bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding diffusion versus scattering devices and how they work
Authors: Lenz Richard L.
Published: July 2024

Nearly 50 years ago, Dr. Manfred Schroeder defined the word “Diffuser” as both a process and a product. Since then, many product manufacturers, acousticians and academics have come to use the term for many different products and designs. A careful reading of Dr. Schroeder's 1975 and 1978 papers reveals a lot of significant information as to why certain products are diffusers and why other products do not meet his criteria for diffusion. This paper will show, with the aid of Schroeder's interpretations and modern particle simulations, exactly what he had in mind when he, and others he was working with, created what ultimately became the Quadratic Residue Diffuser or QRD. Additionally, it will show his journey from primitive-root theory to his final quadratic designs. A discussion of the term “Scattering” will also be included to define how Schroeder uses the word and why we need to be careful as to how it is used as well. Test data showing phase models will be used to show the importance of phase manipulation in describing diffusion.
Musician-led performance perspectives in virtual acoustics
Authors: Zhang Kathleen Ying-Ying , Aydin Aybar , Baran Vlad , King Richard , Woszczyk Wieslaw
Published: July 2024

Musical performance is a complex task that involves juggling performance techniques, creative expression and auditory feedback, all of which in turn affect a musician’s perception of their acoustic environment. Synthesized here are several recent studies conducted at McGill University in variable acoustic spaces: the Multimedia Room (with a Meyer Constellation system) and the Immersive Media Lab (utilizing a proprietary Virtual Acoustics Technology system). In studying the perception of room response, variable acoustic environments allow researchers to physically and/or virtually change the character of a space around a musician without the need for a physical venue relocation. These experiments explore different methodologies and approaches to studying the perception of room acoustic response of various vocalists and instrumentalists who completed both solo and group performance tasks. After contextualizing these studies with previous work done in this area, lessons recently learned point towards new methodologies for musician-led perspectives on room perception.
Residential sound attenuation: Criteria and approaches
Authors: Keefe Joseph
Published: July 2024

A few case studies regarding residential building envelope sound isolation case studies will be presented. The case studies will focus on interior and exterior criteria, measured exterior sound exposure data, and prediction methods/strategies for achieving appropriate wall/window/door/roof sound attenuation values. The presentation will also discuss how to effectively communicate technical and subjective information to project stakeholders.
Using before-after control-impact methodology to quantify effects of full ship shock trial explosions on marine fauna
Authors: Seger Kerri D. , Madhusudhana Shyam , Klinck Holger , Heaney Kevin D. , Boyle John
Published: July 2024

In the summer of 2021, the US Navy conducted a Full Ship Shock Trial (FSST) for the USS Gerald R. Ford. This involved three large underwater explosions off the coast of Florida, USA. We collected underwater acoustic recordings, using low-sensitivity recorders, for the Naval Undersea Warfare Center to validate their underwater acoustic propagation models. We also deployed SoundTraps on the shallow moorings to collect additional acoustical biologics data in hopes of measuring any acoustic responses of marine fauna to the explosions. The acoustic energy of the explosions did not propagate up the continental slope and were hence not captured by the SoundTraps on the shallow moorings. However, our analyses did yield some notable changes in acoustic behavior after as compared to before the explosions. Here, we describe how our field plan was designed for before-after control-impact (BACI) hypothesis testing and discuss our analyses and findings of the few significant cases. These results lend insight for improving the impact assessments and conducting behavioral response studies during a future FSST or other large underwater explosions.
Influence of the liquid ionic strength on the resonance frequency and estimated shell parameters of lipid-coated microbubbles
Authors: Jafarisojahrood Amin , Yang Celina , Counil Claire , Nittayacharn Pinuta , Goertz David , Exner Agata A. , Kolios Michael
Published: July 2024

Measurement of the resonance frequency and shell properties of coated microbubbles (MBs) is important in understanding and optimizing their response to ultrasound. In many applications MBs are in ionic liquids; however, the influence of the medium charges on the MB behavior is not well investigated. This study aims to measure the medium charge interactions with MBs by measuring the frequency-dependent attenuation of the same size MBs in mediums of varying charge density. In-house lipid-coated MBs were size isolated to a mean size of 2.35 μm using differential centrifugation. MBs were suspended in distilled water (DW), Phosphate-Buffered Saline solution (PBS1×) and PBS10×. The frequency-dependent attenuation of the MBs solutions was measured using a system of two aligned 100% bandwidth transducers with 10 MHz center frequency. The MB shell properties were estimated by fitting the linear equation to experiments. With increasing salinity, the frequency of the peak attenuation decreased (13, 7.5 and 6.25 MHz in DW, PBS1× and PBS-10×, respectively) and attenuation peak increased (∼140%). Estimated MBs shell elasticity decreased by 64% between DW and PBS-1× and 36% between PBS-1x and PBS-10x. The estimated shell viscosity reduced by ∼40% between DW and PBS-1× and 42% between PBS-1× and PBS-10×. The significant reduction in the fitted stiffness and viscosity is possibly due to the formation of a densely charged layer around the shell and requires proper inclusion in the related MB models.
A high-resolution ultrafast beamformer for surgical microtransducers
Authors: Brown Jeremy
Published: July 2024

In recent years, ultrasound imaging has become an indispensable tool for intra-surgical guidance. Most neuro and spine surgeries, however, are now trending towards minimally invasive approaches. In these surgeries, the entire surgery is performed using endoscopic instruments inserted into a small surgical pathway. Consequently, surgical imaging technologies such as ultrasound, must also adapt to be compatible with these new approaches where they are confined to narrow surgical corridors. We have recently developed a novel, high-resolution, endoscopic ultrasound system specifically for guiding these minimally invasive surgeries. The entire system including the probe, the electronics, and software has been designed and fabricated from the ground up. This imaging platform has recently been approved for a preliminary patient imaging study has already produced promising, first-of-its kind data during brain tumour resection and spinal cord surgeries. This presentation will discuss the challenges associated with developing high frequency (30 MHz) miniaturized micro-arrays and the associated electronic beamformer. The beamformer we have developed is based on parallelized FPGAs, can process data at rates higher than 10Tb/s, and generate frame-rates higher than 1kHz. The beamforming architecture incorporates a hybrid imaging mode that interleaves ultrafast imaging for Doppler, and line-by-line focusing for B-Mode. The Doppler mode is overlayed on the BMode image in real-time.
Investigation of HIFU beam propagation through acoustic holograms in water
Authors: Krit Timofey , Brecht Luisa , Reinhardt Nina , Lindemeyer Johannes , Grüll Holger
Published: July 2024

We investigated variations in the HIFU beam of a clinical system as it traverses acoustic holograms—small artificial objects of different types—within a tank that was filled in with the degassed deionized water. The pressure distribution within the HIFU beam was assessed in multiple planes perpendicular to the beam axis. The ultrasound transducer with the focal length of 14 cm inside the Sonalleve table top (Profound Medical, Mississauga, ON, Canada) generated the focusing ultrasonic beam, which propagated through the water. Each hologram was positioned 3 cm below the focal plane, with precise adjustments of positions and angles for each measurement. Pressure measurements were conducted using the needle hydrophone HNA-0400 (ONDA Corp, Sunnyvale, CA, USA) mounted on a 3D positioning system. The motors of the positioning system were controlled, and pressure values were recorded using a GUI generated in LabVIEW. The displacement step created by the motors on each axis was 0.01 mm. The properties of the holograms were reconstructed, considering the experimental data obtained. Our findings demonstrated that the shape, size, elasticity, and placement of each acoustic hologram significantly influenced the observed field pattern. This work was supported by the German Federal Ministry of Education and Research (“MR-HIFU-Pancreas”, FKZ:13GW0364D).
Modal reduction for exterior acoustic and vibroacoustic problems
Authors: Marburg Steffen
Published: July 2024

Modal analysis, mode superposition and modal reduction are considered standard approaches for interior acoustic problems as well as for pure vibration problems. Things are different for exterior problems. Only a few methods are known to formulate a linearized eigenvalue problem for unbounded acoustic problems. Even fewer techniques on modal superposition and reduction are found in the literature. This talk will review such techniques which are either based on conjugate Astley-Leis infinite elements or on boundary elements for the unbounded region. While the results appear to be promising, a number of open questions need to be solved in this context. Among others, it is yet unclear which modes are actually required for a modal reduction and how to find a method to just evaluate these modes and the related eigenvalues. The situation is different for vibroacoustic radiation problems with clear resonances. In such cases, a modal reduction is able to substantially accelerate the solution process. Future work might lead to modal reduction using modes from non-linear eigenvalue problems which are known from the numerous papers on the boundary element methods published over the last decade.
Information geometry approach to model reduction
Authors: Spendlove Jay C. , Transtrum Mark K. , Neilsen Tracianne B.
Published: July 2024

Information geometry combines the fields of information theory and differential geometry. In information geometry, a model is interpreted as a Riemannian manifold, referred to as the model manifold, where distance on the model manifold corresponds to statistical distinguishability. Boundaries on the model manifold are reduced-order models where a parameter or parameter combination is taken to an extreme limit and drops out of the model. Therefore, by locating the model manifold boundaries, simpler models with fewer parameters can be obtained. A model reduction algorithm which exploits this insight is the Manifold Boundary Approximation Method, or MBAM, which locates manifold boundaries by calculating geodesics on the surface of the model manifold. This can be done iteratively to find increasingly simple reduced models. We demonstrate this method for model reduction using the Pekeris waveguide transmission loss model. A machine learned surrogate model for the Pekeris waveguide is constructed so that the necessary derivatives for calculating geodesics can be easily obtained using automatic differentiation. [Work supported by the Office of Naval research Grant N00014-21-S-B001.]
History of high-amplitude underwater sound source research at the University of Texas Applied Research Laboratories
Authors: Wilson Preston S. , McNeese Andrew R. , Lee Kevin M. , Rogers Robert L.
Published: July 2024

The Applied Research Laboratories has an extensive history of supporting underwater acoustic research through the development of novel high-amplitude underwater sound sources, such as the Plasma Sound Source (PSS), the Combustive Sound Source (CSS) and the Rupture Induced Underwater Sound Source (RIUSS). These sources generate broadband acoustic pulses capable of long-range propagation and seabed penetration, and can be viewed as alternatives to explosive sources. The PSS is based on the discharge of electrical energy stored in capacitors which results in a plasma bubble. The CSS consists of a submersible combustion chamber, open to the water, which is filled with a combustive mixture that is ignited via spark. Upon ignition, the combustive mixture is converted into high temperature combustion byproducts which expand and ultimately collapse, thereby radiating an acoustic pulse. In this talk, the motivation for alternative impulsive sources is discussed and the PSS is briefly discussed. Next, the early development of CSS, through the end of the 1990’s, is described, which led to the basic understanding of the CSS and the parameters required to modify its output. In the following talk further development of CSS, and the invention of RIUSS, are discussed. [Work supported by ONR and NAVO.]
Pedagogical strategies to enhance learning and awareness of acoustics within our engineering school community
Authors: Doutres Olivier , Rouard Kévin , Lopez Maël
Published: July 2024

Acoustics is taught at the École de technologie supérieure (ÉTS, Montreal, Canada) in a single advanced specialization course during the final year of the mechanical engineering bachelor's program. This course aims to equip students with the skills needed to measure and reduce noise based on the theoretical foundations of industrial acoustics and associated experimental techniques. The fact that the science of acoustics is not well-known among engineering students, coupled with the optional nature of this course, results in an average enrollment of only about thirty students each year (across two distinct sessions), a number further reduced since 2020 due to the unfortunate impact of the pandemic. Paradoxically, Quebec lacks engineers trained in this discipline and often recruits them from abroad. This presentation will aim to showcase various strategies and pedagogical tools that have been used and experimented with in recent years (e.g., flipped classroom, in-class experiments, cellphone measurements, community service-oriented semester projects). The goal is to ensure the quality and enjoyment of student learning and to contribute to raising awareness about acoustics and noise-related issues within the ÉTS community.
Reduced-order equivalent source modeling of aeroacoustic sources
Authors: Dreier Christian , Vogt Xenia , Schröder Wolfgang , Vorlaender Michael
Published: July 2024

The acoustic far-field prediction of high-fidelity aerodynamic simulation data is still not accurately possible when accounting for the surface reflections from an aircraft’s fuselage or wings. By presenting a general method for order-reduced equivalent source modeling of aeroacoustic sound sources, this work is bridging the gap between high-fidelity aerodynamic simulations and its integration to auralization frameworks. At the example of a numerically simulated jet, this study shows the computation of an equivalent source model with minimal complexity by means of spherical harmonic (SH) coefficients. The minimal source extension, in which all acoustic sources of a flow field are confined, is computed by using spherical Hankel extrapolation of sound pressure data from virtual concentric microphone arrays. The result of the SH transform shows that the dominant energy contribution can be associated to nine elementary sound sources. The resulting equivalent source model of jet noise provides a convenient date interface between large-scale computational fluid dynamics and acoustics simulations.
A soundscape perspective for biophilia hypothesis: Theoretical considerations and conceptual approach
Authors: Alimadhi Enkela , Yilmazer Semiha
Published: July 2024

This study proposes a conceptual framework to consider the integration of the soundscape perception into the Biophilia Hypothesis paradigm and to further investigate the positive psychological outcomes such as affection or cognition indicators, and physiological outcomes or neurophysiological outcome indicators based on brain signal analysis on building occupants. The biophilia hypothesis claims that a natural content environment has positive psychological and physiological outcomes identified as restorative. The established soundscape framework, which is still under exploration in indoor environments, will help frame the rationale of this study to understand the soundscape perception and consider how to integrate it into the biophilic theoretical claims. In this line of thought, the conceptual framework emphasizes the significance of not just the visual realm, as suggested by the Biophilia hypothesis paradigm through empirical, experimental, and theoretical claims. Additionally, incorporating sound can contribute to a more holistic approach. To do so, based on an literature review and also on our very preliminary study this conceptual framework is an extension of the soundscape theoretical framework. It proposes the integration of complementary theories such as Attention Restoration, Stress-Recovery Theory, Biophilia hypothesis, and the soundscape framework to be further implemented for healthy designed environments.
Exploring attentive listening in noise through the just-follow conversation task
Authors: Whitmer William M. , McShefferty David , Smeds Karolina
Published: July 2024

Listening to a conversation demands comprehension, attention and prediction. To better understand the impact of these demands, as well as how hearing aids might alleviate them, a conversational listening test should be realistic, repeatable and relatable (i.e., have interpretable units). A test that potentially satisfies these needs is the just-follow conversation (JFC) task, where the listener adjusts the signal level to where they can understand, with effort, the gist of what is being said in a background of noise. Fifty-four participants sat in the centre of a circular loudspeaker array and adjusted the overall level of one monologue, one dialogue, two monologues or two dialogues presented in the front hemifield to where they could just follow the speech four times per trial. Signals were presented in surrounding fixed-level café and same-spectrum noise backgrounds. Bilateral hearing-aid users adjusted aided and unaided; non-users repeated each condition to evaluate reliability. Results showed an increase in JFC for dialogues re monologues. Individual JFC SNRs correlated with SSQ12 speech subscale scores as well as pure-tone threshold averages. JFC reliability was comparable to more objective speech understanding measures, but it may not be suitable to capture perceived conversational benefits for more subtle changes in hearing-aid processing. [Work supported by the UK Medical Research Council Grant No. MR/X003620/1 & WS Audiology.]
Sound absorption analysis of a metamaterial based on parallel dual Helmholtz resonators
Authors: Laly Zacharie , Mechefske Chris , Ghinet Sebastian , Kone Tenon Charly
Published: July 2024

In this paper, a sound absorbing material consisting of four parallel dual Helmholtz resonators is proposed and its sound absorption coefficient is studied using finite element method. The dual Helmholtz resonator is made of neck-cavity-neck-cavity where each neck extends into each cavity. The sound absorption coefficient of the dual resonator presents two resonant peaks. It is demonstrated that when the radius of the first or the second neck increases, the two resonant frequencies of the sound absorption increase while they decrease when the length of the first or the second neck increases. The proposed material design, which combines four parallel dual Helmholtz resonators, presents eight sound absorption peaks and these eight resonant frequencies can be tuned to specific frequencies by adjusting the parameters of the necks. It is a compact sound absorber, which can help to attenuate the noise simultaneously at eight different frequencies in several engineering applications.
Neurophysiological correlates of the perceptual magnet effect in speech perception
Authors: Zhang Yang
Published: July 2024

This study investigated the Perceptual Magnet Effect (PME) in speech perception using behavioral and Event-Related Potentials (ERP) measures. There were two primary research questions: (1) whether category goodness rating influences speech discrimination with reduced sensitivity near the prototype and increased sensitivity in the vicinity of a poor exemplar, (2) whether the PME is domain-specific to speech sounds. Twenty adult native English speakers participated in identification, goodness rating, and discrimination tasks. The stimuli were synthesized vowels for /a/ and their nonspeech analogs by systematically varying the first two formants. ERP oddball conditions included four conditions presented in a counter-balanced order with the prototypical /a/ as the standard stimuli and its variants as deviants, and a non-prototypical /a/ as the standard and its variants as deviants, as well as the nonspeech matches. Results indicated that participants rated vowel category goodness based on the F2/F1 ratio for the /a/ sounds. Mismatch negativity amplitudes in the two speech conditions aligned with PME predictions, but similar patterns were also observed in the nonspeech conditions. The findings collectively demonstrated neurophysiological evidence for the perceptual organization of within-category variations in line with PME, which may transfer to auditory processing of similar acoustic patterns in nonspeech.
Patterning of laxing spreading in Quebec French
Authors: Aigner-Therrien Philippe
Published: July 2024

Quebec French laxing is a rather well-known phonological process, starting from the tense vowels [i], [y], and [u] being rendered lax in some closed syllables. This process can also trigger laxing of high vowels in preceding syllables as well, though the nature of this process remains a source of debate, whether it is a spreading process or vowel harmony. In addition to the nature of the process itself, the patterning that occurs for the laxing spreading is one that has been long discussed, particularly when it comes to words with more than two syllables. Poliquin (2006) lists three different possible patterns that the laxing may take. The goal of this thesis was to not only confirm the presence of the spreading patterns found in Poliquin(2006), but also to determine to what degree they occur within native speakers of Quebec French. While the results seem to confirm the presence of laxing spreading, the frequency at which they occur seems to be rather low and vary not only from speaker to speaker, but also within the same speaker.
Quantifying vowel category distinctness using Bayesian modelling
Authors: Smith Irene , Sonderegger Morgan
Published: July 2024

Phonetic and sociolinguistic studies of vowel merger require a measure of acoustic distinctness between vowel categories. Three desiderata for such a metric are that it be multivariate, in the sense that it account for correlations between dimensions (e.g., F1 and F2), control for other factors affecting vowel formants (e.g. surrounding consonants), and work for unbalanced data (common in naturalistic data). Previous work (Nycz and Hall-Lew, 2013; Kelley & Tucker, 2020) has considered a variety of measures, including variants of Euclidean distance, Pillai score, and Bhattacharyya affinity, but none meet all three criteria. We present a new method for quantifying vowel merger that meets all desiderata and can be applied to different metrics: we fit a Bayesian mixed-effects linear model to jointly predict F1 and F2, then compute any desired metric—here, Euclidean distance, Pillai score, and Bhattacharyya affinity—from the posterior. We evaluate each metric, and the overall method, to describe PIN-PEN across a range of English dialect corpora. We find that controlling for covariates and unbalanced data adds substantial signal, but that multivariate modelling does not perform substantially better than univariate modelling. Additionally, we argue that Bhattacharyya affinity has particularly desirable properties (e.g., allowing for heteroskedastic data: Johnson, 2015).
Vowel quantity/quality redux: Revisiting vowel contrasts in Hakha Lai monophthongs
Authors: Berkson Kelly H. , Ziegler Grayson , Bohnert Amanda , Van Bik Kenneth
Published: July 2024

Previous scholars have documented a phonemic length distinction in the monophthongal vowels of Hakha Lai, a Tibeto-Burman language spoken in Chin State in western Myanmar (Melnik, 1997; Peterson, 2003; Maddieson, 2004). In a previous pilot study of data from two college-aged speakers (the first instrumental acoustic analysis of Hakha Chin vowel quality), our findings revealed stark individual differences: one speaker showed robust quantity and minor quality differences, while for the other, neither duration nor quality played key roles; rather, her system had merged. Maddieson (2004) proposed that the length associated with long vowels in Hakha Lai is mainly realized through lengthening of sonorant codas; we did not find this to be the case for either speaker. However, those pilot data were limited both in terms of sample size and age range. Therefore, to expand on our previous findings, we now present analysis of data from fourteen talkers, including both a group of nine college aged talkers (6 women) and five older talkers (2 women, ages 46 and 77; 3 men, ages 48, 60, and 62). Duration and quality measures are reported for all monophthongs in all possible syllable shapes.
Exploring infant talker bias: Insights from remote speech perception testing
Authors: Alonso Arteche M. Fernanda , Phillips Nicola , Moradi Samin , Shen Lulan , Chen-Ouellet Marianne , Ramloll Leatisha , Abraham Sumana , Zeng Lei , MENARD Lucie , Polka Linda
Published: July 2024

Lab studies show that infants (4- to 7-month-olds) prefer to listen to vowels with infant-like f0 and formant frequencies over those of an adult female (Masapollo et al., 2015; Polka et al., 2021). This Infant Talker Bias may facilitate infants’ mapping of articulatory gestures to acoustic correlates. In this study, 4- to 12-month-olds completed a listening preference task on the Lookit online testing platform. Across eight trials, we presented synthesized infant and adult vowel sounds (/i/ and /a/) paired with a simple animation and recorded the infant’s response via the webcam. Infant looking time and vocalization to each vowel type were coded offline. Preliminary analyses (n = 91) show that listening time increased with age (p < 0.05), and all infants listened longer to infant vowels than to adult vowels (p < 0.01). Preliminary analyses (n = 62) also show an increase in infant vocalizations with age (p = 0.00) and a trend towards more and longer vocalizations in response to the adult vowels. These findings replicate and extend the infant talker bias to new vowel stimuli and to older infants, and support the use of remote testing in infant speech perception studies.
Observations of spatial coherence from a multibeam subbottom profiler
Authors: Brownstead Laura , Brown Daniel C.
Published: July 2024

Sonar data from the Kongsberg SBP-29 (with a 64-channel receive array) aboard R/V Sally Ride is analyzed to judge the value of spatial coherence of signals reflected from the ocean floor. The multibeam sub-bottom profiler collected five days of sonar test data off the coast of Southern California over a variety of sediment types and marine geologies. The spatial coherence of measured signals is sensitive to different bottom types and to sediment layering deep below the ocean floor. Navigational data also permits comparison of sonar data to existing bathymetric maps of the ensonified floor. The flexibility of the transmit and receive arrays permit detailed study of potentially informative seafloor features and landmarks. The findings of primary interest are interpreted in the context of a bivariate Normal surface fit to characterize the spatial coherence of scattered signals and future work is reported based on statistical analysis of the fitted data.
Seabed Analysis on the New England shelf break using ambient sound data and trans-dimensional geoacoustic inversion
Authors: Siderius Martin , Dosso Stan , Quijano Jorge
Published: July 2024

The New England Shelf Break Acoustics (NESBA) Signals and Noise experiment was conducted in April-May 2021. Ambient sound data were collected over several days in the mud-patch area as well as in deeper water closer to the shelf break. A 16-hydrophone vertical array was used to measure the natural sound of breaking waves on the sea-surface. Using beamforming in the 500–700 Hz band, these data were used to obtain an estimate of the bottom reflection coefficient as well as the seabed layering. The reflection coefficient data were subsequently used with trans-dimensional inversion techniques to produce a geoacoustic model for the seabed (e.g., sound speed, density, and layering). Results show the ambient sound data can be used to produce well resolved geo-acoustic parameters, especially in the upper part of the seabed (e.g., <10 m). These results are compared between several locations on the New England Shelf Break area and are also compared with other published results using different estimation techniques. In addition, some of the issues related to the impacts of data errors and preferred measurement geometries will also be presented. [Work supported by the Office of Naval Research.]
Validation of auralized impulse responses considering masking, loudness and background noise
Authors: Heck Jonas , Llorca-Bofí Josep , Dreier Christian , Vorlaender Michael
Published: July 2024

The use of outdoor virtual scenarios promises to have a lot of potential to facilitate reproducible sensory evaluation experiments in laboratory. Auralizations allow for the integration of simulated or measured sound sources and transfer paths between the sources and receivers. Nonetheless, pure simulations can lack perfect plausibility. This contribution investigates the augmentation of auralized outdoor scenes based on simulated impulse responses (IRs) by ambient or background sounds. For this purpose, foreground events such as car pass-bys are created by simplified simulation of impulse responses. Due to their large number of events, however, ambient sounds are typically not simulated. Instead, spherical microphone array recordings can be used to capture the background sound. Using synthesized car sounds, we examine how much the augmentation by background sound improves the auditory plausibility of simulated impulse responses in comparison with the equivalent measured ones.
SoundGarden: Applying healthy soundscapes to support coral reef restoration
Authors: Mooney T. Aran , Aoki Nadége , Weiss Benjamin , Jarriel Sierra , Jézéquel Youenn , Gutting Alexandra , Ward Jessica , Zhang Weifeng G. , Apprill Amy
Published: July 2024

Coral reefs are a hub of ocean biodiversity supporting a range of socioeconomic and ecosystem services. Yet reefs and these important services are imperiled due to climate change and related stressors. Healthy coral reefs can be characterized by distinctive soundscapes, and there is increasing realization that acoustic cues are vital ecosystem components. Here we present a series of experiments examining if replaying healthy soundscapes can increase the settlement of coral larvae, a fundamental ecological process. Work was conducted in the U.S. Virgin Islands, leveraging a decade of soundscape studies on those reefs, and used a novel solar-powered acoustic playback system calibrated in sound pressure and particle motion. We studied larvae from three coral species, brooding Porites astreoides and Favia fragum, and broadcast-spawning Diploria labyrinthiformis. Larvae on degraded reefs enriched with healthy reef sounds settled at significantly higher rates compared to control sites that were not acoustically enriched. Acoustic enrichment settlement rates were influenced by received level, ecosystem properties and species biology reflecting the need for holistically evaluating the reef restoration process. Overall, this work outlines a new, potentially scalable means of supporting healthy reef habitat, and enhancing coral settlement on imperiled reefs undergoing restoration.
Pseudo-spin polarized one-way elastic wave eigenstates in one-dimensional phononic superlattices
Authors: Deymier Pierre A. , Runge Keith , Khanikaev Alexander , Alu Andrea
Published: July 2024

We use a one-dimensional discrete binary elastic superlattice bridging continuous models of superlattices that showcase one-way propagation character and the discrete elastic Su-Schrieffer-Heeger model that does not. By considering Bloch wave solutions of the superlattice wave equation, we demonstrate conditions supporting elastic eigenmodes that do not satisfy translational invariance of Bloch waves over the entire Brillouin zone, unless their amplitude vanishes for some wave number. These modes are characterized by a pseudo-spin, and occur only on one side of the Brillouin zone for given spin, leading to spin-selective one-way wave propagation. We demonstrate how these features result from the interplay of translational invariance of Bloch waves, pseudo-spin, and a Fabry-Pérot resonance condition in the superlattice unit cell.
Development and verification of a method to simulate non-stationary vehicle interior wind noise
Authors: Yu Jinghe , Davies Patricia
Published: July 2024

As speeds and directions of the vehicle and wind change, the time-varying flow creates variations in wind noise, which can be referred to as non-stationary wind noise. To investigate people's perceptions of non-stationary wind noise inside the vehicle, a method to simulate the non-stationary wind noise is needed. Previously, a method was developed that used stationary wind noise recordings taken at several constant wind speeds and directions to form functions that relate the 1/3 octave sound pressure level with wind speed and direction. These functions are used to create time-varying filters based on provided time histories of wind speed and direction. To reduce the cost of taking many stationary measurements, an improved method was investigated. At each yaw angle, one speed sweep wind tunnel measurement was used to estimate the relationship between sound pressure level and wind speed. Two partially correlated white noise signals were then filtered to simulate binaural sounds that had a similar coherence structure between the left and right ear sounds to that observed in binaural measurements in the vehicle. The accuracy of the simulations was validated by comparing wind noise simulations to vehicle interior noise measured in the wind tunnel and on the road.
Construction noise modelling—A comparison of equipment noise emissions data sources
Authors: Zokay Sam
Published: July 2024

The accuracy of any environmental noise impact model depends on the quality and application of its input data, typically consisting of at-source emission levels, propagation factors, and receiver characteristics. In the realm of construction noise modelling, this starts with the determination of the noise emission level for each construction activity or item of equipment. This data can be procured from a variety of sources including manufacturer data, standards and guideline documents, or proprietary measurements. This study explores how emission levels from different data sources can be utilized to assess noise impacts against project criteria, and aims to validate the reliability through real-world case studies.
Probing atmospheric waves and the middle atmosphere dynamics using infrasound
Authors: Hupe Patrick , Pilger Christoph , Le Pichon Alexis , Ceranna Lars
Published: July 2024

Infrasound is defined as pressure fluctuations with frequencies between acoustic cut-off (5 min) and human-hearing frequency threshold of sound (16 Hz). Low-frequent infrasonic waves can travel long distances, ranging from hundreds to thousands of kilometres. The middle atmosphere dynamics mainly control the presence of atmospheric waveguides where energy transmission loss is low. These properties are utilized to record atmospheric explosions at highly sensitive pressure sensors (micro-barometers). A global network of 60 infrasound stations was designed as part of the International Monitoring System (IMS) for the Comprehensive Nuclear-Test-Ban Treaty. IMS infrasound stations can record small pressure fluctuations of a few millipascals, which can originate from numerous atmospheric infrasound sources, including meteorological phenomena. In this study, the capability of IMS infrasound arrays for capturing a broad spectrum of atmospheric wave phenomena is highlighted; for instance, mountain-associated infrasonic waves show features that seem to be correlated with orographic gravity waves. Moreover, the interaction of ocean waves produces quasi-continuous infrasound, so-called microbaroms. Infrasonic signatures from microbaroms can be used for probing the middle atmosphere dynamics and assessing atmospheric circulation models. For opening the unique global infrasound network of the IMS for meteorological applications, we also present open-access BGR infrasound data products of two decades and highlight selected case studies.
Ultrasonic C-scan for micro-crack inspection on semi-flexible solar modules
Authors: Silitonga Dicky , Dubey Pooja , Declercq Nico
Published: July 2024

Solar photovoltaic modules are versatile power sources in diverse materials and configurations, including compact and flexible variants for portable electronic devices. Ensuring the reliability of these modules is crucial for sustaining the functionality of the devices they power. Manufacturing or handling-induced defects, such as cracks or scratches, pose a threat to the performance of solar modules. Hence, non-destructive inspection becomes essential in the quality control process. Ultrasonic C-scan has been an established inspection technique within various industries; however, its application on solar modules remains uncommon. On the other hand, Scanning Acoustic Microscopy (SAM) has been implemented for observing defects in solar cells, yet employing SAM for comprehensive module scanning is inefficient. This study aims to assess the capability of ultrasonic c-scan in detecting micro-cracks within semi-flexible solar panels and to evaluate the effects of frequency selection on the results. This work investigates the specimen with an Ultrasonic C-Scanner at different frequencies. Subsequently, the outcomes are validated by comparing them with the results from the SAM. The potential of using a widely known ultrasonic technique for this purpose, while understanding its limitations, such as the c-scan, will enable a more straightforward integration of the technique into the solar module quality control process.
Assessing spatial non-uniformities in lithium-ion battery state of charge using ultrasound immersion testing
Authors: Ajaereh Mac Geoffrey , Cook Olivia J. , Jones Haley N. , Kizer Nathan , Katch Lauren , Wheatley Christopher , Vagg Chris , Courtney Charles , Kube Christopher M. , Arguelles Andrea P.
Published: July 2024

Enhancing the performance, safety and reliability of battery management systems is crucial for advancing the state of the art in battery electric vehicles. Current research explores the potential of ultrasound to monitor state of charge (SoC) changes in individual cells. Understanding spatial variations in SoC is essential, as non-uniformities could lead to sub-optimal performance, premature ageing, and possible safety risks. This study uses ultrasound immersion C-scans to map wave speed and attenuation at different SoC levels during battery cycling. Results indicate non-uniform wave speed and attenuation suggestive of SoC spatial variations within single cells, emphasising the importance of addressing this issue. Acoustic measurements under various C-rates and relaxation periods are discussed, providing insights into lithium-ion rearrangement in graphite particles. Potential causes of structure and manufacturing variations of the cell are discussed, highlighting the need to address these issues to prevent overcharging or overdischarging in specific battery areas.
Long- and short-term implicit talker familiarity: Effects on children's word and sentence recognition
Authors: Flaherty Mary M.
Published: July 2024

While previous research has highlighted the positive effects of talker familiarity on children’s word recognition in quiet, its role in challenging listening conditions remains poorly understood for this age group. Additionally, the amount of familiarity required to yield benefits remains unclear. The current study explored implicitly acquired short and long-term talker familiarity effects in school-age children (8–12 years), utilizing speech or noise maskers. Experiment 1 assessed open-set sentence recognition in a two-talker-female masker, with the child's mother's voice serving as the target or masker speech. Experiment 2 measured closed-set word recognition in a noise masker, both before and after a 5-day exposure to a female talker. Results from Experiment 1 indicate that children benefit from familiarity when their mother is the target talker, but not when she is the masking speech. In Experiment 2, children exhibited familiarity effects after only a 5-day exposure period to a previously unfamiliar voice, demonstrating a significant impact of implicit short-term familiarity. Working memory and selective attention did not predict performance or benefit. Together, these findings underscore the importance of talker familiarity in children's speech recognition in challenging listening situations. The implications of these findings for understanding the mechanisms underlying familiarity effects will be discussed.
Summary of National Standards on classroom acoustics: The data collection
Authors: Tardini Virginia , Fratoni Giulia , D'Orazio Dario
Published: July 2024

Improving acoustic comfort in classrooms is paramount for enhancing intelligibility, fostering student concentration, and alleviating the vocal strain on teachers. The global discourse on acoustic quality in educational buildings has intensified in recent decades, with each country establishing its unique set of building codes, standards, guidelines, and voluntary point protocols to delineate acoustic quality parameters. Geometrical and architectural classroom variations, influenced by cultural and historical contexts, further contribute to the diversity of approaches. The present work provides a summary that investigates and compares local standards across various countries worldwide, aiming to offer a holistic understanding of the classroom acoustic landscape. The motivation for this summary lies in finding regulations that are not easily searchable on Scholar or Scopus. It involves human interpretation and consideration of building codes, often in local languages. More than 70 experts, distributed across continents, were queried about his local standards, their enforceability, room criteria, design rules; and non-acoustic factors like classroom geometry, average occupancy, and flexibility of learning spaces. By synthesizing insights from diverse regions, this study aspires to provide a global perspective on the state of acoustic quality in educational settings, shedding light on potential areas for improvement.
What is realistic enough? Design considerations for soundscape simulators
Authors: Yanaky Richard , Guastavino Catherine
Published: July 2024

Urban soundscapes reflect life and behaviours in a city. Given the dynamic and ever-changing behaviours of people, this introduces many complexities for soundscape simulators. We focus on bottom-up simulators, wherein every aspect of an environment can potentially be simulated, including 3D models of spaces, people’s behaviours, sound sources, weather, nature, lighting, and the physics behind them to create the illusion of navigating a real space. How much realism is necessary in such virtual environments though? This work discusses realism through the lenses of plausibility, hyperrealism, and ecological validity. Is it ok to just be a plausible reality? Should reality be exaggerated? How faithful should it be and from which perspective (e.g. matching physical or cognitive “realities”)? These questions were considered during the development of our in-house soundscape simulator, City Ditty. City Ditty seeks to be operable by non-sound professionals and support integration into urban projects with minimal expertise and resources, thus encouraging more diverse urban professionals and city users to contribute to how their cities will sound through participatory approaches. Given these requirements, we discuss how suitable levels of realism can be attained to fit people’s needs at technical, practical, and theoretical levels by considering these three lenses for design.
Ontario Class 4 classification
Authors: Garro Giuseppe
Published: July 2024

The Ministry of Environment, Conservation, and Parks introduced the Class 4 noise area classification for land-use planning applications in 2013. A Class 4 classification is used in special cases where new noise sensitive developments are proposed in proximity to existing, lawfully established stationary noise source(s). This infrequently used classification is typically applied for in-fill developments in urban settings where land-use compatibility concerns are common. This work summarizes the Class 4 design criteria and discusses the practical implementation of the classification in the context of land-use planning.
Prediction of sound and vibration levels from heavy-hard impacts in a cross laminated timber—Concrete hybrid building
Authors: Brophy Joshua , Callaghan Aedan
Published: July 2024

Heavy-hard weight impacts in fitness spaces often result in elevated noise and vibration levels, which can lead to complaints in sensitive adjacencies. Previous works have demonstrated a method to predict the resulting noise and vibration levels in fitness space adjacencies. This method involves the analysis of an in situ transfer function in combination with laboratory force data and sound pressure level measurements from a shotput dropped on a calibrated reference rubber impact sheet. It was originally developed for use in concrete structures, which are typical for large multi-residential, commercial, and mixed-use buildings that commonly feature fitness amenity rooms or commercial gyms. The growing popularity of mass timber as a sustainable building material provides an opportunity to expand upon the previous research by examining the validity of the prediction method in another structural type. This paper serves as a case study of heavy-hard impacts in a residential hybrid mass timber structure, where weight drops from a fitness center at the top level of the concrete podium were disturbing apartment residents occupying the first CLT level directly above.
Acoustic implications of thin mass timber panels
Authors: Way Evelyn
Published: July 2024

As mass timber construction becomes more widely adopted, there is an incentive to use thinner, lighter panels. Research sponsored by the American Wood Council and WoodWorks explores the relative performance of 5-ply CLT and 5-ply equivalent panels to 3-ply CLT and 3-ply equivalent panels both bare and with topping slabs. In addition to the comparison of thicker and thinner panels, assemblies using resilient mats and gypsum concrete topping slabs were also developed to meet the IBC residential code minimum performance. Results and acoustic analysis will be presented along with a discussion of the non-acoustic considerations of the move to thinner mass timber structural panels.