bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental changes in phonological and semantic competition during spoken word recognition
Authors: Zamuner Tania , McDonald Margarethe , Salama Samaa
Published: July 2024

Spoken word-recognition is a foundational skill in child language development; the organization and activation of phonological and semantic competitors develops which in turn impacts word recognition. One of the factors impacting spoken word recognition is the ability to resolve lexical competition. The current study first examines how the time-course of lexical activation changes through development, and second, whether children attend more to targets when competitors are visually present or not. To date, 25 children between ages 3–7 who began acquiring French from birth participated in a visual world eye-tracking paradigm. Children were presented with 4 images, each representing a different French word. Images were either presented with both a phonological (e.g., baleine) and semantic (e.g., cerise) competitor of the audio stimuli (e.g., banana) or the audio stimuli had no relation to the competitor images (e.g., épée). Primary analysis reveals that older children look more to the target than younger children [F(2,22) = 3.8, p =.04] and that the presence of competitors does not impact target recognition [F(1,18) = 0.03, p =.87]. Such findings imply that children improve in their abilities to efficiently recognize words with age but are not affected by the visual presence of lexical competitors.
Limits of short-term perceptual training for enhancing Seoul-Korean listeners’ use of English lexical stress in spoken word recognition
Authors: Tremblay Annie C. , Kim Hyoju , Kim Sahyang , Cho Taehong
Published: July 2024

This study investigates whether short-term perceptual training can enhance Seoul-Korean listeners’ use of English lexical stress in spoken word recognition. Unlike English, Seoul Korean does not have lexical stress (or lexical pitch accents/tones). Seoul-Korean speakers at a high-intermediate English proficiency completed a visual-world eye-tracking experiment adapted from Connell et al. (2018) (pre-/post-test). The experiment tested whether pitch in the target stimulus (accented versus unaccented first syllable) and vowel quality in the lexical competitor (reduced versus full first vowel) modulated fixations to the target word (e.g., PARrot; ARson) over the competitor word (e.g., paRADE or PARish; arCHIVE or ARcade). In the training (eight 30-min sessions over eight days), participants heard English lexical-stress minimal pairs uttered by four talkers (high variability) or one talker (low variability), categorized them as noun (first-syllable stress) or verb (second-syllable stress), and received accuracy feedback. The results showed that neither training increased target-over-competitor fixation proportions. Crucially, the same training had been found to improve Seoul- Korean listeners’ recall of English words differing in lexical stress (Tremblay et al., 2022) and their weighting of acoustic cues to English lexical stress (Tremblay et al., 2023). These results suggest that short-term perceptual training has a limited effect on target-over-competitor word activation.
GHOST target suppression for distributed multi-array localization using temporal and spatial correlations
Authors: Kang Mingu , Choo Youngmin , Lee Keunhwa , hong wooyoung
Published: July 2024

We propose a ghost target suppression method for distributed multi-array localization. Triangulation, included in bearings-only target localization method for the well-separated array, is highly dependent on bearing measurements. Its performance is degraded by ghost targets from the ambiguity of bearing measurements. The proposed method is based on the assumption that received signals from the same target have similar frequency components within short-term time and at different locations. We utilize the consistency of acoustic signals in Frequency-Azimuth plots by measuring the frequency component similarities of the target signal over time at a single array (temporal information) and across different arrays (spatial information). The ghost target suppression is evaluated using in situ data from Swellex-96 S5 Event and results reveal the target track along time with much less ghost targets. [Work supported by Korea Research Institute for defense Technology planning and advancement(KRIT)—Grant funded by the Korea government(DAPA(Defense Acquisition Program Administration))(No. KRIT-CT-23-026, Integrated Underwater Surveillance Research Center for Adapting Future Technologies, 2024).]
Comparison of sparse arrays that maximize detection and optimize beampatterns
Authors: Kalaoun Zaynah , Adhikari Kaushallya , Kay Steven
Published: July 2024

In a standard uniform linear array (ULA), the sensors are uniformly spaced on a grid with half wavelength intersensor spacing. The beampattern of an array shows the gain applied by the conventional beamformer to a plane wave arriving at the array from various possible directions. The main lobe width, peak side lobe height, and the side lobe area are important beampattern parameters. Many sparse arrays have been widely studied because of their ability to provide one or more of the same beampattern parameters as a full array using fewer sensors. Examples of such arrays are coprime [Vaidyanathand and Pal 2011] and nested [Pal and Vaidyanathan 2010] arrays. Recently, an exact way to design sparse sampling schemes to maximize detection performance of a known signal in first-order autoregressive noise was introduced [Adhikari and Kay 2023]. In this research, we compare the beampatterns and detection performances of these detection maximizing arrays with the sparse arrays that are designed to optimize beampattern metrics. We analyze beampatterns and detection performances under various conditions using simulated and real underwater acoustic data.
Enhancing ship noise reduction: a deep-learning based noise extraction model
Authors: Chu Hailun , Wang Haibin , Li Chao , Wang Jun , Tai Yupeng , Zhang Yonglin
Published: July 2024

In active sonar detection systems, the self-radiated noise from the platform itself is a primary factor that interferes with system performance. The platform self-noise exhibits non-Gaussian characteristics, comprising line spectrum and continuous spectrum, where line spectrum exhibits higher intensity and greater frequency stability. To reduce the ship noise, this study introduces a deep-learning based time-domain model with an encoder-separator-decoder architecture. In detail, the encoder and decoder modules utilize learnable convolutional layers to generate distinguishable features with a symmetrical structure. For separator module, we observe that noise components prominently predominate within the noisy signal in low signal-to-noise ratio (SNR) scenarios. The extraction of noise components is typically more tractable than of signal components. Therefore, in contrast to conventional frameworks that focus on extracting the signal subspace, this module is dedicated to extracting the noise subspace. Besides, the modified scale invariant SNR (SI-SNR) is proposed as the loss function for model optimization, which yields better performance than non-noise extraction structure. The robustness of the model is validated on the DeepShip dataset with four ship categories, demonstrating that the model consistently outperforms baselines, including matched filter, in all ship categories.
Non-standardized room acoustic metrics
Authors: Vorlaender Michael
Published: July 2024

The first edition of ISO 3382 was adopted in 1997. It already listed T30, Early Decay Time, Clarity, Definition, Center time, Lateral fraction and IACC as relevant room acoustic parameters. They are still up to date, only supplemented by the division into two dimensions of the spatial impression and by the stage support. In the last decade, new research has been conducted on sound perception in concert halls and the results seem to confirm that loudness, reverberation, clarity (intelligibility) and localization are the most important. More recently, auditory-visual interaction, loudness decay and directional reverberation have been found to be factors that describe dimensions of the overall experience of music in a concert hall. This paper highlights the challenges associated with some of the standard parameters and the opportunities presented by newly developed metrics.
An in-depth look at empirical estimates of assembly performance
Authors: Raley Michael
Published: July 2024

Acousticians often look for acoustical test data for wall and floor/ceiling assemblies that match the assemblies on their projects. However, with the endless possible permutations of assemblies, it can be difficult to find testing for an assembly that is an exact match. As a consultant, I frequently created engineering evaluations that documented my predicted performance of an assembly. As a manufacturer, I now have a say in what assemblies are tested, but I still can’t test all the possible permutations. This presentation is an overview of my current approach to assembly estimates, including the development of test series that are specifically intended to produce the data necessary to create good estimates.
A comparative study of modeled and measured room responses
Authors: Dulworth Nicolaus T. , Kanter Shane J. , Giegold Carl P.
Published: July 2024

At the heart of Brown University’s Lindemann Performing Arts Center is a shape-shifting hall capable of supporting a wide range of performance types. Acoustic simulation played a crucial role in optimizing each of the hall’s five primary configurations during design. Leading up to the opening events 2023 and 2024, the lengthy commissioning and tuning process provided an invaluable opportunity to measure subtle and drastic changes in the hall’s form and materiality for comparison to the predictive simulation. Drawing from the Lindemann set, the paper compares modeled and measured data from the PAC to that from other projects designed using similar tools. The paper identifies points of uncertainty during design and delves into commonalities and differences between ray-based simulation and measurement in performance spaces of varying form. This paper will address the inherent complexities of approximating acoustic behavior with side by side comparison of measurement and simulated data, we will share insights that inform our future modeling process.
Exploring variations to ASTM E336 directional sound source positioning
Authors: Lalonde Pier-Gui , Clunis Gregory E.
Published: July 2024

This paper explores variations to the procedures presented in ASTM E336 Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings. Per the Test Standard, directional sound sources must be aimed into corners away from the test partition. For source rooms horizontally adjacent to occupied spaces on all sides, multiple loudspeaker positions are needed to measure noise isolation in all directions. Measurements made in 4 office spaces are presented, each made in two ways: firstly in compliance with the Standard; and secondly, with sound sources orientated and operated differently, to explore whether using a single configuration of directional loudspeakers can produce similar results. Variations in the results are discussed, and suggestions are provided for future work.
Comparing measured sound strength to theoretical sound strength for rooms of varying size
Authors: Dunham Joshua
Published: July 2024

ISO Standard 23591 shows how the sound pressure level in a room can be estimated with the following two pieces of information: the sound power of sources in that room, and the sound strength G of that room as defined in ISO 3382-1. In an earlier study, the theory connecting room volume V, reverberation time T, and sound strength G was summarized, and a comparison of measured G to this theory was explored for a wide range of rooms. That test setup used Odeon software. In the present study, a different test setup is used implementing Dirac software to expand G testing to additional rooms of various sizes for evaluation under the same mathematical model. After a description of the equipment using Dirac software is discussed, a brief review of the additional rooms in which sound strength was measured is provided. Both measured and theoretical sound strength results are presented for these rooms. The difference between measured G and theoretical G using the mathematical model is analyzed statistically both for the Dirac test setup and compared to the results from the previous study.
Measurements of the frequency dependence of geo-alpha in clayey silt at low frequencies
Authors: Diachok Orest , Turgut Altan
Published: July 2024

Transmission loss (TL) measurements in the Santa Barbara Channel, together with co-located chirp measurements, show that geo-alpha (dB/l) in clayey silt increases approximately linearly with frequency (f) at f < 3 kHz. TL was measured between a fixed source and fixed vertical array at 3.7 km at 0.3 < f < 5 kHz. Geo-alpha was inverted from the TL data at 0.3, 1.1 and 1.9 kHz. Inversion calculations at 1.1 and 1.9 kHz considered both geo-alpha and bio-alpha due to layer of anchovies at 12 m. Inversion calculations at 0.3 kHz considered only the effect of geo-alpha; the effect bio-alpha on TL was small. Geo-alpha was also inferred from chirp sonar measurements at 3.2 and 6.2 kHz at the ends and middle of the TL track. Chirp sonar showed that the bottom consisted of a layer of unconsolidated sediments overlying a layer of sand. Co-located cores revealed that the unconsolidated layer consisted of clayey silt. Bio-alpha data were compared to Biot and VGS theories and the theory of attenuation in suspended sediments (Pierce et al., 2017). The measured frequency dependence is consistent with Pierce et al.’s theory. This research was supported by The Office of Naval Research Ocean Acoustics Program.
Parallel- and micro-beamforming challenges in real-time, high-frame-rate, ultrasound imaging
Authors: Tortoli Piero , Castrignano Lorenzo , Giangrossi Claudio , Meacci Valentino , Boni Enrico , Ramalli Alessandro
Published: July 2024

Delay-and-sum beamforming for classic (line-by-line) ultrasound imaging is usually performed in real-time by FPGAs and GPUs. However, when a high-frame-rate (HFR) has to be achieved, beamforming becomes challenging. Here, the echoes following the transmission of multi-line focused beams, plane waves, or diverging waves, must be simultaneously beamformed along multiple view lines. Such parallel beamforming is feasible online when the scanner is endowed with high flexibility and processing power. This talk will show how the FPGAs of the ULA-OP 256, a hardware-based open scanner, were efficiently utilized to enable parallel beamforming at high speed. The talk will also discuss how the data transfer between the scanner boards impacts the frame rate, which actually achieved 4400 frames per second through a new communication topology. The talk will also examine the image quality deterioration emerging when HFR imaging sequences are implemented in probes equipped with a microbeamformer (uB) that was designed for focused beam transmission. Simulations show how the transmitted beamwidth and uB size impact the image contrast and resolution, taking into account that the uB ASIC cannot handle multiple sets of delays and apodization weights after each transmit event. Technological improvements needed in the next generation uBs will be finally discussed.
Enabling support for Octave within the FOCUS software package
Authors: Honer Jacob S. , McGough Robert J.
Published: July 2024

FOCUS, the “Fast Object-Oriented C+ + Simulator” (https://www.egr.msu.edu/∼fultras-web/), is a free software package that enables rapid calculations of continuous-wave and transient pressure fields generated by single transducers and phased arrays. FOCUS achieves small errors in relatively short computation times through linear memory-efficient calculations with the fast nearfield method. This capability extends to quick and accurate biomedical imaging simulations within FOCUS. Moreover, FOCUS supports some nonlinear pressure calculations, such as the continuous-wave and transient Khokhlov-Zabolotskaya-Kuznetsov (KZK) equations for circular and spherical transducers. Additionally, the Angular Spectrum Approach (ASA), a frequency-domain solution to linear computational methods, ideal for large volumetric field computations, is also included within the FOCUS package. Initial success with MATLAB motivates the creation of an Octave version that replicates the core functionalities of the original FOCUS package. GNU Octave is similar to MATLAB, but unlike MATLAB, Octave is a free software. Building and compiling FOCUS in Octave required a few minor alterations due to discrepancies in syntax and function calls. The use of Octave-compiled MEX files simplified the conversion process while introducing addition memory overhead compared to rewriting C+ + code for Oct-file structuring. The performance and capabilities of FOCUS in Octave are demonstrated and discussed.
Hydrostatic pressure effects in periodically structured polyurethane acoustic tiles
Authors: Hacquebard Luke R. , Szabo Jeffrey P.
Published: July 2024

Traditional underwater acoustic materials commonly make use of periodic air voids to improve their ability to absorb or deflect sound through wave-mode conversion and scattering mechanisms. These air voids have the potential to deform or completely collapse under hydrostatic pressure loading, which may significantly affect the material’s acoustic performance. This study investigates the effects of hydrostatic pressure on the acoustic response of two different types of fabricated polyurethane samples. Developed numerical finite element simulations help identify the main factors associated with the acoustic pressure dependence of such tiles. The results of this work may aid in the development of pressure resistant materials that can better maintain acoustic performance at depth.
A comparison of modeled and measured impedance of brass instruments and mouthpieces
Authors: Jackson Miranda , Scavone Gary
Published: July 2024

The impedance of a brass instrument has an important influence on its playability and sound timbre. The geometry of the mouthpiece has various features, such as the cup volume and shape, opening diameter, and length, that determine the characteristics of the overall impedance of the instrument-mouthpiece combination. Brass instruments, and especially mouthpieces, are designed for specific purposes, and horns or mouthpieces are chosen depending on the musical requirements. In order to investigate the relationship between the physical parameters and the impedances of instruments and mouthpieces, they have been modeled with transfer matrix and finite element model techniques, and the results are compared with impedance measurements of instruments, mouthpieces, and combinations of instruments and mouthpieces. Trumpets, flugelhorns, (French) horns, trombones, and the corresponding mouthpieces have been used. A detailed analysis of the estimation of the viscothermal losses has been performed, as the loss estimation in the narrow throat of the mouthpiece and in the flaring part of the brass instrument bell departs from the ordinary transfer matrix calculations. The effect of varying the physical parameters of mouthpieces and instruments is investigated by means of impedance considerations and sound synthesis, and the resulting influences on intonation, playability, and timbre are presented.
Spectral behavior of recorder tones during transitions between notes
Authors: Giordano Nicholas , Saenger Katherine L.
Published: July 2024

We have studied note transitions in a soprano recorder as tone holes are opened or closed. Experimental results with an instrument excited by an artificial blowing machine are compared to Navier-Stokes-based simulations for an essentially identical instrument geometry. Several different cases have been studied. (1) Transitions involving the opening or closing of a single tone hole, with the notes separated by two semitones; e.g., transitions between C5 and D5. (2) Transitions involving the opening or closing of several tone holes simultaneously; e.g., transitions between C5 and G5. (3) Transitions involving a single tone hole but for notes separated by a major fifth; transitions between C5 and G5 using a forked fingering. Our work has focused on tone hole openings and closings at speeds typical of a human player but interesting behavior was also observed for longer tone hole switching times for cases (2) and (3), in which the sound field inside and outside the instrument was found to take much longer than the tone hole switching time to reach steady state. Work supported by NSF grant PHY2306035
Acoustic characterization and optimization of a subsonic closed loop wind tunnel
Authors: Cunnington Bourbonniere Nicholas P. , Rocha Joana , Waudby-Smith Peter
Published: July 2024

A low-speed closed-loop wind tunnel with an open-jet test section having a maximum windspeed of 60 m/s is being modified for future aero-acoustic testing. The wind tunnel is new to Carleton University as of 2021 and no acoustic characterization tests have been completed until recently. The objective of this research is to acoustically characterize the wind tunnel before and stepwise through its acoustic modifications. Multiple tests have been made using ¼-inch microphones at different locations inside the plenum to record the existing out-of-flow background noise. The first planned wind tunnel modification is a height extension to the current plenum with dimensions 0.74 × 1.8 × 1.3 m (H × L × W) to increase the observer distance for the microphones. Once the plenum volume is increased, acoustic treatment will be applied to the interior of the plenum to create a hemi-anechoic measurement environment. An in-flow microphone mount was designed and manufactured with computer-controlled vertical traversing; it will be installed after the plenum modifications are complete.
Applying soundscape: A matter of participation
Authors: Schulte-Fortkamp Brigitte , Brooks Bennett M.
Published: July 2024

Defined as the acoustic environment understood by people in context, the soundscape encapsulates the myriad sounds that shape our daily lives (ISO12913 series). In the intricate tapestry of our sensory experiences, the soundscape emerges as a profound element, weaving together the diverse threads of auditory stimuli and social implications that surround us. Soundscape is not merely an assortment of sounds; rather, it is a complex interplay of natural and human-made elements that contribute to the acoustical and social identity of a place. Participation in the planning and modification of an acoustic environment requires an active and creative approach, it calls for a targeted engagement with the proposed redesigns or reorganizations. Participating in the soundscape approach also entails promoting acoustic ecology and the responsible management of acoustic environments. This involves efforts to minimize noise pollution, protect natural soundscapes, and create spaces where diverse sounds can coexist harmoniously. The paper will discuss different aspects of participation that offers numerous benefits, and as a participatory experience it opens new avenues for creativity, well-being, and community building in our ever-evolving acoustic living situations.
The Catalogue of Soundscape Interventions (CSI) project—A tool to bridge soundscape research and practice
Authors: Aletta Francesco , Chen Xiaochao , Moshona Cleopatra , Kang Jian , Mitchell Andrew , Oberman Tin , Schulte-Fortkamp Brigitte , Fiebig Andre
Published: July 2024

The Catalogue of Soundscape Interventions (CSI) project addressed the growing interest in urban soundscapes by establishing a comprehensive taxonomy for soundscape design. The project development is described, emphasizing its role in connecting soundscape research with practical applications. The proposed concepts for soundscape design interventions and other soundscape interventions are discussed, which seek to inform the creation of “soundscape design briefs.” These briefs, intended for use by local authorities, aim to enhance communication among soundscape consultants and researchers, and other relevant stakeholders. This work also presents the intersection of the CSI project with the technical specifications outlined in the ISO/AWI TS 12913-4 Acoustics Soundscape Part 4: Design and Intervention, currently in development. By aligning with emerging standards, the CSI project seeks to contribute to a unified framework for soundscape practices, and to establish a model to describe phases and necessary action points in the life cycle of a soundscape design intervention.
Taipei performing arts center surrounding soundscape study and its application
Authors: Ghadiri Roxana , Juan Shiang-I , van Brug Stijn Zeger , Manullang Nikita Grace , Muet Juliana Manuela , Diep Tuan Sanh , Thinzar Khaing , Indriyani Ni Made Putri , Wibowo Phoa Angela Grace , Niederberge Gabriela , Averina Clarissa , Truong Chau N. , Tsaih Lucky S.
Published: July 2024

Taipei Performing Arts Center designed by architect Rem Koolhaas and his firm OMA, features three theaters stacked vertically. The cube-shaped structure features a distinctive geometric facade, serving as the seating areas for the three main theaters. These giant facades, due to their sloped seating surfaces, could also function as significant sound-reflecting and focusing panels, potentially amplifying the nearby MRT and traffic noise. The project was strategically located near Shihlin Nightmarket for the area's cultural and economic growth. ISO-12913 soundscape study method is used to document essential sound sources, paths, and levels. The average sound pressure level of 67.4 decibels around the building provides an indication of the ambient noise in the immediate vicinity. While the acoustic comfort level in the plaza beneath the prominent facades may not be optimal, it is crucial to acknowledge their dual role as guiding individuals into the performance hall and serving as a buffer between external traffic and internal events. In addition to evaluating the impact of building mass and envelope design decisions on sound levels, this study uncovers a noteworthy finding related to urbanized traffic beeping. The observed and mapped patterns of local traffic sounds reveal unique cultural messages embedded in the auditory landscape.
The use of in situ infrasound calibration to correct wave parameter estimation
Authors: Kristoffersen Samuel , Le Pichon Alexis , Schwardt Michaela , Vincent Paul , Doury Benoit , Larsonnier Franck , Pilger Christoph , Hupe Patrick
Published: July 2024

As part of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the International Monitoring System (IMS), which includes infrasound stations, has been established to monitor nuclear testing, as well as many other infrasound sources of interest to the scientific community. To minimize the effects of wind-noise, wind-noise reduction systems (WNRS) are installed as part of each sensor. In order to provide the best wave parameter (azimuth, trace velocity, amplitude) estimates, the response of the WNRS must be properly taken into account. Therefore, it is important to perform an in-situ calibration of the sensor using a co-located reference sensors and ambient signals to determine this response. This in-situ calibration can be used to monitor the status of the sensors, and provide feedback to the station operators. Experiments were performed at the IS26 site in Germany using a temporary WNRS to provide quantitative measurements of the effects of the WNRS and its calibration on the wave parameter estimation. These calibration results were used to provide corrections to the raw signal data for retrieval of the corrected wave parameters and were compared to the IS26 measurements, demonstrating that accurate measurements can be retrieved using the in-situ calibration.
Nonreciprocal energy transmission in short discrete systems with strong spatiotemporal modulations
Authors: Wu Jiuda , Yousefzadeh Behrooz
Published: July 2024

Introducing spatiotemporally varying properties in a phononic lattice can enable nonreciprocal transmission of energy. The hallmark of this phenomenon is the unidirectional energy transmission in infinitely long systems. In short lattices, however, identifying nonreciprocity through differences in transmitted energies (norm bias) becomes challenging because the primary contributor to nonreciprocity is the transmitted phases. Although stronger modulation can achieve a higher norm bias, it can also result in parametric instabilities and trigger large-amplitude oscillations that lead to device failure. To better understand the tradeoff between stability and norm bias in strongly modulated systems, we investigate the parametric stability of a finite one-dimensional lattice with spatiotemporally modulated elasticity. We use Floquet theory to compute the stability charts for strongly modulated systems. Thus, we can identify operating conditions that allow for a relatively large norm bias while maintaining a stable, bounded response.
Mitigating low-frequency broadband aircraft noise through a structured assembly of acoustic material and devices
Authors: Kone Tenon Charly , Ghinet Sebastian , Panneton Raymond , GREWAL Anant
Published: July 2024

Addressing the challenge of attenuating low-frequency broadband noise emerges as a critical concern within the fields of aeronautics, ground transportation, and construction industries, requires innovative solutions for enhanced acoustic control. Over the last few decades, the literature has seen an increase in low-frequency noise control solutions centered around acoustic metamaterial designs. These proposed technologies exhibit promising acoustic performance, especially proving superior to conventional sound insulation materials in constrained spaces, such as in aerospace applications. Despite the efficacy of typical metamaterials in attenuating tonal noise through narrow resonant frequency maxima, practical applications reveal some challenges, as even slight variations in tonal noise frequencies can compromise the overall effectiveness of such solutions. In response to this, the present paper introduces a novel thin acoustic metamaterial design aimed at improving broadband noise attenuation at low frequencies. This design uses carefully arranged structured metamaterials within a fiberglass layer to create optimal resonance frequency bands for maximum low-frequency noise attenuation. Performance assessment in the low-frequency domain employed COMSOL Multiphysics finite element methods, predicting sound absorption coefficient and transmission loss. Results confirm the effectiveness of the proposed metamaterial design, showcasing broad noise attenuation at low frequencies.
Unexpected findings from L2 speech research can help us understand how humans process vowels
Authors: Bohn Ocke-Schwen
Published: July 2024

Research on nonnative speakers’ vowel production and perception has provided us with a number of surprising insights on how learners cope with nonnative vowels. Three of these initially unexpected, yet later solidly replicated, findings will be presented: (1) A decline in intelligibility of nonnative vowels as general proficiency improves (when an increase in intelligibility will be expected), (2) the use of acoustic cues in L2 vowel perception that cannot be attributed to transfer from the native language, and that are nonfunctional in the L2, and (3) the maintenance from infant speech perception in adult cross-language vowel perception of a bias favoring peripheral vowels. This presentation will discuss implications of these findings for our understanding of how vowel categories coexist in the minds of multilinguals, and of universally (native-language independent) preferred ways of vowel perception.
The origins of frequency-difference and frequency-sum beamforming
Authors: Abadi Shima , Dowling David R. , Song Heechun , Haworth Kevin J.
Published: July 2024

Beamforming the signals recorded by an array enables the determination of sound source location(s) or the arrival directions of ray paths between a sound source and the receiving array. Frequency-difference and frequency-sum beamforming are beamforming techniques that provide out-of-band information from in-band signal frequencies. Interestingly, the out-of-band frequencies can be chosen by the user, within limits set by the signal recordings, to achieve desired properties of the beamformed output, such as: increased resolution, reduced sidelobes, or greater robustness to random scattering. Both techniques are general and are not limited to any particular acoustic environment, frequency range, or array geometry. Frequency-sum beamforming, generates higher-frequency information from lower frequency signal components, enhancing beamforming results in scenarios with random scattering between the source and the receivers. However, it is limited by artifacts arising from cross-terms when multiple source signals are present in the same bandwidth. Conversely, frequency-difference beamforming manufactures lower-frequency information from higher frequency signal components, effectively mitigating the impact of spatial aliasing in situations where the receiving array is sparse. This presentation delves into the origins of frequency-difference and frequency-sum beamforming, presents the fundamental mathematics underlying their algorithms, and showcases their performance via simulations and experimental results. [Work supported by ONR.]
Frequency difference-wavenumber analysis for direction-of-arrival estimation in sparse vertical array
Authors: Kim Donghyeon , Byun Gihoon , Kim J. S.
Published: July 2024

Frequency–wavenumber (f–k) analysis can determine the direction-of-arrival (DOA) for broadband signals captured by a vertical array [M. J. Hinich, J. Acoust. Soc. Am., 69, 732–737 (1981)]. The sparse vertical array generates numerous sidelobes in the f–k domain due to aliasing errors resulting from the spatial sampling. This presentation introduces the frequency difference-wavenumber (△f–k) analysis, expanding the application of f–k analysis to the sparse vertical array by adopting the concept of frequency difference. The relationship between the frequency difference beamforming and the △f–k analysis is also discussed. Experimental results verify the effectiveness of the proposed △f–k analysis in estimating the DOA of snapping shrimp clicks (11–24 kHz) recorded using a sparse vertical array in a shallow water experiment. During the experiment, a vertical array with an element spacing of 3.75 m (i.e., design frequency = 200 Hz) is utilized, which is extremely sparse because it corresponds to 27.5 wavelengths at the lowest frequency.
A survey of stage acoustic conditions for choral performances
Authors: Martellotta Francesco , Rubino Chiara , Liuzzi Stefania
Published: July 2024

Choral performances, due to a very large number of non-professional groups often operating in small cities, frequently take place in non-dedicated spaces like churches, open atria, and other spaces with unusual acoustic conditions. This results in performances taking place in spaces without a real “stage” and consequently, in acoustic conditions that, as reported by several interviews, lack support and communication among singers. In order to better understand the effective acoustic conditions experienced in real spaces that frequently host choral performances, an on-site survey was carried out in six venues including one semi-open atrium and five churches of different styles and dimensions. Measurements were carried out according to ISO 3382-1 requirements, also taking into account the most recent proposals in terms of stage support to account for actual source directivity and presence of reflecting elements close to the source. Results showed that smaller spaces where vertical surfaces where more likely to be closer to the performers behaved better than large spaces where side volumes (like transepts or high domes) mostly withdrew acoustic energy yielding STearly values much lower than −12 dB.
Development of an acoustic design support tool for HVAC ventilation units
Authors: Khalladi Malek , Tong Hong
Published: July 2024

HVAC equipment is one of the main sources of noise inside or outside a building. Furthermore, many people are exposed daily to HVAC noise, which can lead to health-related troubles. Therefore, an HVAC mechanical unit must be selected to provide an acceptable sound level transmitted to the occupied spaces of a building and not disturb the community. This paper presents a prediction tool named Sound Prediction Tool (SPT) developed by MJM Acoustical Consultants Inc. in 2021 that allows the engineer (i) to design an HVAC unit with specific mechanical components (filter, coil, etc.) according to his input parameters and (ii) to predict and optimize the sound levels produced by the selected design through its casing and openings (inlet and outlet air). This tool has been validated firstly with acoustical tests ‘’in situ’’ on several separate Air Handling Units (AHU) manufactured by our customer and secondly with Finite Elements Method (FEM) models using Comsol-Multiphysics. Several examples are presented to demonstrate the usefulness of the proposed tool.
Transit-oriented development: A case study of exterior-to-interior noise control for buildings near transit and highway noise sources
Authors: Nalls Leisa , Jue Deborah , Bensing Silas
Published: July 2024

A case study of acoustical design for mixed-used, transit-oriented development is presented. The project is two, six-story mixed-used residential buildings near a rapid transit station and heavily traveled elevated highway in the San Francisco Bay Area. The buildings are metal frame construction over concrete podiums. The California Building Code requires the building shell to be designed to provide interior noise from exterior noise sources not to exceed 45 dBA Ldn. Exterior noise due to trains and buses serving the transit station, and traffic on the elevated highway, required high sound attenuating windows and acoustically rated walls and roofs. Initially, none of the exterior wall assemblies included batt insulation in the stud cavities, only continuous rigid insulation behind the façade. Modeling was done to compare the exterior wall assemblies with and without batt insulation in the stud cavities combined with various window configurations. Estimates of the building shell transmission loss are presented along with a summary of noise control recommendations for building roof, windows, and doors.
Silencing the rolling thunder: An almost unthinkable acoustic isolation facade solution
Authors: Kanter Shane J. , Dulworth Nicolaus T. , Giegold Carl P.
Published: July 2024

Situated along a popular motorcycle route, the Lindemann Performing Arts Center at Brown University posed a unique challenge to its design team — isolating the performance space from external road noise while adhering to the demanding RC 15 performance standard. This presentation provides a comprehensive exploration of the intricate development and testing of a robust yet relatively lightweight acoustic isolation façade system. The ultimate approach employed unconventional damping methods, ensuring compliance with dew point requirements. The paper delves into the nuances of the design process, with a focus on key elements such as glazing systems, roofing solutions, access doors, and gypsum buildups that push the boundaries of conventional construction, challenging the possible maximum length of a drywall fastener. Attendees will gain valuable insights into the innovative strategies implemented to achieve effective acoustic isolation without compromising the high-performance standards demanded by the Lindemann Performing Arts Center. This presentation serves as a valuable case study, offering a deeper understanding of the intersection between architecture, acoustics, and the practical challenges encountered in the design of performance spaces.
Design condiserations for secondary glazing systems
Authors: Levins Jennifer , Markham Benjamin E.
Published: July 2024

Addressing high noise levels from intermittent environmental sources, such as from train pass-bys, presents both acoustical and architectural challenges. One effective noise mitigation approach is to provide secondary storm glazing, but this is not always favored by architects, developers, and builders due to operational and aesthetic shortcomings, budget considerations, and installation challenges. These pitfalls are not always well-communicated among the design team, leading to a compromised solution. In this case study, we will discuss the concerns related to secondary glazing and the collaborative process used with the design team—informed by lessons learned on prior projects—to find a solution that addresses the various project goals.
New York City noise code and open windows
Authors: Manley David , Ahrens Steph
Published: July 2024

The New York City Noise Code requires compliance with noise levels from stationary sources such as HVAC equipment to residential receivers to be measured inside the receiver location with an open window or patio door. The presentation will include the review of recent case studies completed by DLR Group with school renovations and calculated noise impact to adjacent properties. Discussion of the corrections used for window openings will be included.
Bulk analysis of underwater sound spectra from vibratory pile driving of cylindrical steel piles in coastal waters
Authors: Caplinger James , Hotchkin Cara , Tyson Moore Reny , Guan Shane
Published: July 2024

Vibratory pile driving is a common means of pile installation in both near-shore and offshore environments. Spectral knowledge of the noise produced by this activity is crucial in modeling and assessing the impacts to aquatic species. With the goal of providing generic representative spectra to better inform propagation modeling and related impacts, approximately 80 near-pile measurements of vibratory pile driving of cylindrical steel piles from more than 19 hydroacoustic reports were analyzed. Included pile diameters range from 24–48 inches and all measurements were of activities in U.S. coastal waters. Results include representative spectra based on the mean and median spectra binned by pile size and the presence of noise mitigation systems, an examination of the variation in the data, marine mammal hearing group weighted spectra, broadband sound pressure levels, and comparisons with general knowledge of vibratory pile driving spectra characteristics in previous literature. Finally, data availability and larger efforts aimed at a comprehensive underwater pile driving acoustic spectral database are discussed.
Size and pressure dependent activity of lipid coated bubbles and finite element simulation of the propgation of focused ultrasound through bubbly media
Authors: Jafarisojahrood Amin , Pellow Carly , Exner Agata A. , Goertz David , Kolios Michael
Published: July 2024

Use of nanodroplets as alternative to bubbles is limited to high pressure applications due to their high vaporization threshold (>1 MPa). For low pressure applications (e.g <800 kPa) and stable bubble activity, size isolated micron or sub-micron bubbles may be used to tackle the pre-focal bubble activity and attenuation. Numerical simulations of the Marmottant model were ran for bubble sizes of 0.45, 1, 2, and 4 μm in response to 1 MHz ultrasound with pressures between 10 and 700 kPa. All agents were volume matched to 20 μl/kg of Definity considering inter-bubble interactions. The pressure-dependent attenuation and the total acoustic power (TAP) were calculated for each population. Finite element simulations (FEMS) were run by taking account the pressure dependent attenuation and sound speed. Using size isolated bubbles an experimental passive cavitation case study was performed for the same exposure conditions and sizes. Numerical results show that TAP and attenuation of the bubbles are size dependent. Bigger bubbles have stronger responses at lower pressures. However, smaller agents exhibit a size-dependent pressure threshold behavior (PT) above which their attenuation and TAP grow stronger than their bigger counterparts in qualitative agreement with experiments. FEMS show that the PT of oscillations may be used to reduce pre-focal attenuation for ultrasound propagation with minimal loss.
Microstreaming profile of a phospholipid-coated wall-attached microbubble undergoing shape oscillation
Authors: Li Hongchen , Wang Yuchen , Su Ruisheng , Cierpka Christian , Versluis Michel , van der Steen Antonius F. , Verweij Martin D. , de Jong Nico , Kooiman Klazina
Published: July 2024

Ultrasound-activated microbubbles induce shape oscillation and microstreaming. However, a thorough understanding remains elusive. This study investigated the 3D microstreaming profile of clinically relevant lipid-coated microbubbles undergoing shape oscillation when bound to a wall. Size-controlled biotinylated microbubbles (radius 3–8 μm) were produced by a flow-focusing device and bound to a streptavidin-coated glass. Insonification spanned 85–425 kPa at 25,000 cycles and 1.25 MHz. Two cameras, operating at 5 Mfps and 10 kfps, coupled to a microscope, captured microbubble shape oscillation and cavitation microstreaming, respectively. Astigmatic particle tracking velocimetry measured 3D particle trajectories of 500-nm beads. In the dataset (n = 79), four microstreaming profiles were observed: quadrupole, dipole, radial, and patternless. Modal decomposition revealed that quadrupole patterns resulted from self-interaction of the predominant shape mode, while dipole patterns arose from strong interactions of two nearby modes at the same oscillation frequency. Microstreaming reached 0.002–0.01 m/s at varying acoustic pressures. Quadrupole microstreaming generally induced higher shear stresses than dipole and radial patterns at identical acoustic pressure. A lower shape mode induced higher shear stresses than a higher mode at the same acoustic pressure. The unique microstreaming characteristics yield diverse outcomes in mechanical impact, which could aid efficient therapeutic applications of ultrasound-activated microbubbles.
Controlling the stability of monodisperse lipid-coated microbubbles by tuning their buckling pressure
Authors: Versluis Michel , van Elburg Benjamin , Lajoinie Guillaume , Segers Tim
Published: July 2024

Through recent years, major hurdles associated with the microfluidic production of phospholipid-coated monodisperse microbubble have been overcome which has granted them a long shelf life. This has heaved the hope of using their unique properties in vivo for improved contrast, controlled therapy, or noninvasive pressure measurement. However, these bubbles are also very sensitive to small changes in ambient pressure which compromises their clinical translation: upon intravenous injection, physiological pressures will cause bubble dissolution, degrading their uniformity. Here, we demonstrate the direct relation between shell buckling and bubble dissolution by acoustically measuring the buckling pressure and the response of bubbles to controlled pressure changes. We show that the concentration of PEGylated lipid, necessary for microfluidic operation, can be used to tune the buckling pressure, and thereby increase bubble stability. We show that this concentration can be changed either directly during bubble production or, more conveniently, by heating the microbubbles after production. The proposed heating step exploits the phase-change of the phospholipids within the shell to selectively expel the PEGylated lipids. Doing so, the bubble buckling pressure can be increased from 0 kPa to 27 kPa which is above physiological pressures.