bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation detection interference in listeners with cochlear hearing loss: Effect of modulation depth and onset delay.
Authors: Lee Jungmee , Yook Soonha
Published: October 2013

Modulation detection interference (MDI) was measured for listeners with normal hearing (NH) and cochlear hearing loss (HI). The signal was 1 kHz, and the interferer was 2 kHz. The stimuli level was 50 or 22 dB SL. The interferer was modulated with 8 Hz at various modulation depths (25, 50, 75, or 100%). The onset of signal was delayed by 0, 125, 250, 375, 500 or 625 ms relative to onset of the interferer. For NH subjects, MDI increased systematically with increasing modulation depth of the interferer. MDI almost disappeared with 375 or 500 ms onset delay except a condition with the interferer of 25% modulation depth where there was no MDI at all across different onset delay conditions. In contrast, for HI subjects, there was quite an amount of MDI even with the interferer of 25% modulation depth, and MDI was greater than NH for all modulation depths at 0 and 125 ms onset delays, suggesting that the perceived modulation depth of the interferer might be exaggerated for HI than for NH.
Three component time reversal imaging using nonlinear elasticity.
Authors: Ulrich Timothy J. , Le Bas Pierre-Yves , Guyer Robert A. , Anderson Brian E. , Griffa Michele , Van Den Abeele Koen
Published: October 2013

The time reversed elastic nonlinearity diagnostic (TREND) has been shown to have the ability to image near surface nonlinear scatterers (e.g., cracks and disbonds) using the normal (out of plane) component of motion. This technique has been advanced with the addition of three-component vector wave field detection using laser vibrometry. This advancement provides the ability of TREND to detect and image features of various orientations, increasing its capability and decreasing the likelihood of overlooking features due to the inability to excite them. Furthermore, the ability to selectively focus each component of motion provides the means to investigate the mechanism of the nonlinear wave generation at the nonlinear scattering sites. Experimental data are presented from samples containing known defects (location and orientation) confirming the sensitivity of three-component time reversal imaging in both linear and nonlinear ultrasonics to feature orientation.
Impact of spherical probe scattering on estimation of acoustic vector quantities.
Authors: Wiederhold Curtis P. , Gee Kent L. , Thomas Derek C. , Sommerfeldt Scott D. , Blotter Jonathan D.
Published: October 2013

Multimicrophone probes are often used to measure energy-based acoustical quantities. In some cases, these probes consist of microphones mounted on the surface of a sphere, which, due to the high level of symmetry, permits scattering effects to be better characterized. Scattering of a plane wave incident on a rigid sphere has been modeled to observe how particle velocity and intensity calculations are affected by the presence of the sphere. These effects have been investigated for the traditional “finite-difference” method and a recently developed “wave vector” estimation method. In the computer model, 3-D surface plots were made showing the calculated error as a function of angle of the incident plane wave and frequency. It is shown that using the wave vector method and purposefully orienting the probe in the planar sound field generally results in the most accurate measurements. [Work supported by NASA Stennis Space Center and STI Technologies.]
Modulation of birdsong by resonance filters in the suprasyringeal vocal tract.
Authors: Suthers Roderick A.
Published: October 2013

The sound generated in the avian vocal organ, the syrinx, is modified by the filter properties of the upper vocal tract before it radiates from the beak as song. Previous investigators have shown that the properties of this vocal tract filter are affected by changes in beak gape, but the basis of this effect remains controversial. In the present study, x-ray cinematography of singing birds was used to investigate the filter properties of the suprasyringeal vocal tract. These experiments show that the dimensions of the oropharynx and esophagus are actively controlled during song by motor patterns involving muscles of the hyoid apparatus. These song-related motor patterns, together with movements of the tongue, which modulate the opening from the mouth into the beak, adjust in real time the volume and dimensions of the oropharynx and cervical esophagus so that the primary acoustic resonance of the upper vocal tract supports and tracks the fundamental frequency that is being generated by the syrinx. In juvenile Northern Cardinals, these song-related movements of the upper vocal tract first appear during subsong, while the beak is closed, and precede the changes in beak gape that typically accompany adult song. [Work supported by NIH.]
Nonlinear source-tract interaction in singing.
Authors: Titze Ingo R.
Published: October 2013

Most approaches to teaching singing are based on concept that there preferred vowel configurations for a given pitch. Speaking vowels are modified not only to create a variety of timbres, but also to support the sound source in self-sustained oscillation. Linear filter theory, traditionally applied to cans or strengthening by vocal tract coupling, or can it account for source bifurcations in vocal fold oscillation related to vowel selection. Singing are contrasted by selection of two fundamentally different mouth configurations, the megaphone shape and the inverted megaphone shape. With the megaphone shape (used by musical theatre and jazz), the second harmonic of the sound source is reinforced at all high pitches by keeping the first formant frequency high. With the inverted megaphone shape (used by classical singers of opera and art song), the second and third harmonics are reinforced by the second formant. A “lift” of the second harmonic over the first formant becomes a critical skill in acquiring a smooth timbre over a wide pitch range. [Work supported by NIH.]
Subglottal effects on the vowels across language: Preliminary study on Korean.
Authors: Jung Youngsook
Published: October 2013

Previous research suggested that subglottal resonances define vowel features [back] and [low] for English. In testing this hypothesis, we explored whether these vowel feature boundaries are independent of language. As preliminary research, we made recordings of speech and subglottal signals simultaneously for several adult Korean speakers. We found acoustic irregularities in F1 and F2 near subglottal resonances in Korean vowels. The boundary between [+low] and [−low] vowels agrees with speakers’ first subglottal resonances (SubF1), while the boundary between [+back] and [−back] agrees with SubF2. In addition, we tested which of these hypotheses is correct for a low vowel in Korean, which has only one low vowel with no contrast of [+back] and [−back]: (1) the low vowel is always [+back] or (2) SubF2 is avoided but the low vowel is front or back depending on adjacent consonants. The measurements of F2 and F2sub were obtained in the context /CaC/, where C is a consonant. We found that SubF2 was always avoided for the low vowel. If the adjacent consonants were labial or velar, F2 of the low vowel was below SubF2, whereas if the consonants were alveolar, F2 of the vowel was above SubF2. [Supported by NIH/NIDCD Grant No. #DC00075.]
An impedance-based inverse filtering scheme with glottal coupling.
Authors: Zanartu Matias , Ho Julio C. , Mehta Daryush D. , Hillman Robert E. , Wodicka George R.
Published: October 2013

Source-filter interactions in voice production arise from considering finite glottal impedances that are comparable with that of the vocal tract and/or the subglottal system. Besides the changes in the source behavior, finite glottal impedances also allow for acoustic coupling between the subglottal and supraglottal tracts. Vowel dependence on the subglottal acoustic pressure is evident in recordings of skin acceleration overlying the suprasternal notch. To obtain estimates of other physiologic signals from skin acceleration, an impedance-based inverse filtering scheme that considers acoustic coupling is proposed. The scheme is based on an electrical analog model of a dipole source and assembles multiple approaches to estimate the system impedances. An experimental platform considers simultaneous measurements of skin acceleration, flexible high-speed videoendoscopy, oral volume velocity, intraoral pressure, electroglottography, and radiated acoustic pressure. Recordings of sustained vowels, co-articulated gestures, and pitch glides provide a comprehensive data set to study tract coupling and source-filter interactions. Preliminary results provide insights into the interrelation among the measured signals and illustrate the tissue instabilities of the vocal folds during some of the gestures. Further evaluation in cases of vocal fold pathology is also planned, where source-filter interactions are expected to be even more pronounced.
Geometric dependence of phonation threshold pressure and phonation onset frequency.
Authors: Zhang Zhaoyan
Published: October 2013

Dependence of phonation threshold pressure and phonation onset frequency on vocal fold geometry was numerically investigated in a continuum model of the vocal folds. The geometric parameters of interest include the medial surface thickness, vocal fold depths of the body, and cover layers. Changes in these parameters may occur either due to laryngeal muscle activation, vocal pathology, or aging. Simulations show that both threshold pressure and onset frequency increased with decreasing vocal fold depth. However, depending on glottal geometry, increasing medial surface thickness may either increase or decrease phonation threshold pressure and frequency. Variation of the medial surface thickness also led to phonation onset occurrence at a different eigenmode, leading to sudden changes in onset frequency and vocal fold vibration pattern. These numerical predictions were further supported by experiments using a self-oscillating physical model. The result of this study confirms previous findings that phonation onset occurs as a matching between the flow stiffness, which is proportional to subglottal pressure, and vocal fold stiffness, which scales with natural frequency squared and depends on geometry and boundary conditions of the vocal fold structure as well as material properties of the vocal folds. [Work supported by NIH.]
Monitoring stress related velocity variation in concrete with a 2×10−5 relative resolution using diffuse ultrasound.
Authors: Eric Larose , Stephen Hall
Published: October 2013

Ultrasonic waves propagating in solids have stress-dependent velocities. The relation between stress (or strain) and velocity forms the basis of nonlinear acoustics. In homogeneous solids, conventional time-of-flight techniques have measured this dependence with spectacular precision. In heterogeneous media such as concrete, the direct (ballistic) wave around 500 kHz is strongly attenuated and conventional techniques are less efficient. In this manuscript, the effect of weak stress changes on the late arrivals constituting the acoustic diffuse coda is tracked. A resolution of 2×10−5 in relative velocity change for stress change is attained. We are thus sensitive to stress change much lower than 50 kPa. This provides an original way to measure the nonlinear parameter with relatively small stress variations (less than 100 kPa).
Bioalpha, transmission loss and validation of scattering models in biologically intense shallow water environments.
Authors: Diachok Orest
Published: October 2013

Scattering and extinction by fish swim bladders are manifestations of the same phenomenon. Scattering causes reverberation from dispersed fish and distinct echoes from fish schools (clutter), and diminishes the magnitude of transmitted signals. The biological extinction coefficient (bioalpha) has been shown to have a large effect on transmission loss (TL) in several biologically intense, shallow water environments, including the Bristol Channel [Weston (1967)], Yellow Sea [Qiu et al. (1999)], Gulf of Lion [Diachok (1999)], and Santa Barbara Channel [Diachok (2005)]. Consequently, models of biological scattering must include the effects of bioalpha on TL in shallow water environments. The objectives of this paper are to review the experimental evidence of the effects of bioalpha on TL, and to describe and demonstrate the effectiveness of an analytical approach to modeling this phenomenon. Since it is not possible at present to predict the effects of bioalpha on TL from first principles (distributions of swim bladder dimensions, spatial distributions of number densities, and timing of diurnal changes in school structures and seasonal migration patterns are only approximately predictable), experiments designed to demonstrate the validity of scattering models in biologically intense, shallow water environments should include concurrent broadband TL measurements during both night and day.
Midfrequency active sonar clutter statistics segregated by broad clutter types.
Authors: Gelb James M.
Published: October 2013

The empirical distributions of normalized matched-filter echoes from a midfrequency active sonar with hyperbolic frequency-modulated waveforms in a myriad of oceanic environments are studied for three broad clutter classes: bottom structures, diffuse compact clutter (e.g., seaweed), and compact nonstationary clutter (e.g., biologics). The distributions are characterized using the K distribution and the generalized Pareto distribution. Methods of parameter estimation are discussed, and parameters are computed for small subregions of the clutter fields. A plot of the Kolmogorov–Smirnov goodness-of-fit statistic of individual subregions is presented for each model and class to highlight the versatility of the models when applied to large quantities of data. Cumulants are computed from the data and are utilized as features in a classifier to demonstrate separability between the classes. An important aspect of this work is the use of distinct clutter classes as opposed to collectively characterizing all clutter as reverberation. Environmental effects are not considered, as the goal of this work is to determine the utility of local clutter estimation models in practical sonar processing systems where accurate environmental data is unavailable. [This work is sponsored by the Office of Naval Research undersea signal processing discovery and invention program.]
Impedance tube absorption testing of poly blend materials presently used in the carpet industry.
Authors: Mazur Ruth Anne
Published: October 2013

Cyril M. Harris authored a paper in 1955 titled “Acoustical Properties of Carpet” in which absorption coefficients for carpet were examined according to specific parameters, including fiber content. Since then, new fibers and blends have been introduced into the carpet industry. This study aims to compare absorption coefficients found from testing of these newer fibers. New blends that are now commonly used and sold in the carpet industry include polyester, polypropylene, and polyurethane. Using a Bruel & Kjaer Two Microphone Impedance Measurement Tube and Bruel & Kjaer PULSE LabShop, normal incidence absorption coefficients are gathered in order to compare the coefficient curves for these materials. Testing is performed in accordance with the ASTM E 1050-98 standard. Preliminary testing on carpet with these fibers shows lower values from 3.5 to 6.5 kHz in the curves for polypropylene carpet with padding compared to other fibers with padding. Several parameters of the preliminary samples were not constant and may have affected the results. Ongoing analysis and testing of newer fibers will enable comparison with previous studies. Absorption coefficients and parameters for carpet available in acoustical modeling programs will also be assessed in relation to the results. [Work supported by Columbia College Chicago.]
Shock waves micro-damage induction in cortical bones: Comparison between experimental and simulations results.
Authors: Padilla Frederic , Cleveland Robin O.
Published: October 2013

Shock waves (SW) are considered a promising method to treat bone non unions. One potential mechanisms of action is the initiation of local micro-fractures, which may in turn trigger the start of bone healing. In this study, a set of eight intact rat femurs have been subjected to SWs (peak positive pressure of 40 MPa and peak negative pressure of −8 MPa, PRF of 2 Hz). The number of SW was varied from 50 to 1500. Micro-CT images of the specimens were acquired before and after treatment (16 microns resolution). In parallel, numerical simulations were used to quantify the stresses induced by SWs in cortical bone tissue. We used a 3-D FDTD code to solve the linear lossless equations that describe wave propagation in solids and fluids. A 3-D model of a fractured rat femur was obtained from micro-CT data. Results demonstrate that damages were induced in the bone tissues from 150 SWs. Comparison of the location of the induced damages on micro-CT images with predictions of maximum stresses by numerical simulations show that damages principally appeared in regions of highest stresses, suggesting that SW-induced tremendous stresses in bone tissue might be an important mechanisms implied in SW bone therapy.
Empirical angle-dependent tortuosity functions and sound transmission through cancellous bone.
Authors: Attenborough Keith , Aygun Haydar
Published: October 2013

Recent literature concerning the angle dependence of sound transmission through cancellous bone has suggested that it might be due either to elastic anisotropy or to microgeometrical anisotropy in the pore structure; e.g., an angle-dependent tortuosity. The elastic anisotropy approach has been found able to explain the observed variation in fast wave speed with angle better than the angle-dependent tortuosity at the cost of underpredicting slow wave speeds. In reality, it is likely that both influences are present in cancellous bone. Nevertheless the angle-dependent tortuosity approach has been revisited on the basis of orthotropic data for sound transmission through air-filled stereo-lithographical bone replicas [Attenborough et al., JASA 118, 2779 (2005)]. [Work supported by Leverhulme Grant F/00181/N.]
A brief history and acoustical analysis of the great highland bagpipe.
Authors: Cheyne Stanley A.
Published: October 2013

A brief history and analysis of the great highland bagpipe will be discussed. Although the bagpipe may have originated several thousands of years ago, the great highland bagpipe, distinguished by three drones and a chanter, is only a few hundred years old. A discussion of the components and operation will be given. In addition, spectral analysis of the drones and chanter will be discussed and how the harmonic content of the drones support the notes played on the chanter. A spectral analysis and sound pressure levels of chanter reeds of varying ages, strengths, and materials will also be presented.
Phonological competition during the recognition of spontaneous speech: Effects of linguistic context and spectral cues.
Authors: Brouwer Susanne , Mitterer Holger , Huettig Falk
Published: October 2013

How do listeners recognize reduced forms that occur in spontaneous speech, such as “puter” for “computer”? To this end, eye-tracking experiments were performed in which participants heard a sentence and saw four printed words on a computer screen. The auditory stimuli contained canonical and reduced forms from a spontaneous speech corpus in different amounts of linguistic context. The four printed words were a “canonical form” competitor (e.g., “companion”, phonologically similar to “computer”), a “reduced form” competitor (e.g., “pupil”, phonologically similar to “puter”), and two unrelated distractors. The results showed, first, that reduction inhibits word recognition overall. Second, listeners look more often to the “reduced form” competitor than to the “canonical form” competitor when reduced forms are presented in isolation or in a phonetic context. In full context, however, both competitors attracted looks: early rise of the “reduced form” competitor and late rise of the “canonical form” competitor. This “late rise” of the “canonical form” competitor was not observed when we replaced the original /p/ from “puter” with a real onset /p/. This indicates that phonetic detail and semantic/syntactic context are necessary for the recognition of reduced forms.
Lexical access across different voices.
Authors: Newman Rochelle S.
Published: October 2013

In many real-world situations, listeners may be trying to attend to one individual while other voices are speaking in the background. These separate streams of sound hit the ear simultaneously. Within a single stream, research has investigated the extent to which lexical activation is limited by word boundary information. For example, Gow and Gordon (1995) found that multiple-word sequences such as “two lips” may activate words such as “tulips” despite the presence of acoustic cues to a word boundary in the middle of the sequence. Yet, no studies have examined whether lexical access could “cross” signals entirely. In a series of four experiments, we test whether lexical access might (ever) cross talker boundaries. We find that when listeners hear two words spoken by two different voices (for example, a male saying “two” followed by a female saying “lips”) they still activate the larger cross-voice word “tulips,” despite the presence of strong cues to an acoustic boundary. [Work supported by NSF.]
Neural dynamics of speech perception: Phonemic restoration in noise using subsequent context.
Authors: Kazerounian Sohrob , Grossberg Stephen
Published: October 2013

Phonemic restoration describes a class of auditory illusions during which broadband noise replacing a deleted phoneme can cause the perceptual restoration of the deleted phoneme. Phonemic restoration exemplifies the brain’s ability to complete and understand speech and language in noisy environments. It also clarifies how both past and future acoustical events can contextually guide completion of a percept that is occluded by noise, and highlights that conscious speech is due to bottom-up and top-down contextual interactions that can operate across hundreds of milliseconds. This work develops a neural model that quantitatively simulates restoration phenomena, including the forward development in time of a conscious speech percept even in cases where future events control how previously presented acoustic events are heard. The model clarifies how acoustic items are stored in short-term working memory, and how they interact reciprocally with unitized representations of item sequences, or list chunks, to generate a resonant wave of activation that embodies the consciously heard percept. Model simulations clarify why the presence of noise is necessary for restoration to occur, and why in the absence of noise a silence gap is perceived. These properties are traced to the brain's ability to rapidly and stably learn language.
Domain-specific processing of Mandarin tone.
Authors: Wang Yue , Behne Dawn , Cooper Angela , Tu Jung-yueh
Published: October 2013

Lexical tone has generally been found to be processed predominantly in the left hemisphere. However, given that tone is carried by a syllable or a word with segmental information and distinctive meaning, the processing of tone may not be easily disentangled from that of the phonetic segments and word meaning [P. Wong, Brain Res. Bull. 59, 83–95 (2002)]. Indeed, previous research has not examined the lateralization of tone independent of segmental and lexical semantic information. The present study explores how syllable-based tonal processing in Mandarin Chinese interacts with these different linguistic domains. Using dichotic listening, native Mandarin participants were presented with monosyllabic tonal stimuli constructed with the following different linguistic attributes: (1) real Mandarin words with tonal, segmental phonetic, and lexical semantic information; (2) Mandarin nonwords with tonal and segmental, but no semantic information; (3) nonwords with non-Mandarin segments (i.e., no native segmental or semantic information); and (4) hums of tones (acoustic pitch information) without any segmental or semantic components. Results from these conditions show significant differences in lateralization patterns and are discussed in terms of the integration of acoustic as well as pre- and post-lexical linguistic domains in lexical tone processing. [Work supported by NSERC.]
The interaction of location with acoustic scale in concurrent speech recognition.
Authors: Ives David T. , Vestergaard Martin D. , Patterson Roy D.
Published: October 2013

Location and acoustic scale cues have been shown to have a significant effect on the recognition of speech in multispeaker environments. The interaction of these two cues is less well understood. In this study, subjects are presented with two triplets of concurrent speech syllables with similar temporal envelopes, and asked to recognize a specific target syllable. The task was made more or less difficult by changing the location of the distracting speaker, the scale difference between the two speakers and the relative level of the two speakers. Scale differences were produced by changing the vocal tract length and glottal pulse rate of resynthesized speech: 32 scale differences were used. Location cues were produced by convolving heat-related transfer functions with the stimulus. The target speaker was located directly to the front of the listener and the distracting/masking speaker located from one of five locations (0, 4, 8, 16, 32 deg) on the 0 deg horizontal plane. Target-to-masker ratios of 0 and −6 dB were used. The results show that direction and scale differences cues do interact and this interaction is greatest when directional and speaker scale cues are small. [Research supported by the U.K. Medical Research Council (G0500221, G9900369).]
R. Bruce Lindsay Award
Authors: Benoit-Bird Kelly J.
Published: October 2013

The R. Bruce Lindsay Award (formerly the Biennial Award) is presented in the Spring to a member of the Society who is under 35 years of age on 1 January of the year of the Award and who, during a period of two or more years immediately preceding the award, has been active in the affairs of the Society and has contributed substantially, through published papers, to the advancement of theoretical or applied acoustics, or both. The award was presented biennially until 1986. It is now an annual award.
From an architect’s perspective: Acoustical challenges in mixed-use buildings.
Authors: Farr Dale , Goodfriend Karyn
Published: October 2013

Incorporating acoustical design in mixed-use buildings can be architecturally challenging. Key issues impacting acoustical design decisions are: (1) the unknown—due to undetermined uses of commercial lease space; (2) the cost—clients do not want to pay for ideal acoustical design because they perceive it to be cost prohibitive. Often clients do not understand the importance of considering acoustic elements during the initial design process until complaints occur much later, postconstruction. Other elements impacting acoustical design are: apartments versus condominiums, existing buildings versus new structures; changes in lease space use; and the possible conflict of the acoustical design not meeting life/safety code. On each architectural project it is ultimately the goal to design to client criteria with a mission to deliver solutions that meet the most needs based on user programs. Often concessions must be made to find the best overall solution for the building and budget. This impacts all of the design consultants, which means designs need to be flexible and are sometimes less than ideal in segregation. It is worth discussing how architects successfully design for the unknown and justify inclusion of acoustical designers early on, while staying within budget.
Sound and vibration issues encountered in mixed use construction involving residential, office, and retail uses created from a combination of renovation and expansion of an existing space.
Authors: Pettyjohn Steven D.
Published: October 2013

Buildings housing mixed uses often encounter acoustic and vibration problems because expectations differ for the users and patrons. Mixed uses could include retail and office spaces; offices and residential; retail and residential; or, as in the case to be discussed, retail (restaurants) on the first floor, offices on the second floor, and residences on the upper two floors. An existing historic three-story concrete structure originally housing a car dealership in an urban area was renovated to provide all three uses. A fourth floor was added to provide a second floor of residential use. The offices and residential areas were designed to meet interior sound level standards from sources within and exterior to the building. The two restaurants were designed individually by their in house teams with only vibration standards provided by the building design group. The lack of coordination between restaurant and building design teams let to both sound and vibration problems that had to be corrected after construction was mostly complete. Construction teams for the restaurant groups were not familiar with such issues based on their previous installations. This paper discusses the myriad of problems and remedies and provides an outline of the issues that need addressing.
An historic conversion: From a bank to a restaurant and residences.
Authors: Pieleanu Ioana , Fullerton Jeffrey , Markham Benjamin
Published: October 2013

A conversion of an old bank building in Boston’s tony South End to a mixed-use building featuring retail on the ground floor and luxury condominiums above was completed in 2007. More recently, a new restaurant (garnering awards for its interior design and rave reviews for its food) has opened in one of the ground floor retail spaces directly below a particularly noise-sensitive resident. Consultants at Acentech worked on two aspects of the project: first, on the base building as consultants to the architect, and second, on the isolation between the restaurant and the second floor residences as consultants to the restaurant. Using this case study and extensive data measured on site, the authors will discuss best practices to achieve good sound isolation in mixed-use buildings, common pitfalls that result from working with existing historic structures, and some difficulties in achieving the high degree of sound isolation that some luxury condominium owners expect.
Shell buckling enhances subharmonic behavior of phospholipid coated ultrasound contrast agent microbubbles.
Authors: Sijl Jeroen , Rozendal Timo , Overvelde Marlies , Garbin Valeria , Dollet Benjamin , de Jong Nico , Lohse Detlef , Versluis Michel
Published: October 2013

Subharmonic behavior of coated microbubbles can greatly enhance the contrast in ultrasound imaging. The threshold driving pressure above which subharmonic oscillations are initiated can be calculated from a linearized Rayleigh-Plesset-type equation. Earlier experimental studies on a suspension of phospholipid-coated microbubbles showed a lower threshold than predicted from traditional elastic shell models. Here we present an experimental study of the subharmonic behavior of individual BR-14 microbubbles (Bracco Research) with initial radii between 1.6 and 4.8 μm. The subharmonic behavior was studied as a function of the amplitude and the frequency of the driving pressure pulse. The radial response of the microbubbles was recorded with the Brandaris ultrahigh-speed camera, while the resulting acoustic response was measured with a calibrated transducer. It is shown that the threshold pressure is minimum near a driving frequency equal to half the resonance frequency of the bubble, as expected. We found a threshold pressure as low as 10 kPa for certain bubble sizes, which can be explained by the shell buckling model proposed by [Marmottant et al., JASA (2005)]. We show that the origin of subharmonic behavior is a result of the discontinuous transition within the bubble shell from the elastic state to the tensionless buckling state.
Shell buckling increases the nonlinear dynamics of ultrasound contrast agents at low acoustic pressures.
Authors: Overvelde Marlies , Dollet Benjamin , Garbin Valeria , de Jong Nico , Lohse Detlef , Versluis Michel
Published: October 2013

The key feature of ultrasound contrast agents in distinguishing blood pool and tissue echoes is based on the nonlinear behavior of the bubbles. Here we investigate the nonlinear properties of the shell which lead to an increased nonlinear bubble response, especially at low acoustic pressures. The microbubbles were studied in free space away from the wall using the Brandaris camera coupled to an optical tweezers setup. The microbubble spectroscopy method [Van der Meer et al., JASA, 121, 648 (2007)] was employed to characterize BR-14 microbubbles (Bracco, Geneva). For increasing applied pressures the bubble resonance curves become asymmetrical and the frequency of maximum response decreases, up to 50% at a pressure of 25 kPa. It was found that the skewing of the nonlinear resonance curve is the origin of the so-called thresholding behavior below resonance. Traditional bubble models account for a purely elastic shell predict linear behavior, whereas the shell buckling model by Marmottant et al. [JASA, 118, 3499 (2005)], originally developed to predict compression-only behavior, captures the asymmetry of the resonance curve in great detail. The full understanding of the nonlinear behavior at low acoustic pressures opens a wealth of new possibilities in contrast-enhanced ultrasound imaging.
Determination of maximum response radius at therapeutic pressure levels.
Authors: Carvell Kelsey J. , Bigelow Timothy A.
Published: October 2013

High-intensity, focused ultrasound therapy is a minimally invasive therapy technique that has shown potential in many therapeutic applications, especially when coupled with the cavitation of microbubbles. The purpose of this study was to determine the effect of pressure amplitude on cavitation resonance frequency/bubble size at therapeutic field levels. Earlier work has indicated that the resonance frequency depends on pressure amplitude; however, the investigation only considered pressure amplitudes up to 1 MPa [Ultrasonics 43, 113 (2004)]. Our study was conducted by simulating the response of bubbles using the Gilmore-Akulichev formulation to solve for the bubble response. The frequency of the sine wave varied from 1–5 MHz while the amplitude of the sine wave varied from 0.0001–13 MPa. The resonance size for a particular frequency of excitation and amplitude was determined by finding the initial bubble size that resulted in the maximum bubble expansion relative to the initial size for an air bubble in water prior to the first collapse. Preliminary simulations indicated that this metric gave the correct resonance size for small excitations. These simulations demonstrated a downshift in resonance size with increasing pressure amplitude.
Achieving publication excellence in the Journal of the Acoustical Society of America.
Authors: Xiang Ning
Published: October 2013

Publications in refereed acoustics journals are of significant relevance for scientists and acousticians in the acoustics-related fields. The Journal of the Acoustical Society of America (JASA) encourages authors to submit papers for JASA publication. In achieving publishing excellence, the JASA regularly publishes detailed, updated guidance and instructions. As a frequent reviewer, an author of JASA papers, and an Associate Editor of the JASA, this paper will provide an outline and overview of its peer-review process of the JASA to analyze possible reasons for successful and unsuccessful publication effort. This paper also discusses how to prepare qualified manuscripts, how to avoid unnecessary delays for publications in the JASA, and how to review manuscripts for JASA.
Important aspects of editorial procedures for the information of inexperienced authors.
Authors: Attenborough Keith
Published: October 2013

Several matters concerning the quality of papers and the editorial process have emerged from editorial activities for three acoustically-related journals (Applied Acoustics, Acta Acustica combined with Acustica, and the Journal of the Acoustical Society of America). Each of the journals suggests particular criteria to reviewers as the basis for their reviews. These factors are compared and discussed. Each of the journals offers various editorial decision options. These options and the uses that are made of them are discussed. Two common factors that influence editorial and reviewer judgements on submission quality include (a) the use of English and (b) the provision of a comprehensive and critical literature review. An increasingly important consideration is the availability of good reviewers in areas related to the topic of the paper. Sanitized examples illustrating some of these points are offered.
Absolute pitch among students in an American music conservatory: Association with tone language fluency.
Authors: Deutsch Diana , Dooley Kevin , Henthorn Trevor , Head Brian
Published: October 2013

Absolute pitch (AP), the ability to name a musical note in the absence of a reference note, is extremely rare in the United States and Europe, and its genesis is unclear. The prevalence of AP was examined among students in an American music conservatory, as a function of age of onset of musical training, ethnicity, and fluency in speaking a tone language. Taking those of East Asian ethnicity, the performance level on a test of AP was significantly higher among those who spoke a tone language very fluently than among those who spoke a tone language fairly fluently, which was in turn higher than among those who were not fluent in speaking a tone language. The performance level of this last group did not differ significantly from that of Caucasian students who spoke only intonation language. An advantage to early onset of musical training was found, but did not interact with the effect of language. Further analyses showed that the results could not be explained by country of early music education. The findings support the hypothesis that the acquisition of AP by tone language speakers involves the same process as occurs in the acquisition of a second tone language.
A spectral analysis of the tuba mirum section of six live concert performances of Verdi’s Requiem as conducted by Arturo Toscanini.
Authors: Chapman Robert C.
Published: October 2013

Arturo Toscanini conducted Verdi’s Requiem 29 times with ten different orchestras between the years 1902 and 1951. Of these 29 performances, six of them were recorded between the years 1938 and 1951 with three different orchestras. An analysis of the Tuba Mirum section of this work was done to determine musical element consistency between different dates of performance and different orchestras. The Tuba Mirum section was selected because of the amount of control a conductor has to have over their musicians in order to obtain maximum musical effect. The musical elements considered in the analysis were rhythmical consistency, tempo, articulation, and dynamics. The amount of time to perform this section of music was also investigated.
Auditory effect of perturbing musical tones by interpolation with other musical tones.
Authors: Beauchamp James W. , Horner Andrew B. , So Richard H. Y.
Published: October 2013

The effect of blending variable amounts of a secondary tone with a primary tone by means of interpolating between their corresponding harmonic amplitudes was investigated. Original tones (bassoon, clarinet, flute, horn, oboe, alto saxophone, trumpet, and violin) were normalized with respect to fundamental frequency, duration, attack and decay times, and loudness; also, harmonic frequencies were flattened. However, the basic time variations of the tones' harmonic amplitudes were preserved. Interpolation was accomplished in the frequency domain using interpolation levels between 5 and 50%. While the effect of perturbation is highly dependent on the primary/secondary instrument pair, results show that the effect of a secondary instrument is heard most easily for primary instruments horn and bassoon and least easily for primary instruments trumpet and saxophone. On the other hand, clarinet and trumpet are heard most easily as secondary instruments, whereas bassoon and violin are slow to be heard. Discrimination scores were correlated with different spectrotemporal measures of the tone spectra: spectral incoherence, normalized spectral centroid deviation, and spectral irregularity. The only significant effect found was that primary instruments with high spectral incoherence tend to mitigate against perturbation by secondary instruments. [Work supported by Research Grants Council Grants 613806 and 613508.]
A real-time music synthesis engine for physical modeling of plucked string instruments.
Authors: Luong Huynh V. , Cho Sangjin , Kim Jong-Myon , Chong Uipil
Published: October 2013

Music synthesis continues to offer huge potential possibilities for the creation of new musical instruments. One of the promising music synthesis techniques is physical modeling which produces output sounds that resemble much more closely their physical counterparts since it offers the potential of more intuitive control. However, this results in tremendous computational and I/O requirements, prohibiting real-time use in composition and live performance. To meet the performance requirements, we introduce a parallel processing engine. Whereas commercial digital signal processors such as TI TMS320C6x families use silicon area for large multiported register files, large caches, and deeply pipelined functional units, our parallel processing engine contain many more simple processing elements (PEs) for the same silicon area. As a result, our engine often employs thousands of PEs while possibly distributing and colocating PEs with the data I/O to minimize storage and data communication requirements. In this paper, we implemented physical modeling of a representative plucked Korean string instrument, called Gayageum, which has 12 silk strings. Our engine achieved 12-notes music synthesis in real-time at 44.1 kHz sampling rate for the physical modeling algorithms. This is in contrast to TI TMS320C6x, which achieves only single-note music synthesis. [Work supported by KOSEF, R01-2008-000-20493-0.]
Acoustical properties of pure sound piano wire.
Authors: Ripplinger David , Anderson Brian , Leishman Tim , Strong William
Published: October 2013

Pure sound piano wire is a stainless-steel wire that has only recently entered the U.S. market. Because of its different composition, which makes the wire more malleable, it should have a considerably lower amount of inharmonicity compared to regular steel wire. Measurements were conducted on several pianos with regular piano wire (Rosslau and Mapes) and pure sound in order to assess their differences in inharmonicity and tonal qualities. The pure sound wire produced measurably less inharmonicity than regular wire on the same kind of piano. However, this difference is much smaller compared to the difference between small and large pianos. This presentation will explain the methods of measurement and analysis, as well as simulations that were implemented in order to analyze the effect that inharmonicity has on the temperament, octave stretching, and interval patterns. [The Brigham Young University Department of Physics is acknowledged for the funding it provided for this research.]
Comparing the sound environments in two critical care settings.
Authors: Okcu Selen , Ryherd Erica , Zimring Craig
Published: October 2013

Critical care nurses perform crucial tasks in complicated sound environments. The existence of many different noise sources (i.e., staff conversation, medical alarms, etc.) with different sound qualities cause nurses to experience constantly changing acoustic conditions while providing care for critically ill. Some of those acoustical qualities in critical care settings can negatively affect nurse well-being and task performance. In different critical care settings, the acoustic qualities can vary. Some architectural qualities of those settings can be an indicator of those variations. In this study, we documented the detailed objective and subjective sound environment of two critical care settings with different architectural layouts. The comparative analyses are used to understand the differences between two acoustic settings and the relationship between subjective and objective sound environments. Perceived qualities of the physical work environments are examined to explore the association between architectural features and acoustic qualities.
Soundscape analysis of a neonatal intensive care unit (NICU) facility.
Authors: Siebein Gary , Skelton Reece , McCloud Victoria , Lilkendey Robert , Paek Hyun
Published: October 2013

A soundscape study was made of an existing NICU facility in a major urban hospital to document the nature and magnitude of sounds experienced by newborn infants in this environment. Focus group discussions were held with hospital administrators, NICU staff, design team members, and families of patients to determine the types of sounds that are heard in normal opera-tion of the NICU. Long-term average sound level measurements of general sounds in the NICU were made for several work shifts. Short-term acoustical measurements of specific acoustic events were also made to obtain octave band sound level data for each of the activities, medical equipment sounds, and building infrastructure sounds that comprise the soundscape of the unit. Audio and video recordings of the specific acoustical events that comprise the soundscape of the NICU were also made. The acoustical measurements and soundscape analysis are used to evaluate proposed acoustical design criteria for NICU facilities compared to nonacoustic health risks reported in the literature.
Audio parametric arrays in air.
Authors: Hamilton Mark F.
Published: October 2013

Following Westervelt’s discovery and theoretical description of the parametric acoustic array reported at the 1960 meeting of the ASA at Brown Univ., and the measurements in both water and air at ultrasonic frequencies, confirming Westervelt’s predictions qualitatively, reported by Bellin and Beyer at that same meeting, it was not until 1973 that Bennett and Blackstock reported convincing quantitative comparisons of theory and experiment for a parametric array in air. While their experiments produced difference frequencies in the audio range, not until the late 1990s did application of the parametric array to directional audio transmission in air achieve any commercial success. This presentation will briefly review the history of developments leading up to modern-day audio parametric arrays. Challenges associated with transducer performance, signal processing, and acoustical measurements specific to audio parametric arrays in air will be described. Features of several audio parametric arrays currently on the market will be discussed. Finally, results will be presented from an ongoing collaboration between the author’s group at Univ. of Texas at Austin and Professor Pierre Khuri-Yakub’s group at Stanford Univ. to create audio parametric arrays in air using capacitive micromachined ultrasonic transducers to transmit the ultrasonic primary beams.