bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of demographic factors on the agreement between audiometric hearing loss and Revised Hearing Handicap Inventory self-reported hearing difficulty
Authors: Dillard Lauren , Matthews Lois J. , Dubno Judy R.
Published: April 2023

This study evaluated the agreement between audiometric hearing loss and Revised Hearing Handicap Inventory (RHHI) self-reported hearing difficulty, and modification by demographic factors (age, sex, race, socioeconomic status [SES]) in adults across the lifespan. Baseline data from the Medical University of South Carolina Longitudinal Cohort Study of Age-Related Hearing Loss (ARHL), a community-based cohort study of ARHL (1988-current) were used. Audiometric hearing loss was defined as pure-tone average (0.5–4.0 kHz) >25 dB HL in the better ear. RHHI hearing difficulty was defined as a score ≥6 on the full and screening (RHHI-S) versions. Sensitivity, specificity, and accuracy evaluated ability of the RHHI(-S) to detect audiometric hearing loss. The number of participants was 1558 (56.9% female; mean age 63.7 [range 18-89 + ] years). Prevalence of audiometric hearing loss, RHHI, and RHHI-S hearing difficulty was 38.2%, 48.8%, and 44.6%, respectively. Sensitivity, specificity, and accuracy were similar for RHHI and RHHI-S hearing difficulty (versus audiometric hearing loss). The RHHI(-S) was less sensitive in detecting audiometric hearing loss in older and non-White adults. Sensitivity was similar by sex and SES but specificity was lower in males and high/low (vs mid) SES. Agreement between audiometric hearing loss and RHHI(-S) hearing difficulty is modified by demographic factors.
Results of the second “clarity” enhancement challenge for hearing devices
Authors: Akeroyd Michael A. , Firth Jennifer L. , Naylor Graham , Barker Jon P. , Culling John , Cox Trevor J. , Bailey Will , Graetzer Simone , Viveros Muñoz Rhoddy , Porter Eszter , Griffiths Holly
Published: April 2023

The clarity enhancement challenges (CECs) seek to facilitate development of novel processing techniques for improving the intelligibility of speech in noise for hearing-aid users through a series of signal-processing challenges. Each challenge provides entrants with a set of stimuli for development and testing of their algorithms. The performance of the algorithms is assessed using objective measures of speech intelligibility and subjective measures conducted with a panel of hearing-impaired listeners. CEC2 featured more complex listening environments than CEC1 with multiple interfering sound sources (speech, music, household appliance sounds) within a simulated living-room environment at signal-to-noise ratios (SNRs) from −12 to + 4 dB. In addition, head rotation towards the target speech was introduced. Target speech came from a new dataset of 10,000 different English sentences spoken by 40 actors speaking 250 sentences each (Graetzer S et al., 2022 Data in Brief 41, 107961). The objective assessment was provided by HASPI (Kates & Arehart, 2021 Speech Comm 131, 35–46). All 18 entries achieved substantial improvements in HASPI, averaging 0.55 across all systems and SNRs. Improvements were greatest (averaging 0.61) for SNRs between −8 and 0 dB. The best-performing system achieved HASPI scores above 0.9 for all SNRs. Listening-test data will be reported.
Audio-visual scene analysis in conditions with head- and eye-steered beamformers in virtual reality
Authors: Ahrens Axel , Westermann Adam , Best Virginia , Dau Torsten , Neher Tobias
Published: April 2023

In crowded social settings, listeners often face the challenge of following a conversation in the presence of other conversations. Several factors influence the difficulty of this task, including the number of talkers, the amount of reverberation, and the hearing status. Beamformers in hearing aids have the potential to mitigate these factors by improving the signal-to-noise ratio, but their effectiveness in real-world settings has not yet been clearly demonstrated. Here, we used virtual reality to investigate the effect of head- and eye-steered beamformers on the ability of participants to analyze complex audio-visual scenes. The participants’ task was to find and locate an ongoing story in a mixture of other stories in scenes differing in terms of the number of concurrent talkers and the amount of reverberation. The talkers were distributed in the frontal hemisphere between ±105°. The primary outcome measure was the time taken to identify the location of the target talker. Preliminary results show shorter response times with beamforming (in comparison to an omnidirectional setting), especially when more talkers were present. This framework provides a new means for examining the effects of hearing technologies on behavior in complex audio-visual scenes.
Effects of spectral resolution and smearing on gated word recognition
Authors: Patro Chhayakanta , Bennaim Ariana , Srinivasan Nirmal Kumar
Published: April 2023

In a word gating task, listeners are presented with increasing amounts of word-onset information (a series of increasingly longer temporal “gates”), and following each gate, they are asked to indicate what they think the target word is. Listeners with normal hearing (NH) typically recognize a target word well before they “hear” the entire word. Listeners with cochlear implants (CIs), however, need to hear almost the entire target word (require a greater amount of word-onset information) to recognize it. Here, we hypothesized that the poor spectral resolution, due to the limited number of channels and interactions between adjacent channels, may have a negative impact on gated word recognition performance. We manipulated spectral resolution by using: (1) a noise-band vocoder with a variable number of spectral channels; and (2) a vocoder with variable carrier filter slopes to simulate channel interaction. We determined the minimum amount of word-onset information required to recognize spoken words. Initial results suggest that the gated word recognition performance remained roughly unchanged as the amount of spectral degradation applied increased up to some extent, beyond which it deteriorated. With eight channels, which resemble the spectral resolution available to most CI users, even the most focused stimulation yielded poorer results.
An adaptive Bayesian algorithm for efficient auditory brainstem response threshold estimation: Numerical validation
Authors: Petersen Erik A. , Shen Yi
Published: April 2023

The auditory brainstem response (ABR) can be used to estimate the hearing threshold of animals or human subjects who are unable to respond to behavioral measures. However, ABR can be time-intensive and is vulnerable to human subjectivity while interpreting the waveforms. An adaptive procedure has been developed to efficiently and objectively estimate ABR threshold. The procedure iteratively fits a Gaussian process (GP) model to the ABR waveforms collected so far and optimizes the subsequent stimulus. The algorithm was validated through numerical simulation using pre-collectedhuman ABR at 0.5, 1.0, 2.0, and 4.0 kHz with levels from below threshold to 90 dB in 5 dB increments from a cohort of normal-hearing listeners. This led to a full stimulus space of approximately 55 stimuli per test ear. For each test ear, the ABR threshold was estimated by human raters based on the entire stimulus space. The ABR threshold was also estimated using the adaptive procedure, which iteratively sampled a subset (∼35%) of the stimulus space. At the end of the adaptive procedure, the fitted GP model was able to capture the individual differences in waveform morphology between listeners. Furthermore, the threshold estimates from repeated runs of the adaptive procedure demonstrated adequate test-retest reliability.
Auditory brainstem responses to peaky speech using zero- versus chirp-phases
Authors: Polonenko Melissa J. , Krocak Samantha
Published: April 2023

Auditory brainstem responses (ABR) are used to identify hearing loss across multiple frequency bands in young children. ABRs typically use brief tonebursts or chirps, but we recently created a “peaky” speech method that uses stories to evoke ABRs—an engaging stimulus that may facilitate testing in infants and toddlers who cannot nap, sit still, or participate in behavioral testing. This study aimed to determine which phase profile (zero versus chirp) of multiband peaky speech evokes the largest ABRs in the fastest recording time. Fifteen adults with normal hearing listened to an hour each of zero- and chirp-phase multiband peaky speech while 2-channel ABRs were recorded. Overall, ABR wave V amplitudes were larger for chirp- than zero-phase multiband peaky speech, especially for lower frequency responses, and took 30 versus >60 minutes for all responses in the 5 bands (0.5–8kHz) and both ears to reach a criterion signal-to-noise ratio. In summary, chirp-phase peaky speech provided larger—and thus, more effective and efficient—multiband ABRs than zero-phase peaky speech for ABR testing using continuous speech. Reducing testing time in half will be important for future application as an ABR hearing screener in toddlers using engaging stories. [Work funded by Hearing Health Foundation ERG.]
Optimal f0–phase parameters for auditory brainstem responses to multiband peaky speech
Authors: Polonenko Melissa J. , Eisenreich Benjamin
Published: April 2023

Multiband peaky speech is a new method that uses narrated stories to evoke frequency-specific auditory brainstem responses (ABRs). However, testing times are not clinically feasible; thus, new efforts focus on maximizing response amplitude to facilitate faster testing. Recent work suggests that narrator f0, as well as chirp rather than zero phases, evoke larger ABRs. This study aimed to identify the optimal f0–phase combination for evoking large ABRs with multiband peaky speech. Using 11 stories with original f0s ranging from 114–230 Hz, the mean f0 over 15 minutes was shifted to f0s from 70–220 Hz in 10 Hz steps and then dichotic multiband peaky speech created using zero- and chirp-phases. A validated computational model of the auditory periphery was used to simulate ABRs using a flat 0 dB HL hearing configuration. Based on the simulated wave V amplitudes across all conditions, the optimal parameters for simulated ABRs to multiband peaky speech include stories with original f0s <170 Hz that have been shifted to a 100–110 Hz mean f0 and modified with a chirp-phase profile. Next we plan to confirm these parameters with measured ABR responses from adults with normal hearing. [Work funded by Hearing Health Foundation ERG.]
Psychophysical performance differences associated with auditory spatial attention in older listeners with and without hearing loss
Authors: Cherri Dana , Ozmeral Erol J.
Published: April 2023

In a busy listening environment with multiple speakers, even normal-hearing listeners may face difficulties in understanding speech (i.e., “the cocktail party problem”). Individual factors related to bottom-up and/or top-down processing difficulties may be associated with the listener’s ability to attend to speech, a key component in navigating complex acoustic environments. The present study tested listeners on a battery of psychophysical measures and compared listener performance to cortical measures (EEG) of spatial-change tuning and auditory spatial attention. The behavioral tests measured both perceptual and cognitive performance and included: frequency modulation detection, spectro-temporal modulation sensitivity, spatial release from masking, temporal gap detection, auditory and non-auditorysustained attention, and visuo-spatial problem solving. The EEG paradigm tested the listener’s ability to attend to moving speech in quiet or background babble in the free field. Older listeners with and without hearing loss (n = 20 per group) demonstrated wide individual performance for some measures and significant correlations between behavioral thresholds and cortical responses, consistent with a more refined view of age-related hearing loss and a need for a more holistic approach in diagnoses for individuals beyond standard clinical tests. [Work supported by NIH R21DC017832.]
Parametric voice difference benefit for speech-on-speech perception in adult cochlear implant users
Authors: Gaudrain Etienne , Harding Eleanor , Harris Robert , Tillmann Barbara , Maat Bert , Free Rolien , Başkent Deniz
Published: April 2023

Speech-on-speech perception remains challenging for some cochlear implant (CI) users. In normal-hearing listeners, differences in voice characteristics such as F0 and vocal-tract length (VTL), which indicate age, sex, and size of the speaker, are known to support the segregation of competing voices. However, previous research indicated that postlingual adult CI users tend not to derive any perceptual benefit from voice differences, whereas prelingually deafened child CI users do. The current study tested speech-on-speech perception in adult CI users. In a coordinate response measure (CRM) paradigm, participants identified a number and color in a target speech stream competing with a gibberish speech masker. The masker voice was either identical to the female target voice, or the F0 and VTL were altered to create either an ambiguous fe/male voice, or a clearly male voice. The target-to-masker ratio (TMR) was also systematically manipulated to take the values: 0, + 6 and + 12 dB. While performance depended on TMR, only some of the CI users were able to benefit from voice differences. Results will be compared with F0 and VTL discrimination thresholds in the same participants, as well as with pediatric data in the same task.
Upward bias in audiometric thresholds is caused by stopping at the first opportunity
Authors: Hoover Eric C. , Menon Katherine N.
Published: April 2023

Tone-detection thresholds are the primary index of hearing. Although standard audiometry nominally estimates the stimulus level corresponding to 50% detection, thresholds are biased upward to an average of 98.1% at 500 Hz [Marshall, L. & Jesteadt, W. J Speech Hear Res 29, 82–91. (1986)]. This has been explained by the large difference in the probability of detection between stimulus levels near threshold. However, bias is greater than predicted for measured psychometric functions and does not change proportionally with step size. In standard audiometry, the stopping rule is defined with flexibility for clinical judgement. Our hypothesis is that upward bias is caused by stopping at the first opportunity, because it makes specific ordered combinations of hits and misses impossible, like hit-hit-miss. Monte Carlo simulations were used to compare audiometric thresholds obtained using different stopping rules. Thresholds obtained when stopping at the first opportunity had greater upward bias compared to a fixed-trial stopping rule independent of the total number of trials presented, as predicted. When a baseline test is biased upward by stopping at the first opportunity, a follow-up test may inadvertently miss a significant change in hearing by continuing to present stimuli after the first opportunity to stop. [Work supported by R01DC015051.]
Externalization of speech through hearing aids differing in microphone position and dome type
Authors: Best Virginia , Roverud Elin
Published: April 2023

An experiment was conducted to examine how different hearing aid styles affect the externalization of speech. Of particular interest were effects of microphone position (behind-the-ear versus in-the-canal) and dome type (closed versus open). Participants were young adults with and without hearing loss, who were fitted with hearing aids that allowed variations in the microphone position and the dome type. They were seated in a large sound-treated booth and presented with monosyllabic words from loudspeakers at a distance of 1.5 m. Their task was to rate the perceived externalization of each word using a rating scale that ranged from 10 (at the loudspeaker in front) to 0 (in-the-head) to −10 (behind the listener). We observed a large intersubject variability in ratings. On average, compared to unaided listening, hearing aids tended to reduce perceived distance and lead to more in-the-head responses. This was especially true for closed domes in combination with behind-the-ear microphones. We also observed a strong association between poor externalization and front-back confusions.
Source separation using bandlimited external microphones and a microphone array
Authors: Mittal Manan , Sarkar Kanad , Lu Austin , Corey Ryan M. , Singer Andrew C.
Published: April 2023

Modern listening devices are equipped with air-conducted microphones and contact microphones. External microphones, like those on a listening device, have been used to estimate relative transfer functions (RTFs) at microphone arrays. With numerous active sound sources, the air-conducted microphones perform poorly while the contact microphones are robust to external noise. A drawback of contact microphones is that they are bandlimited. Past work has shown that the contact microphone and microphone array can be combined to estimate RTFs in the low frequencies. To overcome the limitations of the contact microphone, we propose a method that leverages the full-band signal at the microphone array to provide beamforming gains at higher frequencies. We demonstrate this method by separating three human talkers in a noisy environment.
Intracochlear noise-induced vibrations
Authors: Grosh Karl , Cai Wen , Agarwal Vipin
Published: April 2023

When designing an engineered electroacoustic sensor, a key question is “what is the lowest level sound that can be sensed?” To answer this, we design to achieve a desired input referred noise. In the cochlea, there are many sources of internal noise, such as Johnson noise arising from membrane conductances, clatter noise in channels, and thermoviscous damping that will conspire to cause vibrational responses in the absence of external stimulus. Noise can dramatically affect our ability to sense desired sounds. Experimental and theoretical cochlear mechanics has focused on determining the sensitivity of the cochlea. However, to our knowledge, there is only one set of published measurements of the displacement response of the cochlea in quiet (the levels are low, below 1 atto-meter2 per Hz), and no simulations in a global cochlear model of the noise response. We introduce a method for predicting the global response to noise from electromotile outer hair cells in the cochlea for small fluctuations about equilibrium using our finite-element based numerical model. Furthermore, we show the relative contribution of different noise sources (in particular, channel noise versus conductance noise) and the spatial distribution of the response to these sources.
Vibro-acoustic characterization of the bone-implant system during insertion
Authors: Poudrel Anne-Sophie , Rosi Giuseppe , Nguyen Vu-Hieu , Haiat Guillaume
Published: April 2023

The femoral stem primary stability achieved by the impaction of a beam called “ancillary” attached to the implant during its insertion is an important factor of success in cementless surgery. However, surgeons rely on their proprioception, making the process subjective. The use of experimental modal analysis (EMA) without sensor nor probe fixation on the implant or on the bone is a promising non-destructive approach to determine implant stability. This study investigates whether EMA performed directly on a beam, which is temporary fixed to the implant during its insertion, could provide information on the boundary condition, which corresponds to the implant stability. A cementless femoral stem was inserted into 10 bone phantoms of human femurs and EMA was carried out on the ancillary using a dedicated impact hammer for each insertion step. Two bending modes were identified in the frequency range 400–8000 Hz for which the resonance frequency was shown to be sensitive to the insertion step and to the bone-implant interface properties. A significant correlation was obtained between the two modal frequencies and the implant insertion depth (R² = 0.95 ±0.04 and R² = 0.94 ±0.06). This study opens new paths towards the development of noninvasive vibration-based evaluation methods to monitor cementless implant insertion.
Approximate extraction of late-time returns via morphological component analysis
Authors: Goehle Geoff , Cowen Benjamin , Blanford Thomas E. , Park J. Daniel , Brown Daniel C.
Published: April 2023

A fundamental challenge in acoustic data processing is to separate a measured time series into relevant phenomenological components. In the setting of sensing elastic objects using active sonar, we wish to separate the early-time returns (e.g., returns from the object's exterior geometry) from late-time returns caused by elastic or compressional wave coupling. Under the framework of morphological component analysis (MCA), we compare two separation models using the short-duration and long-duration responses as a proxy for early-time and late-time returns. Results are computed for broadside geometries using Stanton's elastic cylinder model as well as experimental data taken from an in-air circular synthetic aperture sonar (AirSAS) system, whose separated time series are formed into imagery. We find that MCA can be used to separate early and late-time responses in both the analytic and experimental cases without the use of time-gating. The separation process is demonstrated to be robust to noise and compatible with AirSAS image reconstruction. The best separation results are obtained with a flexible, but computationally intensive, frame based signal model, while a faster Fourier Transform based method is shown to have competitive performance.
Sensor array design for sparse sound field reconstruction
Authors: Shen Yang , Bi Chuan-Xing , Zhang Xiao-Zheng , Zhang Yong-Bin , Zhou Rong
Published: April 2023

The compressive-equivalent source method can reconstruct the sound field of the sparsely distributed sound sources through promoting the sparsity of the equivalent source strengths. To reduce the mutual coherence of the sensing matrix, the spatially random sampling is performed. However, different samplings would make the reconstruction results instable, and a fixed sampling would not guarantee satisfied reconstruction results when reconstructing the sound field at different frequencies. To handle this issue, the present paper proposes a sensor array design method for sparse sound field reconstruction. After obtaining the matrix by the sum of the frequency-dependentsensing matrices, the optimization problem of the proposed method is formulated based on the mutual coherence minimization principle, and the solutions indicating the selected positions of the sensors are solved by the gradient projection. Numerical simulation and experimental results show that lower reconstruction errors can be obtained with the designed senor array compared to the spatially random sampling.
Frequency domain method for holographic localization of rotating sound sources
Authors: Feng Jianxiong , Liu Yangfan , Li Kai Ming
Published: April 2023

Most of the previous studies employed beamforming techniques for the localization of rotating sources. These methods usually rely on the use of a virtual rotating array (VRA), in which the Doppler effects caused by source rotation can be eliminated. The VRA signal generation can be achieved in both frequency and time domains. In this presentation, compressive sensing (CS) near-field acoustic holography (NAH) has been extended to the reconstruction of rotating sources using the frequency domain (FD) VRA method. This combination can provide an improved resolution of spatial reconstructions at low frequencies compared to beamforming methods. In addition to the direct combination of the FD-VRA method and CS acoustical holography techniques, a more efficient algorithm for FD-VRA was developed to address the shortcomings of the traditional approach, such as higher computational cost and the requirement of a circular array with equally spaced microphones. The proposed FD-VRA method only involves a direct summation of the rotating sidebands of signals measured on a stationary array, which effectively reduces the computational load. Furthermore, an arbitrary array of microphones can be used. It will be shown that the proposed algorithm works for narrowband sources without overlapping frequency components in the rotating sidebands.
Improving the super resolution focusing above a two-dimensional Helmholtz resonator array using particle velocity decomposition of time reversal focusing
Authors: Basham Andrew , Kingsley Adam D. , Anderson Brian E.
Published: April 2023

Super resolution is possible using resonators placed in the near field of time reversal focusing. This presentation addresses the problem that a two-dimensional Helmholtz resonator array in a three-dimensional reverberant environment has limited ability to produce a high-resolution spatial focus in the time reversal focusing of audible sound. Acoustic waves propagating out-of-plane with the resonator array are not as strongly modified by the resonators, partially negating the effect of the resonators. The use of a two-dimensional waveguide limits the out-of-plane propagation, leading to improved resolution. It is also shown that post processing using an orthogonal particle velocity decomposition of a spatial scan of the focusing can limit out-of-plane particle motion in the near field of the array, which bypasses the effect of the unwanted third spatial dimension of propagation. Each of these techniques results in a pressure field focus reconstruction that has a higher spatial resolution.
Acoustic source localization using Bayesian optimization with a Gaussian process surrogate model
Authors: Jenkins William F. , Gerstoft Peter , Park Yongsung
Published: April 2023

Matched field processing is a computationally expensive approach to estimate acoustic source location, since it relies on a grid search through range and depth. We present an efficient alternative that samples the parameter space with a Bayesian approach using a Gaussian process as a surrogate model of the objective function. The objective function is defined as a Bartlett processor whose output measures the match between a received and replica pressure field on a vertical line array. Replica fields are obtained using a normal mode propagation model whose geoacoustic parameters are selected from the parameter search space. The surrogate model represents the posterior on the objective function and is updated with each model evaluation. Optimization is performed with sequential model evaluations, with an acquisition function guiding the next point in parameter space to be evaluated. We demonstrate our approach using both simulations and real data collected during the SWELLEX96 ocean acoustics experiment. Results indicate Bayesian optimization using the GP surrogate model converges on average within 700 evaluations of the objective function, far fewer than required in matched field processing.
Effect of oceanography on broadband acoustic wave propagation in a range dependent shallow water environment
Authors: Badiey Mohsen , Castro-Correa Jhon A. , Escobar-Amado Christian D. , Wan Lin , Hodgkiss William
Published: April 2023

To investigate the effects of oceanographic variability on broadband acoustic wave propagation in shallow water environments, two experiments were carried out on the New England continental shelf region in 2017 and 2022, respectively. Towed sources were used to transmit chirp waveforms over the frequency ranges of 0.5—1.25 kHz and 1.5 – 4.0 kHz on the same acoustic tracks. The broadband acoustic transmissions were received by vertical acoustic arrays with multiple hydrophones. In 2017, the sound speed in the water column was isovelocity while in 2022 the presence of a duct at the depth of 20 m and upward refracting conditions reduced the interaction of acoustic transmissions with the seafloor compared to the experiment in 2017. Experimental observations show the importance of the water column on bottom interacting broadband waveforms causing challenges for the inversion algorithms. In this paper, we present acoustic and oceanographic results showing how the variability of sound speed could change the characteristics of the broadband transmission. Modeled results versus experimental data are discussed. [Work supported by ONR.]
Joint trans-dimensional inversion for seabed and water-column properties in the seabed characterization experiments
Authors: Dosso Stan , Bonnel Julien
Published: April 2023

This paper considers the information content to resolve both a geoacoustic model of the seabed and a model of the water-column sound-speed profile (SSP) in the inversion of modal-dispersion data. A Bayesian formulation of the inverse problem allows prior information representing varying levels of independent knowledge to be applied separately to the seabed and water-column models. Issues of interest include the extent to which knowledge (or lack thereof) of the SSP affects geoacoustic inversion, and the ability to remotely estimate the SSP from acoustic data in cases where the seabed is either well known or poorly known. The joint inversion for seabed and water-column properties is formulated in terms of a separate trans-dimensional model for each, providing an automated approach to quantitative model selection. The seabed model is formulated in terms of an unknown number of uniform sediment layers, while the SSP is formulated as an unknown number of depth/sound-speed nodes, with the reciprocal of sound speed squared varying linearly between nodes, as per normal-mode propagation models. The approach is applied to modal-dispersion data measured during the seabed characterization experiments at the New England Mud Patch. [Work supported by the Office of Naval Research]
Potential and kinetic energy of underwater noise measured at steep grazing angles over contrasting seafloors
Authors: Dahl Peter H. , Dall'Osto David R.
Published: April 2023

Observed near the seabed, broadband noise emissions from a source or vessel passing directly above the sensor exhibit frequency bands where potential acoustic energy is greater than kinetic energy while the opposite occurs in neighboring frequency bands. The condition where the dynamic and kinematic energy forms differ in this manner is characteristic to interference involving steep angles or near-normal incidence reflection from the seafloor. Recent experiments conducted on the New England Mud Patch (NEMP) and the neighboring (towards offshore) shelf break waters demonstrate the sensitivity to seabed structure, which evolves from the soft mud layers at the NEMP into the harder sediments that are exposed on the continental slope. Results are expressed as a ratio of kinetic to potential energy as a function of frequency, with resulting data series yielding information on seabed properties. Variance components as function of frequency are also isolated based on a singular value decomposition of a matrix constructed from the data series (known as singular spectrum analysis). The components are associated with different sub- bottom layering features. A model for kinetic and potential energy combined with candidate geoacoustic models is used to interpret both the data series and components.
Orchestra listening conditions—Some reflections on reflections
Authors: Scarbrough Paul H. , Blair Christopher
Published: April 2023

Over many years, the authors have worked with orchestra musicians and conductors in efforts to improve their hearing conditions onstage. Experience gained from these efforts has led to some conclusions that vary strongly from common remedial assumptions, particularly with regard to early reflected energy. Anecdotal examples from several of our projects will be presented which indicate that careful reduction of early energy onstage may offer substantial improvements in musician (and audience) responses. The rooms discussed will include experiments conducted in the Sala São Paulo, Indianapolis’ Hilbert Circle Theater, the Sala Minas Gerais, and the Ordway Concert Hall. Model studies that were conducted for the recently completed David Geffen Hall at Lincoln Center revealed interesting differences between predicted onstage EDT and that of the audience chamber, suggesting that a shorter EDT in the platform zone may be beneficial and produce greater satisfaction among musicians.
Comparing measured sound strength to theory as a function of reverberation time and room volume
Authors: Dunham Joshua R.
Published: April 2023

ISO Standard 23591 demonstrates how the sound pressure level in a room may be estimated with a knowledge of (1) the sound power of sources in that room and (2) the sound strength G of that room as defined in ISO 3382-1. In this presentation, the theory connecting room volume V, reverberation time T60, and sound strength G is summarized, and a comparison of measured sound strength G to this theory is explored for a wide range of rooms. After an explanation of the mathematical model, a description of the calibration of measurement equipment using Odeon software is discussed, including measurements taken in a reverberation chamber. A brief review of the rooms in which sound strength was measured is provided. Both measured and theoretical sound strength results are presented for the rooms reviewed. The difference between measured G and theoretical G using this mathematical model is analyzed statistically both for data measured with this test setup and with concert hall data from Beranek’s book. This model lends itself to designing rooms of appropriate reverberance and loudness for a given context, musical or otherwise.
Szilard-Wigner distributions completely define physics and perceptions of concert halls
Authors: Lee James B.
Published: April 2023

At the second joint meeting of the Acoustical Society of Japan and the Acoustical Society of America in 1988 Yamasaki and Itoh presented time-frequency measurements of several concert halls employing Fourier transforms on autocorrelations, the same device Szilard and Wigner had developed for quantum theory in the 1920s. In 1995, it was proved that resonant scattering in the body of good halls generates power spectra resolved in time and frequency, correctly presenting musical information emanating from the orchestra. In poor halls specular reflections from hard flat surfaces generate echoes encoding architectural information about size, shape, features of the hall, necessarily detracting from desired musical information. Yamasaki and Itoh also demonstrated that “reverberation-time” tells essentially nothing about properties, physical or perceptual, of concert halls; impulse responses, from which Szilard-Wigner distributions are computed, tell much more. Careful study of these matters explains why after the era of Wallace Sabine, when “reverberation-time” became the sine qua non of concert hall theory, design of fine concert halls became impossible.
Coral reef soundscapes and noise
Authors: Nedelec Sophie , Radford Andrew , Gatenby Peter , Keesje Davidson Isla , Velasquez Jimenez Laura , Travis Maggie , Chapman Katy , McCloskey Kieran , Lamont Timothy , Illing Bjorn , McCormick Mark , Simpson Stephen
Published: April 2023

Building back coral reefs requires limiting greenhouse gas emissions, limiting local threats, and active restoration. Vessel noise pollution is a widespread threat acting at a local level impacting a broad range of species from cetaceans to cephalopods. Ultimate consequences of noise pollution include death due to injury or predation, failure to develop and reduced offspring quality and survival. We tested the hypothesis that protecting coral reefs from motorboat noise can improve reproductive output in fish on the Great Barrier Reef in Australia. Across an entire breeding season, we limited motorboat traffic at three separate reefs with breeding spiny chromis. We compared these protected nests with nests on three further reefs where motorboats drove regularly nearby. We replicated the breeding experiment in a laboratory setting to isolate noise as the stimulus. Protecting coral reefs from traffic noise was beneficial for breeding fish and their offspring: egg fanning and offpsring growth were enhanced with lower energetic resource use, and reproductive success was enhanced. Limiting traffic noise at the local level presents a valuable opportunity for enhancing resilience in coral reefs by improving reproductive success in fish. This could speed up recovery following climate related mass mortality events caused by bleaching and cyclones.
Acoustic propagation and ambient noise in a thawing Arctic
Authors: Heaney Kevin D.
Published: April 2023

Over the past 50 years, the extent and volume of sea ice coverage in the Atlantic Ocean has been receding at a nearly linear rate due to anthropogenic induced climate change. It is expected that some time within the next 10 to 30 years, there will be an ice free summer. For periods beyond this time, the Arctic Ocean will change from mostly covered by multi-year ice to mostly covered by first year ice. In this talk, the impact of the changes in ice morphology (roughness and thickness) and ice extent will be examined from both an under-ice propagation modeling and an ambient noise modeling perspective. The first year ice is expected to have less loss, leading to better sound propagation. The reduced ice coverage will lead to more open water exposed surfaces for wind generated noise, and more open water for ice-free propagaiton of shipping induced anthropogenic sound. Both of these features will drive up the background level of sound in the Arctic Ocean. Regional differences in ice cover and expected wind and shipping noise will be addressed.
Climate change drives frog call change in Puerto Rico: Predictions and implications
Authors: Narins Peter M.
Published: April 2023

Acoustic signal production and reception in ectotherms are acutely temperature-dependent. We recorded the advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) along an altitudinal gradient and repeated the measurements twenty-three years later. We found that over this period, at any given elevation, calls exhibited both significant shortening of their duration and increases in pitch. We also found that the observed differences are consistent with a movement to higher elevations for the population, a familiar response to rising ambient temperature. Using temperature data obtained from four local weather stations over the same time period, we confirmed a significant ambient temperature increase, the magnitude of which closely predicts the observed changes in the frogs’ calls. Physiological responses to long-term temperature rises include reduction in individual body size and thus, population biomass. These changes can have alarming consequences, since coqui frogs form an essential component of the food web in the Puerto Rican rainforest. (Work supported by UCLA Academic Senate via Grant No. 3501.)
Ocean acidification: Future effects to ocean environments and biologic response
Authors: Eastland Grant
Published: April 2023

Ocean acidification has become one of many consequences of our modern civilization that potentially could cause major changes to Earth’s undersea environments. There are several physical and chemical effects from acidification, one of which affects the undersea acoustic environment. There are various empirical models for acoustic absorption, but an empirical model by Francois and Garrison has a pH dependent contribution. As the ocean becomes more acidic, the pH decreases from its current value and the model predicts a reduction in the amount of acoustic absorption. The result of this absorption reduction changes the overall transmission loss of sound propagation and makes the underwater environment a “louder” place. The consequences of which would be minor complications to ocean exploration but will have a greater impact upon the undersea fauna. As the environment becomes louder, those animals that use acoustics to echolocate food, will find it more difficult to do so and others may find the environment to not be amenable to their survival. These changes are occurring on a time scale on the order of decades, so environmental acoustic monitoring of ambient conditions and large-scale migration can be utilized as an indicator of the changes to the water space.
Vertical migration of the ocean’s deep scattering layer affects the health of the planet
Authors: Benoit-Bird Kelly
Published: April 2023

The vertical transport of carbon, termed the biological pump, mitigates the effects of climate change by sequestering 25% of the carbon dioxide emitted by fossil fuel use each year. The nightly vertical movement of millions of zooplankton, fishes, squid, and shrimp that make up the deep scattering layer may account for as much as half of this carbon sequestration but this process remains poorly parameterized. We use a stationary echosounder deployed at ∼1000 m depth complemented by video imaging and environmental DNA sampling to describe the vertical migration of mesopelagic micronekton in Monterey Bay, California from the darkness of the deep sea to the bounty of food at the surface over 30 months. Vertical migration at this site showed as many patterns as have been described globally, with drastic changes in the proportion of animals migrating, the extent of migration, and the species involved. Patterns were consistent only over periods of a few days even as mobile sampling showed synchrony in patterns throughout the mesopelagic zone of the bay. These results provide critical information for incorporating the effects of this largest migration on Earth on predictions of future climate.
Effective medium modeling of acoustic propagation in a seagrass meadow
Authors: Jerome Thomas S. , Ballard Megan , Lee Kevin M. , Cushing Colby W. , Capistrant-Fossa Kyle , McNeese Andrew R. , Wilson Preston S. , Dunton Kenneth H.
Published: April 2023

Seagrasses are foundation species in many coastal ecosystems, but these environments are declining globally due to climate change and other anthropogenic impacts. Ballard et al. [J. Acoust. Soc. Am. 147, 2020] established the efficacy of acoustic remote sensing techniques for seagrass monitoring by exploiting acoustic sensitivity to gas bubbles produced by photosynthesis and gas channels within the seagrass leaves. However, the effects of seagrass on acoustic propagation are not understood with sufficient quantitative detail, and an improved model describing propagation through a mixture of seagrass leaves, free gas bubbles, and seawater is needed to aid in integrating acoustic methods into conservation efforts. This talk provides an overview of developments in the modeling of acoustic propagation through a Thalassia testudinum meadow using a homogeneous effective medium approach to represent the seagrass leaves and seawater. The model accounts for the complex microstructure of seagrass leaves including the encapsulated gas channels and the elastic properties of the seagrass tissue. The model is intended for use in geoacoustic inference algorithms for the overall goal of providing estimates of seagrass productivity and biomass. Candidate effective medium models include 2D cylindrical seagrass leaves and a micromechanical model of a seagrass leaf cross-section. [Work supported by NSF.]
Towards a cloud optimized data lake for archived water column sonar data
Authors: Wall Carrie , Klucik Rudy , Slater Chris , Anderson Charles , Martinez Veronica
Published: April 2023

Due to their value to the ocean science and fisheries management communities, NOAA National Centers for Environmental Information (NCEI), with NOAA Fisheries and University of Colorado Cooperative Institute for Research in Environmental Sciences, established a national archive for water column sonar data. There are currently 210 TB of data freely and publicly available, and that volume is growing rapidly as sonar technology advances. The spatially and temporally diverse archive is accessible through its dedicated data portal and Amazon Web Services. Throughout 2023, we will develop a cloud-optimized data lake of echosounder files representing a ∼100 TB subset of the archive holdings. The echosounder files will be translated from their complex, binary and proprietary file format into zarr files following the Earth Science Information Partners analysis-ready cloud-optimized standards. The resulting data lake will serve as the foundation for building analytical capabilities that can cost-effectively tap into the archive’s sonar holdings, especially when coupled with compute power. The zarr stores will subsequently feed into EchoFish, the archive’s AWS-hosted interactive data visualization platform to facilitate subsetting and prevent the data lake from becoming a data swamp. The progress and potential applications of this NOAA Center for Artificial Intelligence funded project will be presented.
Characterizing the deep sound scattering layer with a moored upward-looking broadband split-beam echosounder
Authors: Zhuang Zhaozhong , Lavery Andone C.
Published: April 2023

The deep scattering layer (DSL) is a ubiquitous feature of the global ocean. It consists of a large community of mesopelagic organisms which links the marine food web and has recently garnered much interest from commercial fisheries. Such biological communities are inherently coupled with oceanic physical processes such as mesoscale eddies, internal waves and boundary currents. However, very little is known about the physical consequences and biological responses in this coupled system. To address these questions, an upward-looking broadband split-beam echosounder (36kHz – 44 kHz) was moored at ∼580 m depth (bottom depth ∼2790 m) in the New England slope waters in July 2021. The time series analysis focuses on (1) volume scattering strength and spectrum shape and (2) target strength, layer density and compositions, and individual behavior in three dimensions. We demonstrate the seasonal variability in the biomass, distribution, and vertical migration patterns of the deep scattering layer, and quantify the temporal and spatial variability of the DSL under the influence of multiple oceanic physical processes, including warm core rings, semidiurnal internal tides, and near-inertial waves.
Broadband attenuation-based measurements of bubble size distributions
Authors: Kahn Rachel E. , Lavery Andone C. , Bassett Christopher , Petitt Robert
Published: April 2023

Oceanic bubbles generated by breaking waves are a key mechanism for air-sea gas exchange. Dense bubble plumes can also interfere with acoustic propagation in shallow water due to their high scattering and attenuation. Most studies of oceanic bubbles have used narrow-band acoustical and optical techniques to quantify bubble size distributions under breaking waves in open water. To study bubble distributions at estuarine tidal fronts, where localized downwelling and advection can generate large bubbles plumes, we developed a measurement system for estimating bubble size distributions via broadband excess attenuation. The system consists of two transducers (3–30 kHz and 30–110 kHz) and two hydrophones mounted on a towable frame. Testing was performed in a laboratory wave tank to measure bubble distributions below a field-scale (1 + meter) breaking wave. This presentation will discuss the bubble size distributions observed at different locations along the breaking wave crest in the direction of propagation and their associated time scales and sound speed anomalies. We also compare these distributions with those previously observed in open water and will present preliminary results from a field deployment of the system in the Connecticut River estuary.