bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of different procedures to assess spectral weights for speechlike sounds
Authors: Lentz Jennifer , Skinner Kimberly
Published: May 2016

We present a spectral weighting experiment designed to assess whether listeners adopt different listening weights for consonant sounds depending on the sound presented and whether weights depended on the level of analysis—for the individual stimuli (“microscopic”) level or for the stimulus set (“macroscopic”). We used a closed set of speech stimuli modeled after the voiceless fricatives /f/, /s/, and /ʃ/. Subjects heard one of the three stimuli, each containing random level perturbations across multiple frequency bands. They then made an identification decision. For each stimulus, we estimated the weighting strategy by correlating observers’ responses with the random perturbations. This work allows us to estimate the strategies applied to each stimulus in the set. This method differs from other speech weighting studies, which assume that listeners apply a general filter to speech stimuli, enhancing some bands and attenuating others (e.g., the Articulation Index). We will also compare our data to those using a global strategy to determine the importance of analyzing decisions on an individual-stimulus basis. Our data indicate that the listening strategy depends greatly on the stimulus presented to them, and that we can assess the flexibility of the auditory system in adapting to changing stimuli using these methods.
A detection-theoretic analysis of the relation between multitone auditory streaming and masking
Authors: Chang An-chieh , Lutfi Robert A. , Lee Jungmee
Published: May 2016

Research on hearing has long been challenged with understanding our exceptional ability to “hear out” individual sounds in a mixture (the so-called cocktail party problem). Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming). The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking). The two phenomena are clearly related, but that relation has never been specifically evaluated. The present paper offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The underlying premise of the analysis is that streaming is auditory system's way of maximizing the likelihood that sounds from separate sources are perceived as separate. Experiments are reported supporting some basic outcomes of the analysis.
Discrimination of rippled spectra in background of maskers of different frequencies
Authors: Supin Alexander , Nechaev Dmitry , Milekhina Olga
Published: May 2016

Discrimination of rippled-spectrum signals in masking noise was investigated in normal listeners. The rippled-spectrum signal was 0.5-oct wide centered at 2 kHz. Simultaneous masker was a 0.5-oct wide noise centered below, on, or above the signal band (low-, on-, and high-frequency maskers, respectively). Discrimination of the signals was assessed by (i) threshold for discrimination of ripple spacing; (ii) threshold for discrimination of spectrum-pattern shift. The threshold dependence on the masker level was qualitatively different for the low- and on-frequency maskers. For the on-frequency masker, the masking effect primarily depended on the masker/signal ratio: the thresholds steeply increased at a ratio of 5 dB; no ripple pattern was discriminated at a ratio of 10 dB or higher. Alternatively, for the low-frequency masker, the masking effect primarily depended on the masker SPL: the threshold increased at a masker SPL of 70–80 dB; no ripple pattern was discriminated at a masker SPL of 100 dB. The high-frequency masker produced little effect. Hypothetically, the effect of the on-frequency masker appeared due to a decrease of ripple depth when the masker overlapped the signal, whereas the effect of the low-frequency masker appeared due to widening of the auditory filters at high sound levels.
Additivity of masking at the cocktail party
Authors: Merchant Gabrielle R. , Freyman Richard L. , Helfer Karen S.
Published: May 2016

Multi-talker listening environments, like crowded restaurants, are highly complex. In addition to the target talker, the auditory scene may consist of a combination of one or two interfering talkers close to a listener that would likely be relatively high in level (e.g., from people at the same or a nearby table) and numerous additional masking talkers at greater distances whose outputs reach the listener at lower levels. Our understanding of how these masking components combine is limited by the fact that most studies of multi-talker listening present all interfering talkers at the same level. The current study explored the extent to which error rates in a speech understanding task could be predicted from the error rates for two individual components of the masker, specifically from (a) two higher-level (closer) talkers and (b) four lower-level (more distant) talkers. The variables of angular location and level difference of the “closer” and “farther” talkers were explored. At least for an initial subset of conditions in young, normal-hearing listeners, simple additivity of error rates for the individual components appears to be a reasonable model to predict error rates for the combined maskers.
Difference between Mandarin Chinese and English speech masking caused by signal-driven processes
Authors: Chen Jing , Yang Hongying , Xie Zilong , Li Liang , Wu Xihong
Published: May 2016

Speech intelligibility in competing speech is worse in native masking than in non-native masking, which could be caused by signal-driven processes and by knowledge-driven processes. To evaluate the contribution of signal-driven processes, the speech intelligibility of Mandarin Chinese was measured on native Chinese listeners in four types of maskers for both Mandarin and English masking: (1) 1-talker’s normal speech (NOR); (2) amplitude-modulated noise with speech envelope (AM); (3) speech-like signals synthesized according to the speech F0 modulation with steady temporal envelope (FM); (4) speech-like signals with speech envelope (a combination of AM and FM, AFM). The results show that speech reception threshold in Chinese masking was about 4 dB higher than that in English, in which about 2 dB was caused by the AM, −1 dB was caused by FM, and 1 dB was caused by AFM. The results revealed the signal-driven processes might play minor role in the difference of speech masking between Mandarin Chinese and English. The effects of amplitude modulation and F0 fluctuation were analyzed and discussed.
The use of auditory models for the prediction of protected-ear localization
Authors: Romigh Griffin D. , Thompson Eric R.
Published: May 2016

Several authors have shown that listeners’ natural auditory localization performance is degraded significantly when wearing a hearing protection device (HPD) (Atherley and Noble, 1970; Abel and Armstrong, 1993; Bolia et al., 2001; Brungart et al., 2007; Hobbs et al.,2008). Research suggests that this degradation in protected-ear localization caused by the disruption of the natural spatial hearing cues by physical obstructions such as a plug or muff, as well as active systems’ artifacts like a limited frequency response, temporal processing delay, or artificial directionality. The current work investigated the utility of using existing auditory localization models from The Auditory Modelling Toolbox (Sondergaard and Majdak (2013)), along with measurements of the device directional transfer function, to accurately predict behavioral protected-ear localization performance. Ten listeners were asked to localize 250-ms broadband noise bursts originating from 245 spatial locations surrounding the listener while wearing each of 11 different HPDs (a mixture of active and passive, plugs and muffs). Directional transfer functions were also collected for each subject, device, and location. Results indicate good agreement between observed behavioral results and model predictions when viewed macroscopically (global mean error values), but less agreement was seen on a trial-by-trial basis.
Sound system analysis and design of the Minnesota State House
Authors: Olson Bruce C. , Jaramillo Ana M.
Published: May 2016

During the renovations of the Minnesota Capitol we were called to advise on the sound system of the House of Representatives. In order to assess the quality of the current system we performed noise, RT and STI measurements. Using the collected information we created an EASE model for the room to look at improvement proposals. This presentation addresses the differences between measured and simulated (predicted) STI values and the use of modeling tools for design. Due to the type of client we had for this project (final user, political) we were asked to report findings and recommendations in a presentation format and relied on auralizations as a tool for demonstrating changes in speech intelligibility between the existing and proposed sound systems.
Dick Fay’s contributions to bioacoustics
Authors: Popper Arthur N.
Published: May 2016

For well over 40 years, Dick Fay has been making broad, significant, and insightful contributions to our understanding of vertebrate, and particularly fish, hearing. His work has range from psychoacoustics to physiology to, most recently, behavioral responses. While Dick has worked on a number of different species, his primary research animal has been the goldfish (though he has also worked with sharks, cichlids, toadfish, and other species). Through ingenious studies that involved a variety of different psychophysical techniques, Dick not only asked question about what fish can hear, but also did pioneering work on things like masking, critical bands, and auditory scene analysis. Dick’s physiological studies have been of equal importance. These often involved the use of an ingenious “shaker table” that he developed which allow very precise control of the stimulus in three-dimensions. Using this approach, Dick has asked questions about function at many levels of the auditory system, providing important insight not only in fish hearing and their potential for sound source localization, but also in the evolution of the vertebrate auditory system.
Fish hearing and bat sonar
Authors: Simmons James A.
Published: May 2016

The Dynamic Duo of Dick Fay and Art Popper advanced auditory research by bringing to light the diversity of hearing capabilities and auditory mechanisms in different species of fishes. I was lucky to have been a graduate student along with Dick in Glen Wever’s Auditory Research Laboratory at Princeton—a true bastion of comparative hearing science. Fish auditory mechanisms fit into an evolutionary pattern of auditory capabilities that spans the entire vertebrate family tree. There is a ubiquitous hearing capability that covers frequencies of 20–30 Hz to perhaps 500 Hz that is probably shared by all vertebrates. It is mediated by phasic nerve discharges that convey sound period to higher auditory centers by well-defined synchronization to cycles of sounds in this low-frequency region. This regime is critical for coding many vowel-like animal vocalizations that have first or higher harmonics in the temporal coding region. Although the mammalian cochlea is best known for tonotopic representation—important especially for tone frequencies and wideband sounds above 1–2 kHz, a wide variety of vertebrates in fact have evolved place coding through tonotopic organization of auditory receptors. These two coding regimes operate in parallel for biosonar imaging, too. [Work supported by ONR and Capita Foundation.]
What is animal bioacoustics?
Authors: Erbe Christine
Published: May 2016

Animal Bioacoustics is the study of sound in animals. It covers: (1) animal sounds; communication, biosonar, and associated behavior; (2) sound production anatomy and neurophysiology; (3) auditory capacities and mechanisms, anatomy, and neurophysiology; (4) acoustic phylogeny, ontogeny, and cognition; (5) acoustic ecology, acoustic characterization of habitats, and effects of sound on animals; (6) passive acoustic tools and methods, hardware and software, for detection, classification, localization, tracking, density estimation, and behavior monitoring ; (7) active acoustic tools and methods, including animal-tracking sonars and echosounders, acoustic tags, pingers, deterrent devices, etc. Recent publications have treated various taxa: birds, terrestrial mammals (in particular, bats), marine mammals, amphibians, reptiles, fishes, insects, and crustaceans. Animal bioacoustics is beautifully interdisciplinary, and researchers have diverse backgrounds ranging from acoustics, via biology, engineering, mathematics, and physics, to zoology.
Categorical perception of visual speech information
Authors: Weinholtz Chase , Dias James W.
Published: May 2016

Previous research suggests that many speech sounds are perceived in discrete categorical units. For example, perceivers typically identify acoustic stimuli from a continuum that ranges from one syllable to another (e.g., /va/-to-/ba/) exclusively as one syllable with a sharp change in which syllable the stimuli are identified as in the middle of the continuum. Further, pairs of continuum stimuli are typically easier to discriminate if they span this sharp change in stimulus identification. Walden et al. (1987) investigated whether visual (lipread) speech is perceived categorically using a continuum of digitally morphed mouths, but failed to find any strong evidence for categorical perception. In the current investigation, a technique developed by Baart and Vroomen (2010) was used to create a /va/-to-/ba/ continuum of visual test-stimuli. A video of a talker articulating /va/ was digitally superimposed over a video of the same talker articulating /ba/. Opacity of the /va/ video was then adjusted in 10% increments to create an 11-step continuum (from 0% to 100%). Identification and discrimination functions indicate that the visual continuum stimuli were categorically perceived as /va/ or /ba/. The results suggest that visual speech, like auditory speech, can be categorically perceived. Implications for gestural theories of speech will be discussed.
Use of ocean model forecasts during acoustic experiments and naval missions
Authors: Heaney Kevin D.
Published: May 2016

Ocean acoustic propagation is critically dependent upon the spatial (and to a lesser extent the temporal) scales of the ocean. With the advent of high-fidelity data-assimilative ocean models, forecasts are available that can provide an improved level of confidence for acoustic propagation modeling in support of sea-tests and naval exercises. In this paper, a set of experiments will be presented where ocean model forecasts were used within an acoustic model to help inform the experiment planning. Tests include shallow water tests (Key West), continental shelf-break environments (Shallow Water 2006, Quantifying and Predicting Uncertainty) and deep water environments (Philippine sea 2009/2010). Models used include the Navy Coastal Ocean Model (NCOM), the MSEAS model (MIT, Pierre Lermusiaux), the ECCO2 model state estimation and the Scripps Institution of Oceanography version of the ROMS (Bruce Cornuelle) model run. In-situ assimilation of acoustic signals was performed for geo-acoustic information (in shallow water) and not for ocean model forecast updates. Our conclusion for over 10 years of use of models in real-time experiments is that ocean model forecasting does provide useful information for mission planning and experiment design, particularly when combined with on-site measurements.
An Eulerian-Lagrangian study of cloud dynamics near a wall
Authors: Ma Jingsen , Chahine Georges L. , Hsiao Chao-Tsung
Published: May 2016

The dynamics of bubble clouds is studied using an Eulerian-Lagrangian model treating the two-phase medium as a continuum and modeling the microbubbles as discrete sources and dipoles tracked in a Lagrangian fashion. These two are coupled through the local void fractions associated with the instantaneous bubble volumes and locations. Resonance of the bubble cloud, resulting in the highest pressure at the nearby rigid wall, is deduced from simulations with the same initial bubble distribution while varying the excitation frequency and amplitude. This resonance frequency deviates significantly from the classical linearized solution as the relative amplitude of driving pressure increases. It gradually drops as the excitation amplitude increases until reaching a limit value. In the high amplitude driving pressure regime, the peak pressure generated at the wall has a maximum for an optimum value of the initial bubble radius for the same cloud radius. This occurs when the ratio of maximum over initial bubble size is maximum. Too weak or too strong bubble interactions in the cloud inhibit strong collective effects. For the same initial void fraction and for different initial bubble sizes (changing the bubble number), an optimum bubble size also exists, resulting in the highest collective pressure.
Tracking kidney stones during shock wave lithotripsy
Authors: Shoar Kya , Turney Ben , Cleveland Robin
Published: May 2016

Shock wave lithotripsy is a non-invasive procedure by which kidney stones are fragmented by shock waves. Real-time monitoring during shock wave lithotripsy remains a challenge more than three decades after it was introduced into clinical practice. Currently, many shock waves are delivered to the body that do not impact the stone, but do result in tissue trauma. This work presents a monitoring system to locate kidney stones, with the goal of gating shock waves not aligned with the stone, and hence, reduce renal trauma during lithotripsy. A circular array, housing twenty-two 0.5 MHz transducers that can be mounted on a clinical lithotripter, was deployed in a water tank. An algorithm, consisting of threshold detection, including automatic rejection of weak signals, and triangulation, was developed to determine the location of stones. The accuracy of the system was tested using: a spherical steel ball and two stone models made from gypsum cement. The results show that within ±15 mm of the focus of the lithotripter, the accuracy was better than 5 mm in the lateral directions and 2 mm in the axial direction. Using off-the-shelf hardware, the algorithm can calculate stone position every 1.1 s, allowing for real-time tracking during lithotripsy. [Work supported in part by NIH through P01-DK43881.]
A comparison of different methods for calculating complex acoustic intensity
Authors: Whiting Eric B. , Gee Kent L. , Sommerfeldt Scott D. , Neilsen Tracianne B.
Published: May 2016

The Phase and Amplitude Gradient Estimation (PAGE) method of calculating acoustic intensity from multiple pressure measurements [Thomas et al., JASA 137, 3366–3376 (2015)] has been used successfully to calculate active intensity in the laboratory and in-field experiments. The primary result is that the PAGE method increases the bandwidth over which accurate vector intensity estimates can be obtained. Further work has investigated the application of the PAGE method to calculate other energy-based quantities, including the reactive intensity. Simulated pressure and particle velocity fields have been calculated for a single monopole, two out-of-phase monopoles, and, via Rayleigh integration, a baffled circular piston. The analytical intensity fields are then compared to the PAGE and the traditional p-p methods for obtaining both the active and reactive intensity, both in the near and far fields. [Work supported by NSF.]
Cultivating successful undergraduate research by cognitive apprenticeship: A case study
Authors: Ryan Teresa J.
Published: May 2016

A common challenge in academic research is finding a meaningful and productive way to involve undergraduate students in substantive research activities. The Department of Engineering at East Carolina University offers a general Engineering undergraduate degree, and matriculated its first small group of graduate students into a Master’s program in Biomedical Engineering in Fall of 2014. With few master’s students and no doctoral program, our undergraduate students are often given the opportunity to play a role in research that is more typically expected of a traditional graduate research assistant. This fact presents both great opportunity and unique challenges. This work presents the framework for a case study in cognitive apprenticeship that will take place over the next four years. The group of students includes all class levels, from freshmen to seniors. In addition, implementation of a hive or collaborative approach for introducing undergraduate students to advanced technical literature is described.
Wave vortices, structured beams, and their interaction with matter: What can we learn from analogies?
Authors: Volke-Sepulveda Karen
Published: May 2016

One of the many reasons making the study of waves so fascinating is the opportunity it brings to establish links among different areas of physics. In particular, the analogies between optics and acoustics have led to important advances in both directions. Fundamental research on structured wave fields and phase singularities, such as Bessel beams and helical waves, as well as their interaction with matter, is one of the areas that has been benefited greatly from these cooperative advances. Regarding topological studies of scalar wave fields, for instance, sound waves might represent a more versatile alternative than light, since their phase structure can be measured directly with respect to a reference signal. In contrast, the intensity distribution of light can be directly observed, whereas the intensity distribution of an acoustic field has to be determined from measurements of the sound pressure. Therefore, optical and acoustical demonstrations complement and reinforce each other. In this presentation, some specific examples of this productive interchange will be discussed as a starting point, involving the study of acoustic vortices. This will pave the way for introducing some recent results on the analysis of structured light beams, which may find direct translation to the acoustic realm.
Helicity sensitive processing and imaging of a first order vortex beam scattered by a sphere
Authors: Bollen Viktor , Plotnick Daniel S. , Marston Philip L.
Published: May 2016

A vortex beam’s wavefield has a null on the axis of propagation and an angular phase ramp proportional to the order of the beam. The rapid phase ramp at the null leads to the possibility of high-resolution imaging and precise alignment of the system. Using a modified four-panel transducer, a first order vortex beam was generated by driving each panel with an appropriate phase shift [V. Bollen et al., Proc. Meet. Acoust. 19, 070075 (2013)]. Utilizing this transducer, a solid sphere was insonified and the backscattering measured. Recording the backscattering on each panel separately allowed selection between helicity neutral and helicity sensitive detection modes, without changing the experimental setup, by introducing individual phase shifts in post-processing [V. Bollen, et al., J. Acoust. Soc. Am. 137, 2439 (2015)]. Using time delay-and-sum imaging algorithms, we created high-resolution three-dimensional profiles of the beam, relating the sphere location to the beam pattern. With cross-correlation involving measured and computed scattering amplitudes, we showed agreement with a Kirchhoff integration based simulation of the beam. [Work supported by ONR.]
A novel binaural speech enhancement algorithm for hearing impaired listeners
Authors: Zhang Tao
Published: May 2016

With the advent of wireless ear to ear communication, binaural speech enhancement becomes feasible in commercial products such as hearing aids. The first such an example is a fixed binaural beam former that attenuates noise from the nonlook direction while preserving the speech in the look direction. While such an algorithm has shown significant benefits in the lab, it has not produced the wow effect in the field as we have all expected. In this paper, we will discuss some of the practical issues limiting the benefits of such an algorithm in the field. In addition, a novel binaural speech enhancement algorithm is proposed by balancing robustness along with optimal performance. Its benefits will be demonstrated by comparing it with the leading binaural speech enhancement algorithms. Furthermore, future research directions will be discussed.
Comprehensive evaluation of binaural hearing aid pre-processing strategies—Speech intelligibility in realistic noise scenarios
Authors: Ernst Stephan , Baumgärtel Regina , Völker Christoph , Warzybok Anna , Dietz Mathias , Hohmann Volker , Kollmeier Birger
Published: May 2016

For the development of new signal processing approaches, e.g., for hearing aids, a final stage of evaluation is crucial. However, the evaluation procedures for assessing performance and benefit often represent a vast and not unified realm. Thus, we suggest a comprehensive evaluation to describe the efficacy, i.e., the anticipated real-world benefit as precise as possible. This comprises physical, instrumental, and perceptual (human) measurements of objective measures, as well as subjective attributes. Eight signal pre-processing strategies were evaluated following this concept, including directional microphones, coherence filters, single-channel noise reduction, binaural beamformers, and their combinations. Speech reception thresholds (SRTs) were measured with normal-hearing and hearing-impaired listeners in three realistic noise scenarios and compared with predictions of common instrumental measures. Although hearing-impaired listeners required a better signal-to-noise ratio to obtain 50% intelligibility than listeners with normal hearing, no differences in SRT benefit (of up to 4.8 dB) from the different algorithms were found between the two groups. This suggests a possible application of noise reduction schemes for listeners with different hearing status. Although the instrumental measures can predict the individual SRTs without pre-processing, development is necessary to predict the benefits obtained from the algorithms at an individual level.
How individual differences in sensory coding and attentional control impact understanding speech in noise
Authors: Shinn-Cunningham Barbara , Ruggles Dorea , Choi Inyong , Bharadwaj Hari , Mehraei Golbarg , Dai Lengshi
Published: May 2016

Historically, the majority of psychoacoustic studies of hearing ability have viewed individual differences as noise: a nuisance that makes it difficult to see the effects that different acoustic conditions have on auditory perception. This talk reviews how we have begun to use individual differences to tease apart the processes that affect perception, with a particular focus on how listeners understand speech when there are competing sound sources. We find that individual subjects show consistent differences in their ability to understand speech in noise. These consistent differences can come both from differences in the fidelity of sensory coding and from differences in the ability to focus selectively on important sound and suppress unimportant sound. Importantly, which of these factors predicts performance depends greatly on the details of the stimuli used in a given task, and what stage of processing is the resulting bottleneck, determining performance. When fine differences in the sound content, such as small differences in location or pitch, are critical for a task, differences in sensory fidelity dominate individual differences in ability. However, when the acoustic features important for separating sound streams and identifying the target stream from the mixture are very distinct, individual differences in ability reflect differences in attentional control. These results highlight how understanding speech in noise depends on complex interactions between the ear and the brain.
The “meaning” in noise—Evidence for bottom-up information masking of within channel modulation coding of speech
Authors: Carlile Simon
Published: May 2016

Spectro-temporal variations are a consequence of dynamic structural variations of a sounding body. The human auditory system is highly optimized for the detection, segregation and analysis of one class of such variations—speech. Here, we will examine some consequences of this optimisation in the context of complex listening involving multiple concurrent talkers. In such conversational settings, listeners rapidly shift their attention from one to another talker so foreground and background are defined dynamically by listener intent. Up-regulation of the attended-to talker is generally thought to result from endogenous, top-down attention. Here, we review a recent report indicating that substantial informational masking between concurrent talkers may result from bottom-up interactions between sources within frequency modulation channels. This indicates that temporally dynamic aspects of within-frequency channel processing plays a very important role in speech masking by the sort of “noise” most commonly encountered in natural conversational settings. Possibly even more surprising, these interactions appear to be modulated by spatial attention. Attentional enhancement of a foreground sound might then also involve processes at the level of the within-frequency channel. Whether this occurs prior to or as a consequence of grouping is a question of some functional significance but also points to the importance of knowing the listeners focus of attention.
Neural representations of speech, and speech in noise, in human auditory cortex
Authors: Simon Jonathan Z.
Published: May 2016

We investigate how continuous speech, whether presented alone, degraded with noise, or masked by other speech signals, is represented in human auditory cortex. We use magnetoencephalography (MEG) to record the neural responses of listeners to continuous speech in a variety of contexts. We find that cortical representations of continuous speech are robust to noise under a wide variety of conditions, including clean speech, additive stationary noise, band-vocoded speech and noise, and speech with competing speakers. In the last case, individual neural representations of the speech of both the foreground and background speaker are observed, with each being selectively phase locked to the rhythm of the corresponding speech stream. In all observed cases, the temporal envelope of the acoustic speech stream can be reconstructed from the observed neural response to the speech.
Intelligibility of British English for American younger and older adults with and without hearing loss
Authors: Champougny Caroline , Ferguson Sarah H. , Schilaty Sadie
Published: May 2016

In clinics, patients with hearing loss often report that they have difficulty understanding British-accented speech, despite having in the past watched and understood British television shows without trouble. Clopper and Bradlow (2008) examined the intelligibility of four United States regional dialects by American listeners, but to our knowledge, no study to date has quantified the intelligibility of non-U.S. varieties of English for American listeners. The present study will test the intelligibility of British English sentences by American younger and older adult listeners with normal hearing as well as a group of older adults with hearing loss. Participants will be presented with Basic English Lexicon (BEL) sentences produced by one American and one British talker; sentences will be presented in quiet and in a background of 12-talker babble. The resulting data will reveal how well hearing-impaired older adults understand British English, whether talker accent interacts with the presence or absence of noise, and whether older adults are disproportionately impaired in understanding British English compared to younger adults.
Speech produced in noise: Relationship between listening difficulty and spectral and durational parameters
Authors: Graetzer Simone , Bottalico Pasquale , Hunter Eric J.
Published: May 2016

Conversational speech produced in noise can be characterized by increases in intelligibility relative to conversational speech produced in quiet. The objectives of the study were to evaluate the listening difficulty of speech produced in different noise and style conditions, to evaluate the spectral and durational speech modifications that occurred in these conditions, and to determine whether the spectral or durational parameters predicted listening difficulty. Nineteen subjects were instructed to speak at normal or loud volumes in the presence of background noise at 40.5 dB(A) and babble noise at 61 dB(A). The speech signal was amplitude-normalised, combined with pink noise to obtain a signal-to-noise ratio of −6 dB, and presented to 20 raters who judged their listening difficulty. It was found that vowel duration, fundamental frequency (fo, in semitones) and the proportion of the spectral energy in high relative to low frequencies increased with the level of the noise, independently of the effect of style. Listening difficulty was lowest when the speech was produced in the presence of high level noise and in the loud style, indicating improved intelligibility. The difference in spectral energy was observed to predict listening difficulty, and, therefore, intelligibility scores (IS, the percentage of words understood correctly).
Perceived emotion in clear speech: Effect of simulated hearing loss
Authors: Morgan Shae D. , Jennings Skyler G. , Ferguson Sarah H.
Published: May 2016

Previous research suggests that both young normal-hearing and older hearing-impaired listeners judge clear speech as sounding angry more often than conversational speech. Interestingly, older hearing-impaired listeners were less likely than young normal-hearing listeners to judge sentences as angry in both speaking styles, suggesting that age and/or hearing loss may play a role in judging talkers’ emotions. An acoustic cue that helps distinguish angry speech from emotionally neutral speech is increased high-frequency energy, which may be attenuated or rendered inaudible by age-related hearing loss. The present study tests the hypothesis that simulating such a hearing loss will decrease the perception of anger by young normal-hearing listeners. Sentences spoken clearly and conversationally were processed and filtered to simulate the average hearing loss of the older hearing-impaired listeners from a previous study. Young normal-hearing listeners were asked to assign each sentence to one of six categories (happiness, sadness, anger, fear, disgust, and neutral). The judgments will be combined across listeners for each sentence, creating a percentage score for each emotion. The results from judgments of filtered stimuli will be compared with those of unfiltered stimuli as well as with results from young normal-hearing and older hearing-impaired listeners from previous studies.
Theoretical and experimental study of a thin elastic cylindrical shell subjected to a point source
Authors: Shah-Hosseini Soheil , Leon Fernand , Chati Farid , Decultot Dominique , Maze Gerard
Published: May 2016

The aim of this work is to study theoretically and experimentally, the acoustic radiation of a cylindrical elastic shell excited by a point source with no internal loading and immersed in a water tank. We are primarily focused on the theoretical study of a cylindrical elastic shell receiving a point force in the form of a Dirac pulse and the acoustic pressure radiated along the tube into a point at far-field observation. The model used is based on the theory of elasticity. It is therefore interesting, in a second step, to conduct experiments to validate these theoretical calculations and to realize complementary measures corresponding to the case of a focalized observer. The used shell is a cylindrical stainless steel tube characterized by its ratio equal to 0.94. Two experiments are carried out. The first experiment is based on a bistatic method, and the transmission and reception are performed by two focalized transducers, characterized by a center frequency of 1 MHz. For the second experiment, the two transducers are different in nature; the transducer acting as the receiver is replaced by a plane transducer characterized by a center frequency identical to the transmitter focalized transducer
Modes of targets in water and on sand driven by modulated radiation pressure of focused ultrasound
Authors: Daniel Timothy D. , Marston Philip L. , Kirsteins Ivars , Abawi Ahmad T.
Published: May 2016

In a previous work, we had shown that low frequency flexural modes of a circular plate could be excited using modulated radiation pressure generated by focused ultrasound [J. Acoust. Soc. Am. 137, 2439 (2015)]. Recently, we conducted another experiment where we examined plate, spherical, and cylindrical targets with a larger, higher power focused ultrasound, transducer operated at a carrier of 0.5 or 1.5 MHz that was capable of producing much stronger acoustic radiation pressures. A laser vibrometer was acquired to obtain quantitative measurements of the surface velocity of the targets to facilitate analysis of the radiation force generated on the targets as well as the pressure levels of the target sound emissions. The vibrometer was able to identity modes as well as measure mode shape. Furthermore, we were able to estimate the amount of radiation force that was driving the targets by using the vibrometer measurements to calculate their radiation loading from the water. We were also able to measure the response of targets proud on sand, compared to previous “free-field” experiments, and detect resonant modes and scan the source to infer mode shapes of proud targets with both a hydrophone and vibrometer. [Work supported by ONR.]
Heating, ventilating, and air conditioning systems noise and electronic sound masking systems in buildings
Authors: Miller Andrew N.
Published: May 2016

HVAC systems are not typically adequate for both sound masking and neutral background noise quality. Electronic sound masking system cost and overall background noise quality can benefit from considering HVAC system noise character when designing sound masking systems. The contributions of adding electronic sound masking to neutralize background noise character generated by HVAC systems in buildings are explored. Results from general investigations on the topic are presented. General relationships of background noise to speech and noise reduction of construction assemblies are discussed.
A comparison of three manufacturer’s mechanical noise prediction programs and how estimated noise levels from each program compare to field measurements in the subject rooms
Authors: McGowan Eric , Coffeen Robert
Published: May 2016

The estimation of noise due to heating, ventilation, and air conditioning systems using a program supplied by a manufacturer is a common practice in acoustical consulting. There is little published research comparing these programs against each other and comparing the noise levels predicted by these programs against actual measurements taken in the field. Three rooms on campus at The University of Kansas and one multipurpose room off campus were modeled as similarly as possible in these programs using as-built mechanical drawings and manufacturer’s noise data. In addition, ambient noise measurements were taken in each space with the mechanical system operating at a “normal” capacity for springtime in Kansas. The results were used to attempt to determine how the programs compared to each other such as which one was most conservative and which program consistently came closest to predicting the actual noise levels measured in the field.
Status and dissemination of the current calculation algorithms used in the American Society of Heating and Refrigeration Engineers handbooks
Authors: Miller Gregory A.
Published: May 2016

The Fundamentals and Applications Handbooks by the American Society of Heating and Refrigeration Engineers (ASHRAE) include chapters on noise and vibration control that provide the foundation of most HVAC noise control calculations, whether in commercially available software or in custom software developed by practitioners. The handbooks, however, do not always delve into the detailed calculation algorithms that were used to develop the published tables and charts nor do they provide detailed descriptions of the assumptions and limitations of various calculation methods. ASHRAE last published a compendium of all the calculation algorithms in 1991; the handbooks have been updated to reflect recent research, but without a corresponding update of the detailed algorithms. This paper will summarize ways in which the algorithms have changed since 1991 and discuss the nascent work by the ASHRAE Technical Committee on Sound and Vibration Control (TC 2.6) to compile a new updated compendium of algorithms.
Using mechanical noise prediction software to provide suitable solutions
Authors: Butler Kevin
Published: May 2016

Mechanical noise prediction softwares have become a useful tool for consultants to provide noise control recommendations. Two recent projects involving duct breakout will be analyzed to discuss how mechanical noise prediction softwares were used to analyze multiple solutions in order to provide a suitable solution for a medical office building and an open office space.
Insertion loss provided by several commercially available air handling duct wrap materials that are applied to reduce sheet metal duct breakout noise levels
Authors: Coffeen Robert C.
Published: May 2016

Noise breaking out of sheet metal HVAC duct is often a significant and disturbing noise source for a building space being served by a supply or return duct or through which the supply or return duct is passing. Reducing breakout noise is often attempted by using heavy loaded vinyl duct wrap applied directly to the duct or applied over glass fiber insulation or foam sheet. Duct wrap insertion loss data were collected using a portion of a sheet metal duct with noise produced by a loudspeaker assembly suspended within the duct. Breakout noise levels were measured on adjacent sides of the duct with and without duct wrap. This approximate insertion loss data were obtained by a University of Kansas architecture student as a portion of work leading to a Master of Arts in Architecture degree.
Does depth matter? Investigating the effect of recording depth on delphinid whistle characteristics and classifier performance
Authors: Oswald Julie N. , Lammers Marc O. , Kügler Anke , Hom-Weaver Cory , Walker Robyn
Published: May 2016

Seafloor acoustic recorders are commonly used to obtain information about cetaceans, as they allow data to be collected for long periods without the presence of a human operator. Recordings collected using seafloor instruments do not have associated visual observations, so species must be identified based on their calls. Visually validated acoustic recordings are necessary for training acoustic species classifiers and so most are trained using data collected near the sea surface. The suitability of using classifiers trained using surface recordings to analyze recordings obtained at depth is unknown. To investigate this, we used a vertical array of four Ecological Acoustic Recorders (EARs) spaced 90 m apart to record delphinids at different depths. The same whistles were measured from each EAR and median values of 17 spectrographic variables were compared among EARs for six acoustic encounters. For five of the encounters, there were significant differences in whistle variables among EARs, most commonly in frequency variables. When a random forest classifier was used to identify these whistles to species, the same five encounters were classified as different species when recorded at different depths. These results suggest that caution should be taken when applying classifiers developed using surface data to whistles recorded at depth.
Inter and intra specific variation in echolocation signals among odontocete species in Hawaii, the northwest Atlantic and the temperate Pacific
Authors: Yack Tina M. , Dunleavy Kerry , Oswald Julie N.
Published: May 2016

Odontocete species use echolocation signals (clicks) to forage and navigate. The aim of this study is to explore inter- and intra-specific variation in clicks among odontocete species in the Northwest Atlantic, Temperate Pacific, and Hawaii. Clicks were examined for seven species of delphinids in the Northwest Atlantic; common dolphin, Risso’s dolphin, pilot whale, rough-toothed dolphin, striped dolphin, Atlantic spotted dolphin, and bottlenose dolphin. Newly developed PAMGuard tools were used to automatically measure a suite of click parameters. Five parameters were compared among species; duration, center frequency, peak frequency, sweep rate, and number of zero crossings. Significant differences in duration, center and peak frequency were evident among species within this study area (Dunn’s test with Bonferroni adjustment p < 0.05). Geographic variation in click parameters among the three study regions was compared for five species; bottlenose dolphin, common dolphin, striped dolphin, pilot whale, and Cuvier’s beaked whale. Significant differences in several parameters were found for all species among the regions (Dunn’s test with Bonferroni adjustment p < 0.05). These results suggest that there are species specific differences in clicks among delphinids and that geographic variation exists for multiple species. The ecological significance of these findings will be discussed along with implications for classifier development.
Beaked whale acoustic versus visual detection
Authors: Gerard Odile
Published: May 2016

Because of their sensitivity to anthropogenic noise, research on beaked whale habitat is particularly important. During 2010 and 2011, NATO Undersea Research Centre (NURC) conducted sea trials dedicated to marine mammals, in areas of potential beaked whale habitat. The first one took place in North Eastern Atlantic Ocean, Southwest of Portugal, and the second one took place in the Gulf of Genoa, Mediterranean Sea. For both trials: weather conditions allowing, during daylight there were two teams of visual observers, working in two shifts, scanning the horizon and taking note of marine mammal encounters. Acoustic data were collected with the CPAM (Compact Passive Acoustic Monitoring), designed by NURC. The total usable bandwidth is up to 80 kHz. The CPAM was deployed at a depth between 100 and 200 m for about 20 h a day Beaked whale detection obtained by visual observers and by passive acoustic are analyzed. The number of detections and the information obtained by each method are compared. The advantages and drawbacks are highlighted.
Seasonal variability in distribution of fin whales around Wake Island
Authors: Vernon Julia A. , Miksis-Olds Jennifer L.
Published: May 2016

Passive acoustic monitoring in population density estimation of marine mammals provides an efficient and cost-effective alternative to visual surveys. However, one challenge that arises with this method is uncertainty in the animal distribution. Information about distribution is needed in order to account for spatial variability in the probability of detection. Consideration also needs to be given as to how distribution varies between seasons, as seasonal variability also needs to be incorporated into the density estimation. This paper presents bearing estimates of fin whales around Wake Island in the Equatorial Pacific Ocean, using low-frequency ambient noise data (5–115 Hz) acquired by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) International Monitoring System. Bearings were initially calculated using time delay information from the cross-correlation of received signals. However, a simple cross-correlation is not a viable option for many calls, due to distortion of the waveform as a result of modal dispersion, and alternate methods of determining time delays of received signals are discussed. Bearings were calculated for individuals detected over a period of three years: May 2007 to May 2010. Seasonal variability in distribution is presented. [This work was supported by the Office of Naval Research.]