bluuebunny/crossref_metadata_2025 huggingface dataset:
Auditory basis of progressive tone spreading
Authors: Jaykin Hector
Published: October 2005

Relatively low frequencies (which include the F0 of human speakers) are believed by many investigators to be processed by a different mechanism than most of the frequencies involved in speech segments. L. Hyman and R. Schuh [“Universals of tone rules, ”Linguistic Inquiry 5, 81–115 (1974)] noted that tone spreading, in which a linguistic tone spreads its domain in time, is always perseverative, never anticipatory. I hypothesized that the mechanism processing F0 might take more time than the mechanism processing segments, creating an auditory image in which F0 would seem to “lag behind” segments. The results of a psychoacoustic experiment involving 21 subjects support this: an F0 change and a formant change were judged to occur simultaneously most frequently when the tone change occurred 10 msec before the center of the formant change. The apparent lag seems to cause listeners to perceive (and thus produce) tones as spreading into following segments. The explanation should be approached cautiously: although the perceptual facts seem clear, it nevertheless remains to be seen whether a 10-msec lag can lead to sound change. [Research supported by NSF.]
Acoustic “before” and “after” of tonogenesis
Authors: Purcell E. , Villegas G. , Young S.
Published: October 2005

Various investigators have examined the phonological details and implications of tonogenesis in a variety of languages. Few have presented extensive phonetic data on the development of tone in a language. We examined two related languages Panjabi and Hindi, the former having a three tone system, the latter not having a tone system. It has been hypothesized that the development of Panjabi tone is correlated with the simplication of an earlier system of consonantal oppositions, from a breathy voiced/voiced/voiceless system to a voiced/voiceless system. Three native speakers of Panjabi and three native speakers of Hindi recorded samples of words which are cognates in the two languages. Ten measurements of fundamental frequency were made on each vowel of the test words. In all there were 4500 measurements of fundamental frequency. A comparison was made of average fundamental frequency for comparable word types in the Hindi and Panjabi data. The average data show that the Panjabi tonal contours correlate well with Hindi fundamental frequency contours which vary according to the consonantal types adjoining vowels. In other words, Hindi consonantal types correlate with Panjabi tones.
Trill seeking
Authors: Ferrari Disnet Sandra , Ladefoged Peter
Published: October 2005

A comparative study was made of the rate and duration of trills produced with each of the three nonfixed articulators: the lips, the tongue tip, and the uvula. Recordings were made of initial, medial, and final trills produced by speakers of the New Guinea languages Kele and Titan (bilabial trills); of Northeastern Italian, Ecuadorean and Columbian Spanish, Hausa, Kele, and Titan (apiral trills); and of Southern Swedish, Northwestern Italian, and Southern French (uvular trills). Instrumental analysis of these recordings revealed that the mean rate of trill ranges from 26 to 32 closures per second, sustained over a mean of 2–3 closure. There is a great similarity between all these trills in the rate of vibration regardless of the mass of the articulator. Their auditory similarity will be demonstrated by means of a tape recording. [Research supported by NSF.]
Choral speech and phonetic invariance
Authors: Cohen J. R. , Kupin J. J.
Published: October 2005

In rhythmic choral speech, all speakers produce the same phonetic message at the same rate. A recording of such speech can be viewed as an algebraic summation in which speaker dependent variability is essentially reduced to the level of background noise. Intelligibility tests and acoustic analyses will be done on recordings of a large group of speakers producing short phrases containing stressed vowels in CVC syllables. The results will be considered in light of two competing theories of perceptual normalization; Kuhn [J. Acoust. Soc. Am. 58, 428–433 (1975)] which suggests that front cavity information is invariant across speakers; and the standard formant ratio hypothesis. Preliminary data from a mixed chorus of 30 members indicates that intelligibility is maintained for phrase length utterances, and further that several consonants and most vowels are readily perceptible, even in excised syllables.
Application of piezoelectric polymers to audio transducers
Authors: Yamamoto Takeo , Tamura Masahiko
Published: October 2005

Recently, piezoelectricity and pyroelectricity of polymer materials have attracted attention to the possibility of their application as new transducer materials. The first study of the application of piezoelectric biological polymer materials, such as whale bones and tendons, was done by Fukada in phonograph cartridges. Later, synthetic polymer films, poly(γ-methyl L-gultamate), were used as transducing elements of experimental microphones and headphones: however, these transducers were not commercialized, because of their low sensitivity. In 1969, Kawai had found large piezoelectric effects in stretched and polarized poly(vinylidene fluoride) films. The stretched poly(vinylidene fluoride) films exhibit hysteresis characteristics similar to those of ferroelectric crystals under high alternating electric fields of 50 Hz. After being subjected to a polarizing static field of about 600 kV/cm at 100°C for 40–60 min, the film possesses large piezoelectric and pyroelectric constants; for example, in the case of the transverse effect, the d constant of the film is more than ten times larger than that of quartz, namely, 8×10−7 cgs esu. Reversible changes in infrared spectra before and after the poling process imply that the dipolse in the β crystals of poly(vinylidene fluoride) are aligned along the direction of the applied electric field. The alignment is strongly affected by the properties of the amorphous region in the film. The coersive field in the P-E hysteresis curve increases rapidly near the glass transition temperature. Not all of the dipolse in the β crystals, however, can orient themselves along the poling field. Furthermore, this orientation is influenced by the crystal size and the degree of the crystallinity. This soft, thin piezoelectric polymer film has been applied to the design of various transducers, such as stereophonic headphones, direct radiator high frequency loudspeakers, microphones, phonograph cartridges, and very small accelerometers. These transducers have very simple structures because the diaphragms are piezoelectric films and possess the transducing function. Particularly, in the case of the loudspeakers, a pulsating cylinder may be easily obtained which has omnidirectional patterns up to 20 kHz. Some of these transducers have been commercialized already.
Theory of vibrations of coated, thermopiezoelectric laminae
Authors: Dökmeci M. Cengiz
Published: October 2005

In this paper, we aim to construct a theory of vibrations of coated laminae in which there is coupling between elastic and electric as well as thermal fields. The laminas coated completely with perfectly conducting electrodes on both faces may comprise an arbitrary number of bonded layers, each with a distinct but uniform thickness, density and electromechanical properties. Within the framework of 3-D thermopiezoelectricity, we first develop a generalized variational theorem [cf. M. C. Dökmeci L. Al Nuovo Cimento 7, 449–454 (1973)]. Next, following Mindlin [R. D. Mindlin, Int. J. Solids Struct. 10, 625–637 (1974)] and using this theorem, we construct a system of 2-D approximate governing equations of the coated laminae for the case when the mechanical displacement, electric potential and thermal field vary linearly across the laminas thickness. The effects of elastic stiffnesses of, and the interactions between, layers of the laminae and its electrodes are all taken into account. Lastly, we present theorems of uniqueness in the governing equations of the theory. And we examine special cases of interest. [Work supported by the Scientific and Technical Research Council of Turkey.]
Effect of radiation loading on the equivalent circuit for a piezoelectric polymer transducer
Authors: Hadimac A. A.
Published: October 2005

The equivalent circuit for a transducer using distended piezoelectric polymer sheets has been shown to be similar to that using a thin spherical shell, except that the mechanical impedance is given by a summation, in parallel, of impedances associated with a normal-mode expansion. The modal impedances are determined by the shape of the sheet boundary, the magnitude of the distension, and the nature of the radiation interaction between modes. The case of a distended circular sheet, fastened at the outer edge, radiating into a circular tube with rigid walls has been analyzed in detail This can be used to approximate the behavior of one transducer in a infinite hexagonal array. The behavior of distended rectangular sheets in an infinite rectangular array in an infinite baffle has also been studied. In both cases, the radiation field is given. [Work supported by ONR.]
Masking of tone glides II
Authors: Nábělek Igor V.
Published: October 2005

Previous results for downward glides [J. Acoust. Soc. Am. 58, S34 (1975), Hearing and Davis (CID. St. Louis, 1976)] have shown that their masked thresholds were higher than of constant tones. Present measurements with a larger range of stimuli confirmed the previous results and added new ones. Both directions of glides (between 2000 and 1800, 1000, 500, and 250 Hz, respectively) were used. The burst duration was between 0.5 and 5000 msec, the sound pressure level of the masking white noise was 70 dB. Listeners had normal hearing. Below approximately 10-msec duration the upward glides had lower thresholds than constant tones, the downward glides had higher thresholds. In a range between approximately 10 and 400 msec both glides had higher thresholds than constant tones. The thresholds of downward glides below 200-msec duration were consistantly higher than of the upward glides, above 200 msec they were similar. Between 500 and 2000 msec the glide thresholds were lower than the thresholds for the highest frequency and higher than the thresholds for the lowest frequency of the glide. Generally, constant tone thresholds leveled off between 500 and 1000 msec, and glide thresholds at around 5000 msec.
Duration shift and loudness enhancement: Separate but similar phenomena
Authors: Elmasian R. , Pokorny R. , Galambos R.
Published: October 2005

In duration shift (see Pokorny et al., this issue) and in loudness enhancement [e.g., J. Acoust Soc. Am. 58, 229–234 (1975)] subjective perceptions of one signal (the target) move toward those of another signal (the conditioner) presented nearby in time. Because the loudness of short signals increases with their duration (loudness summation), however, a duration shift experiment might merely be a loudness enhancement experiment in which subjects, contrary to instructions, match target loudness instead of target duration. The present study addresses this issue. Both conditioner duration (10 or 40 msec) and conditioner intensity (61, 75, or 89 dB SPL) were varied in the monaural forward paradigm while subjects matched 75 dB white-noise targets of 20- and 25-msec duration. When they matched target duration in these 12 different conditions, changes in conditioner duration produced the greater shifts and when they matched the same signals for target loudness, changes in conditioner intensity produced the greater shifts. Thus, while duration shifts and loudness enhancement share many common characteristics, they are separate perceptual phenomena.
Backward pitch-recognition interference
Authors: Sparks D. W.
Published: October 2005

Recent controversy concerning backward pitch-recognition interference has led some investigators to propose that this phenomenon is probably sensory in its origins; others believe that a disruption in the processing of a preperceptual auditory trace is occurring. Still others argue that pitch recognition disruptions result from an interference to an image, held in short-term store, which may have undergone at least an initial categorical assignment. Several experiments have been performed in which brief tonal-target bursts centered around 820 Hz were preceded or followed by interference signals. These interference signals included tones and noise bursts having a variety of durations, intensities, and center frequencies. Interference signals were ipsilateral or contralateral to the ear receiving the tonal targets. Aggregate results from these experiments support the conclusion that these disruptions occur after at least a preliminary categorical assignment.
Neurophysiological studies on the echolocation system of bats sensitive to Doppler-shifted echoes
Authors: Suga N. , Schuler G. , Jen P. H.-S.
Published: October 2005

Rhinolophus ferrumequinum and Pteronotus parnellii emit orientation sounds consisting of a long CF component and a short FM component. The CF component is used for “Doppler-shift compensation.” In rf, the gate used to obtain the frequency information for the compensation is probably opened at the beginning of the sound emission and is closed shortly after the end of the emission. The cricothyroid muscle is highly developed and its activity decreases proportionately with the amount of Doppler-shift compensation. These bats have peripheral auditory systems highly specialized for the reception of the CF component in orientation signals. The extent of cortical representation of the peripheral sensory field depends on its important for species behavior. In p. p., neurons processing the CF components in the orientation signal and Doppler-shifted echoes occupy a disproportionately large part of the auditory cortex. The separate FM signal processing area is also large. This disproportionate cortical representation related to features of biologically significant signals is comparable to that found in the somato-sensory and visual systems in many mammals. [Work supported by NSF.]
Lateralization by frequency in dichotic tonal sequences as a function of interaural amplitude and time differences
Authors: Deutsch Diana
Published: October 2005

When listeners are presented with a dichotic sequence of tones which alternate in pitch between 400 and 800 Hz, such that when one ear receives 400 Hz the other receives 800 Hz (and vice versa) many hear a single high tone in one ear alternating with a single low tone in the other. This effect is based in part on a lateralization of each fused tonal percept towards the ear receiving the 800-Hz signal. It was found that in four out of five subjects, lateralization towards the 800-Hz signal occurred even when the 400-Hz signal was substantially higher in amplitude, and clearly higher in apparent loudness. However, although this effect was prominent with sequences consisting of 20 dichotic tone pairs, it was weak with sequences consisting of two dichotic tone pairs. With long sequences, lateralization to the 800-Hz signal was also prominent even when it lagged or led the 400-Hz signal by several milliseconds.
Environmental noise of a nuclear power plant and its substations
Authors: Dennison E. E. , Maier R. E. , McGaughey J. W. , Ying S. P.
Published: October 2005

In order to fulfill government requirements for construction of a nuclear power plant, an environmental noise impact as-assessment has been conducted. Ambient noise was measured continuously for 24 hour periods at the plant and substation sites and in the vicinity. Week long surveys were performed in each of the four seasons. A statistical interpretation of construction noise accounts for variability of construction equipment usage, its location and range of sound pressure levels. Histograms of construction noise and measured ambient noise are added to obtain the statistical representation of the predicted construction ambient noise. Operational noise of the plant is similarly predicted. The predicted noise contours of both operation and construction noise are formulated on the topographic maps. Meteorologic and topographic effects on the noise data are discussed.
A true integrating noise monitor
Authors: Schomer Paul D.
Published: October 2005

The Construction Engineering Research Laboratory of the Army Corps of Engineers has been faced with many stringent noise monitoring requirements by both unique Army needs and by special measurements for the Federal EPA. Artillery, armor, demolition, small arms, and helicopter together form a set of sources which are difficult or impossible to measure using standard meters with their associated time constants. Moreover, the true definition of Ldn is an integral. These monitors possess new detectors which employ digital integration in order to eliminate the detector time constant problem. Also, to monitor in accordance with the new recommended impulse criteria, the new monitors are capable of incorporating a low-amplitude cutoff and C weighting. Extreme heat, cold, rain, and snow present no problem; mechanical equipment has been eliminated from the basic monitor and uninterruptable power supplies employed. By the use of a microprocessor, flexibility is enhanced and currently these units are being modified to keep track of time of day and to be self-calibrating.
Auger miner noise control
Authors: Retka T. J. , Burks J. Alton
Published: October 2005

Several auger miner machines were surveyed in underground coal mines to define operational noise levels at worker locations. Noise levels as high as 106 dBA were recorded at worker positions with most noise levels exceeding 100 dBA. Efforts were initiated to devise corrective measures to lower the noise exposure of operating personnel to 90 dBA or less. To perform a noise source identification study, an auger miner system was configured at a nonreverberatory aboveground test site which included provisions to operate in a coal-cutting mode. A comprehensive array of noise source diagnostic tests including (1) cover and expose noise testing, (2) vibration surveys, (3) impulse response (compliance) testing, (4) slow-motion movies, and (5) coherence testing were used to identify auger miner noise-producing components and mechanisms. The specific noise contributions of individual auger miner machinery components were identified as a result of the source testing. During non-coal-cutting operation of the miner, frame radiation due to conveyor motion was found to be the most significant noise source. During coal-cutting operation, radiation of augers, frame, and mine face were each found to be significant noise sources depending on worker locations. Noise reducing modifications for the auger miner have been devised, designed, and are being implemented. [Work supported by U.S. Bureau of Mines.]
Programming noise control in a small caliber munitions manufacturing plant
Authors: Sachs F. Z. , Heymann R. W.
Published: October 2005

Program costs for the implementation of plant-wide noise control through retrofit of existing equipment were developed for a high-volume munitions manufacturing facility. Noise reduction costs were estimated by defining workable approaches for the control of all noise sources. Involved were over 1200 machines and some 37 different manufacturing operations. The principal noise sources were punch presses, parts hoppers, parts feed chutes, conveyor lines, tumblers, and other automatic metal-forming and transfer machines. The most prevalent generating mechanisms were the part impacts during transfer and part impact and surface vibration at the punch presses. The goal was to reduce the existing conditions, reaching 110 dBA in certain locations, to below the U. S. Army's 85 dBA non-time-weighted hearing conservation criterion. The level of design detail of the noise control developed was limited to that required for cost estimation. Design detail for fabrication was not provided since the principal objective was to provide management with program cost data. This crucial information can now be factored into the capital equipment planning function along with traditional projections such as economic equipment life, future production requirements, and equipment modernization schedules.
Experimental investigation of the photoacoustic effect in liquids and solids
Authors: Wetsel G. C. , McDonald F. A.
Published: October 2005

The photoacoustic effect in liquids and solids has been experimentally investigated using light from helium-neon and argon-ion lasers. In an effort to evaluate the theoretical explanation of the effect (see preceding paper), the photoacoustic amplitude Q has been measured as a function of chopping frequency f for several liquids and solids with large values of the optical absorption coefficient β. The experimental results compare favorably with theoretical predictions over wide ranges of f and β. Water solutions with varying concentrations of a common pH indicator were prepared to obtain a controlled evaluation of Q(f,β). It was found that curve fitting the theory to the experimentally determined graph of Q vs f permits the determination of β to at least two significant figures for a solute in water with a β range of at least 50–5000 cm−1. This result indicates that the photoacoustic effect provides an important technique for determining the absolute optical absorption coefficient in highly absorbing liquids and solids.
Acoustic diffraction by an impedance covered half plane
Authors: Kendig Robert P.
Published: October 2005

Exact, closed form solutions for diffraction and backscattering by an edge whose surfaces exhibit arbitrary impedances were determined for the cases of a point source, a line source, and a plane wave. An integral method was devised that could account for the impedance boundary conditions. Since the solution is in a closed form, interpretation of the influence of the impedance covered half plane on the diffraction field is greatly faciliated. Specifically, the effect of each surface on the acoustic field dominates in the half space in which it faces. Though the effect of each surface extends into the opposite half space behind the barrier, this influence is very small and diminishes even more as the observer moves further behind the barrier. [Work supported by NAVSEA.]
New model of resonant acoustic scattering by swimbladder-bearing fish
Authors: Love Richard H.
Published: October 2005

A new model of a swimbladder-bearing fish has been developed in order to provide improved predictions of the resonant frequency and acoustic cross section of such a fish. The model consists of a small spherical shell in water, enclosing an air cavity which supports a surface tension. The shell is a viscous, heat-conducting Newtonian fluid, with the physical properties of fish flesh. A comparison of the results obtained with the new model to experimental data indicates that the new model constitutes a definite improvement over previous models. The new model can predict the high values of damping and elevated resonant frequencies that previous models could not. The model appears to be most accurate for fish in which tension in the swim-bladder wall has a minor effect on resonant scattering. This includes the fish which are of interest in studies of volume reverberation and therefore, the new model should be of considerable value in such studies.
Measurements of underwater forward scattering of acoustic signals by the sea surface
Authors: Plemons T. D. , Pence E. A.
Published: October 2005

Underwater forward scattering measurements of acoustic signals were made this year in Dabob Bay located on Hood Canal in Washington State. Frequencies of 15, 20, 25, and 30 kHz were transmitted in 1.0-msec pulses. Signals reflected from the wind-driven surface of Dabob Bay were measured in the specular direction with grazing angles varying from 5° to 23°. For each grazing angle, surface roughness and transmitted frequency, 100 reflected signals were processed to estimate the average and the coefficient of variation of the scattered energy. The experimental probability density and distribution functions of the scattered energies were also constructed. The dependence of each of these statistical quantities on the surface roughness parameter g is discussed. For an rms surface-wave height σ, grazing angle θ and acoustic wavelength λ, g = 4πσsinθ/λ.
Scattering function for underwater acoustic scatter channels with several bounces
Authors: Tuteur Franz B.
Published: October 2005

The scattering function, or range-Doppler plot for an underwater acoustic channel involving a single surface bounce was derived in a recent paper [J. F. McDonald and F. B. Tuteur, J. Acoust. Soc. Am. 57, 1025–1029 (19xx)] and was shown to have a characteristic horse-shoe shape when the surface waves have a well-defined direction. This shape indicates strong correlation between Doppler shifts and range delays. In practice underwater acoustic channels often involve several reflections, some from the surface and some from the bottom. A calculation of the scattering function for such channels has been performed using an extension of the Kirchhoff integral method described in [F. B. Tuteur, J. Acoust. Soc. Am. 60 (October 1976)]. For a channel involving a single bottom bounce and surface bounce the reverberation time and the Doppler spread are found to be weighted averages of the respective quantities for single bounces, with weighting factors that depend on the geometry and on the statistics of both surface and bottom. The shape of the scattering function can therefore be expected to be qualitatively similar to the one for the single surface bounce.
Stochastic characterization of propagation and target impulse-response measurements
Authors: Mark William D.
Published: October 2005

In many situations, propagation and target impulse-response measurements are most conveniently treated as stochastic transients. Ideally, stochastic characterizations of such impulse-response measurements should possess input-response relationships which permit combination of characterizations of one-way transmission and target impulse-response functions with sonar signals and receiver impulse responses to yield predictions of ensemble-averaged instantaneous (time-varying) squared receiver responses. Two spectral methods [W. D. Mark, J. Sound Vib. 22, 249–295 (1972), J. Acoust. Soc. Am. 59, 1184–1194 (1976)] of characterization of stochastic impulse-response measurements will be described, and properties of series representations of ensemble-averaged squared sonar receiver responses, generated from these characterizations, will be discussed.
Determination of the acoustic properties of deep-ocean sediments from in situ profiles
Authors: Shirley D. J.
Published: October 2005

The acoustic properties of ocean sediments are routinely measured in situ during coring using the ARL sound-speed profilometer. Measurements are made at 200 kHz across the diameter of the core during penetration of the corer into the ocean bottom. Profiles measured on the Southwest Bermuda Rise, the West Antilles Outer Ridge, and the Nares Abyssal Plain in water depths greater than 5 km indicates that some of the acoustic properties associated with sediments of these areas are: (1) a sound speed at the top of the sediment that is 20–30 m/sec slower than that of the overlying water, (2) a linear increase in the gross sound speed of the sediment of from 0.5 to 1.0 m/sec per m depth, and (3) a fine structure of high and low speed layers impressed on the gross structure. [This work was supported by ONR, Code 480.]
Guide for users and designers of open-plan classrooms
Authors: Siekman Bill
Published: October 2005

In 1972 the Acoustical Insulating Materials Association sponsored a program of research by Tracor, Inc., to develop guidelines for optimum design and use of open-plan classrooms, particularly in regard to the effective use of acoustical absorption. This program utilized literature study, visits to open-plan schools, and computer simulation of large rooms to develop performance criteria and procedures for evaluation. One very important conclusion from this study was that less than 10% of existing classrooms were considered acoustically excellent, and two-thirds were just tolerable or worse. Fortunately, the features which distinguished the good rooms were conspicuous and definable. In 1975, the highly technical report from Tracor was rewritten in different language for use by teachers, school administrators, and architects. Engineering data has been reduced to simple tables, charts, and worksheets. Recommendations for accomodation to existing classrooms have also been incorporated. The Guide is now ready for publication and distribution.
Experimental investigation of the effect of a rotating diffuser upon the radiation impedance of a source in a reverberant room
Authors: Hansen C. H. , Bies D. A.
Published: October 2005

The radiation impedance of an aperture in the side wall of a 180 m3 reverberant room has been measured over the frequency range from 100 to 2000 Hz using a simple impedance tube and a high speed data acquisition system which allowed subsequent data reduction on a CDC6400 computer. The room contained a rotating diffuser of 18.71 m3 of swept volume which was capable of continuously variable rotational speed up to 50 rpm. Two apertures were investigated which were the open end of a 10-cm diameter impedance tube and the 43-cm diameter mouth of a conical horn. In the case of the horn the throat impedance was measured. Measurements at approximately two degree intervals of diffuser rotation showed that on average free-field values of radiation impedance obtained at all frequencies tested and for all rotational speeds of the diffuser. However a marked increase in the standard deviation about the mean was observed at frequencies below 900 Hz which decreased with increasing diffuser rotational speed up to approximately 30 rpm after which no further decrease occurred.
Experimental comparison between Mariner's approximation and an exact solution of equations describing the measurement of transmission loss of a test partition
Authors: Bies D. A. , Pickles J. M.
Published: October 2005

The American standard for the laboratory measurement of the transmission loss of a test partition, E90-75, recommends the use of a procedure developed by Thomas Mariner [J. Acoust. Soc. Am. 33, 1131–1139 (1961)] which seeks to minimize the effect of coupling between the source and receiving rooms during calibration of the receiving room by the reverberant decay method. When Mariner's reverberation decay “tuning” is carried out his approximate solution may be used and the possible error in the measurement may be estimated using a procedure which he has outlined. In this paper a comparison is made between Mariner's approximation and an exact solution of the problem as originally outlined by Mariner but not considered by him. The comparison will include a brief outline of the solution as well as experimental work comparing the two methods. The exact solution does not require reverberation tuning but it does require measurements of reverberation in both rooms as well as noise reduction measurements in both directions.
Effect of source position on sound power radiation in a reverberant chamber
Authors: Mange Gary , Tichy Jiri
Published: October 2005

A model reverberant chamber was utilized to measured the variance of radiated sound power of a one inch dome loudspeaker. The chamber was excited by five uncorrelated pure tones at four source positions and the reverberant sound field was spatially sampled with two moving microphones. The spatial variances and the variance of the radiated sound power of the source were determined in five octave bands. The above procedure was repeated for four chamber conditions—with and without added absorption, and with and without a rotating diffuser operating. The experimental values of the variance of radiated sound power showed excellent agreement with previously published results [G. C. Maling, IBM J. Res. Dev. 11, 492–501 (1967)] and were also systematically lower than the theoretically predicted values based on a “next neighbor” Poisson distribution of modes. The added chamber absorption reduces the variance at low frequencies as predicted by theory, but the rotating diffuser had very little effect on this variance.
Automatic measurement of reverberation times using a real-time analyzer and a computer
Authors: Upton Roger
Published: October 2005

Attempts to measure reverberation times automatically using real-time analyzers with computers have failed in the past due to the available analyzers having averaging times that are too long or insufficient dynamic range. With the advent of the Brüel & Kjær Digital Frequency Analyzer type 2131, however, this is no longer the case. A method of using this instrument with a computer or a desk top calculator is described, whereby reverberation times can be measured automatically in parallel in all octaves or 13 octaves of interest, within the frequency range of the analyzer. Time domain resolutions of up to approximately 22 points per second can be obtained, and the method can be used either with interrupted noise or impulsive noise as the excitation. Comparison is made between experimental results obtained using the method. and those obtained using traditional techniques.
PHD—low-frequency transducer
Authors: Nichols C. S.
Published: October 2005

The area of low-frequency sound sources has received considerable emphasis in the past several years. Of particular interest is the development of small, lightweight low-frequency transducers that have broadband capability. One particular low-frequency transducer that fits into this category is the PHD (post hole digger). The PHD is cylindrical in shape with a diameter of 0.3048 m, a length of 0.4572 m and has an in-air weight of 36.3 kg. The driving mechanism for the PHD is a transverse variable reluctance magnetic motor. The unit must be pressure compensated and requires large input currents (15–30 amp) below 30 Hz. The PHD has recently been tested at Lake Pend Oreille to a depth of 61 m. The response of the unit was measured as a function of operating depth during the Pend Oreille tests. At the 61 m depth, the maximum source level that it was possible to obtain was 168 dB re 1 μPa at 1 m. This limit was imposed by the amplifiers used during the tests and is not a limit of the transducer. [Work supported by NAVSEA 06H1.]
History, development, and resources for ship shock hardening
Authors: Pusey Henry C.
Published: October 2005

This paper will cover the historical development of programs designed to increase the survivability of naval ships to shock generated by various sources such as contact and noncontact underwater explosions, impact of projectiles and bombs, firing of the ships guns and other weapons, and air blast. The historical development will touch upon technical advances from World War I to the present in the areas of defining the shock threat, the evolution of design techniques, the methods and desirability of shock isolation, the changing specifications, and the improvements in acceptance methods involving both test and analysis. Finally, the presentation will include a comprehensive description with problems involving the hardening of ship structures and equipment to shock from the various sources.
The geniohyoid and the role of the strap muscles in pitch control
Authors: Erickson Donna M. , Liberman Mark Y. , Niimi Seiji
Published: October 2005

Many investigators have noted a relationship between strap-muscle activity and pitch lowering, but there does not seem to be any single generally accepted theory to account for this connection. The articularly effect of strap-muscle contraction will depend in part on what other forces are acting on the hyoid bone; therefore, in the context of a general EMG investigation of English intonation, we recorded from a supraphyoidal muscle, the geniohyoid. In our data, the three strap muscles show nearly identical patterns of activity; as a group, their activity shows a strong negative correlation with the activity of the geniohyoid. By comparing these patterns of activity for otherwise identical utterances with systematically varied pitch contours, we are able to sort out the effects resulting from tongue and jaw movements from the activity specifically related to pitch control, and to arrive at an hypothesis concerning the effects on vocal-cord tension of the forces applied, by these extrinsic muscles, to the hyoid bond and the thyroid cartilage.
Vocal-tract responses to unexpected, suddenly induced decreases in intraoral air pressure
Authors: Perkell Joseph S. , Gay Thomas
Published: October 2005

In a pilot study [J.S. Perkell, J. Acoust. Soc. Am. 58, S12 (A) (1975)] a vacuum apparatus was used to create suddenly induced, unexpected decreases in intraoral air pressure (suction) during prestressed intervocalic /p/ production. It was found that with labial anesthesia, VOT measured from the moment of consonant onset occurred an average of 20 msec later during suction trials than during normal intraoral air pressure trials. In order to explore the possible relationship of this effect to the function of feedback mechanisms, the experiment is being elaborated. Electromyographic measurements are being made in conjunction with variation in the depth of labial anesthesia and timing of the onset and offset of the “suction” impulse. Preliminary results will be discussed. [Research supported by NIH grants.]
Oscillatory movements of the velum: A factor of mandibular and/or intraoral air-pressure variation
Authors: Williams W. N. , Brown W. S. , Hilderbrand B.
Published: October 2005

It is known that velar elevation in closure for speech correlates with specific sound productions. In addition, the velum has been observed to oscillate during repeated syllable or word utterances. The purpose of this study was to determine whether this oscillatory movement of the soft palate may be related to the build up and release of intraoral air pressure and/or to the opening and closing patterns of the mandible. Simultaneous cinefluorographic films and air-pressure recordings were taken for three subjects during the repeated production of /apa/, /aba/, /asa/, and /aza/. From the cinefluorographic films, variations in velar and mandibular height were determined and correlated with variations of air pressure. Initial analyses indicated that there was no clear relationship between either variation in air-pressure or vertical displacement of the mandible with oscillatory motions of the velum. These results will be discussed in terms of a theory/model of articulatory behavior for oral consonant production.
Stereo fiberscopic investigation of the larynx
Authors: Niimi Seiji , Baer Thomas , Fujimura Osamu
Published: October 2005

Present fiberoptic laryngoscopic techniques [Sawashima and Hirose, J. Acoust. Soc. Am. 43, 168–169 (1968)] are limited because lens-to-object distance cannot be determined. To overcome this limitation, a laryngeal stereo fiberscope, which can supply a side-by-side pair of images within each film frame, has been developed. The fiberscope comprises two independent fiberoptic systems joined to a common viewing and control unit. The two fiberoptic bundles are inserted to the level of the oral pharynx through a subject's two nostrils, then their tips are fixed to a rigid connector, and they are directed toward the larynx. The three-dimensional position of a point in the object field can be determined from measurements of its position in the two images. Measurements of several points on the larynx can be used to determine its vertical position, its orientation (tilt), and its actual dimensions. Measurement error in the vertical direction depends on several factors, but under typical conditions calibration has given a maximum error range of ±5%. Preliminary measurements of laryngeal movements during phonatory and respiratory gestures will be discussed.
Stresses in vocal-fold tissues during normal phonation
Authors: Titze Ingo R.
Published: October 2005

In order to predict the occurrence of pathologic conditions in the vocal-fold tissues resulting from abnormal use and abuse, a theoretical study of various shear and compressional stresses under normal phonation has been attempted. Results are based on a continuum as well as a finite element of model of the vocal folds. These models differ from previous ones in that distributive mechanical properties, i.e., shear elasticity and viscosity, are used to describe the dynamics. It is shown that near glottal closure the stresses at the medial boundary of the vocal folds resemble a doublet, i.e., a sharp negative stress resulting from the short range Bernoulli forces followed by an immediate positive stress after closure resulting from vocal fold collision. The peak to peak magnitude of this doublet can be of the order of 105–106 dyn/cm2 and occurs in a time interval of the order of 10−4 sec. Such an impulse could easily contribute to permanent tissue modification, and the formation of pathologies such as contact ulcers and vocal nodules. Modes of phonation which may avoid such a high stress concentration are discussed.
Oral pressure and laryngeal control
Authors: Ewan William G.
Published: October 2005

It is not clear from studies of larynx movement during stop production that the larynx is perturbed up for voiceless stops or down for voiced stops. One would expect it is the latter, however, since larynx lowering would provide a slight increase in oral cavity volume and would thus help to prolong the pressure difference across the glottis necessary for voicing. A test was made to see whether subjects during continuous phonation would lower the larynx in response to an artificially induced oral pressure buildup. Three subjects were used. Vertical larynx movement was recorded using the thyroumbrometer while a valving device inserted in the subject's mouth simulated an oral closure at random intervals. Valve closure resulted in a significant lowering for all three subjects. The fastest response times (the time between valve closure and the beginning of larynx lowering) approached the lower limits of motor response times associated with voluntary movement. The results indicate the larynx can be lowered during stops in order to prolong phonation. However, the magnitude of this delay in effecting this is large enough to suggest that if a similar lowering of the larynx occurs on voiced stops during speech, it must be an active preprogrammed gesture, not a passive compensatory response to oral pressure build-up. [This research was supported by a NSF grant to the Phonology Laboratory, University of California, Berkeley, and by a NIDR postdoctoral fellowship at the Department of Oral Biology, University of Connecticut Health Center, Farmington, CT.]
Coordination of consonant and vowel articulations in Japanese
Authors: Kiritani S. , Hirose H. , Sawashima M.
Published: October 2005

By means of pellet-tracking technique using an x-ray microbeam system, observations of articulatory movements for a larget set of Japanese nonsense words containing various types of CV syllables, vowel sequences have been conducted. In particular, characteristics of mutual influences of the vowel and consonant articulations upon each other were investigated. It was observed that (1) in V1CV2 articulations, relative timing of consonant articulations and V1−V2 transitions varied depending on the type of consonant; and (2) for the vowel articulation in CVC, the degree of perturbation of tongue tip position for /t/, tongue body position for /k/, and jaw position for /p/ was approximately same, whereas the perturbation of lip position for /p/ was smaller than that of jaw position. Coordinations of the movements of the velum, tongue, and lip were also investigated with special reference to the difference in the syllable initial and syllable-final nasal consonants in Japanese. Basic set of data on English is also being studied for comparing articulatory characteristics of English with those of Japanese.
Repeatability of articulatory movements
Authors: Gay T. , Kiritani S. , Hirose H.
Published: October 2005

In this experiment, we studied the repeatability of articulatory movements using the computer controlled x-ray microbeam system at the University of Tokyo. Small lead pellets were attached to the upper lip, lower lip, lower central incisor, tongue tip, tongue body, and a reference location on the upper central incisor of each of two adult male subjects, both native speakers of American English. Each speaker read a randomized list of six different nonsense syllables and two sentences containing the vowels, /i,a,u/ and the consonants, /p,t,k/ in various VCV combinations, 15 times at a controlled speaking rate. The movements of the pellets were tracked at a rate of 150 scans/sec and recorded in graphical form with the X and Y components plotted separately against time. Spectrograms were obtained from recordings of the corresponding acoustic signal. Both sets of data are used to explore the questions of articulatory and acoustic equivalence in speech production.
Language rhythms as assimilated rhythms in the nervous system
Authors: Creel Warren , Boomsliter Paul C.
Published: October 2005

Electronic studies of neural activity have shown that it is characteristic of brains to assimilate a rhythm from an incoming stimulus, and to maintain an assimilated rhythm through gaps. [E. R. John, Mechanisms of Memory (Academic, New York, 1967), especially pp. 294–343]. In music, a “rest” is a beat supplied by an assimilated rhythm. Rhythmic rests play a role in the typical structure of children's rhymes. A cross-linguistic study of children's rhymes in such unrelated languages as English, Chinese, Arabic, Nigerian, Southern California Indian, etc., finds the same systematic pattern predominating in all, although cultural borrowing is excluded. This indicates they are shaped to cater to processes that come naturally to the nervous system. [Robbins Burling, “The metrics of children's verses: a cross-linguistic study,” American Anthropologist, Vol. 68, No. 6, Pt. 2 (Dec. 1966) pp. 1418–1441]. Instances of rests and filled rests, shown by measurements of English verse, demonstrate that the nervous system makes a basic contribution to rhythm patterns, so that in analyzing them we should not think of the rhythm as continually driven by the stimulus.
Individual differences in temporal integration weightings for the annoyance of sets of noises
Authors: Ahumada A. , Nagel David C.
Published: October 2005

Observers rated the overall annoyance of a group of three brief bursts of noise spaced 15 sec apart. The levels of the bursts within each group were one of three values, 60, 75, and 90 dBA, yielding 27 stimulus groups. Each stimulus was played and rated in the presence of three backgrounds—a noisy street, a playground, and a quiet park. A three mode factor analysis of the ratings was performed using the canonical decomposition option of the Carroll and Chang INDSCAL program. The analysis finds weights for observers, background and stimuli which give the best least squares fit to the ratings. This scaling method was used because it gives a configuration with uniquely determined dimension directions. The best solution has three dimensions. The dimension accounting for the most variance (45%) represents loudness integrated independently of time. The second dimension represents loudness integrated with a sharply decaying time constant (so that the level of the most recent noise dominates). The third dimension accounts for variance introduced by changes in the background level. Observer weights on the dimensions indicate the manner in which individuals differ in arriving at the overall annoyance judgments. [Work supported by Stanford-Ames Joint Institute for Aeronautics and Acoustics.]