bluuebunny/crossref_metadata_2025 huggingface dataset:
Creative collaborations in the design of buildings
Authors: Siebein Gary W. , Paek Hyun , Roa Marylin , Siebein Keely , Miller Jennifer R. , Vetterick Matthew , Siebein Gary
Published: April 2018

Integrating acoustical design features in rooms that fulfill acoustical, architectural, mechanical, and other functions simultaneously requires close collaboration among design team members. The efforts involved each team member understanding the other disciplines to the extent that they could creatively interpret the work. Three case studies will highlight the advantages of this type of collaboration. Full size mock-ups, computer modeling, auralizations, and other advanced design tools assist in this process. The first is a wall panel in a large museum that is used as a spatial divider, a sound attenuating return air plenum, and a surface for exhibiting artwork. A multi-function atrium was used as the central organizing feature in another museum. Design efforts explored how sounds propagated from one level to the next could be reduced. Multi-functional, layered wall assemblies that contained variable acoustic features, sound diffusing/reflecting panels, supply and return air distribution and layers to reduce sounds entering the building from the exterior were used in the renovation of a college theater. Multiple iterations of acoustical, architectural, mechanical and interior design efforts followed by intense analysis and discussion proved very rewarding for the design team with beautiful looking and sounding spaces.
New sound system design in concert halls
Authors: Ahnert Wolfgang
Published: April 2018

In 2017, two concert halls have opened in Germany, in January Hamburg’s Elb-Philharmonic Hall and in Dresden the concert hall inside the existing Kulturpalast. The presentation will report briefly about the history and development of both projects. The sound systems in both halls must serve as an announcement system but also in case of emergency as a Speech alarm system according to the German standard DIN VDE 0833-4. For both halls, the target values of Speech Intelligibility have been developed and the design approach for the needed sound systems is explained in the presentation, not only for the halls but for the partially complicated lobbies too. The excellent architectural design of the two halls led to many problems to ensure the required performance of the speaker systems, but to hide their physical visibility. An influential issue was here the interaction with the existing room-acoustic parameters in both facilities. With high reverberation values and expected high noise floors in case of emergencies the limits of needed speech intelligibility had been reached very fast. This interaction will be discussed and simulation and some measurement results are given.
Comparative analysis of resilient and dense materials in lightweight construction for impact sound attenuation
Authors: Harkin Sean , Watrous Jacob , Schnitta Bonnie , Scinto Jennifer
Published: April 2018

Resilient underlayments are commonly utilized as a primary method of reducing footfall noise in architectural acoustics. Although resiliency is a large component of a partition’s footfall performance, as well its ability to achieve higher AIIC ratings through ASTM E1007 AIIC testing, adding resiliency alone does not always address all of the frequencies which cause disturbances due to footfall. Particularly in lightweight construction, the density of the configuration is also a critical component of a successful solution. Due to the lack of sufficient mass in lightweight construction materials, successful treatment for impact noise disturbances in lightweight conditions becomes more difficult to achieve. This paper compares data with different flooring configurations in mock-up ASTM AIIC testing conditions in order to evaluate advantages and disadvantages of ANISPL (Absorption Normalized Impact Sound Pressure Level) performance in different frequencies. Resiliency and density are added in varying combinations in a wood frame construction in order to better understand their relationship to AIIC ratings and a partition’s success in impact noise insulation.
Acoustic interactions between plants and animals
Authors: Schöner Michael G. , Schöner Caroline R.
Published: April 2018

Acoustic communication and reactions to acoustic cues are widespread and intensively studied in animals but have largely been neglected in other organisms such as plants. However, there is growing evidence for acoustic communication in plant-animal interactions. While knowledge about active acoustic signaling in plants (i.e. active sound production) is still in its infancy, research on passive acoustic signaling (i.e. reflection of animal sounds) revealed that bat-dependent plants have adapted to the bats’ echolocation systems by providing acoustic reflectors, which attract mutualistic animal partners. Studies also show that plants are able to perceive sound and thus, potentially can react to animals (e.g., physiologically). Moreover, in the course of evolution plants should become acoustically more attractive to mutualistic animals that find their plant partners based on sound and less conspicuous to parasites. The current challenge is to discover further examples of plants and animals that acoustically interact with each other. Understanding the underlying proximate mechanisms and ultimate causes of acoustic communication will shed light on an underestimated dimension of information transfer between plants and animals.
Acoustic sensing of macroalgae (kelp) for large-scale marine biomass production
Authors: Fischell Erin M. , Lavery Andone C. , Kukulya Amy , Stanton Timothy K.
Published: April 2018

An important component of the future use of large-scale offshore farms to grow macroalgae (kelp) will be remote monitoring of infrastructure, the environment, and plant health over areas so large that manual inspection is not practical. A new program, the Advanced Research Projects Agency-Energy's Macroalgae Research Inspiring Novel Energy Resources (ARPA-E MARINER), has the long-term goal of domestic energy production using biofuel derived from macroalgae. As part of that program, an integrated sensing system is being developed for unmanned underwater vehicle (UUV) monitoring of infrastructure, macroalgae growth, water properties, and associated organisms in experimental offshore macroalgae farms occupying areas square kilometers in size. A critical component of this monitoring system is acoustic sensing using a split-beam sonar system. Time-of-flight and volume backscattering data from the echosounder will be used to determine the thickness of growth and percentage volume inhabited of macroalgae. The objective is to provide a map correlated to biomass distribution variability across the farm area. Data will also be collected on aggregations of fish and zooplankton both within and outside the farm. Early results from local tests on sugar kelp will be presented, including initial research into the correlation between these acoustic data and biomass.
Effect of carbon content on sound speed and attenuation of sediments in seagrass meadows
Authors: Venegas Gabriel R. , Aslan Aslan , Hinson Ivy M. , Rahman Abdullah F. , Lee Kevin M. , Ballard Megan S. , Sagers Jason D. , McNeese Andrew R. , Dubin Justin T. , Wilson Preston S.
Published: April 2018

Globally, seagrass-bearing sediments contain 19.9 billion metric tons of carbon (C), and account for 10% of all organic C buried in the ocean each year. Protection of these C stores is vital in mitigating climate change [Fourqurean, J. W., et al., Nature Geoscience 5, 505–509 (2012)]. Some sediment acoustic properties are sensitive to the presence of gas bubbles entrained in such C stores due to inherent anaerobic decomposition. Measurement of these properties could therefore provide a means to indirectly monitor C stores and overall seagrass meadow productivity. As a preliminary effort to investigate the relationship between C content and acoustic properties of seagrass-bearing sediments, cores were collected in the seagrass meadows of Lower Laguna Madre, Texas. Sound speed and attenuation from 100 kHz to 300 kHz were measured radially in 2-cm-depth increments. The cores were subsequently frozen, sliced along the same depth increments, and their C content estimated using an elemental analyzer. Acoustic properties were compared with C content along the depth of each core. The potential for sound speed and attenuation of seagrass-bearing sediments to be used as a metric for monitoring seagrass meadow productivity will be discussed. [Work supported by ONR and ARL:UT IR&D.]
Geacoustic inversion using autonomous underwater vehicles
Authors: Lin Ying-Tsong , Pallayil Venugopalan , Fischell Erin
Published: April 2018

Autonomous underwater vehicles (AUV's) are valuable for bottom geoacoustic studies because they can remain in close proximity to the seafloor, maneuver accurately along underwater tracks, and perform multi-platform operations. A REMUS 100 AUV was deployed in the recent Seabed Characterization Experiment, sponsored by the Office of Naval Research (ONR) and conducted in the New England Mud Patch Area from March to April 2017. This AUV was equipped with a sound source transmitting acoustic chirp signals from 800 to 1300 Hz and a 20 m-long digital thin line towed array (DTLA) receiving both the AUV source signals and acoustic signals transmitted from different sources. The AUV track was along a path between a moored source and a fixed receiver sled. With this experimental configuration, three different geoacoustic approaches were investigated: (1) bottom reflection inversion using the AUV source and the towed DTLA, (2) range dependent broadband acoustic inversion using the moving AUV source and the fixed receiver, and (3) range average broadband inversion using the moored source and the fixed receiver. To keep a precise time base, Chip-Scale Atomic Clocks (CSAC's) were utilized in the AUV source, the moored source and the fixed receiver, and the DTLA is synchronized to the AUV source via high-resolution acoustic interrogations. The inversion results will be presented, along with discussions for future work. [Work supported by ONR and ONRG.]
Gradient-based Bayesian geoacoustic inversion for sediment properties at the New England mud patch
Authors: Belcourt Josée , Dosso Stan E. , Holland Charles W. , Dettmer Jan
Published: April 2018

This paper presents nonlinear Bayesian inversion of wide-angle seabed reflection-coefficient data for fine-grained/cohesive sediments recorded in the ONR Seabed Characterization Experiment at the New England mud patch. The inversion is applied to high-resolution broadband reflectivity data from a site characterized by smooth bathymetry and a thick mud layer. Since smooth, continuous gradients in seabed properties are common for low-speed mud layers, this work develops a Bayesian inversion based on a Bernstein-polynomial representation of sediment geoacoustic profiles. The gradient-based Bernstein-polynomial inversion is compared to a trans-dimensional inversion which samples over profiles defined by an unknown number of discrete seabed layers. [The research was funded by the Office of Naval Research, Ocean Acoustics Program, and the Canadian Department of National Defence.]
End-fire synthetic aperture sonar for seafloor volume scattering studies
Authors: Steele Shannon-Morgan M. , Lyons Anthony P.
Published: April 2018

Acoustic returns from seafloor sediment are comprised of scattering from both the interface and sediment volume. Although volume scattering is often the dominant mechanism, direct measurements of this component have rarely been made, if at all, due to interface roughness biasing. This bias is especially prevalent at lower frequencies where beam widths are typically 30–40 degrees. Current synthetic aperture sonar (SAS) systems are side looking and achieve narrow beam widths by coherently combining multiple acoustic pings as the sonar moves. End-fire (forward-looking) SAS would formulate a synthetic array in the same direction of travel by vertically orienting a transducer and lowering it towards the seafloor while pinging. This would create a narrow beam, significantly reducing the interface roughness bias. End-fire SAS array gains are not as substantial as conventional side-looking SAS. However, beam pattern simulations suggest the gains are still significant: a synthetic array length of 100 wavelengths can reduce a sub-bottom profiler’s 40 degree beam width to 7 degrees. This talk will discuss proof of concept, motion controlled experiments performed in an acoustic testing tank and in the field.
Estimation of parameters of gassy layer in sediment in shallow water using measurement of angular dependence and spectrum of reflection coefficient of wide-band signals
Authors: Katsnelson Boris , Lunkov Andrey , Uzhansky Ernest , Ostrovsky Ilia
Published: April 2018

Method of estimation of gassy layer parameters in sediment (sound speed and thickness) on the base of measurement of angular and frequency dependencies reflection coefficient of wideband signals is presented. Experiments were carried out in Lake Kinneret (Israel), which is characterized by remarkable organic content in sediment producing methane bubbles. Direct chemical, biological analysis and usage of frozen cores show comparatively narrow layer (a few tens of cm) changing in dependence on season. Principal point for acoustical method is low sound speed in bubble layer (up to 300–400 m/s) and big reflection coefficient from the corresponding half-space (0.6–0.7 for vertical incident). Due to narrow gassy layer, there should be half wavelength resonances at the corresponding frequencies. In experiments, wideband signals were used (500–2500 Hz) and receiving system: single hydrophone (1 m from source) and vertical line array. Estimation of layer’s parameters was carried out using measured reflection coefficient as a function of frequency and angle of reflection. Resonance frequencies were 800 Hz and 1600 Hz. The corresponding analysis of data give values of thickness 25–30 cm, with the sound speed in layer 400–450 m/c. Results are compared with experimental data obtained by direct measurements. [Work was supported by ONRG and ISF.]
Comparison of conventional transducer and refracto-vibrometry measurements of ultrasonic transmission parameters from heel bones
Authors: Huber Thomas M. , Mehrkens Matthew R. , Rorem Benjamin A. , Huber Matthew T. , Hoffmeister Brent
Published: April 2018

Ultrasonic measurements of the heel bone (calcaneus) are used commonly for osteoporosis screening. Ultrasound pulses that pass through the calcaneus are detected with a receiving transducer. Parameters, such as normalized broadband ultrasound attenuation (nBUA) and speed of sound (SOS) calculated from the wave forms detected by the receiving transducer, are utilized to assess bone health. In the current study, refracto-vibrometry (RV), an interferometric method for optically measuring ultrasound, was compared with conventional transducer measurements of ultrasound transmission in-vitro through a human calcaneus sample. The measurement beam from a Polytec PSV-400 scanning laser Doppler vibrometer was directed through a water tank towards a stationary retroreflective surface. Acoustic wave fronts (density variations) which pass through the ~50μm diameter measurement laser cause variations in the integrated optical path length. The signals detected by the vibrometer at numerous scan points were used to determine the time evolution of ultrasonic wave fronts. Because there is not a physical receiving transducer, the RV measurements do not experience the same frequency response and reflection artifacts of conventional transducers. Parameters such as nBUA and SOS were calculated at multiple RV scan points, and the results were compared to parameters measured using a conventional ultrasound transducer.
Frequency response simulation of the hybrid dual driver earphone using equivalent circuit model
Authors: Tsai Yu-Ting
Published: April 2018

By combining the multiple drivers into an insert earphone, the special filtering of hybrid dual drivers by earphone structure design can be applied to increase efficiency and the overall output level. In general, the back of the earphone structure lays a balanced armature driver for the mid to high frequency reproduction and a dynamic driver in front cavity creates deeper bass. For this distinctive structure of the earphone, this study proposed a frequency response simulation model using the equivalent circuit model. For the sound transmission between the two ports' structure, the correction factors for obtaining the transmitted impedance of special filter are proposed. The simulated responses shows that a good comparison between the measured result and the equivalent circuit simulation. As a result, the study has significant capacity to estimate the desired frequency response of a hybrid dual driver earphone.
Management considerations for noise impacts on the superior National Forest and Boundary Waters Canoe Area Wilderness
Authors: Taylor Peter , Schwaller Ann
Published: April 2018

The USDA Forest Service-Superior National Forest manages the Boundary Waters Canoe Area Wilderness (BWCAW) and multiple use lands located outside the Wilderness. For the BWCAW, the Forest Service is responsible for preserving wilderness character per Section 4b of the 1964 Wilderness Act. Accordingly, Forest Service managers need to understand the effects of human-generated sound on the soundscapes of the Wilderness when making decisions on if, where, and how to permit management activities to occur. Human-generated sound that may affect the Wilderness has been a consideration in management decisions for timber harvest, snowmobiling, ATVing, minerals exploration, and mining. Further, human-generated sound may also be an issue for recreation users or residents located on multiple use lands outside the Wilderness. We discuss the ongoing need for scientific information to inform decision making on this issue. We also discuss our monitoring efforts and data and analysis needs.
Forecasting increases in recreational value that would result from restoration of natural soundscapes in National Parks
Authors: Fristrup Kurt M. , McKenna Megan F. , Mennitt Daniel J.
Published: April 2018

U. S. National Parks are justly celebrated for the superlative quality of their scenic and cultural resources. The Grand Canyon Enlargement Act of 1975 identified natural quiet as an important resource and value. These considerations are two motivations for extensive monitoring of acoustic environments in national park units, and development of models that predict sound levels throughout the system. These models also estimate the spatial distribution of noise of noise exposure. Related social science research has documented the effects of noise on the quality of visitor experience in parks, including the accessibility of wildlife for public viewing. Surveys of park visitors and the American public also document broad support of park efforts to reduce noise. Collectively, this research provides a quantitative framework for estimating the increases in the quality of visitor experience that could be realized through reductions in noise.
“Listening“ Crowdsourced Sound
Authors: Yildirim Yalcin
Published: April 2018

Bearing in mind the influence of internet based instruments for crowdsourcing, landscape architecture, urban planning, and urban design fields are progressively applying these tools to obtain better notions and alternatives from the community. Such instruments generally provide considerable data about what community desires. In spite of this fact, to the best of our knowledge, crowdsourced intelligence in landscape architecture and urban planning has been studied limited. This research concentrates on University of Texas at Arlington campus soundscape in the heart of 6 million populated Dallas-Fort Worth metroplex to examine the opportunities and applications of performing crowdsourced data. To do this, research team applied mixed methods, the study evaluates the opinions of campus users and determines in which aspects those ideas can be connected to soundscape patterns. After investigating the interviews of campus users, the study integrated the information of perceptions about opinions at the end of the research. The findings emphasizes the challenges, limitations, and opportunities in regard to the landscape architecture, urban planning, and urban design disciplines. It is noteworthy that several circumstances have implications on applicability of crowdsourced knowledge on soundscape.
Social investigation on passersby perception of urban fountain sounds
Authors: Velardi Laura , Hermand Jean-Pierre
Published: April 2018

Running water sounds are among the most pleasant sounds to human ears. Beside natural environments, people experience these sounds in urban environments thanks to fountains. The influence of fountain sounds on passersby has little been explored, especially in situ. This paper presents results from social surveys conducted in Rome and Brussels’ squares for monumental and contemplative fountains as well as modern and participative fountains. Over 70 % of survey respondents qualified the fountain sounds as the most interesting feature of the place, even though the questionnaire did not make any explicit reference to acoustics. For each case study, a comprehensive set of timbre descriptors was applied to audio recordings in the fountain surroundings to characterize sound pleasantness in relation to people’s impressions. Beyond their marked interest for the fountain soundmark, the survey identified people’s preferences in terms of arrangement of fountain surroundings. Such information can be useful to forthcoming urban acoustic design, currently lacking any in depth observation about pedestrian land use related to urban sounds.
Scaling of a gas-combustion infrasound source
Authors: Smith Chad M. , Gabrielson Thomas B.
Published: April 2018

For equal storage pressure, the available energy density from propane-air combustion is substantially higher than the available energy density from expansion of a compressed gas. Ordinary liquid propane is stored at a pressure of about 1 MPa (150 psi). The potential-energy density in air that has been compressed to 1 MPa is about 170 kJ/kg; the combustion-energy density in propane is about 50 000 kJ/kg. In addition, there is a substantial volumetric advantage to propane in that it condenses to a liquid under normal storage pressures. Given the successful demonstration of compressed-gas infrasound sources (Barlett et al., J. Acoust. Soc. Am. 141, 3567, 2017), useful levels of infrasound might also be produced by cycling a burner on and off. Previous work (Smith and Gabrielson, J. Acoust. Soc. Am. 137, 2407, 2015) with a 90 kW propane burner demonstrated the potential for generating infrasound by periodic thermal expansion of the surrounding air and the levels measured were supported by a simple thermodynamic model for the periodic-heating process. In this paper, we describe attempts to scale these results to higher levels by using a liquid-propane burner from a hot-air balloon.
Determining essential scales and associated uncertainties for regional atmospheric infrasound propagation by incorporating three-dimensional weather model forecasts
Authors: Alter Ross E. , Swearingen Michelle E. , Wilson D. K.
Published: April 2018

Understanding infrasound propagation is important for geophysical and military applications. Infrasound signatures can be detected from larger sources such as nuclear detonations and from smaller sources such as bridges, dams, and buildings. Infrastructure sources produce signals of lower amplitude, leading to more regional (up to 150 km) propagation. However, current methods for calculating regional infrasound propagation involve assumptions about the atmosphere, such as horizontal homogeneity, that deviate from more realistic environmental conditions and decrease the accuracy of the infrasound predictions. To remedy this issue, we have interfaced three-dimensional forecasts from the Weather Research and Forecasting (WRF) meteorological model with range-dependent parabolic equation propagation models. To test the improvement of infrasound propagation predictions with more realistic weather data, we conducted sensitivity studies with different propagation ranges and horizontal resolutions and compared them to predictions using simplified meteorological parameters. This allowed identification of the scales most ideal for resolving regional infrasound propagation given the limitations of WRF’s spatiotemporal resolutions. Additionally, we present results on quantifying uncertainty in these infrasound simulations by using multiple realizations of WRF forecasts to generate a spread of possible outcomes. Finally, we compare the simulated results to experimental data. (Approved for public release; distribution is unlimited.)
Otoacoustic emissions: Laboratory studies and clinical applications
Authors: Neely Stephen T. , Rasetshwane Daniel M. , Gorga Michael P.
Published: April 2018

Historically, the clinical potential of otoacoustic emissions (OAEs) to diagnosis hearing status was recognized prior to any consensus regarding their cochlear origin. In retrospect, we now understand refection-generated emissions as being closely aligned with Kemp’s (1980) concept of “cochlear echoes,” while distortion-generated emissions are necessarily tied to nonlinearities in cochlear mechanics. Research at the Boys Town National Research Hospital provided evidence supporting the cochlear origin of OAEs by demonstrating an approximate two-times relationship between an estimate of forward-latency derived from auditory brainstem responses and the round-trip latency of OAEs for tone-burst stimuli. Our application of clinical decision theory to distortion-product OAE levels, based on a large number of both normal-hearing and hearing-impaired ears, helped to establish (1) the validity of using DPOAEs to identify the presence of hearing loss and (2) guidelines for the interpretation of DPOAE levels in the clinic. Our exploration of reflection-generated emissions that we call cochlear reflectance is a continuation of our efforts to further extend the clinical potential of OAEs.
Comparative otoacoustic insights
Authors: Bergevin Christopher
Published: April 2018

“Cochlea wave propagation…” These words started off David Kemp's seminal 1978 contribution to auditory biophysics, where he first described “a new auditory phenomenon” [JASA 64(5):1386-1391]. The impact of this report has transcended numerous disciplines, finding an impressive range of scientific and clinical applications (e.g., monitoring cochlear status to ototoxicity, biophysical models of the cochlea, pediatric hearing screening). One area where this is most readily apparent is the “comparative“ one: It appears that animals all across the phylogenetic tree exhibit robust OAE activity. Given broad morphological differences (e.g., cochlear length, presence/absence of a flexible basilar membrane and/or stereovillar hair cells), a comparative otoacoustic approach offers remarkable potential for identifying universal biophysical principles at play. This talk will compare/contrast OAE properties (and the associated implications) across a broad range of groups such as: humans, birds, frogs, lizards, ferrets, non-human primates, tigers, and even insects. Furthermore, by examining OAEs in species where the traditional basilar membrane traveling wave is absent (e.g., reptiles), we stand to gain biophysical insight into the precise role of “wave propagation.” Taken together, the enormous impact the otoacoustic approach has had towards understanding the biomechanics of the inner ear speaks to the truly profound nature of the “Kempian“ discovery.
The acoustic images in the fields of knowledge
Authors: Gossweiler Peter Francis C.
Published: April 2018

Can we provide different acoustic images, ontologically speaking, from the fields of knowledge? As an engineer that experiences acoustic by processing mathematical calculations (with an evaluative approach), an architect by projecting physical spaces (focusing on audible comfort), an artist by proposing sound enigmas and mind gaps (perhaps proposing an audible discomfort), a musician by dealing with the reflections of his sound making (awaking the pleasure of listening), a religious man by preaching spiritual rituals (addressing a meditative state for his assembled group of people), just to name a few. Thus, our research evokes philosophers such as Martin Heidegger (by the concept of dasein), Michel Certeau (which suggests exercising rebellion in everyday life) and Marie-José Mondzain (with the birth of the homo-spectator, by his desire for images) to point out, with those key operative concepts, outstanding approaches to how we can investigate the internal site specifics of the human being, in his dynamic and unfinished possibilities, the variables of the listening regime on acoustic images in the fields of knowledge.
Observations on the shape of hearing sensations in pure-tone lateralization
Authors: Völk Florian , Encke Jörg , Reimann Diana , Hemmert Werner
Published: April 2018

In certain conditions, especially with diotic headphone presentation, hearing sensations are located inside the head. Dichotic headphone presentation can result in lateralization: delaying one of the headphone input signals or reducing its amplitude typically pushes the hearing sensation inside the head towards the contralateral ear. Systematic connections between physical stimulus parameters and hearing-sensation properties provide insight into auditory-localization mechanisms and are helpful in designing and evaluating models thereof. While various studies on the lateral displacement of hearing sensations exist, fewer data is available on the respective shape or spatial extent. Based on observations from a pure-tone lateralization experiment, this study aims at taking a first step towards quantifying the typical shape of the corresponding hearing sensations: in two separate experiments, twelve normal-hearing subjects reported a) the overall spatial extent of the hearing sensation or, if applicable, of all simultaneously occurring sensations and b) the number of simultaneously occurring, spatially separated hearing sensations. The data suggests, in line with earlier studies, considerable differences between the results for pure interaural phase and amplitude differences, respectively. Based on the results, an initial empirical description of the stimulus-dependent hearing sensations in pure-tone lateralization summarizes the observations, especially regarding location and spatial shape.
A real-time method for computing confidence intervals for trial-based psychoacoustic tests
Authors: Hartl Jakob , Christian Andrew
Published: April 2018

The vast majority of psychoacoustic testing involves presenting a subject with a series of short, simple questions (trials). A common desire is to track the level of statistical confidence in the results after each trial so that one can stop the test once a threshold of certainty has been surpassed. Typically, this certainty statistic will take the form of a confidence interval (CI). Past methods to compute CIs involve assumptions that may impact the performance of the resultant test-stopping criterion. This talk proposes a method to compute CIs that is free of assumptions regarding: the testing procedure used (e.g., up-down staircase, PEST, non-adaptive), the testing modality used (e.g., n-alternative forced-choice, yes/no), and the model psychometric function used (e.g., logit, Gompertz). The method involves a fixed-quadrature integration of the likelihood function of the model parameters given the data retrieved after each trial. The execution time is demonstrated to be low enough so that the method may run during the inter-trial pause. The method is demonstrated for a 3-alternative forced-choice detection task involving two interleaved transformed up-down staircases (between which the data is pooled) using a scaled normal CDF as the model for the psychometric function.
Binaural perception of stereo noise bursts as a function of burst duration and degree of interchannel coherence
Authors: Crawford Steven E. , Bocko Mark F.
Published: April 2018

Amplitude panning for virtual sound source rendering in stereo and multi-channel audio reproduction is well established. Binaural fusion can be represented by vector addition of the acoustic wave propagation vectors from individual speakers; however, this applies only to stereo signals with perfect interchannel coherence and does not provide a description of the perceived sound image when the interchannel coherence is less than complete. Listening tests show that the stereo image formed by continuous incoherent noise fills the space between the loudspeakers; however, for a single short noise burst (a few milliseconds long) the virtual source collapses to a single point in space with its location determined by the position of the maximum of the interchannel correlation function. Concatenation of an ensemble of short noise bursts with a distribution of interchannel correlation function maxima creates a long noise burst displaying a broad peak in its interchannel correlation function; the location and width of which correspond to the apparent location and spread of the virtual sound image. We present a simple model that combines the effective averaging time of the human central binaural fusion mechanism and the interchannel coherence of the stereo signal to predict the spatial properties of virtual sound sources.
Vision-induced reweighting of binaural localization cues
Authors: Ferber Maike , Laback Bernhard , Kopco Norbert
Published: April 2018

Normal-hearing listeners apply frequency-dependent weights when combining the two binaural cues (interaural time and level difference, ITD and ILD) to determine the perceived sound source azimuth. Cochlear-implant (CI) listeners, however, rely almost entirely on ILDs. Since current CI systems do not reliably convey ITD information, CI listeners might learn to ignore ITDs and focus on ILDs instead. We investigated whether this reweighting of binaural cues is generally possible. 20 normal-hearing participants, assigned to two groups, completed an experiment in a virtual audio-visual environment. The experiment consisted of a pre-test to establish the initial ITD/ILD weights, a seven-day training, in which visual feedback reinforced one of the cues, and a post-test to measure the effect of training on the weights. Participants’ task was to lateralize octave-wide bands of noise (centered at 2.8 kHz) containing various combinations of spatially inconsistent ITD and ILD. In both groups, the lateralization bias related to the reinforced cue declined significantly from pre- to post-test, suggesting that participants reweighted the binaural cues in accordance with the visual feedback. These results are promising in terms of making ITD information usable by CI listeners once it is conveyed by the implants. [Support: SpaCI Danube Partnership project, H2020-MSCA-RISE-2015 #691229.]
Toward a visual assistive listening device: Real-time synthesis of a virtual talking face from acoustic speech using deep neural networks
Authors: Chen Lele , Eskimez Emre , Li Zhiheng , Duan Zhiyao , Xu Chenliang , Maddox Ross K.
Published: April 2018

Speech perception is a crucial function of the human auditory system, but speech is not only an acoustic signal—visual cues from a talker’s face and articulators (lips, teeth, and tongue) carry considerable linguistic information. These cues offer substantial and important improvements to speech comprehension when the acoustic signal suffers degradations like background noise or impaired hearing. However, useful visual cues are not always available, such as when talking on the phone or listening to a podcast. We are developing a system for generating a realistic speaking face from speech audio input. The system uses novel deep neural networks trained on a large audio-visual speech corpus. It is designed to run in real time so that it can be used as an assistive listening device. Previous systems have shown improvements in speech perception only for the most degraded speech. Our design differs notably from earlier ones in that it does not use a language model—instead, it makes a direct transformation from speech audio to face video. This allows the temporal coherence between the acoustic and visual modalities to be preserved, which has been shown to be crucial to cross-modal perceptual binding.
Effects of vision, listener head movement, and target location on spatial selective auditory attention
Authors: Macpherson Ewan A. , Ransom Serena
Published: April 2018

Listeners can use spatial selective auditory attention (SSAA) to focus on one talker in a complex acoustic scene. We have reported [Macpherson & Ellis, ASA Salt Lake, 2016] that listeners’ ability to attend to a frontal target in the presence of spatially separated distractors is decreased in a head-movement condition, suggesting that listeners cannot rapidly update the focus of their SSAA to compensate fully for head motion. Participants reported anecdotally that being able to see the target loudspeaker seemed beneficial in directing SSAA. Here, we assessed the benefit of access to a visual reference frame in a similar task. Under lighted and dark conditions, on each trial, listeners either fixated toward 0 azimuth or oscillated their heads at ~0.5 Hz with an amplitude of ~±40 degrees while five different simultaneous equal-intensity sequences of four spoken digits were presented as target (at azimuths from 0 to 90 degrees) and four distractors (at azimuths ±22.5 and ±45 degrees relative to the central target). Listeners verbally reported the target sequence heard. Performance declined under head motion and with increasing target eccentricity, but not additionally in dark conditions, suggesting that a visual reference frame was not beneficial in directing SSAA in our task.
Audiovisual speech detection benefits: A comparison across psychophysical approaches
Authors: Lalonde Kaylah , Werner Lynne A.
Published: April 2018

Visual speech reduces uncertainty as to when auditory speech will occur, thereby enhancing detection of speech in noise. These detection benefits reflect a low-level perceptual mechanism of AV speech enhancement that is independent of the linguistic nature of speech. Audiovisual speech detection benefits have primarily been assessed using two-interval forced-choice paradigms. Results from AV speech detection experiments using three different psychophysical approaches will be presented. These include a single-interval yes/no task, a go/no-go task, and a two-interval forced choice task. In all experiments, adults with normal hearing complete an auditory-only condition with a still image of the talker and an audiovisual condition with a synchronous and congruent visual speech signal. The audiovisual condition includes foil trials/intervals that force participants to use the auditory information to make the decision. Adults demonstrate significant audiovisual benefit to speech detection across all three task, but benefit on the yes/no task depended on the analysis method. Differences in benefit across tasks and signal-to-noise ratios will be discussed. Results of ongoing and planned experiments that aim to isolate the contribution of particular visual temporal cues (onsets, amplitude envelope) will also be presented. [Work supported by NIDCD R01 DC000396, F32 DC015387, and T32 DC005361.]
Modeling binaural detection of a Gaussian noise target in the presence of a lead/lag masker
Authors: Braasch Jonas , Pastore M. Torben , Zhou Yi
Published: April 2018

Recently, we presented the results of a binaural masked detection experiment in which a noise target was temporally embedded within a lead/lag noise masker pair [J. Acoust. Soc. Am. 141, 3639]. The results show that the inter-stimulus interval (ISI) between the masker and its reflection changed the detection threshold significantly. For low ISIs of 2-ms, the average masked detection was -11 dB, but for a greater ISI of 20 ms, the threshold was much higher (-2 dB). In the experiment, masked detection thresholds did not depend on whether the masker lead was on the same side as the target (with the lag on the contralateral side) or the other way round. Different model approaches are presented to simulate the psychophysical results, including a precedence effect (PE) model that was extended using a cepstrum-based method to determine the localization cues for the direct sound of the masker. The PE model is used in conjunction with an EC model and a binaural/monaural detector using optimal frequency-weighting functions that were calculated during the above-threshold conditions during the adaptive experiment. The modeling results show that the PE model is not needed to explain the psychoacoustical results. [Work supported by NSF BCS-1539276 and NSF BCS-1539376.]
A comparison of free-field and headphone based sound localization tasks
Authors: Brichetto Devon , Carlson Brock , Gaston Mary Landis , Olson Thomas , Loebach Jeremy
Published: April 2018

Accurate sound localization is critical for identifying the origin of a sound source and for segregating sources in complex auditory scenes. Sound localization tasks often use free-field presentation of stimuli from a speaker array, or synthetic signals presented over headphones. This study compares localization of ITD and ILD cues presented in the free-field using the SoLoArc (Westerberg et al., 2015), a custom designed speaker array that can systematically present auditory and visual stimuli in a 180-degree free-field environment in both the horizontal and vertical planes, with synthetic ITD and ILD cues presented via headphones. Further, we compared two ways for participants to indicate their response: a manual system where participants pointed a laser at the source, which was identified by a spotter, and an automated potentiometer coupled servo system where the voltage derived from the potentiometer is converted into angular location, allowing the participant to indicate source localization without movement of the head or body. Results indicated that localization in the free-field tasks was significantly more accurate than the headphone tasks for both ITD and ILD cues, and that the automated pointing system was superior to the manual system. Pilot data from the elevation task will also be discussed.
The effects of interaural level differences on binaural fusion in normal-hearing listeners
Authors: Glickman Bess , Oh Yonghee , Reiss Lina
Published: April 2018

Sound localization is an important aspect of auditory scene analysis, allowing listeners to group acoustic components from the same location into a single stream (Bregman 1990). Binaural pitch fusion, the fusion of different frequency tones across ears, can be thought of as one type of auditory streaming. Little is known about how sound localization cues affect binaural fusion. The goal of this study was to investigate the effects of interaural level differences (ILDs), one cue for sound localization, on binaural fusion of dichotic tones. Binaural pitch fusion was measured in adult normal-hearing (NH) listeners, using five ILD conditions: ILD = 0, 1.25, 2.5, 5, and 10 dB. Fusion ranges were measured by simultaneous presentation of reference and comparison stimuli in opposite ears, and varying the comparison stimulus to find the frequency range that fused with the reference stimulus. Preliminary results (5 NH; data collection is ongoing) show that small ILDs increase fusion ranges, while larger ILDs decrease fusion ranges. These findings suggest that ILDs can affect fusion range in NH listeners, and imply that simulated sound source location may provide a top-down grouping cue for binaural fusion. [This research was funded by a NIH-NIDCD grant R01 DC013307.]
Using sports equipment for student exploration of vibration and structural acoustics phenomena
Authors: Russell Daniel A.
Published: April 2018

The familiarity which many undergraduate and graduate students have with sports implements (bats, sticks, clubs, rackets, and balls), renders such objects as suitable subjects for student exploration through laboratory projects and homework problems. This paper will illustrate how problems and projects involving baseball bats, tennis rackets, hockey sticks, and golf clubs can arouse student interests in structural acoustics. Homework problems in which students model the contact time between ball and racket, the frequencies of a golf club shaft, the vibration of the face plate in a golf driver responsible for the trampoline effect, and the radiation of sound from structural modes in hollow and spherical balls provide engaging applications of the theory for membranes, flexural bending in beams, boundary conditions, and radiation. Examples will be shown for using baseball bats, cricket bats, hurling and hockey sticks, ping pong paddles, and tennis rackets in more involved laboratory projects. Sports implements also have the advantage of being non-uniform and asymmetric (wide body and thin handle), non-isotropic (wood grain), or involving complicated geometrics (ellipses) so that students can compare simple theory to more complicated realistic systems.
Demonstrating structural waves in rods/beams
Authors: Sommerfeldt Scott D.
Published: April 2018

Structures exhibit some interesting properties in that multiple types of waves can propagate, and the behavior of those waves is different. This demonstration focuses specifically on the difference between longitudinal waves in rods and bending waves in beams. As used here, rods and beams can be the same structure, in practice, but the terms are used to help distinguish between the particular type of wave propagation. For these wave types, the theory of wave propagation for rods and beams is quite accurate in predicting the experimental response, and can be readily demonstrated if near-ideal boundary conditions are used. This demonstration uses a rod/beam that has free-free boundary conditions. For longitudinal waves, the resonances of the rod should be perfectly harmonic. For bending waves, the resonances of the beam are unevenly spaced due to the dispersive nature of the bending waves. It will be shown how the results from a simple experimental apparatus match theory very well, and how the two types of structural waves are consistent with each other. This good agreement between theory and experiment can help reinforce these wave concepts in the minds of the students.
What does it mean for a voice to be “normal?”
Authors: Kreiman Jody E. , Auszmann Anita , Gerratt Bruce R.
Published: April 2018

It is rather unclear what is meant by “normal” voice quality, just as it is unclear what is meant by “voice quality” in general. A clearer understanding of what listeners perceive as normal and what strikes them as disordered would benefit both clinical practice, for which a normal sound is presumably the goal of treatment, and the study of voice quality in general. To shed light on this matter, listeners heard 1-sec sustained vowels produced by 200 speakers (100 male and 100 female), half of whom were recorded in the clinic (ranging from mild to fairly severe pathology) and half of whom were UCLA students with no known vocal disorder. Listeners compared 20 voices at a time in a series of sort-and-rate trials, and ordered them in a line according to the severity of perceived vocal pathology. Any voices perceived as normal were placed in a box at one end of the line. Preliminary results indicate that listeners agreed fairly well about which voices were not normal, but not at all about which were normal. Implications of these findings for evaluation of voice in and out of the clinic will be discussed. [Work supported by NIH and NSF.]