bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase reconstruction: Pitfalls and methods in homomorphic deconvolution
Authors: Gabrielson Thomas B.
Published: October 2005

Success in deconvolution of signals by homomorphic techniques depends on accurate reconstruction of the continuous phase spectrum. The usual algorithms for this process—integration of the phase derivative, adaptive integration, and iterative phase ramp removal—all have subtle but serious flaws of which the user must be aware. Recent processing of high signal-to-noise ratio, broadband geoacoustic data uncovered these problems and led to the development of an alternative procedure incorporating an error monitor. This paper summarizes the evaluation of phase reconstruction processes and illustrates their pitfalls when applied to measurement signals. Also, the error monitoring procedure is described along with applications to ocean geoacoustic measurements.
Microprocessors in collection and analysis of Tursiops truncatus echolocation data
Authors: Kadane J. , Penner R. H. , Au W. W. L. , Floyd R. W.
Published: October 2005

A 6502 microprocessor-based system (Apple II) was used to collect and analyze parameters of the echolocation signals emitted by a bottlenosed dolphin in various target detection tasks. The parameters measured included: the number of transmitted clicks, peak source level of each click, time of occurrence of each click (milliseconds), the pulse train duration, and interclick intervals. Switch closures from response paddles, corresponding to target present and/or target absent decisions by the animal, were interfaced with the microprocessor for collection of response category and latency data. The results of these analyses were displayed on a CRT monitor in alphanumeric and graphic formats. All hardware was microprocessor controlled via either machine or BASIC language. Echolocation clicks were received by an EDO Western 6166 hydrophone, amplified, and passed through a 60–160 kHz bandpass filter and peak detected. When the received signal amplitude exceeded a pre-set level, a flag was set in the microcomputer and the peak signal level was latched. The microprocessor continually, tested the flag status, and when the flag was set, stored the peak amplitude of the signal and time of occurrence for post trial analysis and later transferal to permanent disk storage. The software allowed a trigger to be sent to a transient recorder (i.e., Biomation 810 or Gould 4000 digital oscilloscope) when certain predetermined conditions such as amplitude and click number, were met. The transient recorder then digitized the click for later transfer to the Apple II computer (through a parallel interface). Analysis of other signal parameters could now be performed.
The effect of elevated train noise on reading ability: Followup report
Authors: Bronzaft Arline L.
Published: October 2005

The publicity generated by a study [Bronzaft and McCarthy, Environ. Behavior 7, 517–527 (1975)] reporting children's reading scores adversely affected by train noise, contributed to the selection of that school site for the first testing of resilient rubber pads in quieting noise on elevated structures. Further efforts resulted in the Board of Education equipping three of the noisiest classrooms with acoustic ceilings. After the pads were installed in the fall of 1979, teachers and students reported a quieter classroom atmosphere. In June 1980, reading scores for the last three years were studied. While the scores for the two years, prior to the noise abatement treatment, again showed children on the noisy side of the building lagging behind their counterparts on the quiter side, the scores for the 1979-80 school year indicated no differences between children on the noisy side and those on the quiet side. It is yet too soon to draw firmer conclusions.
The effects of subway/extraneous noise on children's psychomotor, cognitive, and perceptual performance
Authors: Hambrick-Dixon Priscilla Janet
Published: October 2005

The present study sought to ascertain whether an 80dB(A) random, continuous, nursery play period noise differentially affected psychomotor, serial memory words and pictures, incidental memory, visual recall, paired associates, perceptual learning, and coding performance of 5-year old children attending day care centers near and far from elevated subways. Subjects were administered psychomotor tasks at the beginning and end of a noisy or quiet play condition and cognitive and perceptual tasks during a noisy or quiet test condition. Factorial analyses revealed that only psychomotor performance was significantly impaired by the 80 dB(A) noise (p. < 0.04) and marginally, by the subway noise (p. < 10). The findings suggest that noise does not have a universal effect on children's performance; but rather, effects vary as a function of the task.
Experimental mapping of the flow field near a Helmholtz resonator in grazing flow
Authors: Charwat Andrew F. , Walker Bruce E.
Published: October 2005

The acoustic impedance of Helmholtz resonators placed in the boundary of a flow channel is observed to depend on the velocity of the external flow. A research program has been undertaken to map the local instantaneous velocity field in and above the orifice of a two-dimensional resonator mounted in a wind tunnel and excited externally at its resonant frequency, using split film anemometry and a micro-processor data acquisition system. The results disclose a distinct structure which is highly assymetric relative to the orifice. A net inflow exists at the upstream edge of the orifice and a continuous, albeit pulsating outflow occurs at the downstream edge. One can distinguish the formation and shedding of vortices from the orifice. The amplitude and phase of the dominant harmonic of the unsteady velocity waveform varies significantly across the orifice in a streamwise direction. Results of a numerical code which traces the motion of simulated particles through the measured flow structure will be presented, together with a discussion of the experimental technique and the correlation between the details of the flow and observed acoustical behavior of the resonator. [Research sponsored by NASA-Lewis Research Center.]
An evaluation of the cost effectiveness of control valve noise abatement methods
Authors: Brown Dave
Published: October 2005

This paper was motivated by practical difficulties met by industries in determining which methods of noise abatement should be used in design and remedial noise controls. These difficulties are perpetrated by a lack of confidence in predicted noise levels for valves in production installations. An analysis is presented to show the cost relationships between valve selection, pipe schedule changes, noise reducing flow elements and insulation of pipe runs. Allowance is made for the potential error in predicted noise levels.
Acoustic transmission matrix of a variable area duct or nozzle carrying a compressible subsonic flow
Authors: Miles J. H.
Published: October 2005

The differential equations governing the propagation of sound in a variable area duct or nozzle carrying a one-dimensional subsonic compressible fluid flow are derived and put in state variable form using acoustic pressure and particle velocity as the state variables. The duct or nozzle is divided into regions. The region size is selected so that the Mach number can be assumed constant in each region and the area variation in each region can be approximated by an exponential area variation. As a consequence, in each region, the state variable equation has constant coefficients. The transmission matrix for each region is obtained by solving the constant coefficient state variable differential equation. The transmission matrix for the duct or nozzle is the product of the transmission matrices. Solutions are presented for several geometries and flow conditions.
Transduction in optical fibers
Authors: Bucaro J. A.
Published: October 2005

Over the past several years, a significant research effort has been undertaken aimed at the development of fiber optic sensors. This paper will review from a fundamental viewpoint the various acousto-optic transduction mechanisms which take place in both single mode and multimode optical fibers, and which are being exploited in sensor applications. Various frequency regimes will be discussed covering static, sonic, and ultrasonic fields.
Optical hydrophone design
Authors: Cole J. H.
Published: October 2005

Underlying principles of optical hydrophone design will be discussed for both intensity modulated and interferometric sensors. The effect of these principles on hydrophone design will be related to current component and subsystem development. Finally, the performance of interferometric and intensity modulated hydrophones will be presented.
Accurate phase-measurement system for fiber-optic accoustic sensor
Authors: Bush Ira Jeffrey
Published: October 2005

A system has been developed to accurately demodulate the acoustically induced, phase-modulated signal produced by an interferometric fiber-optic sensor. The system utilizes phase-lock techniques to produce a feedback signal to the fiber interferometer that serves the dual purpose of maintaining phase lock and producing an estimate of the acoustic signal. The system is very unique in terms of simplicity of design, versatility, and accuracy of measurement. Its main features are insensitivity to laser intensity fluctuations, the ability to operate in adverse thermal environments, insensitivity to acute polarization rotation, and component minimization. The system was designed and set up at NRL-USRD, Orlando. It demonstrated impressive signal-to-noise levels indicative of the potential to sense very small signals. The theoretical model generated for the system confirms experimental results that demonstrate an accuracy of measurement to less than 1% error.
Representation of sound pressure and particle motion information in the midbrain of the goldfish
Authors: Fay Richard R. , Bolan Kim M. , Hillery Cynthia M.
Published: October 2005

Averaged evoked potentials (AEPs) recorded in and near the torus semicircularis of the goldfish midbrain using multiple electrodes were used to measure relative sensitivity to low (head vibrations) and high (loudspeaker stimulation) impedance acoustic signals before and after swimbladder deflation. The peak-peak voltage of AEPs elicited by 100 ms tone bursts (5 ms rise-fall times) were measured as a function of stimulus amplitude and frequency between 0.07 and 1 kHz. Swimbladder deflation caused a loss in sound pressure sensitivity (20–50 dB) which occurred across all frequencies tested approximately equally, and a small increase in vibration sensitivity particularly at low frequencies. Variation in sensitivity, frequency response, the slopes of input-output functions, the ratios between pressure and vibratory sensitivity, and changes in sensitivity following swimbladder deflation varied with electrode location. The goldfish midbrain is clearly not homogeneous with respect to auditory response. Several lines of evidence point to spatial separation of areas for processing sound pressure and motional stimulus parameters, and to interactions between them. [Work supported by NIH Grants 5R01NS15268 and 1K04NS00479.]
Neurophysiological mechanisms of temporal discrimination in the goldfish
Authors: Fay Richard R. , Passow Betty
Published: October 2005

Following the observation that phase-locking error in auditory neurons accounts for pure tone frequency discrimination behavior in the goldfish (R. Fay, Nature 275, 320–322), it was hypothesized that temporal discrimination using a broad class of quasiperiodic signals could be similarly explained. Temporal discrimination was studied psychophysically by classically conditioning goldfish to suppress respiration when presented with a slow sinusoidal change in the modulation rate (fm) of sinusoidally amplitude modulated (SAM) signals. The jnd for modulation period (ΔP ms) was measured as a function of fm (20–200 Hz) and of modulation depth, m, (100%-6.25%), for 800-Hz tone and noise carriers at 35 dB SL. Modulation period histograms were obtained for 60 auditory (saccular) neurons in response to the same set of SAM signals used in the psychophysical studies. For all modulated signals, the psychophysical ΔPs were linearly related to period histogram variance, indicating that measures of temporal neural error can predict temporal discriminability for a wide range of quasiperiodic signals. However, these results did not conform to the prediction from pure tone studies that ΔP is a linear function of the standard deviation of neural error. [Work supported by NIH grants 5 R01 NS 15268 and 1 K04 NS 00479.]
Lateralization of high-frequency noise with interaural time delays by monkeys (M. nemestrina)
Authors: Houben Dirk , Gourevitch George
Published: October 2005

Monkeys were trained to listen to a diotic burst of noise followed, after a brief silence, by a dichotic burst of interaurally delayed noise. The monkey was rewarded for responding on the left lever when the dichotic noise burst was leading at the left ear, and on the right lever when the dichotic noise burst was leading at the right ear. The magnitude of the binaural time differences and the side of the leading ear were selected at random from trial to trial. Interaural time delay threshold was taken as the delay correctly lateralized on 75% of the trials. Monkeys were tested with four noise bandwidths (100 to 800 Hz) centered at 2, 2.8, and 4.0 kHz. The obtained time difference thresholds are greater for noise bands centered at 4 than at 2 kHz, and tend to decrease with increasing bandwidth. Thus monkeys, in addition to lateralizing interaurally delayed pure tones up to 2 kHz [Houben and Gourevitch, J. Acoust. Soc. Am. 66, 1057–1063 (1979)], can lateralize delayed noise bands centered at higher frequencies. This cue, as suggested for man, may contribute to localization. [This research was supported by NSF Grant No. BNS-7915834.]
Behavioral response of treefrogs to low level sound stimuli
Authors: Zelick Randy D. , Narins Peter M.
Published: October 2005

Acoustic avoidance behavior was demonstrated in a natural population of the neetropical treefrog Eleutherodactylus coqui. An electronically synthesized mimic of the two-note advertisement call, or a single tone of 100-ms duration, were both effective in eliciting a suppression in spontaneous calling during the 10 to 250 ms directly following the end of the stimulus. The duration of the call suppression zone following a 100-ms tone was found to be frequency and level dependent. By adjusting these two parameters, it was possible to determine the threshold for acoustic avoidance at different frequencies in the range of 230 to 3420 Hz. Pooled data from 13 frogs (147 frequency-intensity pairs) were used to construct a behavioral audiogram for this species. Tones of 605 to 2000 Hz were uniformly above threshold when presented at a level of 60 to 70 dB SPL. Below 665 Hz, threshold dropped at 14 dB per octave to a maximum sensitivity of 41 dB SPL at 230 Hz. Tones of 3420 Hz (approximately the third harmonic of the first note of the advertisement call) failed to elicit a response even at high levels (over 81 dB SPL in one case). In a second type of experiment, 1 to 2 s duration single tone stimuli were presented. These were spaced at the frog's spontaneous call interval (2 to 3 s). In every case (7 animals), the frog redistributed his calls in time such that they fell almost exclusively within the brief time window between tone bursts, thereby avoiding overlap with the tone. The average background noise level at the frog's calling site was 39 dB SPL at 500 Hz, 59 dB SPL at 1000 Hz, and 66 dB SPL at 2000 Hz. Thus the avoidance behavior is observed at stimulus levels barely exceeding the noise floor of the frog's environment.
Biosonar interpulse interval as an indicator of attending distance in Tursiops truncatus
Authors: Penner R. H. , Kadane J.
Published: October 2005

In a biosonar detection study, the relationship between interpulse interval lengths and calculated acoustical two-way travel time was found to describe an attending distance appropriate to the distance between the animal and the target. Two bottlenosed dolphins, Tursiops truncatus, were conditioned via differential reinforcement to utilize biosonar to detect and report the presence or absence of a stimulus cylinder presented randomly with 0.5 a priori probability of occurrence. Five stimulus distances of 40, 60, 80, 100, and 120 m were tested, each completed before progression to the next distance. Data were generated from a minimum of 1 300 interpulse intervals for the two stimulus conditions at the five detection distances. The Morozov effect of two-way travel time plus an additional 2 to 20 ms between outgoing pulses was clearly shown. Pulse train intervals from correct detections and correct rejections show marked similarity to each other and specific to each test distance. The distance of the attending area of cylinder absent trials is essentially identical to the attending distance of cylinder present trials, showing surprising specificity and parsimony in attending to an area of interest.
Effects of noise on infant and adult guinea pigs
Authors: Danto Joseph
Published: October 2005

Six infant guinea pigs were subdivided into a control group (no noise exposure) and infant exposed group (exposed at 2 days) and an adult exposed group (exposed at 2 months). 4 kHz narrow band exposure doses of 1 h at 115 dB SPL were presented to the two experimental groups. A conditioned suppression technique used to measure thresholds revealed a significantly greater loss for the infant exposed subjects than either the control or adult exposed subjects. The current project added hair cell counts to the behavioral data using surface preparation techniques. All hair cell counts were taken after greater than two months post trauma. Although the number of subjects may be small, consistent trends in the data suggest a significantly greater susceptibility of the infant ear over that of the adult ear. These trends would suggest concern about the definitions of hazardous noise level doses for this population.
The speed of sound as a function of temperature in mammalian tissue
Authors: Nasoni Richard L. , Bowen Theodore , Dewhirst Mark W. , Roth Howard B. , Premovich Robert
Published: October 2005

The speed of sound in mammalian (canine) tissue was measured as a function of temperature to determine whether these measurements have the stability, repeatability, and freedom from artifact to qualify speed as a scan parameter in a CT ultrasound thermal mapping system. Measurements were made over temperatures ranging from 38° to 45°C on canine tissues both in vitro and in vivo using a 5-MHz pulse transmission velocimeter. 25 in vitro and 14 in vivo runs were made on kidney, liver, spleen, muscle, stomach, and blood. For in vitro runs, the fractions of water, lipid, collagen, and protein in the insonified volumes were determined. Speed was fit to a linear regression model on these components and temperatures. Conclusions are: (1) the speed of sound as a function of temperature can be measured in vivo with stability and freedom from artifact, (2) lack of repeatability from tissue to tissue makes speed an improbable thermal scan parameter; however, (3) because of repeatability in slope, the temperature coefficient of ultrasound may have possible use in thermal dosimetry.
Current trends in electronic music
Authors: Smith Dave
Published: October 2005

Electronic Music synthesizers have recently taken advantage of new integrated circuit technology to make major advances in sound generation possibilities and ease of use. Micro-processor controlled analog synthesizers have become very popular, and all-digital synthesizers are coming out of the lab and becoming available to the musician. With electronic memory storage capability rising with its cost dropping, elaborate sequencers are also becoming more available at reasonable costs. These trends, as well as possible future developments, will be discussed.
The effect of language familiarity on vowel discrimination
Authors: Jacob Batya Levine , Alfonso Peter J. , Maxon Antonia B.
Published: October 2005

Recent studies have shown that phonetic and phonological context influences vowel identification. For instance, vowels are better identified when presented in a syllabic environment than when presented in isolation [Strange, Verbrugge, Shankweiler, and Edman, J. Acoust. Soc. Am. 60, 213–224 (1976)], and when the syllabic environment is represented by natural speech formant transitions rather than “flipped formants” [Fowler and Shankweiler, J. Acoust. Soc. Am. Suppl. 1 63, S4 (1978)]. The identification of steady-state vowels presented in concatenated sequences is also influenced by context factors [Alfonso and Kerivan, J. Acoust. Soc. Am. Suppl. 1 66, S86 (1979)]. Finally, familiarity of contextual language-specific factors affect vowel identification [Gottfried, J. Acoust. Soc. Am. Suppl. 1 65, S6 (1979); Rudnicky, .I. Acoust. Soc. Am. Suppl. 1 65, S110 (1979)]. The study reported here demonstrates that vowel discrimination is also context dependent. Two groups of subjects, native American-English and native Hebrew speakers, discriminated among six vowels, three that are familiar to both groups, and three that are represented in English but not Hebrew. AX discrimination CVC pairs consisted of the following: two vowels familiar to the Hebrew group, designated (FF), two unfamiliar vowels (UU), or combinations of unfamiliar and familiar vowels (UF). The Hebrew group demonstrated significantly poorer discrimination than the English group on the (UF) pairs. The results and the possible use of unfamiliar speech stimuli in the clinical management of the hearing impaired will be discussed.
Quantal characteristics and motor control in early child speech
Authors: Kubaska Cathy A. , Lieberman Philip
Published: October 2005

In the late babbling and early word stages of development, the vowels that children produce are not as “well formed” as those of adults. Taking into consideration the higher formant frequencies of children's vowels, which follow from their shorter supralaryngeal vocal tracts, one finds, for example, that F1 of an [i] is higher than it should be relative to F2 at ages of approximately 70 weeks. This is presumably a consequence of the shorter length of the child's pharynx relative to the oral cavity (King, 1952). As the child matures, the relative position of F1 and F2 of [i] come closer to the adult model. In addition, there is a greater variability in the formant frequencies of all vowels at earlier ages. This may be a consequence of the child's pharynx not being equal in length to the oral cavity, making vowels like [i] less characteristically “quantal” (Stevens, 1952). This variation may also be due to a lack of motor control. In this study, the relative importance of quantalness versus motor control is assessed by comparing the variability of quantal vowels, such as [i] and [u], with other vowels as a function of age.
System resolution in perception and production: Implications for speech signal processing and speech motor control
Authors: Chuang C. K.
Published: October 2005

One global yet rather basic question in regard to speech is the extent to which underlying organic capabilities are utilized for speech functions. Applying the concept of information processing uncertainty to perceptual stimulus discriminability and the productional variability, a unified definition of the system resolution for both processes was derived. The resulting perceptual system resolution for pitch, intensity, duration, and average formant frequency is 4.8 bits, 3.4 bits, 3.6 bits and 3.8 bits, respectively, and the corresponding resolution for production in those dimensions is 4.6 bits, 3.3 bits, 3.2 bits and 3.6 bits, respectively. These results show that the system resolution in the speech mechanism all cluster between 3 and 5 bits. Namely the use of organic resolving function for speech processes do not exceed 32 decimal categories. Surprisingly the perceptual and production function differences are less than 0.5 bits in any dimension. This comparison reveals a very close system resolution match between production and perceptual processes. Implications of this observation in relation to the nonlinear resolution of vowel production and perception will be discussed. [Work supported by NS 13274.]
A kinematic experiment of lip and jaw coordination
Authors: Hasegawa Akira
Published: October 2005

The objective of this study was to document important kinematic characteristics of lip and jaw coordination. A new experimental paradigm was developed, which involved matching computer-controlled, video-displayed articulatory targets to articulations with or without visual feedback. The study was conducted with three male adult subjects to examine motor equivalence for vertical lip separations of 10, 20, 30 and 40 mm. A series of “target dots” were displayed one at a time on a TV monitor in front of the subject. The target dot indicated the vertical distance between the upper and lower lips. The subject was first trained with the aid of another dot on the screen which indicated vertical lip separation between his lips as determined by lateral gnathometry. The subject was instructed to follow the target as accurately as possible. Data collection in lateral gnathometry was carried out first with visual feedback and then without visual feedback. The results indicated that target lip separations were achieved by systematically different combinations of lip and mandible displacement. [Work supported by NIH grant NS11852-04.]
Determination of lower limits of pitch variation in normal larynges
Authors: Coulter D. , Ludlow C. , Gentges F.
Published: October 2005

It was desired to set a lower limit on the required sensitivity of an F0 frequency detector to assist in establishing baseline data on normals for early larynx pathology detection. Synthetically generated vowels with F0 jittered by a small amount were used to evaluate an analog pitch detector developed for this purpose. This detector was found capable of detecting peak-peak jitter values of less than 3 × 10−6 s. The detector was then used to evaluate the pitch of extended vowel productions. Mean adjacent differences, mean deviations of cycles from predicted values based on adjacent cycles, and mean jitter ratios were computed. The subjects evaluated were normals whose smoking and alcoholic consumption histories were known. Their vocal outputs were simultaneously monitored with acoustic microphone, accelerometer, and laryngograph pickups. Each subject was subsequently examined for larynx normalcy. It was concluded from the results of the jitter analysis that to ensure accurate description of the jitter of normal larynges it is necessary for the detector to be sensitive to at least 5 × 10−6 changes in period.
Laryngeal adjustments in stutterers
Authors: Yoshioka H. , Löqvist A.
Published: October 2005

Simultaneous recordings of voice and photoelectric glottogram during the speech production by stutterers were made. The subjects were asked to produce as quickly as possible each of 36 different meaningful words in response to a visual stimulus. The results revealed that some cases of part-word (word initial voiceless stop) repetitions were accompanied by one or two extra opening gestures corresponding to the repeated aspiration noises. Similar trial-and-error types of the glottal movement were also detected even during silent delayed response time in some other cases which were auditorily judged as fluent. As for the production of the words begun with voiced sounds, unnecessary opening gestures prior to the vocalization for the initial voiced segment were sometimes observed, regardless of the judgements on its fluency and/or on the length of its latency. These findings suggest that at least this type of stuttering is linked to temporal disruption of the precisely controlled abducting and adducting gestures of the glottis, which are indispensable to fluent speech production. [Work supported by NINCDS and BRSG.]
Articulation of [i]'s
Authors: Ohala John J. , Kawasaki Haruko
Published: October 2005

The articulation of the palatal vowel [i] in various phonetic environments was studied in one speaker of English and one speaker of Japanese using the technique of dynamic contact palatography. The utterances examined were of the form C1V1C2V2, where V1 or V2 was [i][u] or [a] and the other vowel always [i]. C2 was any of a variety of consonants proper to the languages involved. Preliminary results suggest that the articulation of [i] is influenced in complex ways by both consonantal and vocalic environment. For example, “front” consonants such as [n] serve to preserve the canonical contact pattern for [i] whereas “back” consonants such as [k] permit greater deviation from the canonical form due to coarticulation with adjacent vowels. Other things being equal, [i] seems to dominate in the coarticulation between vowels in the speech of the Japanese speaker. A momentary reduction in the extent of palatal contact during the consonant in an [ipi] utterance was noted. This is apparently due to passive enlargement of the oral cavity caused by impinging oral pressure. [Work supported by NSF.]
Effectiveness of glossectomee palatal augmentation as measured by dynamic palatometry and analysis-by-synthesis techniques
Authors: Christensen J. M. , Hasegawa A. , Hutton J. E.
Published: October 2005

Dynamic palatometry and analysis-by-synthesis techniques were used to determine effectiveness of palatal vault augmentation to enhance the speech capabilities of a glossectomee. The fricatives /s/ and /∫/ were symmetrically combined with three vowels to form six nonsense words which were repeated in a randomized order within the frame sentence. “gay /hΑCVC/ again.” During three evaluation sessions, palatometric and acoustic measures were processed using a PDP 11/40 computer system. in the three assessment sessions, the glossectomee used (1) an unaugmented prosthesis for baseline data, (2) an augmented palate in a A-B-A design, and (3) the augmented prosthesis after having been worn for four weeks. The initial baseline data was essentially the same for /s/-/∫/ comparisons. The augmented pseudopalate data indicated a difference in minimal groove size, but not in location for /s/ vs /∫/. Acoustically, the /s/ was similar to /∫/. These result suggest that the cavity anterior to the groove plays a critical role in distinguishing between these two fricatives. [Work supported by NIH grant NS11852-03.]
New computer-based speech-training aid for the deaf
Authors: Lippmann Richard P. , Watson Charles S.
Published: October 2005

A computer-based speech-training aid, under development, employs the form of template analysis and comparison used in current commercial systems for the recognition of isolated words or short phrases. In this aid, as in such systems, a talker's own utterances are acoustically analyzed to form reference templates to which later utterances are compared. In one training mode, the aid will identify which of a stored list of words has been spoken, and demonstrate to the deaf speaker that utterances which are produced reliably are recognizable, whether or not they are intelligible. This same mode can be used to give a child control over gamelike devices, to promote a high rate of self-paced oral output. In a second, and more novel, training mode, the child's previous most intelligible speech tokens will be used as reference templates in “successive-approximation” procedures for improving the intelligibility of important words or phrases. The use of reference templates selected by perceptual criteria makes it unnecessary that this aid be selectively sensitive to the acoustic correlates that characterize deaf speech. Preliminary data demonstrate the general feasibility of this proposed aid. [Work supported by NIH.]
Acoustic correlates of vocal tension/harshness in the speech of the deaf
Authors: Whitehead Robert , Bancroft John
Published: October 2005

Audio recordings were made of twenty young-adult hearing-impaired males while reading the first two sentences of the Rainbow Passage. The subjects exhibited a range of severity of vocal tension/harshness as judged from the audio recordings by a panel of three trained listeners. The first ten seconds of the continuous speech samples were digitized and analyzed using an autocorrelation computer program that quantified the periodicity of voiced speech. This measurement compared the power between the periodic portion of the voice (the signal) and the uncorrelated aperiodic component of the wave (the noise) and was expressed as a signal-to-noise ratio [J. C. Bancroft, J. Acoust. Soc. Am. Suppl. 1 65, S67(A) (1979)]. The computer program also extracted the average fundamental frequency (F0) for the voiced portion of the signal, as well as the amount of variability of F0. Significant correlations were obtained between the perceptual judgments of severity of vocal tension/harshness and: the signal-to-noise ratios; and, the amount of variability in F0. [Work supported by HEW.]
Effects of vibrotactile feedback upon the production of co-articulated CV syllables
Authors: Saunders F. A. , Franklin B.
Published: October 2005

Eight profoundly deaf and deaf/blind children are receiving ongoing training in the production of speech sounds. An electrocutaneous sensory aid, worn around the abdomen, displays the speech sounds of the teacher and the child as vibrotactile patterns. In the first training activity, the syllables /ba (ba)/, /bee (bi)/ and /boo (bu)/ were presented (1) as a 2-s sustained utterance (to assess the child's ability to control articulators in sustaining a vowel), and (2) as a three-syllable utterance, repeated at a 3/s rate (approximating the rate of normal speech). Training stimuli were presented by videotape, and the children's responses were recorded and spectro-graphically analyzed, over a training period of three weeks. An analysis was made of the suprasegmental features of pitch and rhythm, as well as the articulatory features of transition and formant structure. The children's performance was compared under two conditions, one while wearing their hearing aids plus the vibrotactile belt, the other with hearing aids alone. [Work supported by NIH.]
Acoustic characteristics of the /I-i/ confusion in deaf children's speech
Authors: Levitt H. , Osberger M. J. , Stromberg H.
Published: October 2005

The purpose of this paper is to report preliminary data on the acoustic characteristics of error patterns in deaf children's speech. The /I-i/ confusion was analyzed first because of its high weighting with respect to reduction in percent intelligibility on a multiple linear regression analysis. An acoustical analysis was performed on /i/ in CV syllables which were produced in a sentence context by normal hearing and deaf speakers. Based on the transcriptions of a group of phoneticians, the deaf speakers were then divided into two groups: (1) those who correctly produced the /i/ and (2) those who substituted /I/ for the intended vowel /i/. The data revealed systematic differences in formant values for the three groups of speakers. The two groups of deaf speakers showed the greatest deviation from the normal group in the frequency location of F2. Speakers who produced the /I/ for the /i/ showed the greatest deviation from normal. Measurement of vowel duration revealed no differences between the mean vowel duration for the two groups of deaf speakers, although there were some individual variations. These data indicate that spectral differences associated with the /I-i/ confusion show a more consistent pattern of deviation from normal than do durational differences. [Research supported by PHS grant 09252 from NINCDS.]
Submarine target strength—a random process
Authors: Maples Louis C.
Published: October 2005

In an effort to determine a simple but meaningful basis for comparison of two submarine targets of the same class, it has been found helpful to utilize the arithmetic mean target strength, averaged over all aspects, as a measure. If we look at target strength as a random variable, we may plot a “density” function and examine its characteristics, possibly classify the distribution, and determine whether the use of any statistical measure other than the mean is either justifiable or useful—or do the target strengths representing different aspects also really represent different populations, different distributions? Several sets of data are analyzed in this context and the question of a realistic random aspect target strength as a possible output is considered as well.
Acoustic diffraction and resonance effects for the aided versus the unaided listener
Authors: Kuhn George F.
Published: October 2005

The acoustic pressure at the hearing aid microphone differs from the incident pressure field, be it partially or totally progressive or diffuse, primarily as a result of diffraction by the head and/or torso of the aided listener. However, for the normally hearing subject the incident pressure field, before reaching the eardrum, is additionally transformed by the pinna and the ear canal, which together produce additional resonance amplification and directional effects; neither of these effects is produced at the hearing aid microphone. Results showing the separate effects of the head, torso, and external ear on the pressure transformations of acoustic waves for incidence in the horizontal—and median vertical—planes, as well as for random incidence, will be presented. The frequency response, the horizontal—and median vertical—plane directivities and the available localization cues for aided and unaided listeners will be compared. Some schemes to restore the localization cues for the aided listener to those of the unaided listener will be discussed. Furthermore, a physical mechanism which may cause speech in noisy environments to be less intelligible for aided listeners than for unaided listeners will be proposed.
Subminiature transducers and their acoustic coupling: State of the art
Authors: Killion Mead C.
Published: October 2005

Until recently, the transducers that were available to the hearing aid designer imposed major limitations on the performance which could be offered in headworn hearing aids. Within the last decade, however, these limitations have been largely removed. Today's subminiature microphones and earphones permit a wide variety of hearing aid characteristics, up to and including true high-fidelity performance: a claim substantiated in recent physical and psychophysical experiments [Killion, J. Acoust. Soc. Am. Suppl. 1 64, S103(A) (1978)]. The usable performance of subminiature transducers may be largely determined by their acoustic couplings—so much so that a meaningful definition of their frequency response requires that the coupling system be specified—and a crucial factor in recent performance improvements has been a systematic examination of the acoustic coupling systems available to headworn hearing aids. While sometimes considered a nuisance or worse, the acoustic couplings can be exploited in hearing aid design to (a) improve directional performance, (b) provide desirable frequency-response tailoring, and (c) reduce battery drain. Earmold construction in particular becomes increasingly important as the bandwidth of hearing aids is increased. At low (below 1 kHz), medium (1–3 kHz), and high (above 3 kHz) frequencies, the use of earmold venting, damping, and a stepped-diameter sound channel. respectively, can provide substantial (and predictable) modifications to the real-ear response of hearing aids; modifications which can often be performed at the dispenser level. Examples of the performance allowed by today's transducers and acoustic couplings will be given.
Choosing the frequency responses of hearing aids—the viewpoint of a communications engineer
Authors: Braida L. D. , Dugal R. L. , Durlach N. I.
Published: October 2005

Many of the issues associated with the selection of frequency responses for hearing aids are similar to those encountered in the design of voice communication systems for listeners with normal hearing. The design of such systems typically utilizes the predictions of articulation theory, which incorporate the results of a wide variety of measurements of speech transmission under conditions of restricted bandwidth, additive noise, and limited dynamic range. Although a number of investigations has reported that articulation theory can be used successfully to determine the frequency response of hearing aids, it is widely used for this purpose at present. In this paper we examine the extent to which recent studies of the frequency response of hearing aids can be described by articulation theory and also consider the predictions for the optimum frequency response that can be derived from the theory.
Progress in electrical stimulation of the cochlea
Authors: White M. W.
Published: October 2005

The primary purpose of research in cochlear nerve stimulation is the restoration of speech comprehension in the profoundly deaf individual. Subjects have been implanted and evaluated with single and multiple electrode implants. Only very preliminary data are available for individuals using multiple electrode stimulation. Using animal models, several groups have examined; behavioral threshold and loudness functions; neural thresholds and sites of cochlear excitation; stimulus current distribution within the cochlea; and the physiological and morphological effects of high-level, long-term stimulation. The results of some of these on-going studies will be summarized.
Magnetic audition
Authors: Miller Mary Lou , Hixson Elmer L.
Published: October 2005

Attaching a small permanent magnet to the tympanic membrane and driving the eardrum by an electromagnetically induced force has previously been demonstrated [A. Glorig and G. Moushegian et al., J. Acoust. Soc. Am. 52, 694–696 (1972)]. There are two major advantages to such a hearing aid, where the tympanic membrane is excited by a mechanical force rather than an acoustical signal. The receiver which can contribute to harmonic and transient distortion is eliminated and the closed air column which affects the frequency response is also eliminated. The present study investigates the engineering aspects of an electromagnetic coupled hearing aid. The results of experiments performed outside the car are reported. The vector force on a small permanent magnet produced by current in a coil is determined as a function of distance between the coil and magnet, position of the coil with respect to magnet, and frequency of the magnetic field. In order to relate the mechanical force F of the magnet to an equivalent sound pressure P at the eardrum of area A without clinical testing, the required force for a specified sound pressure is predicted through reciprocity F = PA. Energy requirements for an electromagnetic coupled hearing aid based on design parameters evaluated in this investigation are discussed and compared to the requirements of conventional hearing aids. A model of the system is presented.
Modes of vibration and tonal quality of tuned handbells
Authors: Rossing Thomas D. , Sathoff John
Published: October 2005

Although handbells can vibrate in many different modes, only the two modes of lowest frequency are normally tuned by the bellcrafters. The first overtone mode is generally tuned to the third harmonic of the fundamental. Each of these modes radiates sound parametrically at twice the modal frequency, however, so that the radiated sound spectrum includes the second and sixth harmonics as well. The upper partials are much less prominent than in church bells or carillon bells, thus making them more suitable for use in handbell choirs where several bells are rung together in chords. The tonal quality depends upon the strike point, the hardness of the clapper, and the force of the blow. The different radiation patterns and decay times of the various modes affect the tonal quality in several interesting ways.
Vibrations of cymbals, gongs, and tamtams
Authors: Peterson Richard W. , Rossing Thomas D.
Published: October 2005

Cymbals, tamtams, and gongs are three important examples of percussion musical instruments which employ vibrating plates. When struck, they vibrate in many different modes of vibration and radiate sound which is rich in overtones [T. D. Rossing, The Physics Teacher 15, 278 (1977)]. Gongs convey a fairly strong sense of pitch, whereas cymbals have indefinite pitch. We have studied the modes of vibration and the sound spectra of a number of cymbals, gongs, and tamtams both when struck and when driven in steady state. Various techniques have been employed for studying the modes of vibration, including Chladni patterns, holographic interferometry, probing the nearfield sound, and attaching vibration sensors [T. D. Rossing and R. Ross. J. Acoust. Soc. Am. Suppl. 1 64, S150(A) (1978)]. In some cases the results agree closely with the simple theory of plate vibrations; in other cases, rather unusual effects are observed.
Analysis of Japanese Tsuzumi tones
Authors: Olsen R. D. , Bassett I. G.
Published: October 2005

Four basic types of tones for the (KO) Tsuzumi (an hourglass-shaped, wooden Japanese drum about 25 cm high and 10 cm in diameter with small ropes interconnecting the two heads) were analyzed using a Fast-Fourier Transform computer program. Recordings of the tone were made by Michiko Toyama 1-29-18 Hanegi, Setagaya-Ku, Tokyo, Japan. The tones analyzed are described as follows: (1) “KO,” produced by striking the center of the drum head with two to four fingers of the right hand while the ropes holding the head are at first held loosely and then squeezed quickly. Twelve frequency components have been identified ranging from 254 to 4348 Hz. Maximum intensities cover a range of 35 dB with decay rates from 80 to 597 dB/s. (2) “KU,” produced in a similar manner to the KO tone, but with only one finger. Frequencies are between 311 and 3230 Hz. Intensities cover a range of 25 dB, and decay rates between 98 and 1140 dB/s. (3) “TA” produced by hitting the edge of the head with two fingers while maintaining maximum tension on the ropes. Frequencies are between 311 and 3234 Hz with little or no shift. Intensities cover a range of 38 dB, with decay rates between 96 and 1140 dB/s. (4) “CHI” produced in the same manner as TA, but striking only with the third finger of the right hand. Frequencies of components in this recording lie between 255 and 3465 Hz. Intensities cover a 46-dB range. Decay rates are between 85 and 1355 dB/s. In both the KO and the KU tones, the most pronounced component is the lowest frequency and has the slowest decay rate. On the TA and CHI tones, however, the lowest frequency components are not the most intense. The most intense component is in the area of 780 Hz with a decay rate about four times as rapid as that of the lowest frequency component.
How to measure time varying noise exposure in residential communities
Authors: Borsky Paul N.
Published: October 2005

The controversy over how best to integrate time varying noise exposures in residential communities can only be resolved by an analysis of objective data secured from well-designed community noise surveys. Past community studies have provided clarification of the important complex physical and human variables involved in the harmful health and welfare effects of environmental noise, but new research is needed to quantify the number-level tradeoffs and time of day penalties. Community reactions can be compared where noise exposures are equal in day or evening but differ in the night time. The effects of ambient noise on more intense aircraft noise exposures can also be ascertained. A mail survey of the top 50 airports reveals at least 13 different time of day and type of operation situations with exposed populations up to 8–10 miles from the airport. Considering regional variation, about 16 selected airports will represent the range of physical exposures.