bluuebunny/crossref_metadata_2025 huggingface dataset:
It’s all in the bore!
Authors: Kausel Wilfried
Published: October 2013

A review of the current state of knowledge concerning the influence of wall vibrations on the sound of brass wind instruments, flue pipes, and woodwind instruments is given. The question of whether this influence is strong enough to be objectively observable is still a controversial issue. While instrument makers and musicians make a strong claim that wall thickness, material, and conditioning are crucial factors for sound quality and response of wind instruments, acousticians tended—at least in the past—to attribute all acoustical characteristics to the actual bore profile. Recently this seems to be changing. First, there is growing experimental evidence favoring the hypothesis that wall vibrations do matter; second, theoretical models are starting to be developed which deal with the interaction between the air column sound field and its oscillating boundary conditions. Another suggested theory is that wall vibrations are propagated back to the mouthpiece interacting with the player’s lips affecting the delicate and strongly nonlinear mechanism of sound generation. Even the question of whether vibrating bells can radiate a significant amount of sound does not seem to have reached a final answer. New experiments have been conducted to help answer these open questions. a)R. A. Smith, ‘‘It’s all in the bore!,’’ International Trumpet Guild Journal, 12(4) (1988).
Rapidly converging adaptive state-space-based multichannel active noise control algorithm for reduction of broadband noise
Authors: Berkhoff Arthur P. , Wesselink Johan M.
Published: October 2013

Rapidly changing spectra may lead to performance limitations in adaptive systems for broadband active noise control, especially in multichannel systems. This paper presents techniques to address the negative consequences of two main causes. First, the dynamics of the transfer paths between the noise control sources and the error microphones is compensated for by using a regularized state-space based adaptive filtered-error scheme. Second, for the reference signals a modified adaptive scheme is used, taking into account the nonwhiteness of these signals as well as the correlation between the individual signals. Examples are given for simulated data and for real-time implementations. [This work was partly supported by EC Contract 501084 (InMAR).]
Wigner distribution of an ultrasonic transducer beam pattern through a liquid-solid interface
Authors: Ghoshal Goutam , Turner Joseph A.
Published: October 2013

Diffuse ultrasonic backscatter techniques are useful for probing heterogeneous materials to extract microstructural parameters and detect flaws that cannot be detected by conventional ultrasonic techniques. Such experiments, usually done using a modified pulse-echo technique, utilize the spatial variance of the signals as a primary measure of microstructure. Quantitative ultrasonic scattering models include components of both transducer beams as well as microstructural scattering information. Of particular interest for interpretation of many experiments is the propagation through a liquid-solid interface. Here, the Wigner distribution of the beam pattern of an ultrasonic transducer through a liquid-solid interface is used in conjunction with the Bethe-Salpeter equation to model this scattering problem. The Wigner distribution represents a distribution in space and time of the spectral energy density as a function of wave vector and frequency. The general scattering model to be discussed encompasses the full multiple scattering behavior that occurs within the solid, while a simple Gaussian beam is used to model the transducer beam pattern. A simplified model restricted to the single-scattering regime is then compared with experimental results for materials of common interest. These results are anticipated to impact ultrasonic nondestructive evaluation and characterization of heterogeneous media.
Spacial cognitive timbre dimensions of physical modeling sounds using multi-dimensional scaling (MDS) techniques
Authors: Bader Rolf
Published: October 2013

The cognitive spacial dimensionality of timbre in the minds of listeners is investigated. Physical models of strings, rods, plates, and membranes and couplings of these obtaining simple musical instruments are used. Here, for each model, eight sounds have been produced by linear change of only one parameter of the physical model. So, i.e., the change of inharmonicity in a string sound modeled as coupling of the string differential equation with a bending stiffness equation by linearly increasing the bending stiffness is investigated. After the judgment procedure, the mean judged similarities of all subjects are fit into an n-dimensional space. The spacial dimensions then have to be interpreted in terms of the physical changes of the sounds distributed over those dimensions. It could be shown that linear changes in inharmonicity of strings do have both, a linear perception as well as sudden phase changes, a finding relevant to psychoacoustic noise perception or room acoustics. Also, the problem of changing plate thickness, different striking points of membranes, or coupling of snare membranes to their vessels with changing cutoff angle of the vessel is investigated. Furthermore, just noticeable differences with timbre changes as well as judgments of very different sounds are discussed.
Speech perception from a crudely quantized spectrogram: A figure-ground analogy
Authors: Brungart Douglas , Iyer Nandini , Simpson Brian
Published: October 2013

Recent research into auditory chimeras has shown that comprehensible speech can be generated by superimposing the frequency-dependent modulation envelope of a target speech signal onto the fine structure of music, speech, or almost any other broadband waveform. In this experiment, we show that, in certain cases, intelligibility can be achieved with an even simpler stimulus that preserves only the rough outline of the energy distribution of the target speech waveform. This stimulus was generated by 1) dividing the target speech spectrogram into discrete tiles that were 1/3rd octave band wide and 7.8 ms long; 2) identifying the minimum number of tiles necessary to capture 90% of the energy in the target waveform; and 3) filtering a uniform, broadband noise to activate only those tiles that met the threshold energy criterion in the original stimulus. The resulting stimulus captures the overall outline of the distribution of energy in the target speech, but contains no information about the relative distribution of energy within the spectrogram. In this paper, we discuss the use of this stimulus in a series of auditory figure-ground experiments where the target speech signal differs from the background by only a single parameter (relative level, ITD, ILD, etc.).
Use of polynomial chaos expansions in the design of uncertainty-robust matched field processing algorithms
Authors: LePage Kevin D.
Published: October 2013

The polynomial chaos (PC) expansion method has been recently applied to estimating the statistical properties of underwater acoustic propagation in the presence of environmental uncertainty. Here we use PC estimates of the field covariance structure to design uncertainty robust match field processing (MFP) weights using Krolik’s minimum variance beamformer with sound-speed perturbation constraints (MV-SPC) [J. Acoust. Soc. Am. 92 (3), 1408–1419 (1992)]. The idea behind the MV-SPC beamformer is to realize much of the high sidelobe rejection of MV processors in environments with environmental variability by opening up the signal model to include uncertainty effects. Here we compare the performance of MV-SPC designed with an adiabatic signal uncertainty model to the same beamformer designed with the PC signal model for realizations of the signal vector obtained with fully coupled propagation models, with results showing the superiority of the PC approach. [Work supported by ONR.]
High-resolution particle image velocimetry (PIV) measurements of the flow inside the stack-heat exchanger couple of a thermoacoustic refrigerator driven at high amplitude
Authors: Berson Arganthael , Blanc-Benon Philippe
Published: October 2013

The design of efficient heat-exchangers for thermoacoustic applications is one of the major challenges in the development of high-performance thermoacoustic coolers. With this prospect, an important step has been taken in this study with the characterization of the flow field around both stack and heat-exchangers, especially at high drive ratio when acoustics is nonlinear and edge effects become more important. High-resolution particle image velocimetry measurements are performed in a standing wave thermoacoustic refrigerator using a technique that has already been validated and successfully compared to numerical simulations Blanc-Benon et al., C.R. Mécanique 331, 17–24 (2003). High spatial resolution is achieved with an optical zoom mounted on a digital camera. Measurement areas down to 3×2.5 mm2 are obtained. The resonator is driven at drive ratios up to 5%, with oscillating velocity amplitudes up to 15 ms−1 within the stack. As oscillating velocity amplitude increases, the vorticity layer developing behind each plate of a single stack becomes unstable and an asymmetric street of counter-rotating vortex pairs is observed. A Strouhal number based on the stack geometry is calculated. The consequences of vortex generation on the flow between a stack-heat exchanger couple are also investigated. Experimental data will be compared to numerical simulations from the literature.
Pressurization of high-frequency acoustic heat engines for power applications
Authors: Webb Nick D. , Symko Orest G.
Published: October 2013

Acoustic heat engines show much promise for converting waste heat to electricity. Since most applications require high power levels, high frequency thermoacoustic engines can reach such performance by operating with pressurized working gas. Results on a 3-kHz prime mover, consisting of a quarter-wave resonator and a random stack between two heat exchangers, show that the sound intensity from such device is raised as the working gas is pressurized. At pressures up to approximately 10 atm, the increase in sound power is approximately linear to the increase in pressure, and thus is an effective way to increase the power output of thermoacoustic engines. Further increases in pressure lead to power output saturation because the filling factor needs to be adjusted for the change in thermal penetration depth of the gas. Pressurization also leads to lower Δ onset for oscillations, potentially opening up even more heat sources that can power a thermoacoustic engine. Pressurization promises to greatly increase the applications of acoustic engines to a variety of real world settings, providing a key source of renewable energy for the future.
Effects of masker phase on tone detection as a measure of cochlear compression in normal-hearing and hearing-impaired listeners
Authors: Summers Van , Makashay Matthew , Leek Marjorie , Molis Michelle
Published: October 2013

For listeners with normal hearing, Schroeder-phase harmonic complexes may vary in masking effectiveness by 20 dB or more depending on the temporal details of the stimuli. These masking differences are believed to be associated with curvature in cochlear phase response and compressive growth in the magnitude response for normal cochlear processing. Both curvature and compression may be greatly reduced in listeners with cochlear damage. In the current study, masker levels at masked threshold were determined for 1- and 4-kHz tones at a range of fixed signal levels using harmonic maskers varying in phase curvature. A Bekesy-tracking method, using a long-duration harmonic masker that slowly varied in temporal structure, was used to measure detection thresholds continuously over a range of curvatures. The masker producing the least effective masking and the overall change in masker effectiveness with phase structure were used to estimate phase curvature and degree of compression in cochlear processing for normal-hearing and hearing-impaired listeners. These estimates of cochlear compression will be related to auditory-filter bandwidths measures, also believed to be closely tied to peripheral compression. Further, thresholds from the fast Bekesy-tracking method will be compared with thresholds produced by more traditional, but time-consuming, forced-choice psychophysical methods.
Rate versus time representation of high-frequency spectral notches in the peripheral auditory system: A computational model study
Authors: Lopez-Poveda Enrique A. , Alves-Pinto Ana , Eustaquio-Martin Almudena , Palmer Alan R.
Published: October 2013

We investigated how high-frequency spectral notches are represented in the auditory nerve. Our approach consisted in modeling the paradoxical result of Alves-Pinto and Lopez-Poveda [J. Acoust. Soc. Am. 118, 2548 (2005)] that discriminating between broadband noises with and without high-frequency spectral notches is most difficult at 70–80 dB SPL than at lower or higher intensities. We tested two possibilities: (a) that discrimination is based on the difference between the inner-hair-cell excitation patterns for the two stimuli, a representation related to the auditory nerve difference rate profile, and (b) that it is based on the difference inner-hair-cell modulation-rate pattern, a representation related to the difference in the temporal pattern of auditory nerve discharges. The simulations support the latter. This suggests that spectral features as high in frequency as 8 kHz may be encoded in the temporal pattern of auditory nerve responses despite the rapid decay of phase locking above 2 kHz. The simulations also indicate that the improvement in spectral discrimination at high levels is associated to the saturation of the inner hair cell receptor potential.
Factors influencing the perception of non-familiar spectrally rotated speech syllables
Authors: Azadpour Mahan , Balaban Evan
Published: October 2013

The effects of acoustic features and native phonology on the naïve perception of unfamiliar spectrally-rotated speech syllables were evaluated. Spectrally-rotated syllables were created by rotating the spectrum of naturally produced Italian CV syllables around 1500 Hz resulting in changes in the energy distribution of harmonics while preserving the temporal relationships of spectral trajectories. Italian-speaking participants with no previous spectrally-rotated speech experience were asked to describe spectrally-rotated syllables phonologically by typing onomatopoetic versions of their perceptions on a computer keyboard. The results, also used to estimate the phonological similarity of the rotated sounds, showed that the identification of rotated vowels was related to their location on the F1-F2-F3 map of native (unrotated) vowels. The discriminability of rotated sounds was examined using a separate, naïve subject group using an ABX procedure. Discrimination errors were positively correlated with the estimated phonological similarity between rotated sounds. For rotated vowels, discrimination errors were also related to their Euclidean distance in F1-F2-F3 space as revealed by regression analysis. We conclude that naïve perception of unfamiliar spectrally-rotated syllables is under the influence of native phonology, and that spectrally-rotated vowels are represented by their location in the formant space. a)Also at Behavioral Neurosciences Program, McGill University, Montreal, Canada.
A model with compression for the estimation of speech intelligibility in quiet
Authors: Lyzenga Johannes , Rhebergen Koenraad S.
Published: October 2013

The Speech Intelligibility Index (SII) is an often used calculation method for estimating the proportion of speech information available in noise. For speech reception thresholds (SRTs), measured in normal-hearing listeners using various types of stationary noise, this model predicts a fairly constant speech proportion (about 0.30) necessary for sentence intelligibility. However, when the SII model is applied for SRTs in quiet, the estimated speech proportions are often lower, and show a larger inter-subject variability, than found for speech in noise near the normal speech level (65 dB SPL). The present model attempts to alleviate this problem by including cochlear compression. It is based on a loudness model for normal-hearing and hearing-impaired listeners of Moore and Glasberg [Hear. Res. 188, 70–88 (2004)]. It estimates internal excitation levels of the speech and then calculates the proportion of speech above threshold using similar spectral weighting as used in the standard SII. The present model and the standard SII were used to predict SRTs in quiet for both normal-hearing and hearing-impaired listeners. The present model predicted a set of data for three listener types (normal hearing, noise-induced hearing loss, and age-induced hearing loss) with less variability than the standard SII.
Voice F0 responses elicited by perturbations in pitch of auditory feedback in individuals that stutter and controls
Authors: Bauer Jay J. , Hubbard Seery Carol , LaBonte Rachelle , Ruhnke Lauren
Published: October 2013

This study aims to increase our understanding of the underlying mechanisms of vocal control in frequency-altered conditions of auditory feedback for people who do and who do not stutter by assessing the vocal responses to perturbations in pitch of auditory feedback. Past research has shown that the speech of people who stutter improves during frequency-altered feedback, but the mechanisms responsible for this fluency remain unclear. Typically, brief modulations in pitch of voice auditory feedback lead to short-latency corrective voice F0 responses during sustained phonations and inflected speech in nonstuttering individuals. However, data are lacking regarding audio-vocal control mechanisms in individuals that stutter. Brief upward (+) and downward (−) perturbations in pitch (50 or 600 cents in magnitude) lasting 200 ms in duration were introduced intermittently into vocalizing subjects auditory feedback. To date, N=3 moderate to severe developmental stutterers and N=3 age and gender matched control nonstutterers have been tested using the pitch-shift paradigm. Preliminary analyses indicate that compensatory voice F0 responses during sustained vowels are less prevalent, more variable, and slower in latency in individuals that stutter compared to age and gender match controls. However, subject recruitment and analyses related to inflected speech productions are still ongoing.
Simulations of vocal fold movement and aerodynamics using the Uintah Computational Framework
Authors: Duncan Comer , Scherer Ronald , Guilkey James , Harman Todd
Published: October 2013

This study applies a tightly coupled fluid-structure interaction algorithm to the modeling of phonation. The Uintah Computational Framework models vocal fold material using the Material Point Method (MPM), which permits arbitrarily large material displacements and multiple materials characterizing the vocal fold properties. The air is modeled using a compressible Navier-Stokes solver, the Implicit Continuous-fluid Eulerian (ICE) method developed at Los Alamos National Laboratory by B. A. Kashiwa. The MPM and ICE methods are coupled together to generate a unique simulation tool. Preliminary simulations are shown of 2-D model vocal folds interacting with prescribed transglottal pressures between 100 Pa and 800 Pa illustrating the intrinsic coupling between the vocal folds and the air. Results are presented showing how the new simulation scheme characterizes the materials and how the aerodynamics that results displays the essential characteristics of glottal flow. The next steps of incorporating three-dimensionality and acoustics will be discussed. The present simulations set the stage for a realistic computational glottis and for eventual modeling of the effects of vocal fold pathologies on the acoustical output. [Work supported at Bowling Green State University in part by the National Institutes of Health and at the University of Utah by the Department of Energy.]
Duration and spectral shape as cues to vowel identity.
Authors: Tilton Webster , Sawusch James R.
Published: October 2013

Theories of vowel recognition based on the vowel formant frequencies (or spectral peaks) are less accurate in identifying vowels than human listeners. This has been true even if the model uses dynamic spectral information such as the changes in the spectral peaks over time [H. Houde (2002)]. Studies with synthetic speech and edited natural speech have implicated duration and fundamental frequency as additional perceptual cues. The present work focused on duration, fundamental frequency, and spectral shape using synthetic vowels modeled on the speech of a male and a female talker. Series from /i/ to /I/, /E/ to /ae/, /uh/ to /a/, and /U/ to /u/ were created in which only duration, fundamental frequency, or the shape of the short-term spectrum were varied. Subsequent studies manipulated the formant frequencies and the duration or spectral shape orthogonally. Results indicated that the duration and spectral shape of a steady state vowel exert a potent influence on vowel identification, while varying the fundamental frequency appeared to have little effect.
Perceptual accommodation to sinewave speech.
Authors: Hillenbrand James M. , Clark Michael J. , Houde Robert A. , Hillenbrand Michael W. , Hillenbrand Kathryn S.
Published: October 2013

Many studies have reported good intelligibility for sine wave replicas of sentences (e.g., R. Remez et al., Science 212, 947–950 (1981)]. Recent work, however, has shown poor intelligibility (∼55%) for vowels in isolated syllables [J. Hillenbrand and M. Clark, J. Acoust. Soc. Am. 123, 3326 (2008)]. While enhanced intelligibility for sentences undoubtedly reveals the importance of top-down mechanisms, it is also possible that sentence-length utterances allow listeners to make (as yet unknown) perceptual accommodations to the unfamiliar acoustic properties of sine wave speech (SWS). In this study, the intelligibility of SWS replicas of 16 vowels/diphthongs in isolated syllables (“heed,” “hid,” and “hide”) was compared to that of the same syllables when preceded by a seven-word SWS carrier phrase (CP) spoken by the same talker. Intelligibility was ∼24 percentage points higher when the SWS syllables were preceded by the SWS CP than when the same utterances were presented in isolation. Furthermore, the effect was observed even when the CP and test-syllable talkers did not match, showing that the effect involves more than just talker normalization. Finally, a same-talker natural speech CP preceding the SWS syllable produced a decrement rather than an improvement in intelligibility.
Characteristics of listener sensitivity to talker-specific phonetic detail.
Authors: Theodore Rachel M. , Miller Joanne L.
Published: October 2013

Listeners are sensitive to talker differences in phonetic properties of speech, including voice-onset-time (VOT) in word-initial stop consonants. Earlier findings from our laboratory [R. M. Theodore and J. L. Miller, J. Acoust. Soc. Am. 123, 3934 (2008)] indicate that learning how a talker produces one voiceless stop (e.g., /p/ in pain) transfers to another voiceless stop (e.g., /k/ in cane), providing support for feature-based processing of VOT at the level of individual talkers. Here we examined possible constraints on such processing by asking whether transfer would also occur when the learning and transfer words were not minimal pairs. In familiarization phases, listeners heard two talkers produce pain. Critically, word-initial VOTs were manipulated such that one talker produced pain with relatively short VOTs and the other talker produced pain with relatively long VOTs. In test phases, listeners were presented with a short-VOT and a long-VOT variant of coal produced by each talker, and were asked to select which variant was most representative of the talker. Results showed that the listeners selected the VOT variant of coal in line with their previous exposure to pain, indicating that feature-based processing of talker-specific VOT is robust.
Articulatory gestures influence the perception of speech.
Authors: Yeung Henny , Scott Mark , Gick Bryan , Werker Janet
Published: October 2013

A central claim of the motor theory of speech perception [Liberman et al. (1967)] is that speech perception involves motor representations. We report evidence that articulatory movements influence perception. Subjects made forced-choice identifications of naturally recorded /aba/ and /ava/ tokens, while silently making articulatory gestures in time with presentation of the auditory tokens. These articulatory gestures either agreed with the auditory token (e.g., articulating “aba” while hearing /aba/) or disagreed (e.g., articulating “ava” while hearing /aba/). Subjects more frequently misidentified auditory /aba/ as /ava/ when articulated gestures disagreed, as compared to a base line condition (i.e., simply listening). Two further conditions suggest that simple priming of /ava/-percepts is unlikely. First, subjects articulated “afa” instead of ava while hearing /aba/. If error rates are specifically related to articulatory gestures, then the similarity in gestural movements between /f/ and /v/ should result in similar error rates. A priming account would not make such a prediction. In line with the motor explanation, subjects did have an equivalent error rate in afa and ava conditions. Second, minimal interference was observed when subjects only imagined themselves saying /ava/. These results support the notion that activation of motor movements can influence the perception of speech.
Acoustical considerations for luxury motor homes.
Authors: Shaw Jennifer , Moritz Charles
Published: October 2013

Although not considered a typical single-family home, a large number of luxury motor home owners spend at least 6 months per year living in their coach. A survey of class A motor home owners confirmed that for these owners, the coach becomes a home-away-from-home and requires many of the same amenities of a real home, including low interior noise levels. The survey noted that when parked at a campsite or motor home resort, residential noise issues were a significant concern, particularly noise from a neighbor’s generator. Acoustical issues found in motor homes, along with the results of the survey, will be compared with updated results from previously reported motor home testing [J. T. Kunio and C. T. Moritz, SAE 2003 Trans., 112, 1800–1810 (2003)] to understand how these concerns may be addressed.
Conceptual design considerations for the acoustical design of an animal research facility.
Authors: Davis Byron , Richardson Kevin
Published: October 2013

Conceptual design considerations from the acoustical design of an animal research facility are presented in this paper. Animals in laboratory settings are experimentally stressed to observe outcomes. Stressors external to the experiment confound data and reduce research productivity. Among these experimental contaminants is acoustical noise, which has well-documented extra-auditory effects in animals. Both steady-state and transient sounds can affect development, sleep, reproduction, behavior, and other parameters important to animal models. Reasonably comprehensive sensitivity data exist in the medical and laboratory literature; however, there are few treatments of the acoustical design of vivarium and animal laboratory facilities. Acoustical design of these facilities is challenging due to the broad array of sensitivities (including ultrasonic frequencies), scarcity of high-frequency data for noise sources, contamination control and cleanliness requirements, and surface durability concerns. Acoustical design criteria for animal holding areas and experimental test rooms are considered. The criteria are based not only on sound pressure levels but also on frequency content, isolation of incompatible species, expected vocalizations, and minimization of disruption. Noise sources include mechanical/electrical/plumbing equipment, maintenance activities, and other animals. The design efforts include categorization of animal groups, noise isolation concepts, acoustical design, and noise control measures.
Acoustic hindcasts of array performance using a combination of submesoscale hydrodyamic and acoustic models.
Authors: Finette Steven , Oba Roger , Hayward Thomas , Shen Colin , Gallacher Patrick , Warn-Varnas Alex , Piacsek Steve
Published: October 2013

It is well known that submesoscale ocean processes such as nonlinear internal gravity waves can have a significant effect on both the amplitude and the phase of an acoustic field propagating through this type of ocean environment. We report here on hindcasts computed with a numerical model combination consisting of a submesoscale hydrodynamic solver to compute a set of three-dimensional (3-D) environmental (sound speed) volumes evolving in time and a 3-D wide-angle parabolic equation code for acoustic field computation within each environmental volume. The data set was chosen from the ASIAEX 2001 experiment in the South China Sea, during a period of strong internal wave activity. A nonlinear wave packet was simulated propagating up the shelf and passing through both the acoustic source and receiver positions. The hindcasts computed the time evolving beam response on a horizontal array, located approximately 19 km from a 300 Hz low-frequency modulat source. Comparison of experimental and modeled beamformed results was made using three different submesoscale codes to compute the dynamic ocean environment. Each code was exercised using the judgment of a different oceanographer, given the same set of measured bathymetry and water column properties. [Work supported by the Office of Naval Research.]
Optimization of piano tunings by minimizing perceived beat loudness.
Authors: Carpenter David J. , Tutwiler Richard L.
Published: October 2013

In order to create an ideal piano tuning that best matches the inharmonicities and spectra of each instrument, tuning frequencies are optimized using a new beat loudness perceptual model that considers the time dependence of the frequency and amplitude of individual partials. These optimized tunings are compared to prior inharmonicity-based methods of tuning calculation. First, several pianos are prepared to an initial tuning using traditional methods. The resulting tones are recorded and analyzed in MATLAB. Each partial's frequency and amplitude are estimated at discrete time intervals over the duration of the tones. Beat rates are derived for the consonant musical intervals by employing phase-based high resolution frequency estimation techniques on coincident partials. A beat loudness model is developed based on established perceptual theories of consonance and equal loudness contours. The total perceived beat loudness is then minimized by applying optimization and global search methods that alter the tuning of each note. The resulting tunings achieve more consonance than prior tuning methods. Comparisons show subtle frequency variations in the tuning curve that adapt to each piano's unique inharmonicity, amplitude, and decay rate of individual partials.
Acoustical absorption in the atmosphere at high altitudes.
Authors: Sutherland Louis
Published: October 2013

Before 1978, acoustical absorption in the atmosphere was modeled semiempirically based on numerous experimental studies, especially those of Harris and Tempest. In 1969, this author presented a semiempirical model to explain the divergence of the absorption data from theoretical values predicted from classical absorption and molecular relaxation of just moist oxygen. Joe Piercy published a correction of my error in neglecting molecular relaxation of moist nitrogen. This activity stimulated formation of an ANSI working group on atmospheric absorption chaired by Joe Piercy and included the late Henry Bass and myself as members. The result was ANSI Std. S1.25-1978 (1995) which was stated as being valid only up to 20 km. Later, I had the distinct honor to collaborate with Bass in a paper [J. Acoust. Soc. Am. 115 (2004)] which provided a computational model for atmospheric acoustical absorption up to 160 km. Unique elements of this high altitude atmospheric absorption model are reviewed, including the molecular relaxation loss from carbon dioxide. This high altitude atmospheric absorption model was possible only with the key role played by Bass in its development. The Society has lost a true scientist, scholar, and gentleman of the highest caliber.
Vibrational relaxation effects on rise times of weak shocks.
Authors: Raspet Richard
Published: October 2013

After I finished my Ph.D. on the “Application of Monte Carlo techniques in the analysis of laser induced microfission explosions,” I was unemployed and trying to find a job. Hank had a contract from the Air Force to investigate the generation and propagation of thunder. As part of this work, Hank had assigned an undergraduate student the task of adapting a finite wave propagation program developed by Anderson at the University of Texas to incorporate Hank's newly developed sound attenuation algorithm for the ANSI Standard S1-26, “Sound absorption in the atmosphere.” The student had graduated without making much progress and Hank offered me a summer job to work on the problem. I managed to find the single error in the program and as a result, Hank and I wrote a paper [J. Acoust. Soc. Am.]. This was the start of my career in acoustics and a lifelong collaboration with Hank. We and several co-authors published eight papers based on the study of the interaction of vibrational relaxation with finite wave distortion. This paper will present a summary of the findings of this line of research over a 24 year period.
The interactions of Henry E. Bass with the National Research Council in Canada.
Authors: Daigle Gilles , Embleton Tony , Havelock David , Piercy Joseph , Stinson Michael
Published: October 2013

Interactions between researchers at NRC and Bass span a period of more than 30 years during which many research areas of mutual interest were explored. This paper presents an overview of Bass’ research in atmospheric sound propagation during this period and the synergistic collaborations that developed with his friends and colleagues at the NRC. Early work began with the study of relaxation in gases and absorption of sound in the atmosphere. This expanded to include sound propagation above a finite impedance ground, the effects of refraction and atmospheric turbulence, and the development of fast numerical codes to predict long-range sound propagation. The close collaboration and enduring friendships that we valued so much were forged over the years through many interactions, such as the numerous joint field experiments trudging through muddy fields, working in subzero temperatures, or suffering the blistering desert heat. Throughout, Bass was a driving force, and his contributions will fuel research for the community at large for some time to come.
Informational masking of virtual frequency glides.
Authors: Poling Gayla , Feth Lawrence
Published: October 2013

Informational masking (IM) experiments use multiple-burst maskers to change masker uncertainty. The effect of IM is believed to be mediated by interference in the central auditory processing of the signal. Virtual frequency (VF) glides are produced by amplitude modulating two sinusoids separated by one or more ERB at a given test frequency. The amplitude of the low-frequency tone is initially ΔI dB more intense than the higher-frequency tone, and then falls linearly as the amplitude of the higher frequency rises to be ΔI dB greater at the end. Listeners report hearing a weak rising pitch for such signals although no signal energy moves through the frequencies between the tones. Our hypothesis is that central auditory system processing of these signals is similar to that for frequency-modulated (FM) sinusoids, despite clear differences in their peripheral excitation patterns. This study was designed to investigate the effects of masker uncertainty on dynamic signals (FM and VF glides) for different ERB separations for the anchor frequencies. Preliminary results demonstrate a smaller release from IM for the VF glides, which may be explained by the salience of the VF signals compared to the FM tones. [Work supported by NIH/NIDCD RO1-DC006879.]
Using eye-tracking and long-term repetition-priming to examine talker-effects in spoken word recognition.
Authors: McLennan Conor T. , Luce Paul A.
Published: October 2013

Our research examines the circumstances in which talker variability affects listeners’ perception of spoken words. In our previous work, we used the long-term repetition-priming paradigm in which listeners were presented with two blocks of spoken words. Some words were repeated from one block to the next and some words heard during the second block had not been presented during the first block. We found that repeated words were responded to more quickly than new words (a repetition-priming effect). Moreover, repeated words spoken by the same talker in both blocks were responded to more quickly than repeated words spoken by different talkers (a talker-effect). Crucially, talker-effects emerged relatively late during perceptual processing. In the current study, we extended our previous work by using the eye-tracking paradigm and by investigating whether an attentional manipulation would modulate the role that talker variability plays during the perception of spoken words. Because eye-tracking has been shown to tap into processing quite early, we hypothesized that talker-effects would only be obtained if listeners’ attention were drawn to the talkers during the first block. Results will add to our knowledge of the circumstances in which talker variability affects the perception of spoken words. This research was supported in part by research Grant No. 5 R03 DC 7316-4 from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health.
Sala São Paulo Concert Hall, 1998 to 2008.
Authors: Nepomuceno Jose
Published: October 2013

Sala São Paulo is the house of Orquestra Sinonica do Estado de São Paulo (OSESP), and it is an adaptive conversion of a portion of the Julio Prestes railway terminal in São Paulo, Brazil into a concert hall of 1509 seats. Estao Julio Prestes dates from 1938 and the renovation project began in 1997. The concert hall construction started in 1998, and it was opened in July 1999. Ten years after the construction started, Sala São Paulo is a great success. A moveable ceiling with 15 panels weighing 7.5 tons each provides unique sound adjustments. The system calls attention from musicians, from the public, and from researchers. This paper presents a discussion about Sala São Paulo achievements from 1998 to 2008. For example, before Sala São Paulo, acoustics used to start as soon as the architecture design was finished. After Sala São Paulo, this is no longer the rule. Items designed for this project were further developed and installed in other venues and are now commercially available. Moveable ceiling adjustments changed since the project, strongly influenced by listening experiences, showing limitations of judgment based solely on measurements. Construction issues are discussed.
On the reliability of rhythm metrics.
Authors: Arvaniti Amalia , Ross Tristie , Ferjan Naja
Published: October 2013

In the past decade or so, various metrics of vocalic and consonantal variability have been used to quantify linguistic rhythm, often yielding disparate results. The reliability of several such metrics (percentage of vocalic intervals and consonantal standard deviation, pairwise variability indices, and variation coefficient) was tested using materials from stress-timed English and German, syllable-timed Spanish and Italian, Korean, an unclassified language, and Greek, which has resisted classification. The materials for each language were divided into three subsets: an uncontrolled subset of sentences excerpted from a representative author of each language, a subset exhibiting as much as possible “stress-timing” properties (complex syllable structure and extensive vocalic variability), and a subset exhibiting as much as possible “syllable-timing” properties (simple syllable structure and limited vocalic variability). The results suggest that rhythmic scores can be severely affected by the choice of materials, especially in languages such as Italian, in which it is easy to avoid or accentuate variability (e.g., by excluding or including geminates). Variation coefficient scores were the most resistant to the manipulation of materials but failed to show statistical differences across most of the languages examined. The overall results cast doubt on the reliability of metric scores as indicators of timing and linguistic rhythm.
Acoustic Dopplergram for intruder defense.
Authors: Yang T. C.
Published: October 2013

This paper discusses the concept and presents preliminary experimental results using the Dopplergram to detect and localize an underwater vehicle, intended for harbor defense and/or protection of high value assets. The acoustic Dopplergram displays the Doppler frequency of the target echo from an active source as a function of time similar to the Lofargram (or spectral gram), which is widely used in passive sonar for detection of tonal and/or wideband transient signals. m-sequence signals, which are sensitive to Doppler shift, are transmitted with a rapid repetition rate from a source and received on a colocated receiver. Target detection is improved using the processing gain of the m-sequence and using Doppler discrimination (signal association) by eye-ball integration of the (Doppler) gram data. The target is localized using a two-way travel time and bearing estimation. [This work is supported by the US Office of Naval Research.]
Acoustical design of St. Margaret’s Chapel
Authors: Ono Akira , Nagata Minoru
Published: October 2013

St. Margaret’s School is an all-girls high school located in the quiet, upscale Suginami Ward of Tokyo. The school’s St. Margaret’s Chapel was built some 70 years ago and included a pipe organ. The school decided to replace it with a new pipe organ and commissioned Taylor & Boodie, a U.S. organ builder. They requested adjustments to the chapel’s room acoustics so that the new organ would sound its best. Before the project began, the chapel’s reverberation time measured 1.4 s at 63 Hz and 1.8 s at 500 Hz and 1 kHz. That is, the reverberation time was shorter for low register sounds. The immediate challenge we faced on this project was the school’s requirement that the chapel not be altered at all visually. St. Margaret’s Chapel has historical value that the school wished to preserve. The framework of the chapel building and its floor are entirely made of wood. Moreover, the area around the altar is wood paneling. Upon investigation, we confirmed that the vibrations of these wood elements were absorbing the low register sounds. We determined that strengthening the walls and floor of the altar area would be an effective strategy to improve the chapel’s acoustics.
Development of a cell-embedded tissue-mimicking ultrasound phantom
Authors: Liu Yunbo , Zhong Pei
Published: October 2013

An optically transparent cell-embedded tissue-mimicking phantom was developed to study high-intensity focused ultrasound (HIUF)-induced gene activation in vitro. The phantom was constructed by using agarose hydrogel embedded with dispersed rat mammary carcinoma (Mac) cells that were stably transfected with GFP plasmid under the control of hsp70B promoter. Thermally sensitive bovine serum albumin (BSA) proteins were also incorporated in the phantom so that both lesion formation and gene activation could be quantified simultaneously following HIFU exposure. Both acoustic (sound speed, attenuation, acoustic impedance, B/A ratio) and thermal properties (thermal conductivity and thermal diffusivity) of the phantom were characterized in a temperature-dependent manner. At a peak temperature between 70°C and 90°C and a 10-s exposure using a 3.3-MHz HIFU transducer, the inducible GFP gene expression patterns in the phantom were analyzed and compared with the corresponding 3-D temperature distribution quantified by thermocouple measurements. Overall, the cell-embedded tissue-mimicking phantom was found to be a versatile tool for investigating HIFU-induced gene activation and it may also be used for general ultrasound bio-effect studies. [Work supported by NIH.]
Analytic derivation of adjoint nonlocal boundary conditions for a stratified ocean bottom in parabolic approximation
Authors: Papadakis John S. , Flouri Evangelia T. , Meyer Matthias , Hermand Jean-Pierre
Published: October 2013

In underwater acoustics various types of nonlocal boundary conditions have been developed to handle the semi-infinite bottom in parabolic approximations and to efficiently reduce the computational domain. This paper proposes new exact nonlocal boundary conditions suitable for a layered ocean bottom and presents an analytic derivation of the corresponding adjoint equations. The new boundary condition has the form of a Neumann-to-Dirichlet map (NtD) that explicitly contains the geoacoustic parameters of the stratified bottom, i.e., thickness, density, sound speed, and attenuation of each layer. By means of the analytic adjoint, exact gradient information can be obtained which in turn allows a direct inversion of these parameters using a gradient-based optimization scheme. [Work supported by Royal Netherlands Navy.]
Air-deployable sonobuoy array concepts and their performance against high-frequency noise anisotropy
Authors: Arvelo Juan I. , Ferat Patrick , Mitnick Ronald
Published: October 2013

High-frequency sonobuoy arrays with vertical aperture were developed and tested to exploit the noise anisotropy for enhanced array gain [Ferat and Arvelo, J. Acoust. Soc. Am. 114, 2462–2463 (2003)]. Afterwards, an inexpensive and conformal piezoelectric wire material was employed in the design and construction of a volumetric array [Arvelo et al., J. Acoust. Soc. Am. 116, 2650 (2004)]. However, detection performance of air-deployed sonobuoys is severely affected by noise interference through the beamformers sidelobes. An improved sonobuoy system design with in-buoy processing for sidelobe suppression is introduced and its detection performance in anisotropic wind noise with nearby shipping interference is evaluated and compared against previous designs in selected environmental conditions. The high-frequency array gain for increased vertical aperture will be compared against the gain for increased horizontal aperture to explore coherence limitations. The effects of array tilt, as well as interelement amplitude, phase, and topology errors, on the performance deterioration of the new design will also be addressed. [This effort is supported by the Maritime Sensing (MS) Program of the Office of Naval Research (ONR Code 321).]
Signal detection theory and noisy communication
Authors: Wollerman Lori
Published: October 2013

Signal detection theory (SDT) has had little influence on thinking about the evolution of animal communication, despite its wide application in psychology. SDT is a model that describes the detection of signals in the presence of noise, a situation that clearly applies to animals that communicate in aggregations, such as many frogs and singing insects. Through SDT we can better understand fundamental issues about the evolution of communication. In many realistic signaling conditions receivers are unable to avoid making an error of one sort or another regardless of the criterion they use for responding to signals. Signals that are more exaggerated would be more detectable and receivers would be more likely to respond to these signals than to those that are less exaggerated and less detectable. Signal detection theory therefore provides a sufficient explanation for the exaggeration and elaboration of male displays used to attract females for mating. Moreover, principles of SDT apply to any communicatory interaction. Thus, SDT establishes universal conditions that any hypothesis regarding the evolution of signals must satisfy.