bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissociating sensitivity from bias in the mini profile of music perception skills
Authors: Whiteford Kelly L. , Goh PuiYii , Stevens Kara , Oxenham Andrew J.
Published: November 2021

The Mini Profile of Music Perception Skills (Mini-PROMS) is a widely used objective measure of musical competence that has been validated for online data collection [Law and Zentner, PLoS One 7, e52508 (2012); Zentner and Strauss, Ann. NY. Acad. Sci. 1400, 33–45 (2017)]. This measure involves determining whether a comparison melody is the same or different from a standard on a 5-point scale (“definitely different”, “probably different”, “I don’t know”, “probably same”, or “definitely same”). The traditional PROMS scoring method is to calculate a composite score, which differentially weights correct responses based on participant confidence. In this method, a high score can only be achieved with a confident response bias. The present study employed signal detection theory to calculate the participants’ sensitivity (d′), which is a bias-free measure of sensitivity if the signal and noise distributions (1) are normally distributed and (2) have roughly equal variance. 74 participants were tested on the Mini-PROMS with the purpose of calculating empirical ROC curves to test whether the assumptions of normality and variance are met. The study findings will provide important insight into how using different analysis methods might improve the validity of the Mini-PROMS. [Work supported by NIH grant R01 DC005216.]
Attention effects on cortical neural processing in spatial listening
Authors: Cheng Fan-Yin , Xu Can , Goodall Heather , Ornelas Miah Elise , Gold Lisa , Smith Spencer
Published: November 2021

Speech understanding in complex acoustic scenes relies on the formation of and attention to auditory objects. Spatial information is an essential cue in the formation of auditory objects and may facilitate attention-based neural enhancement and suppression of target and non-target speech, respectively. Previous studies have used cortical auditory evoked potentials (CAEP) to measure how attention modulates neural representation of spatially separated auditory objects. The current study further extends this work to investigate how expected and unexpected shifts in spatial location of speech signals affect neural processing of these signals. In the experiment, listeners were directed where to listen with a spatial cue presented from one of five locations (±90, ±45, or 0 deg azimuth); the following target sequence was either presented in the cued location (congruent trials) or from a non-cued location (incongruent trials). We hypothesized that neural responses to target sequences would be enhanced when presented from the cued location, whereas neural responses to incongruent sequences would initially be suppressed before spatial attention was shifted toward the target. Further, we expected the size of this suppression to be proportional to the size of the relative shift between cue and incongruent target.
Neural correlates of bilateral summation between natural and vocoded speech
Authors: Smith Francis X. , McMurray Bob , Litovsky Ruth Y. , Choi Inyong
Published: November 2021

The normal auditory system integrates redundant information across ears, which aids listeners to detect weak sounds. For patients with single sided deafness (SSD), cochlear implants (CI) have been attempted expecting improved speech recognition in challenging listening scenarios. However, it is not yet known whether CI recovers the bilateral summation for weak sound detection in SSD. The binaural benefit of soft-speech recognition was tested in six SSD CI patients and thirty normal hearing (NH) listeners. The task was identifying quietly presented (i.e., RMS ∼6 dB SL) monosyllabic words. CI patients were tested in three conditions: acoustic-ear only (A1), electric-ear only (E1), or both ears (A+E). NH participants were tested in four conditions: monaural natural speech (A1), monaural vocoded speech (E1), dichotic natural and vocoded speech (A+E), or dichotic natural speech (A2). Electroencephalography was recorded during the task. Bilateral conditions (A+E and A2), even when one ear was vocoded, resulted better accuracy than monaural conditions (A1 and E1). However, A+E condition exhibited smaller early auditory cortical responses (i.e., N1P2 complex) than any natural-speech conditions (A2 and even A1). This result may imply that bilateral summation benefits in SSD-CI users are achieved by later cognitive processing rather than immediate early integration.
An auditory-like region in the motor cortex
Authors: Herrera Ortiz Christian , Whittle Nicole , Leek Marjorie R. , Barnes Samuel , Holshouser Barbara , Yi Alex , Venezia Jonathan H.
Published: November 2021

Left premotor cortex is activated during listening to speech, but whether this reflects a motor mechanism or a response to auditory features is debated. Previously, we showed that left dorsal premotor cortex (dPM) responded to vocal pitch in a degraded speech recognition task, but only when speech was rated as unintelligible. Crucially, vocal pitch was not relevant to the task. Here, we hypothesize that left dPM will respond to vocal pitch for increasingly intelligible speech in a competing speech task that emphasizes pitch for talker segregation. We use fMRI (N = 25) and apply spectrotemporal modulation distortion to modulate pitch in two-talker (male/female) mixtures across two conditions (Competing, Unison), only one of which requires pitch-based segregation (Competing). A Bayesian drift-diffusion model was used to predict speech recognition performance (3-AFC response times) from the pattern of spectrotemporal distortion imposed on each trial. The model’s ‘drift rate’ parameter, a d’-like measure, was strongly associated with vocal pitch for Competing but not Unison. Trial-wise predictions of ‘pitch-restricted’ drift rate—i.e., that component of performance driven only by pitch – were positively associated with activation in left dPM for Competing but not Unison. These findings show that left dPM responds to auditory features during speech recognition.
Contralateral noise degrades frequency-coding accuracy in normal-hearing adults
Authors: Jeng Fuh-Cherng , Stehura Kelley A. , Hart Breanna N. , Giordano Allison T.
Published: November 2021

Noise presents a constant challenge in daily communication. Previous research has demonstrated the effects of ipsilateral noise on speech processing in the human brain. In this study, we examined the effects of contralateral noise on the accuracy of frequency coding at the subcortical level. Byusing a speech stimulus that mimicked the English vowel /i/ with a rising frequency contour, we obtained scalp-recorded, frequency-following responses in nine normal-hearing adults. To determine the effects of contralateral noise, we performed two experimental conditions: with and without the presence of contralateral noise. Results indicated that the fidelity of frequency coding, as reflected through Tracking Accuracy and Slope Error, were significantly degraded when continuous white noise was added to the contralateral ear. These findings provide important information and help us better understand how frequency cues are processed in noisy environments.
Neural correlates of top-down attention in auditory and visual contexts reflect individual differences in the population
Authors: Kwasa Jasmine , Noyce Abigail , Shinn-Cunningham Barbara
Published: November 2021

Individual variability in performance on selective attention tasks that require top-down control can be large. Recent neuroimaging and electroencephalography (EEG) experiments also suggest that auditory spatial selective attention engages the same fronto-parietal network used by visual spatial selective attention. We therefore hypothesized that individual differences in spatial selective attention would correlate for similar auditory and visual tasks and produce correlated changes in sensory responses in the two modalities. We calculated EEG-derived correlates of top-down, spatial attention during auditory and visual tasks that required subjects to sustain selective attention at one of two cued spatial locations (left or right) and report the auditory or visual sequence that appeared in that direction. Individual behavioral performance on the tasks correlated across sensory modalities. Spatial attention differentially modulated event-related potential N1 responses at the group level for both auditory and visual tasks. At the individual level, these attention-modulated N1 responses correlated with task performance for the auditory task; however, the ERP peaks were noisy and unreliable in the visual task. In contrast, the inter-trial coherence (ITC) in a time window encompassing the N1 correlated to performance for the visual, but not the auditory task. Our work highlights differences in how top-down attention modulates these representations across the two modalities.
A finite element formulation to determine the complex wavenumber spectrum of an underwater leaky wave antenna
Authors: Broadman Craig W. , Goldsberry Benjamin M. , Naify Christina J. , Haberman Michael R.
Published: November 2021

Underwater acoustic imaging traditionally utilizes phased arrays of electro-acoustic transducers to steer acoustic energy in specific directions. An alternative approach to steer acoustic beams is to use an acoustic leaky wave antenna (LWA). Acoustic LWAs consists of a single transducer attached to a dispersive antenna that enables frequency-dependent directionality of acoustic radiation and reception. Finite element analysis of an underwater LWA presents a unique computational challenge due to the presence of fluid loading from the surrounding water domain. Previous unit cell analyses performed on the underwater LWA approximated the surrounding fluid as a lumped mass on the surface of the LWA [Broadman et al., J. Appl. Phys., 129(19), 194902 (2021)]. In this work, we investigate LWA unit cell analysis that includes fluid-solid coupling and an exact absorbing boundary condition to enforce outgoing waves from the LWA. We solve for the complex wavenumbers of the propagating and leaky modes of the LWA given a real-valued frequency via a nonlinear eigenvalue problem, providing insight into the propagation and attenuation of elastic waves in the LWA. Finally, we compare the present approach with the lumped mass approximation and numerical results from a finite LWA. [Work supported by ONR.]
Buckling-mediated phase transitions in nano-electromechanical phononic waveguides
Authors: Kanj Ali , Ferrari Paolo F , Kim SunPhil , Bunyan Jonathan , Vakakis Alexander F. , van der Zande Arend M. , Tawfick Sameh
Published: November 2021

Acoustic signals in the megahertz to gigahertz regimes enable applications in phononic, electric and photonic circuitry. Hence, advancement in these multi-physics circuitries requires studying the transmission of elastic waves in micro/nano-electromechanical systems. Therefore, our work investigated the transmission of flexural waves in unidirectional phononic waveguides of coupled nano-electromechanical drumhead resonators. In particular, we studied the manipulation and tailoring of the transmission by thermal control of buckling within the waveguide. We showed—via experimental and computational evidence—that buckling tunes the frequency of transmission within the waveguide as determined by previous studies in literature. However, in our work, we demonstrated that excessive buckling stops the transmission in the fundamental (lowest frequency) passband of the waveguide, thus, inducing a phase transition in the waveguide leading to the absence of transmission in the respective frequency range. We computationally proved that this buckling-mediated phase transition necessitates the presence of weak inhomogeneities (∼5% variations) within the waveguide, which are inevitable in any fabrication process. In fact, these inhomogeneities are amplified due to buckling-residual stresses leading to structural aperiodicity that only affects the fundamental passband by converting the extended shapes of the transmission modes into localized shapes that prevent signal propagating throughout the waveguide.
Emergence of stegotons in phononic materials with strongly nonlinear rough contacts
Authors: Patil Ganesh U. , Matlack Kathryn
Published: November 2021

The incorporation of nonlinearity in phononic materials enables complex wave interactions in both space and time enriching the dynamic response of the underlying linear media. In this talk, we discuss the strongly nonlinear wave response of continuum phononic material with periodic and discrete nonlinearity. The studied phononic material is a periodic architecture of contact interfaces with rough surfaces, connecting linear elastic layers. These contacts exhibit strong nonlinearity, stemming from variable contact areas under compressive loads and their inability to support the tensile loads. We reveal the evolution of propagating waves using finite element time-domain simulations. The interplay of strong nonlinearity, and dispersion, in the presence of elastic layers, generate traveling localized waves, referred to as “stegotons.” Unlike classical solitons, these stagotons exhibit evolving spatial wave profiles and local variations in wave speed. Moreover, the elastodynamic effects arising from the nonlinearly coupled elastic layers enable strongly nonlinear energy transfer in the frequency domain by activating acoustic resonances of the layers. This study sheds light on the role of the strongly nonlinear coupling of linear media on the formation of traveling localized waves, and could open opportunities for enhanced dynamic response not possible with pure discrete or continuum phononic materials.
Generating characteristic acoustic impedances with hydrogel based phononic crystals for use in ultrasonic transducer matching layers
Authors: Daly Paul , Windmill James , Jackson Joseph
Published: November 2021

Quarter wavelength acoustic impedance matching layers (IMLs) are often attached to an ultrasonic transducer (UT) to enhance energy transmission into a load medium. Natural materials are rarely suitable as an IML but even composites with a suitable impedance can be excessively attenuating, or unsuitable for UT mounting. It would be beneficial then, if a non-absorptive IML with the specified impedance could be manufactured using common fabrication tools. Recent publications have shown that phononic crystal (PC) structures, made using modern printing and curing technology, can operate as IMLs and may satisfy these criteria. It is important to continue this research because it has the potential to improve UT performance, and simplify or surpass existing solutions. Here, finite element analysis (FEA) is used to validate a hydrogel-matrix / steel-inclusion PC IML that separates PZT and water domains. The PZT boundary is excited over a frequency range and the resultant in water pressure is averaged. Results are compared with an ideal, bulk IML and common, in practice materials. Comparison of spectra demonstrate that the PC increases in water pressure at the expected frequency, is an effective medium in the long wavelength regime, and is comparable to the ideal IML.
Engineering bandgaps in TPMS structures by breaking their underlying symmetries
Authors: Carrillo-Munoz Maria , Keattitorn Saranchana , Sharma Bhisham
Published: November 2021

Triply periodic minimal surface (TPMS) structures are an attractive choice for multifunctional applications—their surface curvature reduces stress concentration locations, they provide excellent stiffness- and strength-to-density scaling, and they are robust thermal and acoustic energy dissipators. Here, we study their elastic wave propagation properties and investigate the possibility of generating wave attenuation bandgaps by breaking their underlying symmetries. We limit our focus to the most used TPMS geometry: the gyroid lattice. We model three dimensional shell-based gyroid structures and calculate their dispersion properties using the finite element approach. Our analysis shows that a significant number of degeneracies exist within the gyroid lattice band structure. We then investigate the possibility of lifting these degeneracies by breaking the underlying symmetric architecture in two distinct ways. First, we disturb the symmetry by altering material properties across the line of symmetry; the effects of elastic and density perturbations are individually studied. Next, we break the symmetry by altering the lattice geometry by directionally stretching the lattice along the x, y, and z directions, individually. Our results show that while both material and geometrical perturbations help create additional directional and polarized bandgaps, both methods result in very different wave propagation and attenuation behaviors.
Acoustical properties of spinodoid porous structures
Authors: Wojciechowski Brittany , Sharma Bhisham
Published: November 2021

Recently, Kumar et al. [1] have proposed a new class of non-periodic cellular structures called spinodoid (spinodal-like) metamaterials. Spinodal decomposition is a diffusion-driven phase transformation mechanism by which a multiphase solution separates into distinct phases, separated by surfaces with smooth, non-intersecting, and non-periodic topologies. Modifying the classical linear Cahn-Hillard equation—which describes this spinodal decomposition process—by biasing the sampled phase field in a controlled manner, Kumar et al. have provided a numerically efficient method for designing spinodal-like structures. Here, we use this method to generate porous structures with spinodoid topologies and investigate their acoustical properties. The designed spinodoid structures are fabricated using an additive manufacturing process and experimentally studied using a normal incidence impedance tube setup. We investigate the effect of various topological parameters on the acoustical properties, including the effects of through-thickness gradients with finite transition layers. Our results show that the sound absorption and transmission loss properties of such structures can be conveniently altered by altering their cellular anisotropy, making them a suitable candidate for multifunctional applications that require simultaneous high stiffness, high sound absorption performance. [1] S. Kumar, S. Tan, L., Zheng, and D. M. Kochmann, “Inverse-designed spinodoid metamaterials,” npj Comput. Mater. 6(1), 1–10 (2020).
Ultra-sparse near-perfect sound absorbers
Authors: Ji Jun , Li Junfei , Cummer Steve , Jing Yun
Published: November 2021

Sparseness of an absorber array and its sound absorption performance is a trade-off, which has attracted much research interest. Here, we demonstrate near-perfect absorption (99% absorption) when the spatial period of monopole-dipole resonators is close to one working wavelength (95% of the wavelength). The condition for perfect absorption is to render degenerate monopole-dipole resonators critically coupled. Frequency domain simulations, Eigenfrequency simulations, and coupled mode theory are utilized to reveal the underlying physics and the acoustic performances, showing a good agreement with measurements. The sparse-resonator-based sound absorber could greatly benefit noise control while maintaining air flow and the results of this study could have implications for electromagnetic wave absorbers.
Effective design of metamaterial to stop system generated harmonics during nonlinear ultrasonic testings
Authors: Ghodake Pravinkumar R.
Published: November 2021

System-generated higher harmonics during nonlinear ultrasonic testing mask the actual higher harmonic response due to early-stage damages in solids. To block such unwanted higher harmonics, the periodic arrangement of different materials in phononic crystals shows features like bandgap formation resulting in creating stopbands and passbands. Trial-and-error methods are used by Mostavi et al. (2017) to design phononic crystals to stop second unwanted harmonics. They reduced the amplitude of second harmonics by 24 times lower. Here in this study, a more systematic size optimization problem is defined and solved to design metamaterial by considering more realistic boundary conditions and geometric nonlinearity of the phononic materials during finite element simulations using COMSOL. The Nelder-Mead algorithm is used to solve size optimization problems. The optimization problems are solved to block second harmonics due to monochromatic wave and one-way two-wave mixing by considering constraints such as keeping the shape of output pulse and without keeping the shape of output pulse exactly similar to the sinusoidal shape of the input pulse. The amplitude of second harmonics is reduced at maximum up to 50 and 80 times in cases such as with and without maintaining the shape of the output pulses, respectively.
Age and sex effects in emotional prosody processing revealed in infants' mismatch responses but not in preferential looking time
Authors: Kao Chieh , Zhang Yang
Published: November 2021

Emotional prosody is crucial in early communication, but the developmental trend and the emergence of sex differences in infants’ emotional processing remain unclear. This report compared 46 infants’ behavioral and neurophysiological responses to four vocal emotions (happy, angry, sad, and neutral). We used a central fixation paradigm to measure infants’ listening times to different emotions and a multi-feature oddball paradigm with electroencephalography (EEG) recordings to measure infants’ mismatch responses (MMRs) to vocal emotional changes. We modified both paradigms by including non-repeating words within each emotion, enforcing infant listeners to respond to the overarching emotional prosodic category. We only observed age and sex effects in infants’ MMRs. Older infants showed more negative MMRs to happy and sad voices than younger infants, but more positive MMRs to angry voices. Female infants showed more positive MMRs at a later time window than male infants across all emotional changes, indicating an emotion-general sex effect. The behavioral study showed longer listening times for happy and sad prosodies across age and sex. The findings indicate that neurophysiological measurement may be more sensitive in capturing age and sex effects in early emotional prosody perception when complex speech materials are used.
Disentangling acoustic measures from lexical statistics in child-directed speech
Authors: Cychosz Margaret , Edwards Jan R. , Bernstein Ratner Nan , Torrington Eaton Catherine , Newman Rochelle S.
Published: November 2021

Acoustically, North American child-directed speech is hyperarticulated: it is slower than adult-directed speech and the vowel space is more expanded. Lexically, child-directed speech is composed of shorter, more frequent words, from denser neighborhoods. The issue is that hyperarticulation, including vowel space expansion, varies according to word structure and statistics: speakers hyperarticulate low-frequency words and phonetically reduce words from denser neighborhoods (Bell et al., 2009; Gahl etal., 2012). Since the acoustic and lexical parameters of child-directed speech co-vary so tightly, it may be important to disentangle them when modeling the effects of child-directed speech for developmental outcomes. In this longitudinal study, we measured a battery of acoustic-lexical characteristics of child-directed speech from n = 84 caregivers speaking to their infants aged 7, 10, 18, and 24 months. We then fit a series of models to regress out how eachcharacteristic independently predicted the children’s vocabulary sizes and phonological processing at 24 months. Results confirmed that many characteristics, such as vowel space, coarticulation, and speaking rate, co-varied with the lexical statistics. We nevertheless founddirect effects of coarticulation, as well as word frequency, length, and diversity, on the children’s development, demonstrating the need to carefully disentangle these co-varying parameters going forward.
Bottom-up and top-down effects on the perception of children's speech
Authors: Munson Benjamin
Published: November 2021

This study examined adult’s perception of spoken words produced by children and by other adults in audio-only (AO) and audiovisual (AV) contexts, to determine whether talker age affects the magnitude of AV benefit. One-syllable words produced by five 4-6 year old child talkers and five adult talkers were presented to 151 adult listeners at three signal-to-noise ratios. The SNRs were determined through pilot testing to be the ones at which adult and child talkers’ productions were recognized equally accurately in the AO condition. The magnitude of AV benefit was statistically equivalent for the adult and child talkers. However, lexical factors affected the perception of children and adults’ speech differently. Word frequency had a larger effect on the perception of children’s speech, perhaps reflecting listeners’ expectation that children would be especially unlikely to use a low frequency word. Lexical factors also affected the nature of listener errors: listeners were less likely to provide a low-frequency word when misperceiving a child than when misperceiving an adult. Listeners were also more likely to guess a word with a different CV structure than the target for children than for adults. Results suggest that listeners apply qualitatively different expectations when listening to adults and children.
A longitudinal study of gender-specific characteristics of children’s vowels
Authors: Wong Eugene , Munson Benjamin
Published: November 2021

Cisgender adult men and women’s vocal tracts differ in length, but the vocal tracts of children assigned male at birth (AMAB) and assigned female at birth (AFAB) do not. Despite this, a growing body of literature has shown that naive listeners robustly rate AMAB and AFAB children’s speech to sound different from one another. Recently, Munson et al. (2019) found that this was true for children as young as 2.5 years old. However, it is unclear what gender-specific phonetic features exist in children’s speech, and how children acquire them. The current study investigates the vowel-space size and shape for the 55 AMAB and 55 AFAB children examined in a longitudinal study by Munson et al. at two time-points: 2.5 to 3.5 years old, and 4.5 to 5.5 years old. We aim to assess whether the AMAB and AFAB children’s vowel spaces differ in size and shape, and to determine whether these predict the ratings collected by Munson et al. As women’s vowel spaces are typically more expanded than men’s (Bradlow et al., 1996), we expect to find larger vowel spaces in AFAB children than AMAB children. Data analysis is ongoing. [Funded by NIH R01 DC002932.]
The Children’s English and Spanish Speech Recognition Test (ChEgSS): Normative data
Authors: Leibold Lori , Calandruccio Lauren , McCreery Ryan , Oleson Jacob , Rodriguez Barbara , Buss Emily
Published: November 2021

The Children’s English and Spanish Speech Recognition Test (ChEgSS) is a clinical tool for assessing children’s English and Spanish word recognition in a noise or two-talker masker. The English and Spanish versions of the test are acoustically, phonetically, and linguistically similar. The goal of this study was to establish threshold norms for Spanish-English bilingual and English monolingual children, and to evaluate effects of age and language proficiency on performance. Participants were 81 Spanish-English bilingual and 89 English monolingual children (4–17 years) with normal hearing. Children completed word recognition testing using an adaptive, 4AFC procedure with a picture-pointing response. All children completed testing in both a noise and a two-talker masker. Bilingual children were tested in English and in Spanish, and monolingual children were tested in English. Language proficiency was assessed using standardized assessments of receptive vocabulary as well as parent report. Both groups of children performed more poorly in two-talker speech than in speech-shaped noise. Preliminary results indicate that age and receptive vocabulary were significant predictors of word recognition performance in both languages and for both maskers. Performance for balanced bilinguals (i.e., similar language proficiency in Spanish and English) was similar for Spanish and English stimuli.
Vowel acoustics in Greek-speaking children with cochlear implants
Authors: Okalidou Areti , Koenig Laura , Moran Thomas , Kyriafinis George
Published: November 2021

Children who are deaf have been reported to have atypical, often reduced vowel spaces. Improved auditory input via a cochlear implant [CI] may ameliorate such issues, although wide variation among CI users has been observed. Much of the existing literature on speech development post-cochlear implantation assessed speakers of English, which has a rather large vowel inventory. Smaller vowel inventories may be associated with differences in the overall vowel space area as well as in the size of individual vowel areas. This study investigates children acquiring Greek, which has five phonemic vowels /i ɛ a ɔ u/. Seven children with CIs, ages 4–16 years, were age-matched with typically developing children. Vowels were elicited in disyllabic words matched for preceding (bilabial) and following (alveolar) phonetic context: pita, peta, pata, puse, pote. Ten productions of each word were elicited using a picture-naming paradigm. Analyses will compare overall vowel space sizes and the degree of variability of individual vowel categories between the two groups. Investigations of children learning phonologies with smaller vowel inventories will lead to a fuller picture of how deafness and subsequent cochlear implantation impact speech communication across languages. [Work supported by Fulbright Greece and iCARE.]
The effect of mild dementia on speech perception in quiet and noise
Authors: McClannahan Kate , Mainardi Amelia , Luor Austin , Chiu Yi-Fang , Sommers Mitchell , Peelle Jonathan
Published: November 2021

Difficulty understanding speech, particularly in background noise, is a common complaint of older adults. In quiet, speech perception is often assumed to be relatively automatic. In background noise, however, additional cognitive abilities likely play a more substantial role in successful communication (Koeritzer et al., 2018; Rönnberg et al., 2013). We used a word identification task in quiet and two levels of speech-shaped noise ( + 6 and + 3 SNR), to examine the impact of mild dementia on speech perception. In addition to noise, the number of similar sounding words (i.e., number of neighbors) also influences spoken word recognition — words with high neighborhood density (many competitors) are more difficult to perceive compared to low-density words (Luce and Pisoni, 1998). We predicted that individuals with dementia would perform significantly worse in conditions with the highest cognitive demands (high-density words, least favorable SNR). Preliminary results revealed that identification scores were significantly lower for conditions with more background noise and that, even after controlling for hearing loss, individuals with dementia had significantly reduced performance in all conditions. These results suggest that after accounting for differences in hearing, individuals with mild dementia still struggle with speech understanding, even in the absence of background noise.
Labiodentalization of bilabial stops in spontaneous english smiled speech
Authors: Wu Linda X. , Liu Yadong , Purnomo Charissa , Purnomo Gracellia , Wang Melissa , Gick Bryan
Published: November 2021

The co-occurrence of facial expressions and speech production presents a conflict of opposing muscular activation. Existing English research indicates a pattern of bilabial stops being resolved as labiodentals during smiled speech. Electromyographic data suggests that suppression is imposed on one muscle force to resolve the smiling-lip closure conflict [Liu et al., in ISSP Proceeding (2020), pp. 130–133]. These results have limited generalizability as data was collected from one speaker performing reading tasks under laboratory context. The present study continues the investigation of bilabial productions by investigating bilabial phonemes in spontaneous smiled speech. Natural speech samples from 16 native English speakers were extracted from YouTube interviews and vlogs. Bilabial phonemes in neutral and smiling conditions were analyzed for labiodentalization using facial imaging software. The intensity of Facial Action Units (FAU) “lip corner puller” and “lip tightener” during labial token productions were examined. Results show that labiodentalized variants of bilabial tokens also occurred during natural smiled speech. FAU intensity measurements indicate lower “lip corner puller” intensity during bilabial closures than labiodental ones when smiling. This suggests that smile suppression was observed when lip closure was prioritized, validating earlier laboratory conclusions that selective muscular suppression is utilized in the resolution of conflict between articulators.
Equivalent circuit model to study super resolution in time reversal focusing in a periodic network of Helmholtz resonators
Authors: Kingsley Adam D. , Anderson Brian E.
Published: November 2021

This presentation will introduce equivalent circuit modeling techniques that have been used to simulate the focusing of acoustic signals in a 1-D waveguide. The presence of resonators in the near field of the focus location decreases the effective wavelength of the focus and leads to super resolution. A circuit is created that represents the complete waveguide with the sources. Circuit elements are used to represent both resonators and the propagation of the wave. The spatial extent is simulated at individual frequencies using additional circuit junctions. The wideband response is determined by the superposition of the individual frequency results. Important parameters such as resonator density and the quality factor of the resonators are examined and their influence on the focus will be presented. Methods for solving the circuit models and improving computational efficiency will also be discussed.
Cancellation of dolphin sonar click in communication signal
Authors: Kim Donghyeon , Song Jiyoung , Kim J. S.
Published: November 2021

In long-range underwater communication, the conventional passive Time Reversal Processing (TRP) is widely used to mitigate the distortion due to the multipaths and temporal spreading. However, the signals produced by marine animals were present in the data acquired during the experiment, contaminating the communication signal and acted as an unwanted signal. In particular, because the impulsive signal such as a dolphin sonar click has a wide bandwidth and a short pulse duration, it is difficult to separate the communication signal from the impulsive signal. This overlapping problem affects critically the communication performance. In this study, we propose a method to successfully cancel click sound. The method involves combining the adaptive TRP and the estimation of Green’s function of click sound. The adaptive TRP was successfully used in canceling crosstalk between interferers in a multiuser environment. Also, the estimation of Green’s function utilized the characteristics of the impulsive signal with clear distinction between paths. The effect of spatially nulling click sounds without distorting the phase of the communication signal showed a remarkable improvement in communication performance in the seagoing experimental data of BLAC18.
Acoustic surface impedance of sandy shores
Authors: Cobb Faith A. , Vecchiotti Andrea , Vignola Joseph , Turo Diego , Ryan Teresa J.
Published: November 2021

This work presents an effort to characterize the relationship between moisture content and acoustic surface impedance of sandy soils. This effort is part of a larger project seeking to model long-range acoustic transmission loss over coastal areas. Previous studies were done to measure moisture content along the shore and collect samples for bench-testing with an impedance tube. This work seeks to build on those experiments by performing in situ acoustic surface impedance measurements with an omnidirectional sound source and two microphone receivers. These measurements follow the protocol set forth by the ANSI/ASA S1.18 and are recorded at multiple distances from the water on the shore. At each measurement location, sand samples are collected for gravimetric moisture analysis. Atmospheric conditions and ambient noise level are also recorded in accordance with the standard. These results demonstrate the variation of sand surface impedance from the fully saturated swash zone to nominally dry sand.
Green's function of the rigid half cylinder with soft free surface for application to ship noise
Authors: Cros Elina , Roger Michel , Serre Gilles
Published: November 2021

The present study addresses an experimental and analytical investigation of the scattering of the tonal noise of low-speed propeller by a half-cylinder and a soft free surface. The interest is marine propeller noise of surface ships at the first harmonics of the blade passing frequency. Indeed, installed marine propellers correspond to very compact configurations. Both sizes blade tip radius and the distance to the ship hull are small compared to the wavelength. Thus, in view of the extremely low Helmholtz numbers, some amplification due to an asymptotic scattering regime is expected. Measurements made in air in similar conditions, in anechoic chamber confirmed that noise from small-scale isolated propeller is dramatically intensified near a half cylinder with reflecting plane. The problem is formulated analytically by using the formalism of source-modes near a scattering half cylinder combined with the effect of the free surface in two dimensions. In this configuration, the diffraction is found to induce an amplification but with a different wave pattern to what the diffraction is with a cylinder only. The results show that the installation effect is crucial for the analysis of marine propeller noise at the very low frequencies.
Architectural acoustics short course presentation material
Authors: Hoover K. Anthony
Published: November 2021

The Technical Committee on Architectural Acoustics (TCAA) is a Registered Provider in the American Institute of Architects (AIA) Continuing Education System (CES). The TCAA has developed a standardized introductory short course for architects called “Architectural Acoustics.” An architect can earn one continuing education unit (CEU) by attending this short course, if presented by a qualified member of TCAA. The course covers topics in sound isolation, mechanical system noise control, finish treatments, and implementation of quality acoustical spaces. This paper will cover the course material to prepare and qualify potential presenters. In order to qualify as an authorized presenter for this AIA/CES short course, attendance at this special session and membership in TCAA are required.
Making music during a pandemic
Authors: Moore Thomas R.
Published: November 2021

Efforts to mitigate the spread of COVID-19 among musicians have recently produced a significant body of original research on the flow of the breath while making music. Percussion and string instrument players have no special considerations beyond those of the general population in reducing the spread of COVID-19, but the other musical instruments involve the exhalation of breath through the instrument toward other players and the audience. Similarly, singing produces both aerosol and ballistic droplets from the mouth and thelouder one sings the greater the distance the exhaled particles travel. This presentation will review recent attempts to understand the flow of breath during musical performance, as well as the acoustical effects of some of the methods that musicians have used to reduce the spread of COVID-19 during rehearsal and performance.
Similarity spectra-based decomposition of noise from an installed F404 engine
Authors: Merrill Cooper D. , Epps Kristi A. , Leete Kevin M. , Gee Kent L. , Campbell Steven C.
Published: November 2021

Similarity spectra analysis has long been a popular method for identifying both the fine-scale and large-scale components of jet noise. For an imperfectly expanded supersonic jet, addition of a broadband shock-associated noise (BSN) model allows spectra to be better represented. A similarity spectra analysis of T-7A-installed GE-F404 engine noise has been performed at conditions ranging from intermediate to full afterburner. The BSN contributions are significant at military and afterburner conditions. The combined model captures the noise reasonably well with some caveats. First, spatiospectral lobes present in the measured noise are not well represented. Second, the measured low-frequency spectral slope is steeper at higher engine conditions in the region of maximum radiation. Third, the measured high-frequency slope is shallower across most of the radiation angles. Fourth, the noise at large inlet angles, beyond the peak radiation lobe, are not well represented by the combined model. The successes (and failures of the model) for different spatial regions and frequencies will aid in developing improved models for noise radiation. [Work supported by ONR.]
Near-field acoustical holography-based noise source analysis of an installed, afterburning F404 engine
Authors: Mathews Logan T. , Leete Kevin M. , Gee Kent L. , Wall Alan T.
Published: November 2021

Near-field acoustical holography has been used previously to study characteristics of jet noise radiated from tactical aircraft. This paper investigates frequency-dependent source and radiation characteristics of an installed GE F404 engine at afterburner, as determined using multisource statistically optimized near-field acoustical holography. Included in the analyses are the number of partial fields required to represent the source, the extent of the region of maximum sound power production, and directional characteristics. Comparisons are made with other source reconstructions of high-performance engines. [Work supported by ONR.]
An investigation of dissipation processes in a multi-component gas-mixture: Application to acoustic-wave absorption in the thermosphere-ionosphere
Authors: Pineyro Benedict , Sabatini Roberto , Snively Jonathan
Published: November 2021

Infrasonic waves generated in the lower atmosphere can propagate into the thermosphere and perturb the ionosphere. These disturbances are accompanied by a change in the ionospheric electron density, which can be detected via remote sensing methods, such as Global Navigation Satellite System derived measurements of integrated total electron content. The altitude-dependent decrease in density strengthens dissipative phenomena which affect these measurements by reducing the acoustic-wave amplitude. Sutherland and Bass [https://doi.org/10.1121/1.1631937] have described atmospheric absorption, but only up to 160 km, and neglected interspecies diffusion. However, the atmosphere above the mesopause is a mixture of three major gases, namely, N2, O2, and O, where processes associated with mass-fraction-density gradients could affect acoustic-energy dissipation. This work revisits absorption processes via numerical simulations of the equations of fluid mechanics for multicomponent-gas mixtures, under the assumption of a small Knudsen number (i.e., satisfying continuum approximation). More specifically, diffusion due to mole-fraction, pressure, and temperature gradients, and heat diffusion due to concentration gradients are included alongside classical thermo-viscous terms. Their impact is investigated on vertically-propagating acoustic pulses with varying frequencies, <1 Hz, and different amplitudes that match typical values observed from geophysical and anthropogenic sources (e.g., earthquakes, thunderstorms, explosions).
Infrasound signature measurements for U.S. Army infantry weapons during training
Authors: Medda Alessio , Carr Walter , Funk Robert , Garfield Bradley , Ahuja Krish
Published: November 2021

United States Military personnel are exposed to blast overpressure from a variety of sources during training and military operations. While it is known that repeated exposure to high-level blast overpressure may result in concussion like symptoms, the effect of repeated exposure to low-level blast overpressure is not well understood yet. Impulsive acoustic sources such as pressure waves generated by explosions, artillery launches, and rocket launches are typically characterized by a broadband energy distribution with resulting pressure measurements that exhibit frequency components well into the infrasound range. This study focused on data acquired in the audible and infrasound range during infantry weapons training for machine gun, grenade launcher and rocket fire events. Time, frequency and time-frequency analysis are used to quantify infrasound intensity for each event type. High resolution time-frequency analysis using the synchrosqueezed wavelet transform is used to precisely quantify energy content in the lowest frequency range. Preliminary results indicate that data collected from these weapon systems exhibited a large amount of infrasound in the range between 2 and 20 Hz. This energy can couple directly with the human body and in case of repeated exposures this coupling can include altering of physiological processes.
Hard-fought “pearls of wisdom” (?) from a senior structural acoustician
Authors: Koch Robert M.
Published: November 2021

Throughout the course of a relatively long career in science and engineering, including advanced degrees, teaching, and a host of other external technical activities, there are numerous lessons learned and perspectives gained that are frequently much more important than specific technical advice. Oftentimes, the most important and critical teachings to be passed on to fellow present and future researchers are not narrowly-focused but wide-ranging and generally applicable. The most essential of these “pearls of wisdom” are learned occasionally out of successes yet more often out of apparent failures and frustrations. Almost invariably, the most valuable information is wide-ranging and universal and independent of any particular scientific discipline or field. This paper presents numerous technical and life-/career-related lessons that are hopefully of value and interest to current and upcoming scientists, engineers, and students. In addition, time permitting, a particular specific technical case study is presented.
Elevator machine room noise
Authors: Razavi Zohreh
Published: November 2021

While elevators are sources of noise and vibrations in high- and low-rise buildings, this problem is overlooked and not enforced by many jurisdictions, including in Canada. Although the STC rating requirements of the demising walls between the elevator shafts and dwelling units are mandatory in Building codes, the noise limit of the elevator machine room is not addressed. The noise levels from elevators are not high, however they can be bothersome, especially for the residences at higher levels. In this paper, a summary of a noise review from an elevator machine room due to the low-rise occupants’ complaints along with noise mitigation recommendations are reviewed. A sound control review requirement is mandated by most by-laws in Canada. However, it is at the architect's discretion to decide whether acoustical engineering services are required or not. Guidelines promoting occupant well-being and comfort should be included in the sound control requirements, and enforced in bylaws, and it is the duty of acoustic consultants to promote this.