bluuebunny/crossref_metadata_2025 huggingface dataset:
Multilevel modeling and regression as applied to community noise annoyance surveys
Authors: Wilson D. K. , Wayant Nicole M. , Nykaza Edward T. , Pettit Chris L. , Armstrong Chandler M.
Published: June 2017

Tolerance to noise varies between communities, and between individuals comprising the communities. A multilevel modeling approach is useful for capturing such individual- and community-level variations. Here, we consider a model in which the community-level variations are sampled explicitly with community noise surveys, while the individual-level variations are sampled only in a statistical sense (i.e., hidden). The community-level variations are specifically quantified by the community tolerance level (CTL) [Fidell et al., J. Acoust. Soc. Am. 130(2), 791-806 (2011)]. Simulations based on the multilevel model indicate that the community- and individual-level variations have distinct statistical signatures, both of which are evident in noise annoyance surveys involving transportation noise. The annoyance curve for a previously unsurveyed community depends on the mean and variance of the CTL, and the sum of the hidden variances in noise tolerance and exposure among individuals in the community. Regression analyses of transportation noise annoyance using a multilevel, generalized linear model (GLM) enable noise tolerances and their variations at the two model levels to be distinguished and quantified.
Prediction of various sonic boom signatures observed in large scale experiment
Authors: Kanamori Masashi , Takahashi Takashi , Makino Yoshikazu
Published: June 2017

Results of predicting sonic boom signatures observed in D-SEND#2 flight test are presented in this study. D-SEND#2 flight test was held in northern Sweden in 2015 in order to demonstrate JAXA’s low-boom design concept. The flight test provides three kinds of waveforms: conventional N wave, diffracted U-shaped waveform, and the low-boom waveform. In this study, the method of predicting one or more waveforms above will be introduced.
The importance of attentive listening
Authors: Harris. Andrew S.
Published: June 2017

We all live in a world full of sounds. During my life, I have been aware of the sounds around me. Until I was about 23 years old, I experienced many noise environments and tried to remember how they sounded, but did not have any knowledge of acoustics. My knowledge of acoustics began when I took Bob Newman’s architectural acoustics courses at MIT. It continued with work at BBN. Bob used examples of sounds, to illustrate his teaching. Bob stressed the importance of listening carefully and remember what you heard. If you need to analyze noise environments, it vitally important to listen very carefully and to remember the sounds. Always participate in noise measurements if you are responsible for reporting the noise and recommending noise reduction treatments. During the 55 years since I began studying acoustics, there have been many changes in the issues we face. Focusing on the importance of careful listening, this paper will consider major sources of changes in the outdoor noise environment, i.e., increased numbers and kinds of sources; increased levels of activity; and increased desire for quiet.
Modelling the transmission of ultrasound pulses through grain-to-grain contacts
Authors: Van Damme Bart
Published: June 2017

Wave propagation through packed spherical particles is characterized by two distinct mechanisms, depending on the frequency of the wave content. Coherent wave pulses occur when the Hertzian contact model can be used, i.e., for frequencies low enough so that the granules behave as rigid bodies. Above a certain frequency, a chaotic time signal is the result of diffusive energy transmission through the grain contacts. This so-called coda wave is important for applications tracking the microstructure of materials, e.g., in nondestructive testing. This work looks for parallels between the two approaches by investigating the transmission of short ultrasound pulses in the unit cell of a granular material: two spheres in contact. Laser measurements on two identical large steel spheres show that the energy transmission happens in discrete steps, due to guided surface waves. The measured and modeled energy distribution evolution are similar to the one predicted by the diffusive theory. However, we show that the Hertz contact law can be applied locally in the region of the contact to quantify the pulse transmission, despite the fact that the entire sphere no longer behaves as a rigid body. This approach allows for the design of a configurable non-linear waveguide.
Numerical simulation of key linear alternator performance indicators under thermoacoustic-power-conversion conditions
Authors: Abdelwahed Ahmed Y. , Ibrahim Essawey A. H. , Abdel-Rahman Ehab
Published: June 2017

Thermoacoustic power converters consist of thermoacoustic heat engine and linear alternator. The linear alternator converts the acoustic power generated by the thermoacoustic engine to electric output. Efficient and stable operation of a thermoacoustic power converter requires acoustic matching between the engine and the alternator. It also requires matching between the linear alternator and the connected load. An experimental setup was built to measure and analyze the linear alternator performance under different thermoacoustic power converter operating conditions. The effects of the different design and operation factors on the key linear alternator performance parameters such as mechanical stroke, the generated electric power, the acoustic-to-electric conversion efficiency, the mechanical motion loss, the electric loss, and the fluid-seal loss were investigated experimentally and numerically. The experimental results were simulated using DeltaEC and reasonable agreement was obtained.
Improving infrasonic location estimates for underground nuclear explosions Improving infrasonic location estimates for underground nuclear explosions
Authors: Dannemann Fransiska K. , Blom Philip , Park Junghyun , Marcillo Omar , Stump Brian W. , Che Il-Young
Published: June 2017

Infrasound data from underground nuclear explosions conducted by North Korea in 2006, 2009, 2013 and 2016 were recorded on six seismo-acoustic arrays co-operated by Southern Methodist University (SMU) and the Korean Institute of Geosciences and Mineral Resources (KIGAM). No infrasound signals were observed during the 2006 test, while signals from the others have been used to determine event locations and yield estimations. Prior location studies have demonstrated that wind corrections for back azimuth deviation improve location estimates. Additionally, recent improvements to the Bayesian Infrasonic Source Localization (BISL) methodology have shown to reduce 90% confidence contours for location by 40% through the utilization of propagation-based likelihood priors for celerity and backazimuth deviation from seven years of archival atmospheric specifications. Relocations of the 2009, 2013 and 2016 nuclear explosions will be presented to demonstrate the application of BISL to underground nuclear explosions.
Bianisotropic acoustic metasurfaces for independent control of reflection and transmission wave
Authors: Cho Choonlae , Park Namkyoo
Published: June 2017

We propose bianisotropic acoustic metasurfaces which manipulate reflection and transmission wave-front independently. We design one-dimensional bianisotropic meta-atom controlling density (ρ), inverse of bulk modulus (B-1) and bianisotropy (ξ) near zero-index point in water, based on separation of characteristic oscillations. Through derivation of the density, bulk modulus and bianisotropy as a function of S-parameters, we show full-access to the reflection and transmission amplitude and phase in the tailored bianisotropic media. Utilizing bianisotropic meta-atom, we numerically demonstrate independent control of reflection and transmission wave. Furthermore, design process of the metasurfaces of independent manipulation of forward- and backward- reflection waves is presented.
The contributions of Nathaniel I. Durlach to the study of informational masking
Authors: Kidd Gerald
Published: June 2017

Beginning in the year 2000, Nat Durlach collaborated with our research group on the study of auditory masking and, in particular, the study of informational masking. During this collaboration of more than one and a half decades, Nat's energy, enthusiasm, creativity, and insight provided the stimulus for many research projects and ultimately a variety of publications. These many contributions to our understanding of auditory masking are embodied in journal articles, letters to the editor, grant proposals and papers at scientific conferences. This presentation will review the diverse body of empirical work that Nat drew on to formulate his views on informational masking and the implications of his work on this topic for contemporary auditory theory.
Blocking oblique wave sound transmission through a multi-element barrier using alternate resonance tuning
Authors: Fleming Meredith C. , Bliss Donald B. , Villa Mauricio
Published: June 2017

Alternate Resonance Tuning (ART) utilizes a structural barrier subdivided into dynamic panel subsystems with different resonant behaviors. The underlying idea involves adjacent panel subsystems tuned differently to take advantage of the outofphase vibratory behavior, causing the 180° phase shift at different frequencies. In the intermediate range between the two resonance frequencies, the panels vibrate out of phase, leading to strong cancellation of the transmitted sound field. The method has been demonstrated analytically and experimentally for waves striking a barrier at normal incidence. The current work considers the effectiveness of ART to block the transmission of incident oblique waves, and considers both discrete frequencies and angles, and more realistic broadband random incidence fields. The research goal is to show that flexibility and controlled resonant behavior in subsystems can substantially block sound transmission, even for low structural damping. The subsystems alter the vibrating surface wavenumber spectra to reduce coupling between the structure and the acoustic field. Not only is the transmission of incident oblique waves reduced, but the transmitted and reflected waves radiate at a variety of angles due to the modification of the surface wavenumber spectrum. Applications include the development of lightweight flexible sound blocking barriers for vehicles and architectural spaces.
Reflection and transmission of acoustic energy by an elastic plate with structural discontinuities forced by multiple angle oblique broadband sound waves
Authors: Villa Mauricio , Bliss Donald B. , Franzoni Linda P.
Published: June 2017

An analysis is presented for acoustic reflection and transmission from an infinite fluid-loaded plate with spatially periodic discontinuities. The plate, with similar or dissimilar acoustic fluids on both sides, is excited by an oblique wave incident acoustic field. The fully-coupled structural/acoustic problem is treated by the method of Analytical-Numerical Matching (ANM). The ANM framework separates the problem into global numerical and local analytical solutions, and handles rapid spatial variation around the structural discontinuities in closed form, improving the numerical accuracy and convergence rate. The ANM approach includes a novel way to handle difficulties associated with coincidence frequencies. The periodic spatial discontinuities, modeled by various boundary conditions, create deviations from specular directivity with multiple reflection and transmission angles, the effect being most pronounced at structural resonances. The periodic discontinuities redirect part of the structural energy into reverberant resonant substructures having wavenumbers different from the oblique wave forcing, reradiating with different directivity angles. Discrete frequency and broadband diffuse results are presented. These results are also compared to a baffled finite barrier with a fluid loading correction introduced to the structural wavenumber. The goal is to develop efficient methods for structural-acoustic reflection and transmission of broadband acoustic energy between coupled acoustic domains.
The energy method for solving electroacoustic problems using combining finite element analysis and analytical methods
Authors: Brown David A. , Yan Xiang , Aronov Boris
Published: June 2017

The energy method for solving electroacoustic transducer problems requires calculation of the electrical, mechanical and electromechanical energies of a piezoelectric body from the vibration mode shapes, which are often difficult to obtain analytical particularly with structures having complex boundary conditions. An alternative approach is to determine the vibration mode shapes either experimentally or by finite element analysis and to proceed with computing the energies analytically. The frequency response can then be determined from an equivalent electromechanical circuit approach. An example of this hybrid approach applied to a flextensional transducer will be presented with comparison to experimental results. [Work supported by ONR Code 321.]
Influences on lip-reading ability: Aging, sensory, and cognitive functions
Authors: Dawson Katherine M. , Whalen D. H.
Published: June 2017

To explore the previously reported effect of aging on lip-reading ability, older (60-75 years) and younger (18-35) adults gave oral responses to sentences from a modified version of the build-a-sentence (BAS) test [Tye-Murray et al., Int. J. Acoust., 47(S2), S31-S37, (2008)]. These sentences have predictable syntactic form but contain some words selected from a randomized list of nouns, e.g., ‘The duck watched the cop’. Participants identified these nouns from videos of a single female talker, and responses were transcribed by the experimenter. The 30 participants (15 native English speakers in each age group) were also tested for general cognitive function, vision, hearing, working memory (WM), attention, inhibition, and speech motor ability. They were also asked to gauge their own lip-reading abilities. Preliminary results indicate that the cognitive variables have effects independent of age. Sentence length and syntactic complexity contributed differently in the two age groups, perhaps due to WM capacity.
A bear called Baddington? Variability and contrast enhancement in accented infant-directed speech
Authors: Schertz Jessamyn L. , Buckler Helen , Klammer Chris , Johnson Elizabeth
Published: June 2017

This work examines the realization of the English stop voicing contrast in read speech directed to infants (IDS) and adults (ADS), as well as in words in isolation, as produced by three groups of speakers: native speakers of Canadian English (where /b/ and /p/ differ in aspiration), native speakers of languages in which /b/ and /p/ differ in phonetic voicing (e.g., Spanish), and native speakers of languages which have a 4-way stop contrast /b, p, bʰ, pʰ/, where both aspiration and voicing are contrastive (e.g., Hindi). In words in isolation, speakers from both “accented” groups tended to produce English voiceless stops as unaspirated, and voiced stops as phonetically voiced. However, there was variability in accented speakers’ voiceless stops, as well as in native speakers’ use of phonetic voicing in voiced stops, and this variability appeared to be augmented in the read speech conditions (ADS and IDS). We test the hypotheses (1) that IDS results in phonologically-informed contrast enhancement, with accent-specific modifications expected for the three groups of speakers, and (2) that speakers aim for more precision in phonetic targets when talking to infants, resulting in less within-speaker variability in realization of the contrast in IDS as compared to ADS.
Three-dimensional numerical simulation of sound waves propagating near the west coast of Brittany
Authors: Sturm Frédéric
Published: June 2017

Numerical results of sound wave propagation in a realistic three-dimensional (3-D) oceanic environment are reported. The region of interest is the west coast of Brittany, near the harbor of Brest, France. The numerical simulations were performed running a fully 3-D parabolic equation based code considering omnidirectional point sources emitting at low frequencies (e.g. 50—100 Hz) and located in the water column near the entrance of the strait linking the roadstead of Brest to the Atlantic Ocean (also known as 'Goulet de Brest'). Numerical simulations clearly show that, depending on position of the acoustic sources, sound waves can be strongly affected by out-of-plane propagation effects resulting from complicated multiple reflections off the sloping bottom and channeling effects due to the three-dimensionally varying bathymetry in this particular region, and hence can predict interesting modal arrivals at specific receivers (with typical source-receiver distances of 30 km), not predicted by two-dimensional models. Note that the 3-D effects predicted here for a realistic marine environment are very similar to the ones described in detail for (now classical) benchmark problems (e.g. 3-D wedge and 3-D canyon test cases), though the environmental parameters are different. Several source depths and positions are investigated.
Three-dimensional sound propagation and scattering in an ocean with surface and internal waves over range-dependent seafloor
Authors: Lin Ying-Tsong , Lynch James
Published: June 2017

Underwater sound propagation in an oceanic waveguide can be influenced by environmental fluctuations on the boundaries at the sea surface and the sea floor and also in the ocean interior. These fluctuations can in fact cause three-dimensional acoustic propagation and scattering effects, especially when the horizontal/azimuthal gradients of the fluctuations are significant. Many studies have only been considering individual environmental factor, but the current work presented in this talk is investigating the joint effects by surface and internal waves over range-dependent seafloor consisting of sand waves, ripples, or scours. This scenario represents better the reality in some dynamic areas on the edge of continental shelf (shelfbreak), continental slopes, submarine canyons, and also riverine and estuarine environments. Two research methods are taken here: one is theoretical analysis utilizing acoustic mode theory, and the other is numerical modeling with three-dimensional parabolic-equation models. The frequency dependency of the joint effects will be analyzed, as well as the dependencies on the source and receiver positions, acoustic mode numbers, and/or ray angles. Numerical examples of underwater sound propagation and scattering with realistic environmental conditions will be presented with statistical analysis on the temporal and spatial variability. [Work supported by ONR.]
Encomium For Antonio Pérez López
Authors: Taroudakis Michael
Published: June 2017

EAA AWARD for contributions to the promotion of Acoustics in Europe
Archaeoacoustics of Mexico City's cathedral
Authors: Ramos-Amezquita Alejandro , Padilla Pablo , Jaramillo Ana M. , Boren Braxton B. , Caro Guadalupe , González Julio , Mendoza Victor H. , Salazar Francisco , Pérez Gabriela , Rivera Alberto , Tápia Rodrigo , Paz Carlos , Zamudio Jezzica
Published: June 2017

We consider the acoustics of the architectural design of Mexico City's Cathedral. Using measurements of the impulse response of the building and a virtual reconstruction of the architectural space, the reconstruction of the soundscape is developed with statistical and geometric methods and a standard computational platform (EASE). This reconstruction and contrast of experimental and simulated results allow to pose meaningful hypotheses related to the acoustical functionality of this temple, which played and continues to play a significant role in the religious and social activities of the country. We also present possible connections with other architectural, historical, and musicological aspects.
Acoustics in Dalby church in Middle Ages and today
Authors: Bard Delphine
Published: June 2017

The subject for the research is Dalby church in Sweden which supposes to be the oldest stone church in Scandinavia. There are holes in the ceiling of Dalby church. Behind these holes are ceramic pots. In Swedish Musicology studies, the relationship between acoustic pots and acoustic resonators is poorly documented. Similarly, there is limited information on the difference in reverberation time in churches from late Middle Ages compared to present time. In the late medieval churches, the reverberation time must have been different than it is in churches today. There were more visitors and they had clothes made of heavy fabrics which would have affected the reverberation time. Currently, the reverberation time measurements are made without visitors which affect the reverberation time itself. This investigation is based on theoretical studies combined with practical reverberation measurements in Dalby church and simulations in ODEON in a 3D-model of the church. Following questions will be answered: What was the difference in reverberation time in Dalby church in late Middle Ages compared to present time? What's the contribution of ceramic pots to reverberation time, speech transmission index, or speech intelligibility?
The contribution of human sciences to the interpretation of the use of acoustic pots in France and in bordering countries from the 12th to the 17th century
Authors: Valiere Jean-Christophe , Bertholon-Palazzo Benedicte , Carvalho Pauline , Dupuy Estele , Fiala David , Zara Vasco
Published: June 2017

In occidental Europe, the technique of inserting acoustic pots in churches’ walls spread from the 12th to the 17th century. Acousticians consider this technique as a pre-scientific anticipation of Helmholtz Resonator. This point of view has been questioned by numerous authors, especially in the domain of historical sciences with solid arguments. Based on one of the largest enquiries on French churches with pots achieved these last 15 years by a multidisciplinary team, we propose a scheme of interpretation of this technique taking into account the point of view of archaeologists, musicologists, and linguists and involving experimentation with singers. We show that voice was the target of this technique, by analyzing the frequency of the pots and their positioning in churches in connexion to liturgy. Their symbolic meaning will also be presented in relation to the medieval conception of sciences and music. In the end, the controversial question of a deliberate action on the acoustic of the churches will also be enlightened by the analysis of texts, particularly the vocabulary of French 16th century translation of Vitruvius.
Efficient spatialization techniques for immersive real-time soundscapes
Authors: Azevedo Matthew
Published: June 2017

A simulated soundscape requires many independent sound sources to create an immersive experience. However, the challenges of rendering many simultaneous sources can force a choice between an interactive real-time simulation with limited sources and a static, pre-rendered soundscape with more sources. We will discuss production techniques for optimizing soundscape auralizations to maximize the number of concurrent sources which can be rendered in real time to achieve an immersive level of detail with the potential for a high level of interactivity. Topics covered with include source prioritization, benefits and limitations of various spatialization techniques, including ambisonics, VBAP, and MIAP, and hybrid techniques for independent rendering of direct and reflected sound.
Reduction performance of floor impact sound of the existing apartment buildings in Korea
Authors: Lee Won-Hak , Song Gukgon , Kim Yonghee , Yoon Yongjin , Kim Myung-Jun
Published: June 2017

Recently, the revision of regulation in the Ministry of Land, Infrastructure, and Transport, new apartment buildings are required to construct concrete slabs of 210 mm or more and to ensure floor construction with impact insulation performance within 4th grades. However, in Korea, most of the apartment buildings was constructed with a slab thickness of 120 ~ 180 mm prior to the enactment of the related laws in 2006. There are causing disputes and complaints due to floor impact sound. Therefore, this study investigates reduction performances of floor impact sound in the existing apartment buildings constructed before the effectuation of the legal regulation from Ministry of Land, Infrastructure, and Transport in Korea. Since the regulations were not applied to the existing apartment buildings, understanding of reduction performances of floor impact sound is important for effective redevelopment or retrofit construction process. In this study, field measurements according to KS F 2810-1 and KS F 2810-2 were carried out in the 70 existing apartment buildings. In addition, including 124 data from the literature review, the present state of reduction performances of floor impact sound in the existing apartment buildings was discussed. [This research was financially supported by the Seoul R&BD Program (No. PS150001) through the Research and Development for Regional Industry.]
Measurement, visualization, and modeling of acoustics of a barrel-vaulted sanctuary
Authors: Lai Heather L. , Foote David J.
Published: June 2017

This investigation centers on a recently constructed church with a barrel-vaulted sanctuary ceiling (13.1 m x 12.7 m x 6.0 m) exhibiting excessive reverberation times. An acoustical engineer consulted during design recommended that the original arched ceiling be replaced with a series of flat surfaces constructed to create a similar visual appearance without causing focused echoes. However, due to miscommunication, these recommendations were not incorporated into the construction of the building. Based on complaints of poor speech intelligibility at specific locations, an investigation was made consisting of reverberation time measurements developed from logarithmic sine sweep data and sound pressure level measurements in the diffuse sound field. Reverberation times in excess of 5 seconds in the speech-frequency range were observed at locations along the center aisle, along with correspondingly elevated sound pressure levels. A CAD model of the sanctuary was developed, imported into Odeon and used to simulate the acoustical behavior. Multiple means for visualizing the acoustical behavior are presented, demonstrating how the long reverberation time can be detected in the measured data as well as the models. Odeon analysis of proposed solutions for retrofit of the space to improve intelligibility are also described.
Two research on the effect of interior acoustics on the number of user in library architecture: Metu and Atilim University libraries
Authors: Kocyigit Filiz B. , Lokce Sevgi
Published: June 2017

The library's readership services can be likened to the generosity of the ice mountain. A source goes through many stages until you reach the reader. Therefore, when the library activities and sections are examined, it is seen that different acoustical environments require different functions and spaces. These places include direct or indirect connections and transitions. Acoustic control should be solved by architectural methods in areas where there are continuous, direct connections, and transitions, while the absence of distinct acoustical features in areas with indirect transients does not create a problem. The librarian, the reader, or the user can experience the problem of adapting in transitions between different places, or it can be noisy due to the fact that there are no interrupters between the spaces. Acoustic comfort also does not just mean quiet as it is generally known. It should be able to serve different activities of users and readers and provide psychological acoustic comfort. In interviews conducted with many readers, it has been observed that the complete silent environment creates distrust due to insecurity in mass and wide areas, and thus prevents the desire to stay in the space for a long time. Comfort can be quantified and measured in terms of Articulation Index (AI) or other metrics based on signal-to-noise ratio. In highly reverberant library spaces, Speech Transmission Index (STI) may be more correlative to subjective impression of acoustic comfort.
Auralization of a car pass-by using impulse responses computed with the pseudospectral time-domain method
Authors: Georgiou Fotis , Hornikx Maarten
Published: June 2017

Car noise is the main environmental noise source in the urban environment. In this paper, a method for auralization of a car pass-by in a street from using a wave-based acoustic prediction method is explored. For the transfer paths between sound source locations and a listener, binaural impulse responses are computed with the pseudospectral time-domain method for various source locations. A dry synthesized car signal is convolved with the binaural impulse responses of the different locations in the street and cross-fade windows are used in order to make the transition between the source positions smooth and continuous. The auralizations are performed for the simplified scenarios where buildings are absent, and for an environment where a long building block is located behind the car. A subjective evaluation was carried out in order to detect the maximum spacing between the discrete source positions that still can produce a perceived continuous car pass-by auralization.
The calibration of an aural spatial mapping tool using an architectural approach to the soundwalk method: A validation study
Authors: Barakat Merate A.
Published: June 2017

A series of on-site surveys are conducted as part of the validation process of a research seeking to create a tool that integrates the theoretical spatial and soundscape design concepts, to aid architects when considering sound as a design driver for urban design. The investigation is founded on establishing a relationship between aural architecture theories and the urban spatial experience and design. The surveys are pattern validation experiments that aim to observe possible qualitative aural pattern formations occurring within Covent Garden Market in London by using spatial measurements as fundamental parameters. The method assimilates the Soundwalk technique and the Relative Approach from the fields of soundscape and psychoacoustics, respectively, and are integrated within a customary architectural site-survey proposed to map the sonic morphology of urban spaces. The experiment is designed to compare the tool’s preliminary prediction patterns to in situ listening and the spectral patterns recorded. The patterns are assumed to deviate at this point because not all sound factors are considered, and the patterns are assumed qualitative. However, the discussed comparative process aims to establish value in the current state of this aural mapping tool and establishing the limitations provide an opportunity for further development.
Some effects of microphone format and location on assistive listening system performance
Authors: Mapp Peter
Published: June 2017

Approximately 10—14% of the general population (USA & Northern Europe) suffer from a noticeable degree of hearing loss and would benefit from some form of hearing assistance or deaf-aid. However, many assistive listening systems do not provide the benefit that they should, as they are often let down by their poor acoustic performance. The paper investigates the acoustic and speech intelligibility requirements for assistive listening systems and examines a number of microphone pick-up scenarios and configurations in terms of their potential intelligibility and sound quality performance. The results of testing carried out in a number of rooms and venues are presented, mainly in terms of the resultant Speech Transmission Index (STI) measurements. The paper concludes by providing a number of recommendations and “rules of thumb” for optimal microphone formats and placement. Although the research has primarily been directed towards Audio Frequency Induction Loop Systems, the acoustic aspects are equally applicable to other technologies such as Infrared and Wireless Systems.
Degraded telecoil performance with assistive listening systems
Authors: Chester Ryan T.
Published: June 2017

For more than 50 years, telecoils have been used in hearing aids to bypass the microphone, inductively couple to the telephone receiver, and improve audibility. Because they are widely used in European teleloop systems for public address applications, stringent homologation testing is required before a device is accepted in any government contract. This testing includes benchmarking the performance of their directional nature, frequency response, signal-to-noise, and robustness to orientation within the inductive field. Optimizing a telecoil for one situation usually means degraded signal to noise and reduced bandwidth in other situations. This presentation will discuss susceptibility of telecoils to perform poorly due to environmental factors related to position and orientation.
Technical considerations for assistive listening applications using wireless, digital audio streams
Authors: Burns Thomas
Published: June 2017

Assistive listening applications can be grouped into two categories: public announcements and live reinforcement. Each has unique needs. For public announcements, system temporal latencies of hundreds of milliseconds are irrelevant. For live reinforcement, temporal latencies are much more critical—especially in large venues where the assistive signal must be synchronized with the visual presentation and acoustic performance. If the assistive signal is recorded with the intent to preserve stereo imaging of the performance, binaural latencies are also critical; one millisecond can produce severe comb filtering while tens of milliseconds can produce echo. Digital audio streams take time to encode, transmit, receive, decode, and present to the user. While reviewing the technical requirements for digital audio streaming in this application, and to demo the effect of latency offsets, a G.722 wideband stream will be broadcast within the room to a handful of binaural devices available to the earliest attendees.
Improving the reproduction of an operatic performance in an IMAX cinema
Authors: Ballestero Eric , Dance Stephen
Published: June 2017

In 2016, the Acoustic Group was asked to assist the IMAX cinema in London with the aim of improving the emissive experience of listening to the streamed New York Metropolitan Opera. IMAX cinemas are designed and constructed to meet specific standards they were not built to reproduce an operatic experience. The IMAX cinema at London Waterloo was built in 1999 before streaming was invented; as such it was optimized for the IMAX film format only. Room acoustic measurements were taken in the room in accordance to ISO 3382-1 so that a CATT-Acoustics model of the auditorium could be calibrated. Auralization was then used in the model to create a more immersive operatic experience. A questionnaire was then created so that the settings established from the auralization could be subjectively tested using a two minute clip of Wagner. The paper will report on the results from three of the settings for 15 listeners in the IMAX cinema.
Sound propagation through an aperture with edge diffraction modeling
Authors: Svensson U. Peter , Asheim Andreas , Martín Sara R.
Published: June 2017

The scattering of sound by convex bodies with rigid surfaces can be modeled accurately without any wavenumber restriction using an edge source integral equation (ESIE) [A. Asheim and U. P. Svensson, J. Acoust. Soc. Am. 133 (2013) 3681-3691]. This edge diffraction-based approach has known limitations for non-convex scattering geometries, and the most challenging case might be an aperture in a thin screen. For such apertures, the ESIE predicts that only first-order diffraction occurs because the ESIE has no inclusion of the so-called slope diffraction effect. This effect occurs when the diffraction wave vanishes but its derivative is different from zero. This paper focuses on the low-frequency sound transmission through apertures in screens, as well as into ducts. A reference solution is established with a boundary element (BE) method for the particle velocity field in the aperture, which illustrates the singular behavior near the edges. The field in the aperture is also computed with first-order diffraction modeling. Possibilities to use this first-order diffraction modeling as part of a BE solution are then presented. Such an approach could facilitate that a BE model is used only for a low-frequency correction of the diffraction model.
Are sample rates for wave file recordings too low for transient signals?
Authors: Cooper Steven E.
Published: June 2017

While the concept of higher sample rates is understood for the recording of high frequencies, measurement of infrasound pulsations associated with wind turbines found higher sample rates were required (than normally expected) to reproduce the time signals associated with dynamically pulsed amplitude modulation occurring at an infrasound rate. An assessment of transient early decays in room acoustics found the need for higher sampling rates to capture such transients. Audibly one can detect the difference in such transients. The results of the above investigations are discussed.
Arthur Popper's contribution to bioacoustics
Authors: Meyer Michaela
Published: June 2017

During his research career spanning over 40 years, Arthur Popper has had a profound impact on the field of bioacoustics. He studied a broad range of vertebrate taxa, focusing on fish, but also including amphibians, reptiles, and mammals, and published over 200 papers. His work has improved our knowledge of the morphology of vertebrate inner ears and has made significant advances to our understanding of the evolution of vertebrate hearing. In recent years Dr. Popper has focused his research on the important question of how underwater noise impacts aquatic vertebrate hearing. A long standing and fruitful collaboration with his friend and colleague, Richard Fay, has resulted in numerous scientific papers and nearly 60 books including the well-known SHAR-series of the Springer Handbook of Auditory Research.
Acoustic signaling in fish: Does it contribute to increased fitness?
Authors: Amorim M. Clara P.
Published: June 2017

Animals often use acoustic signals when competing for limited resources. However, knowledge on how vocal behavior contributes to individual fitness in fish lags considerably behind that for terrestrial taxa. Here, I provide examples on how fish acoustic signals may confer an advantage in gaining access to food and mates. Fish sounds provide information on fish motivation and quality which is relevant for mutual assessment during agonistic interactions, such as competitive feeding, and during mate choice. Fish sounds also play a role in synchronizing the reproductive behavior and gamete release to maximize external fertilization. Considering that anthropogenic noise is increasingly changing the natural soundscape that have shaped fish acoustic signals, there is an urgent demand to better understand the importance of acoustic communication for fish survival and fitness.
Popper, Hawkins, Fechner, Weber: Recalling the importance of experimental psychophysics in the study of environmental noise
Authors: Gisiner Robert C.
Published: June 2017

To bring the study of internal experiences into the reach of science, pioneers like Fechner and Weber framed a new branch of science called psychophysics. Current leaders such as Art Popper and Tony Hawkins have illustrated through their research the power of psychophysical methods in parsing a complex external and internal world into lawlike patterns of sensory performance. Recent studies of human influences at ecosystem and global scales have focused increasingly on our ability to use sophisticated statistical methods to analyze large complex data sets collected opportunistically, often without an a priori hypothesis. This celebration of the careers of two leading scientists in this field is an excellent opportunity to remind ourselves of the value of parsing complex phenomena into their constituent parts; framing simple hypotheses for relatively simple statistical analysis; and perhaps most important of all, using experimental methods to minimize sources of bias inherent in the study of internal states not available to direct observation, such as the behavioral effects of manmade sound.
Directional hearing in fishes
Authors: Lu Zhongmin
Published: June 2017

The ability to determine the direction of sound sources is a fundamental function, which has been commonly observed in many vertebrate species in all major groups from fish to mammals. It is well known that terrestrial vertebrates including humans use binaural cues such as interaural time and intensity differences to localize sound sources. However, how fish perform sound localization has been puzzling researchers for many decades since Karl von Frisch. In this talk, I will highlight some behavioral, anatomical and physiological work addressing the question of directional hearing in teleost fishes, primarily focusing on two fish species—the oscar, Astronotus Ocellatus and the sleeper goby, Dormitator latifrons, during my postdoctoral research with Art Popper at the University of Maryland, College Park, and later in my lab at the University of Miami. Most of the studies were conducted using the Fay shaker apparatus that can provide directional stimulation simulating underwater acoustic particle motion in the three dimensional space. Results of this work help us understand behavioral detection ability and peripheral neural encoding of acoustic particle motion in fish.
Professor Ed Carstensen—A personal University of Rochester perspective
Authors: Lerner Robert M.
Published: June 2017

Many contributions to biomedical ultrasound pioneered at the University of Rochester may be traced either directly or indirectly to Ed Carstensen. Armed with strong scientific background in physics, tremendous ability to get along with people and great insight into what was needed to accomplish scientific goals, he was able to help attract great faculty to the University of Rochester across many disciplines, all with interests in ultrasound, to add to the great talent pool already there. Eventually, he formalized the expertise in the Rochester ultrasound community by founding the Rochester Center for Biomedical Ultrasound. This paper provides examples of how Professor Carstensen was able to teach, inspire and lead individuals to seek answers to important questions in the biomedical sciences. His easygoing manner did not detract from his rigorous scientific standards. His ability to facilitate collaboration among physicians, bioscientists and engineers contributed greatly to the phenomenal growth of biomedical engineering and ultrasound at Rochester. Two of the author’s research projects greatly influenced by Professor Carstensen are discussed: (1) the lack of frequency dependence for thermal lesion production in biological tissue by focused ultrasound, and (2) sonoelasticity research which has led to shear wave quantitation and imaging with ultrasound and MRI.
Cavitation nucleation in medical ultrasound
Authors: Crum Lawrence , Bailey Michael R. , Sapozhnikov Oleg , Simon Julianna C.
Published: June 2017

In 1980, Ed Carstensen coauthored the first of several articles on the effects of ultrasound on drosophila [Child, et al., Ultrasound in Med. & Biol., 6, 127-130 (1980)]. As diagnostic ultrasound became an ever-increasing imaging modality, it was important to determine if there were any bioeffects of the relatively high pressure amplitudes, but relatively low time-averaged intensities, used in these systems. Ed and his colleagues discovered that drosophila larvae and eggs, had air channels within them and these channels acted as cavitation nuclei. When it was determined that there were few preexisting gas nuclei present in human tissue, it was assumed that diagnostic ultrasound devices were safe for human use. More recently, therapeutic ultrasound has gained considerable support from the clinical community, and High Intensity Focused Ultrasound (HIFU) systems have been approved for clinical use. Furthermore, ultrasound contrast agents—stabilized gas bubbles—are also in common use. Accordingly, cavitation can be very important in this application of medical ultrasound. Recently, we have examined the source of potential gas nuclei that may give rise to cavitation inception and will report on these studies along with a discussion of Ed’s earlier contributions.
Edwin Carstensen’s unique perspective on biological effects of acoustically-excited bubbles
Authors: Gracewski Sheryl
Published: June 2017

Edwin Carstensen made significant contributions to the understanding of the interactions between ultrasound and biological tissues. He was especially interested in how acoustically-excited bubbles interact with biological systems. In his experiments, sources of these in vivo bubbles included gas in respiratory tubules of fruit fly larvae, ultrasound contrast agents, and gas in murine lung and intestine. While much of Ed’s work was experimental, he had keen insight and a unique perspective for understanding the mechanisms of the bioeffects. He realized that the shear strains in the vicinity of an oscillating bubble could be much greater than they would be if the bubble were not present. Not only was Ed a remarkable scientist, he was also a great mentor. When I first arrived at the University of Rochester, Ed introduced me to the field of biomedical ultrasound and the many outstanding researchers working in the area. It has been a great pleasure and rewarding experience to collaborate with Edwin Carstensen and his student, then close colleague, Diane Dalecki over that last 30 years. This paper will present some of our collaborative work on investigating the response of acoustically-excited bubbles and the stresses and strains induced in the surrounding media.
Defining ultrasound for bio-effects at all frequencies
Authors: Duck Francis
Published: June 2017

Ed Carstensen made pioneering contributions to our understanding of the interaction between ultrasound and living bodies. His observations have been applied to its safe medical use. As human exposure to ultrasound grows, in medical, environmental and industrial contexts, a need is arising for frequency-specific interpretation of bio-effects observations. The International Commission on Non-Ionising Radiation Protection is exploring this issue, which has given rise, for example, to naïve interpretation of low-frequency ultrasound studies, and incorrect application of medical regulations for MHz exposure. A proposal under discussion defines frequency bands for ultrasound in a manner similar to UV radiation. The three proposed bands are: Band A, centered around 100 kHz, for which local forces at gas-liquid interfaces, including cavitation, dominate biological effects: Band B, centered around 10 MHz, for which temperature rise is the dominant bio-effect mechanism: and Band C, centered around 100 MHz, for which many biological effects result from acoustic forces. The frequencies of band boundaries should be agreed by international consensus. Suggested values will be presented and justified. Such a banding structure could serve to improve clarity and avoid obfuscation during bio-effects discussion and to assist in the establishment of improved guidelines and regulations.