bluuebunny/crossref_metadata_2025 huggingface dataset:
The ongoing sound change between /l/ and /n/ in Gan Chinese: Random forest classification
Authors: Wang Fenqi , Deng Delin , Wayland Ratree
Published: November 2021

The contrast between /l/ and /n/ in syllable-initial position may be absent or not consistently maintained across sub-dialects of Gan Chinese. To see if the /l/ and /n/ contrast is acoustically differentiated among speakers of Gan Chinese, a set of acoustic measurements were extracted from their production of words beginning with /l/ and /n/ and submitted to random forest classification. The extracted acoustic measurements were: (1) consonantal duration; (2) frequency and formant intensity of F2 and F3; (3) H1*-H2*, H1*-A1, and H1*-A2; (4) A1-P0 and A1-P1 measurements (at the 25% point of the following vowel). Post vowel context binary: /i/ and non-/i/. All tokens (/l/: 73%; /n/: 27%) were partitioned into a training set (953 tokens) and a test set (318 tokens). After training with the training set, the final classifier was applied to the test set to evaluate the categorical prediction of /l/ and /n/ with a classification probability. The results obtained indicated that most variants of /n/ would be categorized as /l/, suggesting an ongoing sound change between /l/ and /n/ that may be influenced by the vowel context.
Optimal reduced-order solution to the 3D deterministic parabolic wave equation
Authors: Charous Aaron , Lermusiaux Pierre F.
Published: November 2021

In weakly scattering media, the parabolic wave equation is often utilized to develop approximate solutions to the Helmholtz equation. However, in three dimensions, at high frequencies, and when the computational domain becomes very large, computational cost grows quickly. We propose using a reduced-order modeling approach for the deterministic 3D parabolic wave equation via the dynamical low-rank approximation. This approach is similar in spirit to the normal-mode technique; however, instead of using fixed modes for the entire computational domain, we instantaneously optimally evolve the modes in range according to the PDE dynamics. This dynamic order reduction provides a more accurate low-rank approximation to the parabolic wave equation. We demonstrate the efficacy of this technique on realistic ocean acoustic test cases.
Generative deep learning model for broadband acoustic metamaterial design
Authors: Amirkulova Feruza , Tran Thang , Khatami Ehsan
Published: November 2021

This study presents a promising data-driven approach for approximating and minimizing acoustic wave scattering in 2D acoustic cloak design, in which the optimal arrangement of cylindrical structures is found via a combination of generative deep learning models and optimization based on data generated by multiple scattering theory. In forward design, a fully connected neural network and convolutional neural network is trained with binary images of planar configurations of rigid cylinders to predict the total scattering cross section (TSCS) at discrete values of normalized wavenumber. In inverse design, generative deep learning models are developed that encode cylindrical structures into a continuous representation called a latent vector, and new structures are generated by decoding random latent values in this representation. In these models, the variational autoencoders, supervised and unsupervised learning, and Gaussian process are combined to predict optimal arrangements of scatterers for the desired minimal TSCS. Comparison of the scattered wavefield between the generated configurations and the numerical result shows the validity and effectiveness of the proposed method.
Algebraic method for shaping percussive bars
Authors: Elliott Greg
Published: November 2021

In the tuning optimization problem for percussive bars, shape profiles are parameterized in terms of some appropriate set of functions, and parameters are sought that produce desired mode frequencies. For a specific bar shape, the bending mode frequencies can be accurately determined within the Timoshenko-Ehrenfest model using a finite element analysis. Under certain conditions, a useful set of functions that reduces the differential equation to a purely algebraic problem can be constructed from solutions to the corresponding uniform system problem. These constructed functions vary on the same scale as the uniform beam bending modes and hence couple effectively to shift the mode frequencies. This algebraic methodology is applied to the percussive bar problem, and a Monte Carlo optimization is performed to determine shape functions that produce bars with the frequency ratios of the marimba (1:3:6), the xylophone (1:4:10), and an "octave bar" with ratios 1:2:4:8. Bars were constructed according to these designs, and acoustical measurements are in good agreement with model predictions.
Microphone placement investigation for standard aircraft ground run-up noise measurements
Authors: Wall Alan T. , Campbell Steven C. , Mobley Frank S.
Published: November 2021

The correct placement (height, orientation, and mounting techniques) for microphones used in standard data collection practices for aircraft environmental noise models is a topic of frequent debate. Previous studies have demonstrated and quantified the dependence of spectral data recorded as a function of microphone placement variations and relative source origin. In this work, an in-depth investigation of microphone mounting effects is performed with an emphasis on (1) microphone height and (2) ground-mounting configuration for the purpose of quantifying ground run-up aircraft noise emissions for environmental noise model generation. Data for this investigation were collected on the T-7A Red Hawk in both standard (see ANSI S12.75-2012) and off-standard configurations for comparison.
Far-field characteristics of installed F404 engine noise
Authors: Christian Matthew A. , Mathews Logan T. , Gee Kent L. , Johnson Jon P. , Campbell Steven C.
Published: November 2021

Noise measurements have been recently made of a T-7A-installed GE F404 engine in both the near and far-fields (Leete et al., AIAA paper No. 2021-1638). This paper describes far-field analyses of data collected along a 76 m (250 ft) arc at inlet angles spanning 30 to 160 degrees, at engine conditions ranging from intermediate through full afterburner. From calculated overall and frequency-dependent directivity curves, far-field noise properties are obtained as a function of engine condition, including change in peak directivity angle and associated spectral properties, radiation lobe width, overall sound power level, and sound power spectra. The results guide physical insights regarding changes in jet characteristics with engine condition as well as serve as benchmark data for comparing with laboratory and numerical datasets. [Work supported by ONR.]
Seismometers as infrasound sensors
Authors: Costley Richard D. , Hayward Chris , De Jesus Diaz Luis
Published: November 2021

An experiment was conducted in West-Central Mississippi in which five explosive charges were detonated. The TNT equivalent sizes of the charges ranged from 0.57 to 10.91 kg (1.25 to 24 lb). Among the arrays of sensors deployed, seismometers were deployed near microphones at distances of 0.5, 2.1, and 8.4 km from the source. The blast wave at these distances had decayed in amplitude to an acoustic wave. The coherence between the seismometer and microphone signals showed that the seismometer provided reasonable representation of the acoustic wave over a limited frequency band. This band changed with distance from the source. In addition, two 3-component seismometers were deployed near each other 8.4 km from the source. These seismometers were of different types, one having a resonance frequency of 1 Hz and the other 4.5 Hz. The signals from the horizontal components of these seismometers were analyzed to determine their effectiveness as vector sensors. The results showed that the back-azimuth determined from the seismometers agreed reasonably well with ground truth for the first arrival of the acoustic wavefront, however the results degraded as the trailing part of the wavefront passed. Permission to publish was granted by the Director, Geotechnical and Structures Laboratory.
Simulation of sound field in a reverberation chamber using the diffusion equation model
Authors: Hao Ryan , Xiang Ning , Navarro Juan
Published: November 2021

The acoustic diffusion equation model has been applied within a wide range of enclosure types to simulate diffuse sound fields. Recently, focus has been drawn to its applicability in reverberation chambers to simulate sound fields among a heterogeneous distribution of absorbing materials, particularly those that are highly absorptive. Where quasi-diffuse or non-diffuse sound fields are generated in the presence of highly absorptive material, the acoustic diffusion equation model has convenient capabilities to simulate sound energy flow. Furthermore, it has continued to show promise in characterizing the absorption coefficients of sound absorbing material. Challenges for reproducibility in reverberation room measurements have been well-documented and where traditional chamber-based measurement have shown to be inconsistent, this work will evaluate the acoustic diffusion equation model’s suitability as an alternative and accurate method to characterize absorption coefficients.
Target density estimation of mesopelagic fish using a towed, broadband, split-beam, acoustic scattering system
Authors: Zhuang Zhaozhong , Lavery Andone C.
Published: November 2021

The ocean mesopelagic zone (200–1000 m) features a complex temporal and spatial distribution of organisms which may play an important role in ocean biogeochemical cycles. Yet a quantitative account of the abundance, biomass and migration behaviors of mesopelagic inhabitants is still lacking. Shipboard echosounders are limited by acoustic attenuation at higher frequencies constraining the usable frequency band for investigating deep sound scattering layers, as well as large acoustic sampling volumes, a result of the large depths associated with the deep scattering layers, combined with the inherent complexity of mesopelagic communities. Deep-See, a towed platform carrying multiple broadband sonars, focuses on individual targets in the deep scattering layers, to help interpret shipboard data. Target density estimation is the first step towards determining biomass in the mesopelagic zone. Two methods are investigated and applied to a summer 2019 dataset collected using two broadband split-beam echosounders (5.5–18.5 kHz, 18–47 kHz) on Deep-See in the slope waters off the New England Continental Shelf. The echo-counting method utilizes echo magnitude and phase information to determine singe targets while echo-statistics involves comparison of data to a physics-based numerical simulation to predict the statistics of broadband echoes from which target density can be extracted.
Investigating the impact of ambient noise on candidate sonic boom metrics
Authors: Anderson Mark C. , Gee Kent L. , Durrant J. T. , Loubeau Alexandra , Doebler William
Published: November 2021

One goal of NASA’s X-59 flight campaign will be to collect low-amplitude sonic boom data over several communities. The combination of lower-amplitude booms with greater ambient noise could pose challenges in measuring and calculating accurate sonic boom perception metrics intended to be correlated with human annoyance. This study uses two NASA sonic boom flight test and simulated X-59 datasets to investigate the impact of limited measurement bandwidth due to ambient noise for multiple candidate metrics. An estimate of the signal-to-noise ratio spectrum allows for the comparison of metrics calculated with full bandwidth, limited bandwidth, and those calculated by applying a low-pass filter that approximates a noise-free full-bandwidth spectrum. The low-pass filter is chosen to approximately match the expected high-frequency roll-off of the sonic booms. Results indicate that Perceived Level and A-weighted sound exposure level are strongly affected by ambient noise and bandwidth limitations, but that B-weighted sound exposure level is much less affected. These results contribute to community noise test planning by demonstrating the ambient noise impact on candidate sonic boom perception metrics. [Work supported by NASA Langley Research Center through National Institute of Aerospace.]
Propagation of plane acoustic noise of finite amplitude
Authors: Pestorius Frederick M.
Published: November 2021

I was Professor Blackstock’s first doctoral student at the University of Texas. I arrived at Texas having been away from serious academic work for six years while serving on submarines. David took me under his guidance and proposed an investigation of the propagation in air of plane finite-amplitude noise waveforms. The work was both theoretical and experimental, and the results obtained were valid both before and after shock formation. Starting with David’s formulation of weak shock theory, we included Kirchhoff tube wall attenuation and dispersion because the experimental work was done in a pipe. The 96-foot pipe possessed an anechoic termination to permit the study of traveling waves. The theoretical model is unique in that it combines the effects of nonlinear distortion as well as tube wall attenuation and dispersion, and it is valid for input waveforms of arbitrary shape. The model was implemented in FORTRAN code and uses FFTs, relatively new at the time, to alternate between the time and frequency domains at each step along the propagation path. We initially tried to solve this problem analytically, but that effort failed in a sea of algebra. Outstanding agreement with the measured waveforms was obtained.
Reflecting on David Blackstock’s contributions to understanding nonlinear propagation of jet noise
Authors: Gee Kent L.
Published: November 2021

In 2002, my Ph.D. advisor, Vic Sparrow, and I began to research a problem in physical acoustics that had been relatively untouched for many years: modeling the nonlinear propagation of noise from high-speed jets. Without a steady progression of recent research to rely on, and flummoxed by seemingly nonphysical approaches to the problem by others, I found myself revisiting papers and reports authored by David Blackstock and his students in the 1970s: Pestorius, Anderson, Webster, and others. Within these reports, I found both critical insights and direction. In this talk, I will review David’s foundational contributions to nonlinear jet noise propagation and some meaningful interactions.
Phase velocity imaging using acoustic radiation force-induced shear wave with a multi-frequency excitation pulse
Authors: Hossain Md Murad , Konofagou Elisa
Published: November 2021

The viscoelastic properties of tissues are often assessed by analyzing the phase velocity dispersion curve computed using a 2-D Fourier transform onthe single fixed duration acoustic radiation force excitation pulse (FD-ARFEP)-induced shear wave with broadband frequencies. This study proposes a multi-frequency ARFEP (MF-ARFEP) using a single imaging transducer to generate shear waves at target frequencies of 100:100:1000 Hz to reduce noise in the phase velocity images. The MF-ARFEP is generated by summing sinusoids with target frequencies and then sampled to collect tracking pulses in-between the sampled MF-ARFEP. The MF-ARFEP is validated by imaging 6 and 70 kPa inclusions in a 18 kPa background, exvivo canine liver, and in vivo 4T1 breast cancer mouse tumor with comparison to the FD-ARFEP. The median phase velocity was similar between MF-ARFEP versus FD-ARFEP. However, the CNR was on an average 1.3 times higher in MF-ARFEP versus FD-ARFEP -derived images of inclusions and the coefficient of variation was on an average 1.1 and 2.2 times lower in MF-ARFEP versus FD-ARFEP-derived images of tumor and liver. These results demonstrate the feasibility of the MF-ARFEP excitation pulse to generate phase velocity images at 100:100:1000 Hz frequencies with reduced noise compared to the FD-ARFEP. Ongoing studies entail the translation of this new viscoelasticity imaging method for the characterization of breast cancer tumors in patients.
Soundwalks in new and existing intensive care units
Authors: Siebein Gary W. , Miller Jennifer , Vetterick Matthew , Jones Ian
Published: November 2021

Soundwalks were taken in 3 existing ICU’s in a hospital. New ICU’s were designed to address acoustical and other issues identified in the 3 existing ICU’s. Sound walks were taken in the 3 new ICU’s after they were constructed. While sounds of individual acoustical events were similar in the new and existing ICU’s, the overall sound levels and frequency of sounds decreased in the new ICU’s compared to the existing ICU’s. In other words, the sounds of people speaking were measured similarly in both ICU’s as were the sounds of doors closing, the ice machine operating and other specific acoustical events. However, the design of the new ICU removed the sounds of nurses speaking at the nurses’ station from proximity to patient rooms so the sound levels of people speaking who were not communicating directly with the patient or family were reduced in the new ICU. Additionally, the sounds of medical equipment were largely removed from the patient rooms in the new ICU. Equipment such as ice machines, coffee pots and other items were also removed from patient areas in the new ICU. Overall, the new ICU had a quieter environment for patients, nurses and visitors.
The soundwalk is a tool
Authors: Woolworth David S. , Brooks Bennett M.
Published: November 2021

Soundwalk protocols and procedures are formally established in ISO Standard 12913; the intention is a general reproducibility of results and to be able to compare soundwalk data for different walks, and even to bring the experience to the lab where it can be further examined. In general standards themselves require a reasonable level of technical expertise to execute, may require resources not available to laypeople, or may not align with the needs of a project. This paper will examine the soundwalk as a tool adaptable for given purposes and draw from soundwalks to entertain some of the questions related to the human elements such as perception, preconceived notions on sound, and repeated walks. The use of soundwalks to develop community sound ordinances will also be discussed.
Urban soundscape complexity
Authors: Botteldooren Dick
Published: November 2021

The soundscape approach has become common practice in urban sound design. ISO12913 provides methods for assessing it within context. One of the proposed approaches is grounded in the affect that the sound environment may trigger. In addition we have proposed that in everyday situations—that is when persons are not instructed to listen to the sound environment—saliency and attention should be considered and explain the existence of non-influential sound environments. However, the underlying mechanism causing a soundscape to be calming, stimulating, or disruptive are not completely explained by classical psycho-acoustic. We argue that complexity could be the missing factor. Complexity at the sensorial level has been suggested many years ago and it is now common in bio-acoustics. However, semantic complexity determined by the understanding of the interplay between sounds, has seldomly been considered. Yet, in an urban context, several auditory streams will likely co-exist. This conceptual idea is complemented by a measurement method relying on sound recognition by artificial intelligence to quantify the variation in likelihood over time of multiple sounds. Complexity indicators such as entropy and spectral slope can be calculated on this likelihood trend. It can be shown that they are related to effects of environmental sound.
David T. Blackstock and kidney stone lithotripsy
Authors: McAteer James A. , Bailey Michael R. , Crum Lawrence A.
Published: November 2021

For the past 25 years, David Blackstock served as External Advisor to an NIH Program Project Grant (PPG) dedicated to improving shock wave lithotripsy (SWL) of kidney stones. Invented in the 1980s, SWL revolutionized stone management, eliminating the need for open surgery. As a truly noninvasive surgery, SWL remains the flagship of medical acoustic therapies. Study of its engineering, bioeffects, and physical mechanisms of action helped make SWL safer and more effective and led to new modalities of diagnostic and therapeutic ultrasound. Dr. Blackstock’s role in this effort cannot be overstated. He was a regular participant in our series of in-depth, two-day, semiannual meetings where in addition to reviewing new data related to his areas of expertise in shock wave propagation and nonlinear acoustics he absorbed, dissected, and eloquently critiqued research in the broad array of fields (e.g., clinical urology, renal vascular physiology and pathology, fracture mechanics, and more) otherwise unrelated to his experience. Dr. Blackstock had the ability to learn on the spot and then add incisive, valuable suggestions based on his expertise, intuition, and critical thinking. He kept us focused. He elevated our thinking. He stimulated our creativity and encouraged us toward new ideas. Work supported by NIH-P01-DK043881.
From laboratory-scaled experiments to numerical predictions of sonic boom level variability due to atmospheric turbulence
Authors: Blanc-Benon Philippe
Published: November 2021

Supersonic flights of aircraft through the atmosphere create shock waves called “sonic booms.” Atmospheric turbulence affects the perceived loudness of sound at the ground level, mainly by changing its amplitude and rise time, which are significant factors in determining the acceptability of supersonic flight. Some authors compared theoretical predictions of sonic boom distortion to sonic boom recordings, but such analyses are limited because the parameters of turbulence cannot be measured accurately enough to allow detailed quantitative comparisons. In the 1990s David Blackstock showed that laboratory scaled experiments using N-waves produced by electrical sparks and a downscaled atmosphere offer an attractive alternative to field measurements since both the acoustic source and the turbulence can be controlled (Lipkens and Blackstock, JASA 1998, Lipkens and Blanc-Benon, CRAcadSci Paris 1995). Following this research, we developed at Ecole Centrale de Lyon two experimental setups to study separately the influence of temperature or random velocity fluctuations on the waveform distortion in relation to the occurrence of random caustics at large distances of propagation (Blanc-Benon, Lipkens, Dallois, Hamilton, and Blackstock, JASA 2002). The aim of this paper is to present recent experimental results obtained using optical interferometry and numerical predictions based on the nonlinear KZK propagation equation.
David Blackstock and the reflection and refraction of finite amplitude waves
Authors: Sparrow Victor W.
Published: November 2021

In honor of David Blackstock, this presentation recalls his contributions regarding nonlinear acoustics in the areas of reflection and refraction. Some of this is well documented and other pieces are not. For example, in his 1960 Ph.D. dissertation David was the first to recognize Pfriem’s pressure amplification equation would apply to finite amplitude plane-wave reflection from a rigid surface. Acoustic pressure MORE than doubles for finite amplitude rigid surface reflection, and it is the variational sound speed that exactly doubles. And this result provides a basis for an understanding of oblique reflection and the formation of finite amplitude Mach stems. Further, the work of David’s Ph.D. student Frederick Cotaras on finite amplitude refraction from 1989 will be highlighted in addition to other contributions as time permits.
Smartphone-derived 3D head and pinnae modeling for personalized 3D virtual audio
Authors: Pajunen Kirsti , Davis Shakti , Alberts Gabriel , Wright Hannah , Jones Heath , Smalt Christopher J.
Published: November 2021

3D audio is commonplace augmented or virtual reality environments, and is used simulate the direction of arrival for sounds presented over headphones. The Head-Related Transfer Function (HRTF) enables 3D audio by characterizing how sound is received from a sound source in every direction. Optimal sound localization performance with HRTF-based 3D audio is thought to require personalized HRTFs because the localization cues are dependent on the size and shape of the head and pinnae. In this work, we propose a prototype pipeline to generate HRTFs from high resolution smartphone videos of the head and ears, and we validate the localization performance of the resulting HRTFs through human-subject behavioral experiments. To create a personalized 3D HRTF, a video was taken of a subject’s torso, left ear and right ear using a smartphone camera. Acoustic simulation with Boundary Element Modeling was performed in COMSOL, taking an approximately 1 h to complete. Preliminary virtual sound localization results were obtained on a pilot subject for each of 3 different HRTF types: A generic HRTF, a gold standard acoustically measured HRTF, and the smartphone video HRTF. We found a mean angle error of 36.6, 21.1, and 14.0 deg, respectively, indicating that the smartphone-based HRTF developed in this study provides higher localization accuracy than other methods on this pilot subject. Further testing will add additional subjects, and compare to free-field localization over loudspeakers.
Are there binaural consequences of speech envelope enhancement?
Authors: Baltzell Lucas S. , Cardosi Daniel , Swaminathan Jayaganesh , Best Virginia
Published: November 2021

Fluctuations in the amplitude envelope play a critical role in the spatial perception of sounds. For example, listeners place increased perceptual weight on binaural cues occurring at onsets, and the steepness of onset slopes can influence binaural sensitivity. For speech stimuli, we recently showed that the temporal weighting of binaural cues is non-uniform and depends in part on the detailed behavior or the envelope. Here, we examined the potential binaural consequences of two monaural speech enhancement strategies that operate by altering the speech envelope: consonant enhancement (CE) and envelope expansion (EE). While CE and EE improve speech intelligibility under certain conditions, their effect on binaural perception has not been considered. We measured sensitivity to interaural time differences (ITDs) carried by single-word stimuli that were either unprocessed or processed with CE/EE. Thresholds were measured in quiet, in the presence of multi-talker babble, or for a vocoded condition designed to limit the availability of fine-structure ITDs. For ten listeners with normal hearing, while sensitivity depended on the specific word token, there were no systematic effects of speech enhancement on ITD sensitivity. Ongoing work is considering supra-threshold binaural tasks and listeners with hearing loss who have reduced spatial sensitivity. [Work supported by NIDCD.]
Effects of entropy in real-world noise on speech perception
Authors: Jorgensen Erik , Wu Yu-hsiang , Choi Inyong
Published: November 2021

Traditional tests of speech-in-noise perception use artificial background noise, leading to results that do not generalize to real-world scenarios. There is a significant need for improved ecological validity in laboratory and clinic speech-in-noise tests, particularly with respect to the types of noise used. However, the acoustic complexity and random nature of real-world noise poses challenges to its use and the interpretation of results. In this study, the complexity of real-world noise from 8 environments was systematically quantified in the time and frequency domains using entropy. Then, segments of noise distributed in entropy from low to high were extracted and combined with target sentences at fixed signal-to-noise ratios. Ten normal-hearing subjects were tested on 200 sentences-in-noise across the entropy distribution in both the time and frequency domains in a trial-by-trial design. Linear mixed effect models showed a significant effect of entropy in the time and frequency domains on number of words correct per trial. There was a systematic improvement in speech perception with increases in entropy variance in both time and frequency domains. Entropy in real-world noise affects speech perception even when the overall signal-to-noise ratio is fixed. Experiments using real-world noise should consider this effect in their design and interpretation.
Fusion of dichotic vowels with level differences across ears in normal-hearing listeners
Authors: Fan Langchen , Molis Michelle R. , Reiss Lina A.
Published: November 2021

Fundamental frequency (voice pitch) is an important cue for sound segregation. Previous studies show that normal-hearing (NH) listeners fuse pure tones with similar pitches. When two different vowels with the same fundamental frequencies are presented dichotically to the two ears, NH listeners often fuse the two vowels and perceive one vowel. Sometimes the perceived vowel is not one of the two vowels presented. Interaural level difference is an important cue for sound localization, which also helps with sound segregation. The current study introduced level differences into the dichotic vowel pair to examine how level differences affect vowel fusion. Dichotic vowel pairs were selected from synthetic vowels /i/, /ae/, /ɔ/, and /ʊ/ with the fundamental frequency of 109.9Hz. The level difference varied between -8 and 8 dB. The results showed that there was no significant effect of level difference on fusion in NH listeners. However, for some vowel pairs, the single fused vowel perceived changed significantly with level difference, indicating that internal representations of fused vowels can shift with level differences. This research was funded by NIH-NIDCD-R01-DC013307.
Binaural model analysis of wave-field-synthesis auralization over extended listening areas
Authors: Braasch Jonas , Chabot Samuel , Huang Mincong , Mathews Jonathan , Pastore M. Torben , Scott E. Ellington
Published: November 2021

This paper evaluates the performance of a recently proposed method to create auralizations with a 2D ray-tracing algorithm and publicly available floor plans. Using this method, acoustic landmarks were simulated for a 128-channel wave field synthesis (WFS) system. Late reverberation parameters are calculated using additional volumetric data. The approach allows the rapid sonic recreation of historical concert venues with adequate sound sources. The listeners can walk through these recreations over an extended user area (12 × 10 sqm), and the software suite can be used to calculate room acoustical parameters for various positions directly using a binaural rendering method or via the WFS simulation. To evaluate the performance of the auralization system binaural sound fields are rendered for various grid positions across the listening area and analyzed using a binaural model algorithm. The Binaurally Integrated Cross-correlation Auto-correlation Mechanism (BICAM) [J. Acoust. Soc. Am. 140(1), EL143] was selected for this purpose because it can estimate binaural activity patterns from a running signal with a 2-layer cross-correlation algorithm. Using this algorithm, the reflection patterns of early reflections and traditional room acoustical parameters (ISO 3382) were compared between the WFS auralization and direct binaural rendering method. [Work support by NSF IIS-1909229.]
Effects of target level on release from masking by voice-gender difference and spatial separation between talkers
Authors: Oh Yonghee , Schoenfeld Hannah , Layne Allison O. , Bridges Sarah E.
Published: November 2021

In multi-talker listening situations, spatial and voice-gender separation of the target from the masking speech are two major acoustic cues leading to substantial release from masking in normal-hearing listeners. A recent study demonstrated that the masking release by those two cues elicits an unequal perceptual weighting and a single point of intersection where the magnitude of masking release was the same for the two cue types, with a gender-specific difference of transition between two types of masking release [Oh et al., JASA-EL (2021)]. The goal of this study was to investigate how the interactions of these two cues are affected by various levels of the target (30, 40, and 50 dB SL). Speech recognition thresholds in the competing speech were measured, and masking release benefits by either voice-gender difference or spatial separation cues were calculated. Results revealed that the weighting of masking release from two cues is non-linearly related to the target levels. In addition, gender-related masking release was maximized when the target was presented at 40 dB SL. These results imply that a target level can be one major factor associated with maximal speech perception in noise in normal-hearing listeners. [Work supported by ASHA New Century Scholars Research Grant.]
Exploring a listener's ability to “eavesdrop” on two simultaneous conversations
Authors: Spencer Nathaniel J. , Thompson Eric R. , Simpson Brian D.
Published: November 2021

Most speech perception studies assume that the talkers are speaking to the subject, but little is known regarding subject ability to monitor exchanges between interlocutors (i.e., “eavesdrop”). The current study measured subject ability to monitor two concurrent, artificially generated “conversations” using phrases from the Coordinate Response Measure corpus. Individual conversations consisted of a “prompt” phrase of the form: “Ready [call sign] go to [color]-[number] now” and a “response” phrase of the form: “[same call sign] going to [color]-[number]”. A color and/or number prompt-response mismatch occurred within a conversation on 50% of trials. The listener was asked to identify whether a mismatch took place and, if so, identify in which of the two conversations the mismatch occurred. The (virtual) conversations were either co-located or spatially separated (±15°, ±90°). All talkers were of the same gender, or competing prompters and competing responders were of different genders. Group-mean performance ranged from about 65–80% correct in mismatch detection, and about 70%–85% correct in call sign identification (for mistake-ID correct trials). Performance improved when competing talkers were separated to ±15 deg in space, and/or in gender. This suggests that, on average, listeners can follow simultaneous conversations over time, particularly when competing talkers differ in pitch or space.
Tracking the evolution of structural resonances during the build phase of a wire-arc additively manufactured part
Authors: Fisher Karl A. , Elmer John , Candy James
Published: November 2021

Acoustic resonance tracking is investigated for a wire arc additive manufacturing process as a possible real time in situ diagnostic during the build. A small 40kHz acoustic emission sensor was attached to one end of a 5 × 1.5 in. cylindrical 316 SS rod. A series of layers (weld beads) were programmed into the control software of the robot to build a thin bar upward off the end of the cylinder. A high-speed long-duration digitizer-recorder was used to capture the transient acoustic signals (100 Hz–70 kHz) during the build process. Typical build durations were on the order of 1–2 h. The transient data were analyzed using short time window FFTs, as a function of build parameters. The model and experiment share similar features, however there are some notable differences. In particular, the number of actual modes recorded in the experiment is less than predicted due to the sensors low in-plane sensitivity. The current results indicate that the evolving spectral response of a part during the build process has the potential to provide real time process monitoring information. The time-frequency analysis of the diffuse sound field in the part, reveals a unique spatial and temporal perspective of temperature, stress and geometric features.
Effect of architecture and process on the ultrasonic mapping of hybrid additively manufactured materials
Authors: Sotelo Luz D. , Ley Jazmin , Pratt Cody , Avegnon Kossi Loic , Sealy Michael P. , Turner Joseph A.
Published: November 2021

Hybrid additive manufacturing enables the creation of materials with functional microstructure and mechanical property patterns. While samples with functional patterns provide unique advantages in the overall performance of the material, they present a challenge for nondestructive evaluation. In particular, the nondestructive mapping of the properties imparted by hybrid AM processes is critical. In this work, hybrid 316 stainless steel samples are created using laser powder bed fusion (LPBF) with varying hybrid architectures and with a variety of hybrid processes. The ultrasonic responses of these samples, in terms of wave speed, attenuation, and backscatter amplitude, are evaluated for each architecture and process combination. These responses are compared with those from conventionally manufactured samples and traditional AM samples. This evaluation provides information on the sensitivity of ultrasonic responses to hybrid architecture and process, highlighting the potential of ultrasonic nondestructive methods for the characterization of hybrid AM components. [This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 1610400. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.]
Additive manufacturing of architected ceramics foam for noise reduction
Authors: Nevarez-Saenz David , Adler Ted , Sharma Bhisham , Wei Wei
Published: November 2021

Porous foams are routinely used for noise control applications; their open cellular structure provides good sound dissipation performance over a broad frequency range while retaining low bulk density. However, conventional acoustic foams cannot satisfy the mechanical and flammability constraints frequently encountered in aerospace applications. While fiberglass blankets are currently used for high temperature noise dissipation applications, their batch-to-batch performance variability and lack of mechanical stiffness remains an engineering hurdle. In this study, we investigate the viability of additively manufacturing ceramic foams for high temperature noise dissipation applications. We demonstrate the use of a low-cost, material extrusion 3D printer to fabricate ceramic foams with controlled porous architectures that can be tuned to provide exceptional sound absorption properties. The printed and sintered ceramic foams are tested using a normal incidence impedance tube and the effect of various print, sintering, and geometrical parameters on the acoustical impedance are studied. Our work shows that low-cost additive techniques present a viable step toward scalable fabrication of ceramic foams with tailored mechanical and acoustical properties.
The untapped potential of human language: Investigating the perception of typologically unattested and rare consonants
Authors: Brislane Catherine
Published: November 2021

Though research into this area is scarce, the perception of rare and unattested consonants has potential for research in speech phonotactics and pronunciation, especially in relation to the creation of ConLangs which typically use non-native’ sounds in their phonological inventories. Previous studies explored the “nativeness” of rare/ non-English phonemes (Davidson, 2005; Linzen and Gallagher, 2017) or conducted ABX tests to gauge perceptual similarity (Noguchi and Hudson Kam, 2017; Pisoni et al., 1982). This paper explores why rare and unattested phonemes may be less common in speech today by using a variation of the ABX methodology. Using information from PHOIBLE (Moran and McCloy, 2019), each question contained three distinct sounds: a common phoneme, an English phoneme, and a rare/unattested phoneme (e.g., a palatal tap). The participant would then pick which sound (either 1 or 2) was most like the third “hook” phoneme (sound 3). Sounds 2 and 3 would then swap, creating a new “hook.” Similarity identification relative to sound 1 was analysed via logistic regression in R. Notably, several unattested phonemes were chosen over the opposing sound to a significance rate of p > 0.05, with a proportion of rare phonemes also being chosen to a degree of significance over English sounds.
Investigating the perceptual magnet effect in speech perception: An event-related potential study
Authors: Zhang Yang , Miller Sharon , Zhang Xiaojuan , Cheng Bing
Published: November 2021

The “Perceptual Magnet Effect” (PME) is characterized by perceptual warping in favor of stronger assimilation near the prototypical sound against other nonprotypical variants. This ERP study adopted a modified oddball paradigm to examine the PME predictions. The participants were 18 normal adults. The stimuli were computer-synthesized /a/ sounds and their acoustic controls by replacing the formant frequencies with sinewaves. Prior to the ERP sessions, the prototype (P) and nonprototype (NP) were chosen based on behavioral identification and goodness rating. Then 4 variants were created with ±40 mels apart in reference to P or NP, respectively, in either the first formant (F1) or second formant (F2). Mismatch negativity (MMN) responses were derived with the P (or NP) as the standard and the 4 variants as the deviant. The same ERP procedure was used for the nonspeech stimuli. Behavioral results showed that individual subjects consistently rated vowel category goodness based on the F2/F1 ratio. MMN amplitudes in the P and NP conditions showed a pattern consistent with the PME model. This pattern was observed for both speech and nonspeech stimuli. These results provide neural evidence in support of the PME that may extend to general auditory processing of spectral patterns.
Generalization and specificity in adaptation to unfamiliar speech
Authors: Baese-Berk Melissa M. , Drake Shiloh , Foster Kurtis , Lee Dae-yong , Staggs Cecelia , Wright Jonathan
Published: November 2021

Unfamiliar accents are often harder for listeners to understand than familiar accents; however, previous work has demonstrated that listeners are able to quickly adapt to unfamiliar speech. Further, when listeners are trained on speech from multiple unfamiliar accents, they are able to generalize to a talker with a novel unfamiliar accent. However, tasks used in previous studies are not sensitive enough to determine whether this increased generalization also comes with costs for the specificity of learning. That is, when a listener is trained on multiple talkers and multiple accents, do they demonstrate costs for adaptation to an accent as compared to listeners who are trained on multiple talkers from a single accent? Here, we present data from multiple tasks designed to investigate both whether listeners generalize after exposure to multiple accents, but also whether this more diverse training results in a cost to specificity of learning for a single accent.
How intonation and articulation cues impact gender perception for cisgender and transgender speakers
Authors: Merritt Brooke , Bent Tessa
Published: November 2021

Gender identities beyond cisgender male and female are poorly represented in speaker gender perception research. Incorporating transgender speakers may reveal speech characteristics that extend beyond hetero-cis-normative standards and better reflect listeners' real-world experiences and cognitive representations of gender. This study compared how intonation and articulation impact listeners’ judgements of speaker gender identity and masculinity/femininity using cisgender male and female, transfeminine, and transmasculine speakers. Cisgender speakers' fundamental and formant frequencies were shifted to gender-ambiguous range and transfeminine and transmasculine speakers to prototypically cisgender female or male range, respectively. Listeners judged speaker gender in conditions that either removed fundamental frequency variation, frequencies above 500 Hz, or both cues. There were nonuniform effects of intonation and articulatory modifications on listener perceptions of gender across speaker groups. However, articulation influenced listener perception more than intonation. When listeners heard articulatory as compared to intonation cues, gender identification scores were generally higher for all speaker groups and masculinity/femininity scores more aligned with cisgender female and transfeminine speakers’ gender identities. Although most prior work with transgender speakers has focused on intonation, articulation can substantially impact gender perception and should be considered in gender affirming communication training.
Perceptual assimilation of regionally accented Mandarin lexical tones by native Beijing Mandarin listeners
Authors: LI Yanping , Best Catherine T. , Tyler Michael D. , Burnham Denis
Published: November 2021

Pronunciations of Beijing Mandarin are those of Standard Mandarin (hereafter Mandarin), which developed from the Beijing dialect. Native speakers of other regional dialects in China learn Mandarin as an early second language, and produce its four lexical tones (level, rising, dipping, and falling) with regional accents. This study investigated how native Beijing Mandarin listeners perceptually assimilate regionally accented Mandarin lexical tones. Native Beijing Mandarin listeners (Mage = 21.31 years) were recruited to identify 16 Mandarin real words (4 consonant-vowel syllables: ba, di, du, gu × 4 tones) produced by speakers of Beijing, Shanghai, and Guangzhou dialects and to rate how similar the productions were to the Beijing accent. Stimuli were blocked by syllable, maintaining minimal contrasts between the tones. The Beijing listeners identified Mandarin words in all three accents with high accuracy (>90%), indicating that they reliably assimilated the regionally accented tones into the four Mandarin tones. However, their reaction times were longer and their rating scores were lower for the regional accents than for the Beijing stimuli. This indicates that while Mandarin listeners are sensitive to accent differences in Mandarin lexical tones, they show phonological constancy across regional accents, which is crucial for tone categorization and discrimination of tone contrasts.
Judgments of self-identified gay and heterosexual male speakers of American English: Which vowels do listeners rely on to form their sexual orientation judgments?
Authors: Tracy Erik C.
Published: November 2021

Prior research (Tracy et al., 2015) demonstrated that, upon hearing a single phone, listeners differentiated between gay and heterosexual male talkers of American English. For instance, listeners relied on seven vowels (e.g., /æ/, /eɪ/, /ε/, /iː/, /oʊ/, /ɑ/, and /uː/) to form their judgments. From this particular finding, it is unclear whether the results could be replicated and whether these are the only vowels that listeners rely on; it is possible that listeners might rely on additional vowels. To further explore these issues, the present study examined a wider range of vowels (e.g., /i:/, /ɪ/, /eɪ/, /ɛ/, /æ/, /ɑɹ/, /ɑ/, /ɔ/, /oʊ/, /u:/, /ai/, /aʊ/, /ɔɪ/, /ɪr/, / ^/, and /ju/) and, in most instances, presented two different tokens of each vowel to listeners. Some tokens of a vowel (e.g., /i:/, /ɛ/, /æ/, /oʊ/, /u:/, and /ju/) came from a stressed syllable and some tokens came from an unstressed syllable. Only four vowels (e.g., /ɔ/, /aʊ/, /ɔɪ/, and / ^/) were presented once. Across all instances of every vowel, participants were able to significantly discriminate between gay and heterosexual speakers. Thus, listeners use a wide range of vowels to form their sexual orientation judgments of male talkers.