to be prosodically correct than the more complex forms, for all children. The pattern of errors was different, however, among the three language groups. For example, the French children tended to drop final weak syllables, whereas the Austrian children showed a reverse tendency, dropping initial weak syllables, and the Swedish children did neither. Each of these error patterns conforms to the phonology of the children's target language. [Work supported in part by NSF.]
Tectorial membrane: Static mechanical properties in vivo
Authors: Zwislocki Jozef J. , Chamberlain Steven C. , Slepecky Norma B.
Published: October 2005

In a mammalian cochlea, stimulation of the hair cells must be associated with shear motion between the organ of Corti and the tectorial membrane. Knowledge of the mechanical properties of the tectorial membrane in its natural environment is essential for our understanding of this process. Recently, the present authors have been able to visualize the tectorial membrane in live Mongolian gerbils by fenestrating the scala media of the second cochlear turn without disturbing Reissner's membrane. The anatomical configuration of the cochlea in these animals allowed us to observe the tectorial membrane over its entire width. A micropipette was inserted into the membrane and moved radially and longitudinally approximately parallel to the membrane surface. When vitally stained with Janus green, the membrane showed astonishing toughness and resilience in both directions. Its deformation patterns resembled those of a rubber band. When vitally stained with Alcian blue, its tensile strength was decreased, and it tore rather easily. Subsequent microscopic investigation of the membrane in vitro showed that the two stains bind to different structures.
Perilymph volume flow measured under physiological conditions
Authors: Ohyama Kenji , Salt Alex N. , Thaimann Ruediger
Published: October 2005

This study made use of an ionic tracer (trimethylphenylammonium, TMPA) to mark perilymph in one region of the cochlea. Perilymph flow was assessed by monitoring tracer movement to other regions with ion selective electrodes. Small, nontoxic, quantities of tracer (typically a 50-nl bolus of 150 nM TMPACI) were required, since concentrations as low as 1 μM were readily detected. Stringent precautions were taken to seal the injection and recording electrodes into the perilymphatic scalae so that no artifactual flow was induced by perilymph leakage. Results were compared with a mathematical model of tracer dispersion by volume flow and passive diffusion. For scala tympani, TMPA dispersion corresponded to a flow rate of 1.6 nl/m in the apical direction. This rate was significant (p < 0.05), although the physiological effects of such a low flow rate are presumed to be negligible. Perforation of the cochlear apex resulted in flow rates of over 1 μ1/m, almost 1000 times the physiological rate. In scala vestibuli, no significant flow could be detected under normal conditions. These results demonstrate that in the sealed state, longitudinal volume flow of perilymph is extremely low. Artifactual volume flow is readily induced by procedures which involve perforation of the otic capsule. [This work supported by NIH.]
The contribution of absorption to tissue attenuation
Authors: Parker Kevin J.
Published: October 2005

The relative contributions of ultrasonic scattering and absorption to the overall attenuation coefficient of tissues is an important issue in diagnostic and therapeutic ultrasound. This paper presents a range of experimental evidence and case studies which support the postulate that absorption dominates attenuation in soft tissues. Comparisons of tissue absorption coefficients (using thermal pulse decay) and attenuation coefficients (using radiation force insertion loss) are given, along with results of tissue homogenization experiments. Other evidence is gained from measurements of total scattered power, and clinical observations of backscatter and attenuation of focal lesions. Finally, comparisons are made of the attenuation of dilute protein solutions and whole liver specimens, in order to establish the role of multiple relaxation mechanisms at the macromolecular level in the overall attenuation coefficient of mammalian liver tissue.
Energy transmission into the human hand from vibrating tools
Authors: Reynolds Douglas D.
Published: October 2005

A method for calculating power transmitted to the hands of operators who use vibrating hand tools is presented. Results that relate to a comprehensive multidisciplined NIOSH field study of several hundred chipper and grinder workers who used pneumatic hand tools are discussed. These results indicated that the total power in the frequency range of 6.3 to 1000 Hz transmitted to the hand ranged from 1080 to 7230 J/s for the chisel and from 0.852 to 157 J/s for the handle of chipping hammers. For pneumatic grinders the power transmitted to the hands of the tool operators was in the range of 0.00658 to 0.235 J/s over the same frequency range.