bluuebunny/crossref_metadata_2025 huggingface dataset:
Burst, murmur, vowel duration, and transition cues in the identification of final stop voicing by hearing-impaired and normal-hearing listeners
Authors: Revoile S. , Pickett J. M. , Holden Lisa , Talkin David
Published: October 2005

The effects on voicing identification of progressive neutralization of the voicing cues was examined further (99th ASA meeting, Paper GG6). Cue modifications were digital deletions or iterations performed on ten voicing-cognate pairs of token syllables, spoken in a randomized list of 10× the set: dap, dak, dat, dab, dag, dad. The cue modifications consisted progressively of neutralized vowel durations, equalized closure duration, burst deletion, murmur deletion, and transition deletion. For voiced-consonant syllables, about half of the 25 hearing-impaired were sensitive to vowel duration and the presence of transitions; some of these listeners and others were sensitive to the presence of the burst and/or murmur. For syllables with unvoiced consonants, vowel duration and the presence of release burst affected identification for about half of the hearing impaired. Among the remaining impaired listeners, sensitivity varied unsystematically as a function of burst presence and/or transition deletion. Normal listeners appeared generally to make use of the transition cues more than did the hearing impaired. [Work supported in part by the U. S. Public Health Service.]
A comparative evaluation of four telephone coupling methods for the hearing impaired in the presence of background noise
Authors: Stoker Richard
Published: October 2005

Four methods that hearing-impaired persons employ to use the telephone were evaluated: amplifier handset, magnetic coupling (hearing aid on “T” switch), acoustic coupling (hearing aid on “M” switch), and tube microphone adaptation (a 50–75-mm extension of hearing aid microphone port onto cheek of user). Two levels of competing background noise were used, 76 dB(A) and 85 dB(A). Three groups of subject (N ≃ 100 each) were tested at six different sites. There were two groups of hearing-impaired subjects (moderate and severely impaired) and one control group of normally hearing individuals equated to the experimental groups by age and sex. The task was a test of speech intelligibility in noise (SPIN) and the data were expressed in terms of percentage correct scores. Results showed that the overall best coupling mode was the telephone used with the amplifier handset. Next best was the magnetic coupling mode. Acoustic and tube microphone modes were significantly poorer. A nonsignificant small group of moderately impaired subjects actually performed better on the tube microphone than the other modes, however. Intra- and intergroup variance was high, indicating a strong tendency for individual differences on the basis of variables impossible to control, such as etiology, age of onset, and personality.
Pure-tone thresholds for listeners with normal hearing and with ear-canal collapse under various earphone conditions
Authors: Marshall Lynne , Norris T. W. , Gossman M. A.
Published: October 2005

Thresholds were measured at 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz in 20 normal ears and in 16 ears, age 21–86, with varying amounts of ear-canal collapse caused by pressure from MX-41/AR cushions. In an attempt to alleviate the attenuation due to ear-canal collapse, ear-canal inserts (made from otoscope tips), postauricular pads, or Telephonics 510-020 circumaural cushions were used with TDH-49 earphones. Effects of ear-canal collapse were largest above 2000 Hz although for listeners with more severe collapse the attenuation extended to lower frequencies as well. The ear-canal inserts were better for most of the listeners in providing a means to cope with ear-canal collapse. However, the ear-canal inserts were not suitable for listeners with more severe ear-canal collapse because the insert was displaced when the supra-aural cushion was put on the pinna. Both the circumaural cushion and the postauricular pad reduced the effects of ear-canal collapse in these listeners. [Work supported in part by Nebraska Center on Aging.]
A model of peripheral auditory processing
Authors: Bienvenue G. R. , Celmer R. D. , Martin J. E. , Michael P. L.
Published: October 2005

A critical-band based hybrid computer model of cochlear hearing processes has been developed at the Environmental Acoustics Laboratory. The model incorporates elements representative of the mechanical response of the cochlear partition, integration patterns in the organ of corti, inhibitory mechanisms at the cochlea, and some primitive decision processes representative of brain stem Operations. The model has been developed for the Pennsylvania State University's hybrid computer which is a PDP 10 digital computer interfaced with an EAI 680 analog computer. The model's ability to discriminate certain acoustic stimuli has been assessed and its performance is compared to the performance of normal-hearing listeners on similar psychoacoustic tasks. Implications of the results for hearing theory and for the understanding of mechanisms of cochlear hearing impairment are discussed.
Measurement of atmospheric attenuation for bat sonar signals
Authors: Lawrence B. D.
Published: October 2005

The high-frequency (20–200 kHz) sonar signals of bats are known to be severely attenuated during their propagation through air, which acts as a low-pass filter. The effects of atmospheric attenuation on batlike signals were measured over varying distances; attenuation was in the range of 1–10 dB/m. The acoustic image of a target assembled by a bat from sonar echoes is restricted by the range of frequencies transmitted by the bat as well as by the sensitivity of the echo-location receiver. The use of exceptionally high frequencies exposes the bat's signal to such intense atmospheric attenuation as to override any gain in target resolution afforded by improved wavelength-to-target ratios. The resultant loss in intensity of high-frequency echoes is sufficiently pronounced to have placed a major evolutionary constraint on the design of sonar echoes. [Work supported by NSF.]
Attentional factors in dichotic ear advantages
Authors: Studdert-Kennedy Michael , Kerr Lynne
Published: October 2005

An ear advantage in dichotic listening depends on two factors: Hemispheric specialization for the task, or materials, and privileged access of one ear's input to the specialied hemisphere. Two dichotic experiments, both using a CV syllable test and a pitch contour test, assessed the effects on privileged access of manipulating attention. In the first experiment the two types of materials were presented either in separate blocks or randomly mixed in a single block: Random mixture eliminated a significant right ear advantage (REA) for syllables, and significantly reduced a significant left ear advantage (LEA) for pitch contours. In the second experiment, subjects were required to hold either a sentence or a melody in memory during each dichotic trial. Sentence storage significantly increased and melody storage significantly decreased the speech REA, but neither had any effect on the pitch LEA. The results are compatible with the view that while the right hemisphere could perform only the pitch task, the left hemisphere could perform both pitch and phonetic tasks. [Preparation of this paper supported by NICHD.]
Selective adaptation of VOT in Polish
Authors: Ganong William F. , Keating Patricia A.
Published: October 2005

In order to test the hypothesis that selective adaptation and range effects in speech perception are produced by the same proccesses, we compared the size of range effects and adaptation effects for monolingual Polish and English subjects. Previous work has indicated that Polish speakers show much larger range effects in phonetic categorization of VOT than do English speakers. We therefore tested the adaptation effect of a +70 ms VOT stimulus on the perception of two apical VOT continua (ranging from −70 to +30 and −30 to +70 ms VOT). Eight monolingual Polish and English subjects participated. As in our previous work, Poles showed large range effects in categorizing VOT stimuli. (Their mean boundaries were at −3.4 vs 8.4 ms VOT.) They also showed substantial selective adaptation boundary shifts (mean = 18.2 ms), which were reliably larger than the adaptation effects shown by the English speakers (mean = 7.6 ms). Thus, the Polish speakers' perception of VOT is more sensitive than English speakers' to both selective adaptation and range effects, as a unitary model for adaptation and range effects would predict.
Speaking rate affects perception of good exemplars of a phonetic category
Authors: Miller Joanne L. , Schermer Trude M.
Published: October 2005

An important property distinguishing syllable-initial stop consonant, /b/, from semivowel, /w/, is the duration of the initial formant transitions: Relatively short transitions specify /b/, whereas longer transitions specify /w/. We reported earlier [J. L. Miller and A.M. Liberman, J. Acoust. Soc. Am. 68, S31 (1978)] that the transition duration at the /b/-/w/ phonetic boundary is not absolute. Instead, as the syllables become longer, an increasingly longer transition is required to hear /w/. We proposed that the alteration in syllable duration specifies a change in speaking rate, and that the shift in boundary location reflects the listener's adjustment to that change. In the present experiment we asked whether the effect of syllable duration is limited to stimuli near the /b/-/w/ boundary or extends to the processing of good exemplars of the phonetic categories. A selective adaptation procedure was used to assess perception of two series of syllables that varied in transition duration and ranged from /bæ/ to /wæ/; the series differed from each other only in overall syllable duration. On the basis of the adaptation data we were able to infer that both the location of the /b/-/w/ boundary and the location of the prototypical or “best” /wæ/ were located at a longer transition duration for the long syllables, as compared to the short syllables. These data indicate that a change in speaking rate affects the way in which acoustic information is mapped onto phonetic categories, in terms of both the boundary between categories and the best exemplars of a given category. [Supported by NIH.]
Phonetic integration as a potential test for controversial surface structures
Authors: Dechovitz David Ross
Published: October 2005

It is a familiar result that a silence the length of a stop closure can be a cue to stop or affricate manner. However, the silence cue fails to work if the silence coincides with certain syntactic boundaries and extraction sites. This “blocking” effect provides a potential test for competing syntactic analyses which make conflicting predictions about the locations of surface boundaries. For example, the present results suggest that infinitival complements with “expect” and “persuade” act essentially alike, with no evidence of a major boundary between “expect” and the following NP, weakly supporting the Raising analysis.
Patterns of durations as information for rate and intervocalic voicing
Authors: Fitch Hollis L.
Published: October 2005

Temporal differences between intervocalic voiced and voiceless consonants include the duration of the acoustic segment corresponding to vocal tract closure, and the duration of the vocalic section preceding the closure (the ‘vowel’). Yet differences in these durations are also produced by changes in speaking rate. A potential problem for perceivers of speech would thus seem to be the confounding of temporal information for voicing and rate. But the signal need not be described in terms of the variable ‘duration’ as applied to single acoustic segments. A consideration of more temporally extensive patterns, over closure and vowel, establishes a distinction between voicing and rate changes. A voicing change from /b/ to /p/ lengthens the closure and shortens the vowel; a rate change from fast to slow lengthens both. It was in fact found that changing the closure-to-vowel ratio (as in the inverse voicing relationship) affected judgments of voicing more than rate, and changing the closure-plus-vowel sum (as in the direct rate relationship) affected judgments of rate but not voicing. [Research supported by NICHD.]
Temporal interactions between sinusoids and amplitude-modulated noise
Authors: Wakefield Gregory H. , Viemeister Neal F.
Published: October 2005

When a low-frequency sinusoid is added to sinusoidally amplitude-modulated wideband noise that is bandpass-filtered at 10 kHz, a slight mistuning of the sinusoid from the frequency of modulation may produce a beating sensation in the modulation at 10 kHz. This interaction was studied by measuring the modulation threshold at 10 kHz as a function of the relative phase between the modulator and that of a sinusoid set to the modulation frequency (100, 200, or 400 Hz). The function relating modulation threshold (in dB) to relative phase is approximately sinusoidal with a minimum threshold generally occurring when the envelope and the sinusoid are in phase. The difference between minimum and maximum threshold was unaffected by changes in carrier level, but increased to about 15 dB as the level of the sinusoid was increased from 70 to 90 dB SPL. These interactions between the sinusoid and the amplitude-modulated noise do not result from distortion products at the frequency of modulation. Furthermore, under no circumstances did the presence of the sinusoid raise the detection threshold for the 10-kHz band of noise. [Supported by NIH grant NS12125 and by a USPHS HD07151 traineeship from the Center for Research in Human Learning.]
Temporal summation in the auditory system of the goldfish
Authors: Fay Richard R. , Patricoski Marian L.
Published: October 2005

Previous investigations of temporal integration in fishes have presented conflicting results. Popper [J. Acoust. Soc. Am. 52, 596–602 (1972)] found no evidence for integration for signals between 10 and 500 ms in duration, while Offutt [J. Acoust. Soc. Am. 41, 13–19 (1967)] clearly did. Since one of the differences between these studies was the level of a noise background, we determined to measure the effect of noise on the detectability of tone pulses as a function of pulse duration. Three goldfish (Carassius auratus) were classically conditioned to detect tone pulses ranging from 2.5 to 100 ms in duration for repetition periods of 100 and 1000 msec under both ambient (unmasked) and broadband noise conditions. The threshold function of signal duration under noise showed nearly perfect integration (3 dB decrease in threshold per doubling of duration). The function under ambient conditions showed no consistent effects of signal duration, and thus no evidence for the type of integration expected from simple models [R. Plomp, J. Acoust. Soc. Am. 33, 1561–1569 (1961)]. We conclude that the presence of masking noise may account for the previous conflicting results, and that the nature of the neural processes used in signal detection by the goldfish are fundamentally different under noisy and quiet conditions. [Work supported by N.I.H. grants to R.R.F.]
Specific loss of sensitivity to frequency modulation in multiple sclerosis (MS)
Authors: Quine Douglas B. , Regan D. , Murray T. J. , Beverley K. I.
Published: October 2005

Psychophysical thresholds for rising and falling FM ramps were both measured after subjects listened to an FM adapting tone of 40 dB SL (rising or falling FM ramp) for 10 min. All 23 control subjects' ears tested showed threshold elevations greater than 100%, as did all 12 ears of patients with noise-induced hearing loss. In contrast, 5 (out of 10) MS patients' ears tested showed threshold elevations less than 100%. Control subjects show elevated FM thresholds after adapting to an FM tone, while AM and pure tone thresholds are little affected [Regan and Tansley, J. Acoust. Soc. Am. 65, 1249–1257 (1979)]; this finding can be understood if there are independent sets of channels for FM and AM. In these terms MS, but not noise-induced deafness, would be associated with disordered FM channels. Since the detection of formant transitions seems to be important in speech comprehension, disordered FM channels might provide a partial explanation why some MS patients experience degraded speech comprehension though their audiograms are normal. [MS Society (Canada) and NSERC supported.]
Delayed auditory tone perception and delayed BEPs in multiple sclerosis patients
Authors: Quine Douglas B. , Regan D. , Murray T. J.
Published: October 2005

Delays of auditory perception were measured in 30 multiple sclerosis patients. The method was to switch on a tone in one ear some variable interval T before a second tone was switched on in the other ear. This variable interval was adjusted until the patient judged the two tones to switch on simultaneously. The interval T measured the difference in perceptual delays between the left and right ears. Eleven patients had abnormal delays at one or more tone frequencies, though all but one patient had normal audiograms. In addition, resolution of left-right asynchrony was abnormally poor in 15 patients, 11 of whom had normal audiograms. Brainstem evoked potentials (BEPs) correlated fairly closely with psychophysical results, though in principle each test can pick up defects missed by the other. Our finding that specific frequency ranges can be delayed even though the audiogram is normal might provide a partial explanation for degraded speech comprehension in some multiple sclerosis patients. [Supported by Multiple Sclerosis Society (Canada) and NSERC of Canada.]
On linear rotor-bearing dynamics
Authors: Adams M. L.
Published: October 2005

Dynamics of rotating machinery has long been an active field of study and research because of its importance to a wide variety of applications. Extensive analysis of complex machinery configurations is now a routine practice in many quarters as a result of advancements in computerized methods. However, basic physical insights are often obscured in the presence of enormous computational power. To a large extent, this is because certain fundamental properties of rotor-bearing systems have not been sufficiently exposed in the literature, in contrast to computational methods and results. Specifically, the equations of motion for typical rotor-bearing systems [MẌ, + CẊ + KX = F(t)l frequently result in nonsymmetric C and K matrices. Decomposition into symmetric and skew-symmetric matrices can readily be shown to amount to a separation of conservative and non-conservative interactive force fields [see M. L. Adams and J. Padovan, “Insights Into Linearized Rotor Dynamics,” J. Sound Vib. (in press)]. The skew-symmetric portion of K embodies a nonconservative circulatory force field which is responsible for classical rotor-bearing instability. The skew-symmetric portion of C embodies a conservative force field which produces spectrum bifurcation, e.g., gyroscopic and fluid-annulus inertia effects.
Vibration diagnoses in fossil fuel power plants
Authors: Dennison E. E. , Ying S. P.
Published: October 2005

Vibration problems in fossil fuel electric generating plants rated from 12.5 to 850 MW were diagnosed by existing methodologies involving state-of-the-art techniques over the past five years. The vibration diagnoses covered the areas of excessive vibration of rotating machinery, dynamic response of machine foundation, shaft misalignment vibration resulting from foundation differential settlement, and vibration of piping systems. The fast Fourier transform (FFT) technique analyzed the causes of rotating machinery vibration. The severities of the vibrations were assessed using international standards. The machine vibration magnitudes attributed to dynamic responses of their foundations were analyzed by using the FFT transfer function technique. The foundation differential settlement was investigated from the measured results of the foundation stiffness. The time histories of both water hammer and steam hammer were studied theoretically and experimentally for the development of prediction methods and for the elimination of transients. Steady-state piping vibration was correlated with the measured pressure waves in the pipes to analyze the pipe stress waves. Installation of rigid restraints and an increase of pipe wall thickness overcame the problem of fatigue cracking.
Structural sources of forge hammer noise: An application of residual spectrum techniques to source identification from field data
Authors: Evensen Harold A. , Trethewey Martin
Published: October 2005

Vibration and sound pressure records obtained during two production forging operations are analyzed to rank the principal structural sources of the sound received at the operator's position. The least-squares modeling technique described in [J. S. Bendat, J. Sound Vib. 49 (3), (1976)] has been applied to develop effective frequency response functions between the sound pressure and the vibrations of the principal structural elements; e.g.: the ram, two columns, anvil, and yoke. Comparison of three-, five- and seven-input models shows that as few as three to five well-placed transducers may suffice to characterize the contributions of the five structural elements. Perfect shrouding is simulated in the resulting models to show that the ram is the major radiating element (70%) for the hammers studied, though the anvil (30%) and columns (20%) are roughly equivalent sources. The model also shows a strong interaction between adjacent elements, sufficient to render conventional shrouding studies of sound energy ineffective and pointing to the need for redesign of structural interfaces.
Finite element analysis of sandwich structures
Authors: Johnson Conor D. , Kienholz David A.
Published: October 2005

Sandwich panels composed of metal face sheets and viscoelastic core layers are widely used as structural elements in situations where resonant vibration cannot be avoided. The damping afforded by the viscoelastic material allows significant improvements in fatigue life, noise radiation, etc. The analysis of such structures to predict dynamic properties including damping has recently become practical through the use of finite element methods. In this survey paper, finite element modeling techniques and solution techniques appropriate for that purpose are described. The Properties of various plate and solid elements which have been found useful in modeling of sandwich panels are reviewed. Solution techniques such as complex eigenvalue methods, the direct frequency response method, and the modal strain energy (MSE) method are explained. Advantages and drawbacks of each are cited. Primary emphasis is placed on the MSE method because of its applicability in design work. The method is illustrated in terms of comparison to closed form solutions for various simple structural elements such as beams, plates, rings, etc.
Monitoring turbine generator torsional vibrations due to network disturbances
Authors: Rusche Peter A. E.
Published: October 2005

Shafts in turbine generators represent a torsional vibration system. The system is coupled by the generator air gap torque to disturbances in the electrical network. Recent investigations have shown successive network disturbances capable of amplifying the poorly damped shaft torsional oscillations to damaging levels. A synopsis of such disturbances, capable of causing torsional oscillations in excess of material yield and endurance limits, is given. Dominant mechanical and electrical parameters affecting the response are identified. Analytical methods to determine the torsional response and consequential accumulative material fatigue are described. Torsional monitoring systems are functionally described. Commissioning and initial test results obtained by such a system installed on a 1000 MVA tandom compound generator are presented. The system is part of an Electric Power Research Institute effort to determine magnitude and frequency of torsionally significant network disturbances.
Vibration and noise from surface mine blasting
Authors: Siskind David E.
Published: October 2005

Potentially serious environmental problems can result from blasting in mines and quarries and at excavation sites. Among the possible hazards of flyrock, dust, fumes, vibrations, noise, the last two are most critical because of the numbers impacted and the widespread consequences. An extensive research program has recently been completed quantifying the problems of vibration and noise (airblast) near mines and similar blasting sites. Response and damage potentials were established for residential-type structures, with the most serious problems occurring at vibration levels above 0.75 in./s (19 mm/s), frequencies below 40 Hz, durations exceeding approximately 1 s, airblast overpressures above 0.015 1b/in.2 (100 N/m2), and for cases of old construction (plaster on wood lath). Measurement and analysis methods appropriate to blasting were determined, including the importance of anchoring for high acceleration (exceeding 0.2 g) and required low-frequency response for airblasts (a 5-Hz high pass or better). Research continues on long-term effects (fatigue), human response, and blast design. The final products of this effort are technically established criteria to serve as the basis for realistic and practical design techniques to meet these criteria.
Brain stem mechanisms for sound localization: Monaural and binaural pathways to the inferior colliculus
Authors: Casseday J. H.
Published: October 2005

The current view that the medial and lateral superior olives have binaural functions related to localization of sound in space grew, in part, from observations on the ascending connections to these nuclei. The anteroventral cochlear nucleus is the origin of the major projections to these nuclei, which in turn, project as a “binaural pathway” to the inferior colliculus. Because the anteroventral cochlear nucleus is also the source of a “monaural pathway” to the contralateral inferior colliculus, the question arises as to whether or not these two pathways overlap at the inferior colliculus. Our anatomical evidence shows that these two pathways converge in the lateral part of the central nucleus of the inferior colliculus of the tree shrew. Observations on these pathways in other mammals suggest that this convergence is a general feature in mammalian auditory pathways. Behavioral evidence suggests that both binaural and monaural pathways are important for localization of sound in space. [Supported by grants from NIH and NSF.]
Directionality—A way to solve the barrel effect problem
Authors: Wojcik J. J.
Published: October 2005

The quality of voice information transferred through the telephone depends on the input device of the telephone set. In an average office or residential acoustic environment the handset microphone will give relatively clear voice message when typical loudspeaking devices will disturb communication with phenomena like excessive or variable noise and rain barrel effect. The performance of the loud-speaking telephone can be improved by adequate electronic and electroacoustic design. The impact of the microphone on barrel effect and noise will be discussed. Typical directional patterns: omnidirectional, quasiomnidirectional, cardioid, and bidirectional will be included as examples.
Acoustics of single-box, duplex loudspeaking telephones
Authors: Botros R. , Fatovic P. , Lafrance C. , Wojcik J. J.
Published: October 2005

Analysis of acoustic, electronic, and environmental design parameters of some existing, voice-switched loudspeaking telephones has shown that, under certain conditions, full duplex operation (full transmit and full receive simultaneously) is possible, without sacrifices from the telephone bandwidth (voice quality). Analysis showed also that a limited amount of switched loss (10–15 dB) is required to secure stable operation in realistic conditions, without impairing the duplex operation significantly. Accordingly, some experimental models have been constructed and tested. The results have proven the validity of the analysis. Preliminary subjective evaluation indicated users' preference of duplex and quasiduplex over voice-switched apparatus.
Acoustic coupling of hearing aids to telephone receivers
Authors: Rayment Stephen G.
Published: October 2005

Several significant problems are encountered by users of the telephone who wear a hearing aid and attempt to couple the aid acoustically to the telephone receiver. Many of the problems are caused by the inability of the aid wearer to achieve a good acoustic seal between the aid and the telephone receiver. This poor seal causes large losses at low frequencies and permits the intrusion of room noises onto the desired signal from the telephone receiver. Another problem, acoustic feedback between the aid receiver and microphone, is worsened by the resonance conditions present when the telephone handset is brought into proximity. These degradations have been characterized and a variety of solutions have been examined at Bell-Northern Research. Low-frequency response can be improved either in the aid or the handset. Attempts to reduce the perceived room noise level have been made using an adaptive noise cancellation technique. The feedback problem has been addressed via a variety of techniques, including use of an acoustic tube coupled to the aid microphone, automatic gain control circuitry, tracking notch filters, etc.
Sensitivity of predicted barrier attenuations to errors in specifying ground plane geometry
Authors: Nobile Matthew A. , Lawther James M.
Published: October 2005

When the ground behind a noise barrier may be regarded as acoustically locally reacting, and where it has reasonably level topography, there is a plausible rationale for a traffic noise prediction model based on barrier diffraction of geometric image terms with coherent summation. Often in real life, however, even when sideline terrain surface is essentially plane, its plane is neither coplanar with the highway pavement nor even parallel to it. Defining the ground “plane” from measurements on the site, moreover, is not a task likely to be done with great precision in normal noise assessment practice. The sensitivity of traffic noise level predictions to errors in ground-plane location then becomes of interest. In this connection a study has been made of a series of ground-plane configurations approximating to cases arising in practice. Each case has been perturbed systematically, and the resulting differences in predicted noise levels have been observed. It has been particularly of interest to note the decrease in sensitivities resulting from averaging over frequency and over a traffic line. [Work supported by FHWA.]
Model measurements of diffraction loss due to barriers
Authors: Nicolas Jean , Embleton T. F. W. , Piercy J. E.
Published: October 2005

Propagation of tone bursts from a point source have been studied in a reverberant chamber 8.5 × 14 × 7 m. The insertion loss of a 30-cm-high barrier has been measured directly over the frequency range 1 to 10 kHz using first arrivals. Preliminary results show discrepancies with predictions from theory similar to those found by outdoor measurements described in the preceeding paper.
Relations between tone, pitch, harmony and consonance
Authors: Houtsma Adrianus J. M.
Published: October 2005

The concepts of pitch, consonance, and harmony are considered from a musical as well as from a psychoacoustical viewpoint. Relations between pitch and frequency for pure and complex tones are reviewed, and modern pitch theories are discussed. The issue of consonance versus dissonance is treated in the light of theories by Helmholtz, Rameau, and Schonberg, and modern psychophysical evidence. The discussion is augmented by sound demonstrations.
Musical performance. A synthesis-by-rule approach
Authors: Sundberg Johan , Askenfelt Anders , Frydén Lars
Published: October 2005

The general purpose of the present paper is to demonstrate some effects on the musical acceptability of a performance of a melody, which may be achieved by means of a synthesis-by-rule strategy. Both the structure of a melody and the playing technique of the performer seem important to the music perception and musical performance quality. The synthesis equipment used here consists of a computer controlled synthesizer. The input is the melody written in ordinary notation, and optionally complemented with phrase markers. This is the input material to a text-to-speech conversion program [Carlson and Granström, in Speech Communication II. edited by G. Fant (Stockholm, 1975) pp. 245-253] now adapted to for notation-to-music conversion. Some of the rules relating the performance to the structure operate on a phase level, and other rules operate on sequences of two or three notes only. As regar-s production aspects, the influence of a raising of the larynx in singing on the perceived musical quality of the performance is demonstrated. Acoustical parameters used for modelling larynx height variations are the formant frequencies and the amplitude of the source spectrum fundamental.
Growth of loudness, annoyance, and noisiness of noise-tone complexes
Authors: Hellman Rhona P.
Published: October 2005

A previous investigation [Hellman and Aylward, J. Acoust. Soc. Am. Suppl. 1 67, S7 (1980)] was extended to include the effect of spectral shape on loudness, annoyance, and noisiness (perceived magnitude). Single tones were added to three different broadband noise spectra: flat, low-pass, and high-pass. Judgments of perceived magnitude were obtained by absolute magnitude estimation (AME) supplemented by loudness matching. Results obtained with the three noise spectra show that the growth of perceived magnitude is a nonmonotonic function of the overall SPL of the noise-tone complex. More summation between tone and noise was found for relatively small tone-to-noise ratios (+5, +10, +15 dB), as measured in ⅓-octave bands, than for relatively large tone-to-noise ratios (+20 dB and greater). Data analysis suggests that the extent of the increments and decrements in perceived magnitude depends on the absolute loudnesses of the component stimuli, the interaction between a specific tone frequency and noise spectrum, and the attribute judged. An attempt is made to quantify the observed effects. [Supported by NASA-Langley Research Center.]
An array performance analysis utilizing selective sensor exclusion
Authors: Mole Louis A.
Published: October 2005

This paper presents the results of an investigation into the question of whether a selective sensor exclusion concept can be employed to improve array gain when the classical beamforming conditions concerning the phase and amplitude of the received signal and noise fields are not met. With conventional array beamforming conditions as the basis, sensor exclusion criteria are developed to characterize array performance in terms of the number of sensors. Probability of improvement expressions for the criteria’s effectiveness are also formulated, and these concepts are substantiated by experimental data processing. The results indicate that the degree of improvement provided by the sensor criteria is directly related to the magnitude of the departure from classical assumptions of the acoustic fields present at the array.
Investigation of chemical sound absorption in sea water: Part III
Authors: Mellen R. H. , Browning D. G. , Simmons V. P.
Published: October 2005

Chemical sound absorption in sea water cannot be considered the sum of independent relaxation processes because many equilibria have common ions. Effects of coupling on the MgCO30 and MgB(OH)+4 relaxations can be explained as simple buffer reactions that equilibrate rapidly and follow the slower reactions. The B(OH)3 relaxation, however, is explained by a different mechanism involving exchange with the HCO3−/CO32− system.
Spatial processing beyond adaptive beamforming
Authors: Mermoz H. F.
Published: October 2005

Underlying assumptions of classical directivity pattern application are identified. Adaptive beamforming principles are related to relaxation of these assumptions, and the limitations of adaptive beamformers are developed in terms of lack of a priori knowledge of source distribution and medium propagation parameters. Progress in spatial processing beyond current adaptive beamforming is discussed in terms of estimating jointly source distribution and medium properties using the outputs of an N-element array of sensors.
On the elastic profiles of a layered medium from reflection data. Part I. Plane-wave sources
Authors: Coen Shimon
Published: October 2005

It is shown that the density and the two Lamé profiles of a layered elastic medium can be uniquely determined from the impulse responses due to obliquely incident SH plane waves at two precritical angles of incidence and a normally incident P plane wave. A direct (noniterative) inversion algorithm is developed which construct the three elastic profiles of the layered medium from the reflection data. The equation of motion for an obliquely incident SH plane wave is transformed to the Schrödinger equation whose potential is related to the density profile, shear modulus profile, and the angle of incidence. The Gelfand–Levitan theory is used to recover the potential of the Schrödinger equation from the impulse response. When the impulse response is available at two angles of incidence, the shear modulus and density profiles can be separately obtained as a function of depth. It is further shown that the incompressibility profile can be obtained from the impulse response due to a normally incident P plane wave and the density and shear modulus profiles.
Scattering of acoustic waves by a coated pressure-release ellipsoid
Authors: Dassios George
Published: October 2005

We consider low-frequency scattering by a penetrable ellipsoid with a soft confocal ellipsoidal core. The second-order terms for the field and the fourth-order terms for the scattering amplitude are obtained. Physically degenerate forms, such as the penetrable, the rigid, and the soft ellipsoid as well as special geometrical cases, such as spheroids, sphere, needle, and disk, are obtained by assigning appropriate values to the physical and geometrical parameters of the problem.
Calibration of earphones on a flat-plate coupler: Exploring two setup procedures
Authors: Heidbreder Arnold F.
Published: October 2005

The frequency responses of two earphones with circumaural cushions and one earphone with a supraaural cushion were repeatedly measured on a flat-plate coupler. The coupler was used in a normal position with the earphone on top and in an inverted position with the coupler resting on the earphone cushion. The advantage of the latter configuration lies in the ease with which the coupler and the earphone can be precisely mated; which, in turn, suggested that reliability may be improved with the inverted configuration. However, measurements made after careful mating of the earphone and the coupler indicated that the reliabilities of the measurements for both the normal and inverted configurations were satisfactory with the standard deviation of a measurement having an average value of 0.45 dB. For two of the phones the sensitivities did not differ significantly between the two configurations; while for one, slight but reliable differences were observed.
High order Lamb wave excitation in piezoelectric plates as transducer for cylindrical waves
Authors: Pappalardo Massimo
Published: October 2005

The displacements of the edge surface of a piezoelectric plate in which a symmetrical Lamb wave is propagating is used for generating cylindrical waves in liquid. The potential of this transducer derives from the possibility of performing a pre-elaboration of the signal already at the stage of electroacoustic transduction.
Fluctuations of resolved acoustic multipaths at long range in the ocean
Authors: Spiesberger John L. , Worcester Peter F.
Published: October 2005

A phase-coded signal centered at 220 Hz with 64-ms resolution was transmitted at 10-min intervals between an acoustic source moored at 2-km depth and a bottom-mounted receiver at ∠3-km depth and at ∠900-km range. A variety of fluctuation statistics (pulse and cw) are computed for three resolved multipaths from a 32-day record. The fluctuations are compared with theoretical predictions based on internal wave scattering. Some measurements agree with theory; measurements that disagree differ by amounts that are statistically significant but not large. Uncertainty of the internal wave energy level could account for some discrepancies. Some theoretical results are very sensitive to small changes of the second derivative of the mean sound-speed profile. There are substantial fluctuations at frequencies below those that can be accounted for by internal waves.
Acoustoelastic theory for elastic–plastic materials
Authors: Johnson George C.
Published: October 2005

A generalized acoustoelastic theory is presented for the determination of propagation speeds of plane waves in bodies experiencing elastic–plastic deformation. The development is carried out in the framework of an isothermal theory for the response of an elastic–plastic continuum by considering the small deformations of a propagating wave superimposed on a finite homogeneous deformation. Specific expressions for the velocities are generated by assuming an isotropic form of the free energy which includes cubic terms in the elastic strain. The velocities are first presented for a finite strain theory and then reduced to linear form for the case of infinitesimal strain.
Perturbation corrections to the equation of radial motion of a cavitating spherical bubble in an inviscid compressible liquid
Authors: Lastman G. J. , Wentzell R. A.
Published: October 2005

A perturbation analysis is made of a nonlinear wave equation describing the velocity potential of a spherical bubble in an inviscid compressible liquid. The resulting solution is used to modify the bubble’s equation of radial motion in the neighborhood of the first bubble-radius minimum. Computational results show that the effect of the nonlinear terms is to markedly decrease the bubble’s rate-of-collapse to the first bubble-radius minimum. A comparison with the Gilmore equation is also made.
Handbook of sonar transducer passive materials
Authors: Capps R. N. , Weber F. J.
Published: October 2005

Some aspects of the engineering applications of elastomeric materials in sonar transducers are discussed. A sonar materials handbook being published as NRL Memorandum Report 4311 is also briefly reviewed.
Relations between auditory functions in normal hearing
Authors: Festen J. M. , Plomp R.
Published: October 2005

The relations among a number of auditory functions were studied by concentrating on small interindividual differences in these functions. For this purpose a battery of 12 tests was applied to 50 normal-hearing subjects. The tests included absolute threshold, auditory bandwidth measured with comb-filtered noise in direct and in forward masking, psychophysical tuning curve both in direct and in forward masking, temporal integration measured with intensity-modulated noise, forward- and backward-masking curves, cubic-difference-tone strength, and lateral suppression. In all cases the test frequency was 1000 Hz. Among the relations found, are (1) a positive correlation between the shift of the steep edge of the tuning curve, away from the probe frequency, and the width of the auditory filter as measured with comb-filtered noise, (2), an inverse relation between the width of the tuning curve and the width of the temporal window, and (3) a positive correlation between the width of the auditory filter and the strength of the cubic difference tone. Low correlations among tests were not caused by poor test reliability.
Compact theory of a multielement broadside array of uniformly spaced echosonde antennas
Authors: Adekola S. Adeniyi
Published: October 2005

This paper develops a compact theory, which is an important extension of a single element theory previously formulated [S. A. Adekola, J. Acoust. Soc. Am. 62, 524–542 (1977)], for a multielement broadside array of echosondes (acoustic echo-sounding antennas), uniformly spaced, and consisting of elements that are identical in all respects. The formulation enunciated allows for echosonde array design that gives low side-lobe strengths, which can considerably minimize any ambiguous target detection of the weak echoes backscattered from the lower atmospheric structure, and an invaluable attribute arrived at, is the directivity-pattern obtained, which can provide an improved target resolution required in acoustic echo sounding. A workable expression developed for the directivity, provides an inclination that is in good agreement with physical intuition, when expressed in a series form. The theory formulated here, permits an accurate echosonde-array design when use is made of a computer, and some accurate computer-generated directivity patterns are produced when an optimization procedure is adopted for the determination of interelement separation required for any particular echosonde array. A number of directivity patterns, illustrating numerous design examples, is presented. Results of several computations show, in general, that if a carrier frequency is specified, then the half-power beamwidth reduces when the number of array elements is increased, whereas, if the size of the array is given, the 3-dB beamwidth decreases when the carrier frequency is increased. As an example, when we use a carrier frequency fixed at 2250 Hz, the half-power beamwidths calculated for a six- and twenty-four-element array are 6.137° and 5.094°, respectively, whereas the 3-dB beamwidths obtained when the number of array elements is fixed at twelve, are 7.184° and 4.159° at carrier frequencies that assume values of 1750 and 3500 Hz, respectively. The question of how directivity patterns can be realized without high intensity side lobes that may produce an ambiquity of target resolution, and which may obscure the weak backscattered signal when use is made of the entire echosonde system for remote sensing applications, is investigated, and it is shown that, acceptable side-lobe reductions can be produced, provided the interelement separation is less than a wavelength, and if a second large interference lobe is attenuated from the visible range of a directivity pattern. A comprehensive design table provided describes some optimum interelement separations which are determined for a number of array elements. For example, an optimum spacing of 0.907λa, where λa is the acoustic wavelength, is determined for an eight-element array. When the optimum spacing just stated is employed, the directivity pattern computed when uniform, Gaussian and Lorentzian-line shape distributions are assumed at the illuminating antenna aperture, shows that the side-lobe attenuations realized are as low as −70 dB in each case.
An articulatory synthesizer for perceptual research
Authors: Rubin Philip , Baer Thomas , Mermelstein Paul
Published: October 2005

A software articulatory synthesizer, based upon a model developed by P. Mermelstein [J. Acoust. Soc. Am. 53, 1070–1082 (1973)], has been implemented on a laboratory computer. The synthesizer is designed as a tool for studying the linguistically and perceptually significant aspects of articulatory events. A prominent feature of this system is that it easily permits modification of a limited set of key parameters that control the positions of the major articulators: the lips, jaw, tongue body, tongue tip, velum, and hyoid bone. Time-varying control over vocal-tract shape and nasal coupling is possible by a straightforward procedure that is similar to key-frame animation: critical vocal-tract configurations are specified, along with excitation and timing information. Articulation then proceeds along a directed path between these key frames within the time script specified by the user. Such a procedure permits a sufficiently fine degree of control over articulator positions and movements. The organization of this system and its present and future applications are discussed.