bluuebunny/crossref_metadata_2025 huggingface dataset:
The songsmith story, or how a small-town hidden Markov model dade it to the big time
Authors: Basu Sumit , Morris Dan , Simon Ian
Published: May 2014

It all started with a simple idea—that perhaps lead sheets could be predicted from melodies, at least within a few options for each bar. Early experiments with conventional models led to compelling results, and by designing some user interactions along with an augmented model, we were able to create a potent tool with a range of options, from an automated backing band for musical novices to a flexible musical scratchpad for songwriters. The academic papers on the method and tool led to an unexpected level of external interest, so we decided to make a product for consumers, thus was Songsmith born. What came next surprised us all—from internet parodies to stock market melodies to over 600 000 downloads and a second life in music education, Songsmith has been an amazing lesson in what happens when research and the real world collide, sometimes with unintended consequences. In this talk, I’ll take you through our story, from the technical beginnings to the Internet-sized spectacle to the vast opportunities in future work, sharing with you the laughter, the heartbreak, the tears, and the joy of bringing Songsmith to the world.
Sound classification of dwellings—A comparison between national schemes in Europe and United States
Authors: Berardi Umberto
Published: May 2014

Schemes for the classification of dwellings related to different performances have been proposed in the last years worldwide. The general idea behind previous schemes relates to the increase in the real estate value that should follow a label corresponding to a better performance. In particular, focusing on sound insulation, national schemes for acoustic classification of dwellings have been developed in more than ten European countries. These schemes define classification classes according to different levels of sound insulation. The considered criteria are the airborne and impact sound insulation between dwellings, the facade sound insulation, and the equipment noise. Originally, due to the lack of coordination among European countries, a significant diversity among the schemes occurred; the descriptors, number of classes, and class intervals varied among schemes. However, in the last year, an “acoustic classification scheme for dwellings” has been proposed within a ISO technical committee. This paper compares existing classification schemes with the current situation in the United States. The hope is that by increasing cross-country comparisons of sound classification schemes, it may be easier to exchange experiences about constructions fulfilling different classes and by doing this, reduce trade barriers, and increase the sound insulation of dwellings.
Sound insulation analysis of residential building at China
Authors: Xiangdong Zhu , Jianghua Wang , Xiaoyan Xue , Xuguang Wang
Published: May 2014

Residential acoustic environment is one of the living environments that are most closely related to the daily life. The high-quality residential acoustic environment depends not only on the urban planning, building design, construction, and supervision, but also on the related regulations. In some developed countries, the residential acoustic regulations have been built up and evolved into a relatively complete system with high quality standards required. This thesis (1) conducted a questionnaire survey for resident building which be constructed at different period; (2) investigate the Technical level, the legal system, and the quality of residents to analysis the sound environment satisfaction of resident and compare it with developed countries.
Mechanisms for wind noise reduction by a spherical wind screen
Authors: Raspet Richard , Webster Jeremy , Naderyan Vahid
Published: May 2014

Spherical wind screens provide wind noise reduction at frequencies which correspond to turbulence scales much larger than the wind screen. A popular theory is that reduction corresponds to averaging the steady flow pressure distribution over the surface. Since the steady flow pressure distribution is positive on the front of the sphere and negative on the back of the sphere, the averaging results in a reduction in measured wind noise in comparison to an unscreened microphone. A specially constructed 180 mm diameter foam sphere allows the placement of an array of probe microphone tubes just under the surface of the foam sphere. The longitudinal and transverse correlation lengths as a function of frequency and the rms pressure fluctuation distribution over the sphere surface can be determined from these measurements. The measurements show that the wind noise correlation lengths are much shorter than the correlations measured in the free stream. The correlation length weighted pressure squared average over the surface is a good predictor of the wind noise measured at the center of the wind screen. [This work was supported by the Army Research Laboratory under Cooperative Agreement W911NF-13-2-0021.]
Nonlinearity spectral analysis of high-power military jet aircraft waveforms
Authors: Gee Kent L. , Neilsen Tracianne B. , Reichman Brent O. , Thomas Derek C. , James Michael M.
Published: May 2014

One of the methods for analyzing noise waveforms for nonlinear propagation effects is a spectrally-based nonlinearity indicator that involves the cross spectrum between the pressure waveform and square of the pressure. This quantity, which stems directly from ensemble averaging the generalized Burgers equation, is proportional to the local rate of change of the power spectrum due to nonlinearity [Morfey and Howell, AIAA J. 19, 986–992 (1981)], i.e., it quantifies the parametric sum and difference-frequency generation during propagation. In jet noise investigations, the quadspectral indicator has been used to complement power spectral analysis to interpret mid-field propagation effects [ Gee et al., AIP Conf. Proc. 1474, 307–310 (2012)]. In this paper, various normalizations of the quadspectral indicator are applied to F-22A Raptor data at different engine powers. Particular attention is paid to the broadband spectral energy transfer around the spatial region of maximum overall sound pressure level. [Work supported by ONR.]
Application of time reversal analysis to military jet aircraft noise
Authors: Harker Blaine M. , Anderson Brian E. , Gee Kent L. , Neilsen Tracianne B. , James Michael M.
Published: May 2014

The source mechanisms of jet noise are not fully understood and different analysis methods can provide insight. Time reversal (TR) is a robust data processing method that has been used in myriad contexts to localize and characterize sources from measured data, but has not extensively been applied to jet noise. It is applied here in the context of an installed full-scale military jet engine. Recently, measurements of an F-22A were taken using linear and planar microphone arrays at various engine conditions near the jet plume [Wall et al., Noise Control Eng. J. 60, 421–434 (2012)]. TR provides source imaging information as broadband and narrowband jet noise recordings are reversed and back propagated to the source region. These reconstruction estimates provide information on dominant source regions as a function of frequency and highlight directional features attributed to large-scale structures in the downstream jet direction. They also highlight the utility of TR analysis as being complementary to beamforming and other array methods. [Work supported by ONR.]
Medial olivocochlear efferent effects on auditory responses
Authors: Guinan John J.
Published: May 2014

Medial Olivocochlear (MOC) inhibition in one ear can be elicited by sound in either ear. Curiously, the ratio of ipsilateral/contralateral inhibition depends on sound bandwidth; the ratio is ~2 for narrow-band sounds but ~1 for wide-band sounds. Reflex amplitude also depends on elicitor bandwidth and increases as bandwidth is increased, even when elicitor-sound energy is held constant. After elicitor onset (or offset), nothing changes for 20–30 ms and then MOC inhibition builds up (or decays) over 100–300 ms. MOC inhibition has typically been measured in humans by its effects on otoacoustic emissions (OAEs). Problems in such OAE studies include inadequate signal-to-noise ratios (SNRs) and inadequate separation of MOC effects from middle-ear-muscle effects. MOC inhibition reduces basilar-membrane responses more at low levels than high levels, which increases the response SNRs of higher-level signals relative to lower-level background noises, and reduces noise-induced adaptation. The net effect is expected to be increased intelligibility of sounds such as speech. Numerous studies have looked for such perceptual benefits of MOC activity with mixed results. More work is needed to determine whether the differing results are due to experimental conditions (e.g., the speech and noise levels used) or to methodological weaknesses. [Work supported by NIH-RO1DC005977.]
Does the efferent system aid with selective attention?
Authors: McFadden Dennis , Walsh Kyle P. , Pasanen Edward G.
Published: May 2014

To study whether attention and inattention lead to differential activation of the olivocochlear (OC) efferent system, a cochlear measure of efferent activity was collected while human subjects performed behaviorally under the two conditions. Listeners heard two independent, simultaneous strings of seven digits, one spoken by a male and the other by a female, and at the end of some trials (known in advance), they were required to recognize the middle five digits spoken by the female. Interleaved with the digits were one stimulus that evokes a stimulus-frequency otoacoustic emission (SFOAE) and another that activates the OC system—a 4-kHz tone (60 dB SPL, 300 ms in duration) and a wideband noise (1.0–6.0 kHz, 25 dB spectrum level, 250 ms in duration, beginning 50 ms after tone onset). These interleaved sounds, used with a double-evoked procedure, permitted the collection of a nonlinear measure called the nSFOAE. When selective attention was required behaviorally, the magnitude of the nSFOAE to tone-plus-noise differed by 1.3–4.0 dB compared to inattention. Our interpretation is that the OC efferent system was more active during attention than during relative inattention. Whether or how this efferent activity actually aided behavioral performance under attention is not known.
The function of the basilar membrane and medial olivocochlear (MOC) reflex mimicked in a hearing aid algorithm
Authors: JÃrgens Tim , Clark Nicholas R. , Lecluyse Wendy , Ray Meddis
Published: May 2014

The hearing aid algorithm “BioAid” mimics two basic principles of normal hearing: the instantaneous compression of the basilar membrane and the efferent feedback of the medial olivocochlear (MOC) reflex. The design of this algorithm aims at restoring those parts of the auditory system, which are hypothesized to dysfunction in the individual listener. In the initial stage of this study individual computer models of three hearing-impaired listeners were constructed. These computer models reproduce the listeners’ performance in psychoacoustic measures of (1) absolute thresholds, (2) compression, and (3) frequency selectivity. Subsequently, these computer models were used as “artificial listeners.” Using BioAid as a front-end to the models, parameters of the algorithm were individually adjusted with the aim to ‘normalize’ the model performance on these psychoacoustic measures. In the final stage of the study, the optimized hearing aid fittings were evaluated with the three hearing-impaired listeners. The aided listeners showed the same qualitative characteristics of the psychoacoustic measures as the aided computer models: near-normal absolute thresholds, steeper compression estimates and sharper frequency selectivity curves. A systematic investigation of the effect of compression and the MOC feedback in the algorithm revealed that both are necessary to restore performance. [Work supported by DFG.]
Mimicking the unmasking effects of the medial olivo-cochlear efferent reflex with cochlear implants
Authors: Lopez-Poveda Enrique A. , Eustaquio-Martin Almudena
Published: May 2014

In healthy ears, cochlear sensitivity and tuning are not fixed; they vary depending on the state of activation of medial olivo-cochlear (MOC) efferent fibers, which act upon outer hair cells modulating the gain of the cochlear amplifier. MOC efferents may be activated in a reflexive manner by ipsilateral and contralateral sounds. Activation of the MOC reflex (MOCR) is thought to unmask sounds by reducing the adaptation of auditory nerve afferent fibers response to noise. This effect almost certainly improves speech recognition in noise. Furthermore, there is evidence that contralateral stimulation can improve the detection of pure tones embedded in noise as well as speech intelligibility in noise probably by activation of the contralateral MOCR. The unmasking effects of the MOCR are unavailable to current cochlear implant (CI) users and this might explain part of their difficulty at understanding speech in noise compared to normal hearing subjects. Here, we present preliminary results of a bilateral CI sound-coding strategy that mimics the unmasking benefits of the ipsilateral and contralateral MOCR. [Work supported by the Spanish MINECO and MED-EL GmbH.]
A study of multi-element/multi-path concentric shell structures to reduce noise and vibration
Authors: Bliss Donald B. , Raudales David , Franzoni Linda P.
Published: May 2014

Vibration transmission and noise can be reduced by dividing a structural barrier into several constituent subsystems with separate, elastically coupled, wave transmission paths. Multi-element/multi-path (MEMP) structures utilize the inherent dynamics of the system, rather than damping, to achieve substantial wide-band reduction in the low frequency range, while satisfying constraints on static strength and weight. The increased complexity of MEMP structures provides a wealth of opportunities for reduction, but the approach requires rethinking the structural design process. Prior analytical and experimental work, reviewed briefly, focused on simple beam systems. The current work extends the method to elastically coupled concentric shells, and is the first multi-dimensional study of the concept. Subsystems are modeled using a modal decomposition of the thin shell equations. Axially discrete azimuthally continuous elastic connections occur at regular intervals along the concentric shells. Simulations show the existence of robust solutions that provide large wide-band reductions. Vibratory force and sound attenuation are achieved through several processes acting in concert: different subsystem wave speeds, mixed boundary conditions at end points, interaction through elastic couplings, and stop band behavior. The results show the concept may have application in automotive and aerospace vehicles, and low vibration environments such as sensor mounts.
Scattering from a cylindrical shell with an internal mass
Authors: Norris Andrew , Titovich Alexey S.
Published: May 2014

Perhaps the simplest approach to modeling acoustic scattering from objects with internal substructure is to consider a cylindrical shell with an internal mass attached by springs. The earliest analyses, published in JASA in 1992, by Achenbach et al. and by Guo assumed one and two springs, respectively. Subsequent studies examined the effects of internal plates and more sophisticated models of substructure. In this talk we reconsider the Achenbach—Guo model but for an arbitrary number, say J, of axisymmetrically distributed stiffeners. The presence of a springs-mass substructure breaks the cylindrical symmetry, coupling all azimuthal modes. Our main result provides a surprisingly simple form for the scattering solution for time harmonic incidence. We show that the scattering, or T-matrix, decouples into the sum of the T-matrix for the bare shell plus J matrices each defined by an infinite vector. In addition, an approximate expression is derived for the frequencies of the quasi-flexural resonances induced by the discontinuities on the shell, which excite subsonic shell flexural waves. Some applications of the model to shells with specified long wavelength effective bulk modulus and density will be discussed. [Work supported by ONR.]
Active noise control for cylindrical shells using a sum of weighted spatial gradients (WSSG) control metric
Authors: Aslani Pegah , Sommerfeldt Scott D. , Cao Yin , Blotter Jonathan D.
Published: May 2014

There are a number of applications involving cylindrical shells where it is desired to attenuate the acoustic power radiated from the shell, such as from an aircraft fuselage or a submarine. In this paper, a new active control approach is outlined for reducing radiated sound power from structures using a weighted sum of spatial gradients (WSSG) control metric. The structural response field associated with the WSSG has been shown to be relatively uniform over the surface of both plates and cylindrical shells, which makes the control method relatively insensitive to error sensor location. It has also been shown that minimizing WSSG is closely related to minimizing the radiated sound power. This results in global control being achieved using a local control approach. This paper will outline these properties of the WSSG control approach and present control results for a simply supported cylindrical shell showing the attenuation of radiated sound power that can be achieved.
Frequency domain comparisons of different analytical and computational radiated noise solutions for point-excited cylindrical shells
Authors: Koch Robert M.
Published: May 2014

Among a multitude of diverse applications, the acoustics of cylindrical shells is also an important area of study for its applicability to and representation of many US Navy undersea vehicles and systems. Examination of structural acoustic predictions of cylindrical-shell-based system designs are frequently made using a variety of analytical and computational approaches including closed-form 3D elasticity, numerous kinematic plate/shell theories, Finite Element Analysis (FEA), Energy-based FEA (EFEA) coupled with Energy Boundary Element Analysis (EBEA), and Statistical Energy Analysis (SEA). Each of these approaches has its own set of assumptions, advantages, and applicable frequency range which can make for confusion. This paper presents radiated noise solutions in the area of cylindrical shell structural acoustics from the above list of methodologies for the canonical problem of a point-excited, finite cylindrical shell with/without fluid loading. Specifically, far-field radiated sound power predictions for cylindrical shells using many different classical analytical and modern day numerical approaches (i.e., 3D elasticity, closed form plate and shell theory solutions FEA, EFEA/EBEA, SEA) are made and compared. Of particular interest for this comparison is the applicable frequency regimes for each solution and also how the solution approaches compare/transition from one to the other over a wide frequency range.
Free and forced vibrations of hollow elastic cylinders of finite length
Authors: Ebenezer D. D. , Ravichandran K. , Padmanabhan Chandramouli
Published: May 2014

An analytical model of axisymmetric vibrations of hollow elastic circular cylinders with arbitrary boundary conditions is presented. Free vibrations of cylinders with free or fixed boundaries and forced vibrations of cylinders with specified non-uniform displacement or stress on the boundaries are considered. Three series solutions are used and each term in each series is an exact solution to the exact governing equations of motion. The terms in the expressions for components of displacement and stress are products of Bessel and sinusoidal functions and are orthogonal to each other. Complete sets of functions in the radial and axial directions are formed by terms in the first series and the other two, respectively. It is therefore possible to satisfy arbitrary boundary conditions. It is shown that two terms in each series are sufficient to determine several resonance frequencies of cylinders with certain specified boundary conditions. The error is less than 1% for free cylinders. Numerical results are also presented for forced vibration of hollow steel cylinders of length 10 mm and outer diameter 10 mm with specified normal displacement or stress. Excellent agreement with finite element results is obtained at all frequencies up to 1 MHz. Convergence of the series is also discussed.
Internal three dimensional tongue motion during “s” and “sh” from tagged magnetic resonance imaging; control and glossectomy motion
Authors: Ziemba Joseph K. , Stone Maureen , Pedersen Andrew D. , Woo Jonghye , Xing Fangxu , Prince Jerry L.
Published: May 2014

This study aims to ascertain the effects of tongue cancer surgery (glossectomy) on tongue motion during the speech sounds “s” and “sh.” Subjects were one control and three glossectomies. The first patient had surgery closed with sutures. The second had sutures plus radiation, which produces fibrosis and stiffness. The third was closed with an external free flap, and is of particular interest since he has no direct motor control of the flap. Cine and tagged-MRI data were recorded in axial, coronal and sagittal orientations at 26 fps. 3D tissue point motion was tracked at every time-frame in the word. 3D displacement fields were calculated at each time-frame to show tissue motion during speech. A previous pilot study showed differences in “s” production [Pedersen et al., JASA (2013)]. Specifically, subjects differed in internal tongue motion pattern, and the flap patient had unusual genioglossus lengthening patterns. The “s” requires a midline tongue groove, which is challenging for the patients. This study continues that effort by adding the motion of “sh,” because “sh” does not require a midline groove and may be easier for the patients to pronounce. We also add more muscles, to determine how they interact to produce successful motion. [This study was supported by NIH R01CA133015.]
Spectrotemporal alterations and syllable stereotypy in the vocalizations of mouse genetic models of speech-language disorders
Authors: Castellucci Gregg A. , McGinley Matthew J. , McCormick David A.
Published: May 2014

Specific language impairment (SLI) and developmental dyslexia (DD) are common speech-language disorders exhibiting a range of phonological and speech motor deficits. Recently, mouse genetic models of SLI (Foxp2) and DD (Dcdc2) have been developed and promise to be powerful tools in understanding the biological basis of these diseases. Surprisingly, no studies of the adult vocalizations—which exhibit the most elaborate and complex call structure—have been performed in these mouse strains. Here, we analyze the male ultrasonic courtship song of Dcdc2 knockout mice and Foxp2 heterozygous knockout mice and compare it to the song of their C57BL/6J background littermates. Preliminary analysis indicates considerable difference between the three groups. For example, Foxp2 heterozygous knockout song contains less frequency modulation and has a reduced syllable inventory in comparison to that of wildtype littermates. The call production and phonological deficits exhibited by these mouse models are reminiscent of the symptoms observed in humans with these disorders.
Listening effort in bilateral cochlear implants and bimodal hearing
Authors: Fitzgerald Matthew , Glassman Katelyn , Mehta Sapna , Seward Keena , Neuman Arlene
Published: May 2014

Many users of bilateral cochlear implants, or of bimodal hearing, report, reduced listening effort when both devices are active relative to a single device. To quantify listening effort in these individuals, we used a dual-task paradigm. In such paradigms, the participant divides attention between a primary and secondary task. As the primary task becomes more difficult, fewer cognitive resources are available for the secondary task, resulting in poorer performance. The primary task was to repeat AzBio sentences in quiet, and in noise. The secondary task was to recall a digit string presented visually before a set of two sentences. As a control, both the primary and secondary tasks were tested alone in a single-task paradigm. Participants were tested unilaterally and bilaterally / bimodally. Relative to the single-task control, scores obtained in the dual-task paradigm were not affected in the primary sentence-recognition task, but were lower on the secondary digit-recall task. This suggests that a dual-task paradigm has potential to quantify listening effort. Some listeners who showed bilateral benefits to speech understanding had higher bilateral than unilateral digit-recall scores. However, there was considerable variability on the digit-recall task, which hinders our ability to draw clear conclusions.
Automatic speech recognition of naturalistic recordings in families with children who are hard of hearing
Authors: VanDam Mark , Silbert Noah H.
Published: May 2014

Performance of an automatic speech recognition (ASR) system [LENA Research Foundation, Boulder, CO] has been reported for naturalistic, whole day recordings collected in families with typically developing (TD) children. This report examines ASR performance of the LENA system in families with children who are hard-of-hearing (HH). Machine-labeled segments were compared with human judges' assessment of talker identity (child, mother, or father), and recordings from families with TD children were compared with families with HH children. Classification models were fit to several acoustic variables to assess decision process differences between machine and human labels and between TD and HH groups. Accuracy and error of both machine and human performance is reported. Results may be useful to improve implementation and interpretation of ASR techniques in terms of special populations such as children with hearing loss. Findings also have implications for very large database applications of unsupervised ASR, especially its application to naturalistic acoustic data.
The contribution of speech motor function to the cognitive testing
Authors: Wang Emily , Sheft Stanley , Shafiro Valeriy , Shah Raj
Published: May 2014

This pilot study was to explore speech function as a possible confounding factor in the assessment of persons with Mild Cognitive Impairment (MCI) due to Alzheimer’s disease (AD). In the United States, over 30 million people are 65 and older with 10 to 20% of them suffering from MCI due to AD. Episodic memory is tested in diagnosis of MCI due to AD using recall of a story or a list of words. Such tasks involve both speech and hearing. Normal aging also impacts one’s speech and hearing. In this study, we designed a test battery to investigate the contribution of speech and hearing on testing of episodic memory. Sixty community-dwelling Black and 60 demographically matched White, all over 74 years, non-demented persons participated in the study. They each produced a story-retell and named animals in one minute. All subjects were tested with hearing and speech measures (maximum-sustained vowel phonation and diadochokinetic rates). Preliminary results showed that small but consistent differences were seen between the two racial groups in the diadochokinetic rates (p < 0.05). There were negative correlations between the Story-retell and diadochokinetic rates, which may suggest that speech motor control may indeed be a confounding factor in episodic memory testing.
Processing methods for coprime arrays in complex shallow water environments
Authors: Pyzdek Andrew T. , Culver R. Lee
Published: May 2014

Utilizing the concept of the coarray, coprime arrays can be used to generate fully populated cross-correlation matrices with a greatly reduced number of sensors by imaging sensors to fill in gaps in the physical array. Developed under free space far-field assumptions, such image sensors may not give accurate results in complicated propagation environments, such as shallow water. Taking shallow water acoustic models under consideration, it will be shown that image sensors can still be used, but to a more limited extent based on spatial variability. Performance of a coprime array with limited image sensors and full image sensors will be compared with that of a fully populated array. [This research was supported by the Applied Research Laboratory, at the Pennsylvania State University through the Eric Walker Graduate Assistantship Program.]
Compressive beamforming in noisy environments
Authors: Edelmann Geoffrey F. , Gaumond Charles F. , Rogers Jeffrey S.
Published: May 2014

The application of compressive sensing to detect targets of interest could greatly impact future beamforming systems. Inevitably, at-sea data are contaminated with measured noise. When the ocean is stationary enough to form multiple snap-shots, a covariance matrix may be formed to mitigate noise. Results of compressive beamforming on a covariance matrix will be shown on at-sea measurements. Results will be compared with a robust adaptive beamformer and compressive beamformer. It will be shown that the dictionary of a compressive covariance beamformer goes as the number of measurements squared leading to a compromise between processor and array gain. [This work was supported by ONR.]
Data fusion applied to beamforming measurement
Authors: Fonseca William D. , Ristow JoÃo P.
Published: May 2014

The aim of this work is use data fusion in a set of data obtained from measurements done with a microphone array in different times to improve beamforming results. Beamforming is a technique that basically samples the sound field with an array of sensors. The correct summation of these signals will render a reinforcement of the recorded sound for a chosen direction in space. In addition, processing a set of possible incoming directions enables the creation of sound maps. The spatial resolution in beamforming is directly related to array’s constructive factors and frequency of analysis. One way to improve resolution is increasing array’s size and number of sensors. Considering the measured source statistically stationary, it is possible to use signals obtained in different times to evaluate it. In this way, the array can be placed in different positions, and the data acquired can be processed and fused in order to create a single set of data corresponding to a virtual array composed by all aforementioned positions.
Passive multi-target localization by cross-correlating beams of a compact volumetric array
Authors: Gebbie John , Siderius Martin , Nielsen Peter L. , Miller James
Published: May 2014

A technique is presented for passively localizing multiple noise-producing targets by cross-correlating the elevation beams of a compact volumetric array on separate bearings. A target's multipath structure inherently contains information about its range, however unknown, random noise waveforms make time separation of individual arrivals difficult. Ocean ambient noise has previously been used to measure multipath delays to the seabed by cross-correlating the beams of a vertical line array [Siderius et al., J. Acoust. Soc. Am. 127, 2193–2200 (2010)], but this methodology has not been applied to distant noise sources having non-vertical arrivals. In this paper, methods are presented for using a compact volumetric array mounted to an autonomous underwater vehicle to measure the directionality and time delays of multipath arrivals, while simultaneously rejecting clutter and interference. This is validated with results from the GLASS'12 experiment in which a small workboat maneuvered in shallow water. Short ranges could be estimated reliably using straight ray paths, but longer ranges required accounting for ray refraction effects. Further, this is related to striation patterns observed in spectrograms, and it is shown that measured multipath time delays are used to predict this pattern, as well as the waveguide invariant parameter, β.
Development of vector sensors for flexible towed array
Authors: Korenbaum Vladimir , Tagiltcev Alexandr
Published: May 2014

Main problems of application of vector sensors (VSs) for flexible towed arrays are providing high performance under small dimensions as well as necessary flow noise immunity. The objective is to develop VSs met these demands. A simulation of performance of VS embedded in a flexible towed array body formed with sound transparent compound is performed. The developed one-dimensional model, predicts existence of a suspension resonance, dividing frequency band of VS into two parts. The lower part of the band is more applicable for VS of inertial type while the upper one is more preferred for VS of gradient type. A possibility to control the suspension resonance frequency in limits of 500–2000 Hz is shown for experimental model. The flow noise immunity problem is analyzed for different frequency bands and types of VSs. Various methods of flow noise cancellation are developed for different frequency bands and types of VSs, which include power flux processing, compensation of vibration response, convolution processing. Examples of design of one- and two-component VSs are represented. [The study was supported by the grant 13-NTP-II-08 of Far Eastern Branch of Russian Academy of Sciences.]
Acoustic particle velocity amplification and flow noise reduction with acoustic velocity horns
Authors: Donskoy Dimitri , Hassan Scott E.
Published: May 2014

Small wavelength size acoustic velocity horns (AVH) were recently introduced [J. Acoust. Soc. Am. 131(5), 3883–3890 (2012)] as particle velocity amplifiers having flat amplitude and phase frequency responses below their first resonance. AVH predicted amplification characteristics have been experimentally verified demonstrating interesting opportunities for vector sensors (VS) sensitivity enhancement. Present work provides enhanced analysis of amplification and characteristics of complex shape horns. Additionally, we address another AVH feature: turbulence flow noise reduction due to turbulence field spatial averaging across horn’s mouth area. Numerical analysis demonstrated up to 25 dB convective turbulent pressure and velocity reduction at the horn throat.
Localizing low-frequency sounds in a room and the dominance of interaural level differences
Authors: Hartmann William M. , Rakerd Brad , Macaulay Eric J. , Crawford Zane D.
Published: May 2014

In a room-environment study of the duplex theory of sound localization, listeners reported the azimuthal locations of low-frequency sine tones in free field and in three very different rooms. Interaural differences in time (ITD) and level (ILD) were continuously monitored by probe microphones in the listeners' ear canals. As the frequency increased from 250 to 1000 Hz, the correlation of listener responses with the ILD increased while the correlation with the ITD decreased precipitously. The increased importance of the ILD was especially prominent for the least reverberant environments. The decreased importance of the ITD occurred primarily because of interaural phase differences (IPD) that became large (>90 degrees) and consequently weak. The large IPD effect occurred more frequently in the highly reverberant room, and in the less reverberant rooms at 750 and 1000 Hz, where the peak of the IPD distribution occurred well above 90 degrees. The two effects caused the ILD to become more important than the ITD when the frequency was greater than about 500 Hz with only a small dependence on the different rooms. The increased emphasis given to the ILD normally led to more accurate localization. [Work supported by AFOSR grant FA9550-11-1-0101.]
On the sensitivity of older hearing-impaired individuals to acoustic attributes
Authors: Whitmer William M. , Akeroyd Michael A.
Published: May 2014

In previous work, we have run a series of experiments with hearing-impaired adults to examine how age and hearing loss affect sensitivity to changes in apparent auditory source width. In two experiments, the interaural coherence of broadband noises presented over headphones and loudspeakers was varied to induce changes in width; in a third, older participants sketched the width of noise, speech, and musical stimuli in simulated rooms with varying reflection absorption. The results of those experiments showed generally decreasing sensitivities to interaural-coherence-induced changes in width as a function of age and hearing impairment. To examine how these results might influence acoustic design for the aged, a new study considers a more basic task that avoided the auditory-visual transformation implicit in sketching. Participants with normal to moderately impaired hearing will compare simulated utterances in a same/different room-discrimination task. Binaural impulse responses will be generated for open-plan buildings of varying size from the ODEON database with sources and receivers centered in each space, convolved with speech and music tokens and presented over headphones. The differences in the relationship between presbycusis and sensitivity to source width vs. general acoustical attributes will be discussed. [Work supported by the MRC and the CSO.]
Perception of loudness in directional sound fields
Authors: Robinson Philip W. , Pätynen Jukka
Published: May 2014

An often utilized assumption in room acoustics is that the room produces a diffuse field, in which sound is uniformly distributed in space and arrives at the listener equally from all directions. This assumption greatly simplifies many calculations, e.g., Sabine's reverberation time (RT). However, the reverberant field, particularly the early part of the impulse response in typical concert spaces, is highly directional. Hence, the diffuse assumption leads to errors, for example, in the prediction of loudness when using omni-directional measures. Lateral reflections contribute to perceived loudness more than their omni-directionally measured sound energy. This is due the filtering of the head and torso, which amplify reflections from lateral directions more than others, particularly at high frequencies. Listening test results will be presented that demonstrate this effect. Spatial analyses of concert hall impulse responses demonstrate the practical applicability of this finding and make evident the relevance of the effect.
Temporal weighting of binaural cues in real rooms: Psychophysical and neural modeling
Authors: Stecker G. Christopher , Brown Andrew D. , Tollin Daniel J.
Published: May 2014

Although interaural time and level differences (ITD and ILD) comprise the primary cues to sound location in azimuth, both are distorted by echoes and reverberation in many real environments. Consequently, the “effective” cues exhibit complexities and evolve temporally due to interactions of direct and reflected sound. One approach to studying the perceptual effects of such distortions is to measure the relative influence, or “temporal weight,” of cues contained within brief temporal segments of sound on spatial judgments made by human listeners. Temporal weighting functions (TWFs) measured in this way reveal binaural sensitivity to be temporally nonuniform and cue-specific. For many sounds (tones and high-rate click trains), judgments appear dominated by the ITD and ILD occurring at sound onset and the ILD occurring near sound offset, while middle portions contribute very little, consistent with expectations about the temporal statistics of these cues in real rooms. In this presentation, psychophysically derived TWFs are compared to the frequency-dependent statistics of ITD and ILD in room recordings. Models of the auditory periphery and early nervous system are used to transform the recordings to estimate the effective cues “as heard by” central brain mechanisms. [Work supported by NIH R01 DC 011548 (GCS) and DC 011555 (DJT).]
Subjective perception of varying reflection densities in room impulse responses
Authors: Hong Hyun , Wang Lily M.
Published: May 2014

The commonly used objective metrics for analyzing room acoustics are each tied to some aspect of subjective perception. For example, the widely used reverberation time is linked to the perceived reverberation in a room. Two different rooms having the same reverberation time, though, can have different reflection densities in their impulse responses, and this difference in reflection density may affect how listeners perceive the size of the rooms. This project investigates the subjective perception of reflection densities and how sensitive humans are to a change of reflection density. First, assorted parameters for quantifying reflection density are reviewed. Then, preliminary results of perceptual tests using different room impulse responses with varying reflection densities are presented.
Influence of manipulated early reflections on room acoustical perception
Authors: Klockgether Stefan , van de Par Steven
Published: May 2014

The binaural room impulse response (BRIR) can be used to study the perception of room acoustics and consists of different parts such as the direct sound, early and late reflections, and a diffuse reverberant tail. For this study, the contribution of early reflections to several perceptual attributes was investigated. For this purpose, the strength of the early reflections of recorded BRIRs were either increased or decreased. The resulting BRIRs as well as the original BRIRs have then been convolved with anechoic music signals to obtain the stimuli that were presented to the subjects in a psychoacoustic experiment. The subjects had to rate the spatial impression of these manipulated and none-manipulated signals for the perceptual attributes “Listener envelopment,”” Apparent source width,” “Distance” and “Presence.” In addition to determining the influence of manipulated early reflections on the spatial impression of a room, also a comparison was made with the perceptual effect of an artificial increase of the interaural cross-correlation. Results indicate that the perceived source width increases with increasing level of the early reflections. The effect of the level manipulations on the listener envelopment seems to be small compared to the influence of the cross-correlation.
Changes in the acoustical requirements of the 2014 editions of the Facility Guidelines Institute's Guidelines for Designand Construction of Hospitals and Outpatient Facilities and its reference document Sound & Vibration Design Guidelinesfor Health Care Facilities
Authors: Horan Daniel M.
Published: May 2014

Acoustical design criteria for health care facilities as defined by the FGI Guidelines have been updated in the recently published 2014 edition. Sound & Vibration Design Guidelines for Health Care Facilities (S&V3.0) serves as the sole acoustical reference for the FGI Guidelines and has also been updated as part of the 2014 FGI cycle. The S&V reference is authored and edited by the FGI's acoustical working group. The secretary of this group (Horan) will summarize these changes and will also discuss the public review and comment process that led to the updated Guidelines. This same process will be used in the forthcoming cycle in preparation for the 2018 edition(s).
Evidence based design for improved patient experience
Authors: Miller Melinda , Van Wyk Kenric , Murphy Kristen
Published: May 2014

In addition to the health benefits of improving acoustical comfort for patients and staff in healthcare environments, there is now a financial incentive. Since October 2012, Value Based Purchasing reimbursements of Medicare from the Federal Government is dependent in part upon Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) patient satisfaction survey results, which includes a rating for the noise level at night. This study explores the relationship of sound level with their associated patient satisfaction scores from hospital noise surveys performed by Acoustics By Design. The noise study results are presented across different parameters such as the type of patient unit, patient noise levels, nurses’ station noise levels, time of day, and private versus semi-private rooms. Measurements were also performed prior to and after completion of acoustical/noise mitigation.
The effect of implementing an electronic sound masking system into a 42-bed oncology unit on “quiet at night” Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores
Authors: Madaras Gary
Published: May 2014

In December 2012, the facilities personnel at a major New York medical center used a donation to install an electronic sound masking system in the patient rooms of a 42-bed oncology care unit. Monthly top-box scores for the unit’s ‘quiet at night’ HCAHPS question as reported by Press Ganey for the years preceding and succeeding the installation will be provided and discussed. Other observations based on staff interviews, personal listening, and acoustical measurements will be provided.
International harmonization of approaches to define underwater noise exposure criteria
Authors: Lucke Klaus , Winter Erwin , Lam Frans-Peter , Scowcroft Gail , Hawkins Anthony , Popper Arthur N.
Published: May 2014

An international workshop was held in 2013 with a group comprised of scientists, regulators, and other stakeholders. The workshop focused on how new scientific information related to the effects of underwater noise on marine life influences permitting practices for human activities at sea. Also discussed were how individual countries regulate underwater noise and opportunities for harmonizing approaches on an international scale. The workshop was intended to build momentum toward an international exchange of information and to potentially establish a network for the regulation community. Large gaps in knowledge still exist. In particular, hearing sensitivity in baleen whales, long-term effects of TTS and relevant information on other taxa such as bony fishes, sharks, or invertebrate species, need to be studied more intensively. Regulators need reliable and understandable baseline information on cause-effect relationships. This information could be partially provided through targeted training material for regulators. Another critical regulator need is for opportunities to speak with each other and share knowledge across wide geographic regions. Additional keys to future success are commitments from the regulatory senior management and politicians, invite nations who were not represented in the discussions so far and raise awareness of this topic across a broad audience, including the public.
Aircraft dose-response relations for day-use visitors to backcountry areas in National Parks
Authors: Rapoza Amanda , Sudderth Erika , Lewis Kristin , Lee Cynthia , Hastings Aaron
Published: May 2014

The Federal Aviation Administration and National Park Service conducted joint research to better understand visitor response to noise from commercial air tour operations over units of the National Park System. Dose-response relationships developed for heavily visited, frontcountry sites in National Parks showed significant differences in responses between visitors to overlook and short-hike sites, suggesting that activity and visit duration are key influences. An extensive recently collected dataset from backcountry day-use visitors was utilized to further explore these and other influences on dose-response relationships. In this second of two papers on this research, we describe the model-fitting approach used to identify the combination of noise exposure metrics (dose variables) and mediator variables that best predict visitor responses to aircraft noise. The interpretation and application of the best fit model is presented along with the previously developed front-country model. Such dose-response relationships can be used as a tool for evaluating potential impacts of air tours on visitors to National Parks.