bluuebunny/crossref_metadata_2025 huggingface dataset:
Echolocating bats face a cocktail party nightmare when they fly together in cluttered environments
Authors: Moss Cynthia F. , Cechetto Clement , Warnecke Michaela , Chiu Chen , Xian Wei , Falk Benjamin
Published: May 2014

Echolocating bats often operate in the presence of conspecifics and in cluttered environments, which can be characterized as a “cocktail party nightmare.” Each bat's sonar vocalization can result in an echo cascade from objects distributed in direction and range. Adding to the acoustic clutter are the signals from neighboring bats. Past studies demonstrate that bats adapt their echolocation to avoid signal jamming from conspecifics by adjusting the frequencies of their vocalizations, as well as going silent. When bats fly alone in densely cluttered environments, they adjust the frequencies of call pairs to disambiguate overlapping echo streams. How do echolocating bats adapt to both conspecific signals and clutter? We sought to answer this question by flying big brown bats in a large room equipped with high-speed video and audio recording equipment. In baseline trials, bats flew alone in an empty room and were later introduced to an artificial forest, first individually and later in pairs. The echolocation behavior and flight paths are analyzed to evaluate the spectro-temporal adjustments of bat calls and silent behavior as animals progressed from open room, to forest, to forest with conspecifics. The results shed light on how echolocating bats adapt to a “cocktail party nightmare.”
Neural representations of the cocktail party in human auditory cortex
Authors: Simon Jonathan Z.
Published: May 2014

An auditory scene is perceived in terms of its constituent auditory objects. Here, we investigate how auditory objects are individually represented in human auditory cortex, using magnetoencephalography (MEG) to record the neural responses of listeners. In a series of experiments, subjects selectively listen to one of two competing streams, in a variety of auditory scenes. In the acoustically richest example, subjects selectively listen to one of two competing speakers mixed into a single channel. Individual neural representations of the speech of each speaker are observed, with each being selectively phase locked to the rhythm of the corresponding speech stream, and from which can be exclusively reconstructed the temporal envelope of that speech stream. The neural representation of the attended speech, originating in posterior auditory cortex, dominates the responses. Critically, when the intensities of the attended and background speakers are separately varied over a wide intensity range, the neural representation of the attended speech adapts only to the intensity of that speaker, but not to the intensity of the background speaker. Overall, these results indicate that concurrent auditory objects, even if spectrally overlapping and not resolvable at the auditory periphery, are indeed neurally encoded individually as objects, in auditory cortex.
Deep-diving autonomous underwater vehicle provides insights into scattering layer dynamics
Authors: Benoit-Bird Kelly J.
Published: May 2014

Organisms within deep scattering layers are often too densely packed to be ensonified as individuals using surface or seafloor based sensors, are too fast to be easily captured by research nets yet too small for most fishing gear, and are mixed with other individuals, making it difficult to interpret acoustic data from these ecologically important animals. To address this, we integrated a two-frequency, split-beam echosounder into an autonomous underwater vehicle (AUV) capable of flight at 600 m. As part of a study on whale foraging ecology off the Channel Islands, California, we flew the echosounders through scattering layers found at three depth ranges. Echoes were obtained from individual scatterers within layers being foraged upon by Risso's dolphins. Examining the echo statistics throughout layers revealed remarkable heterogeneity of echo strength and frequency response within layers that generally appeared homogeneous with respect to these same characteristics from ship-based echosounders. Some layers were internally layered but most features showed distinct, small patches of similar scatterers adjacent to those with different characteristics. The extensive horizontal coverage and near target sampling permitted by the AUV-based echosounders are providing a new understanding of the scales of biological organization within horizontally extensive scattering features.
Mapping the scatterscape of pelagic side scan sonar targets relative to oceanographic features
Authors: Grothues Thomas M. , Newhall Arthur E. , Lynch James F. , Gawarkiewicz Glen G. , Vogel Kaela S.
Published: May 2014

Sonar reconnaissance of fishes for stock assessment and research has been an effective and minimally invasive method of gathering abundance and distribution data on scales of 10s to 100s of km since the 1950s. Yet, classification of fishes remains one of the greatest challenges of active sonar surveys. Many variables affect sonar reflection, including size, shape, orientation to the sonar source, the spatial relationship of individuals in a school to each other, and the number and distribution of individuals within a school. The long wavelengths of low frequency (typically <60 kHz) that allow depth penetration provide poor small scale resolution for identifying objects. High frequency side scan sonar (600—900 kHz), while imaging only over short ranges, can resolve individual fish and thus orientation and behavior relevant to understanding low frequency sonar returns and ecology. We demonstrate here that autonomous underwater vehicles (AUVs) offer a mechanism for putting side scan sonar transducers near potential targets together with telemetry, imaging, and oceanographic sensors, and can thus work together with low frequency sonar to develop holistic scatterscapes of oceanographic features, inclusive of information on species identity, orientation, behavior, abundance, individual size, and feature stability.
High definition ultrasound of the breast
Authors: Kruger Robert , Lam Richard , Reinecke Daniel , Del Rio Stephen
Published: May 2014

We propose to develop high definition ultrasound (HD-US) based on a hemispherical synthetic aperture and backscattered sonic waves. This configuration will produce direct three-dimensional maps of ultrasound reflectivity of breast tissues and will display higher signal-to-noise, reduced speckle, and greater spatial resolution compared to ultrasound arrays based on linear or curved planar sampling apertures. Our prototype hemispherical array consists of four interdigitated sub-arrays, each having 128 discrete elements. Currently, this array is used to capture 3D photoacoustic images of the whole breast using a spiral scanning strategy to increase the field of view sufficiently to perform whole-breast screening—photoacoustic mammography (PAM). We will add a multiplexed pulser, pulse sequencer, and T/R switches to capture ultrasound reflectivity data sufficient to form a 3D ultrasound image using the same reconstruction strategy used in PAM. Full 3D image acquisition will take 1.7 min, the same as currently used for PAM data collection. HD-US will be combined with PAM to produce 3D images of soft tissue and microcalcifications. The 3D images will be co-registered with the PAM images of hemoglobin distribution in the breast using a single hemispherical transducer array.
Boundary condition-free elastic modulus reconstructions from ultrasound measured quasi-static displacements
Authors: Babaniyi Olalekan A. , Seidl Daniel T. , Oberai Assad A. , Richards Michael S. , Barbone Paul E.
Published: May 2014

Quantitative elastic modulus imaging from quasi-static displacement data requires the solution of an inverse elasticity problem. The inverse problem formulation generally requires specification of either displacement or traction boundary conditions. Most current ultrasound devices are not capable of measuring traction data, and the measured displacement field is noisy. The incomplete and imprecise nature of the available boundary information often necessitates that educated guesses be made in order to have adequate knowledge of the boundary conditions to compute mechanical properties. These assumed boundary conditions, however, can to lead to errors in the reconstructions. This abstract proposes a method to perform reconstructions without knowing the boundary conditions a priori. This method relies on using the constrain imposed by the equilibrium equation and an optimization algorithm to estimate the modulus field. This method was verified with simulated displacement data, validated with phantom displacement data, and applied to in-vivo displacement data measured from patients with breast masses. [Authors gratefully acknowledge funding from NSF and NIH (NSF Grant No. 50201109; NIH NCI-R01CA140271).]
Comparative analysis of small versus large transducers for high-frequency ultrasonic testing of breast cancer
Authors: Peterson Madison J. , Bliss Nathan M. , Doyle Timothy E.
Published: May 2014

High-frequency ultrasound (20–80 MHz) has been found to be sensitive to margin pathology from breast cancer surgery. In order to improve the resolution and sensitivity of this method, transducers are needed that have smaller piezoelectric elements than those currently in use. This study's purpose was to determine if small-element transducers (Blatek, 50 MHz, diameter <2 mm) produce similar results as those from large-element transducers (Olympus NDT, 50 MHz, 6.35-mm diameter). Pulse-echo and through-transmission measurements were performed on bovine heart tissue and 10 phantom specimens containing chopped nylon fibers and polyethylene microspheres. The density of peaks in the ultrasonic spectra of the small or mini transducers (MT) paralleled those of the large transducers (LT) in the bovine tissue, with higher peak densities associated with connective tissue and lower peak densities with muscle tissue. The MT data from the phantoms showed greater variance than the LT data, indicating that the MT were more sensitive to the heterogeneous wavefields arising from microsphere scattering. Additional in vivo testing is currently being performed on breast tumors grown in mice treated with Avastin. Small-element transducers may ultimately provide in vivo cancer detection in margins, allowing more precise excision of cancerous tissue and thus eliminating follow-up surgeries.
Teaching acoustics in the time domain and frequency domain: Going back and forth
Authors: Sabra Karim G.
Published: May 2014

Our common experience with acoustic signals typically occurs in the time domain: for instance when listening to a conversation or recording an audio signal. On the other hand, acoustics in the classroom is often taught in the frequency domain; for instance, doing so can offer clear simplification of the wave equation (e.g., when solving the Helmholtz equation). Exact time-domain solutions can ultimately be obtained back from these frequency solutions using Fourier synthesis; but it typically requires numerical methods or extra analytical work. However, based on classroom experiences, it can be valuable that students develop an intuitive interpretation of these frequency-domain solutions in the time-domain without using any computers or actual inverse Fourier transform evaluation. For instance, a question one may ask students is “how would you predict the overall shape and features of time-domain waveform corresponding to this specific frequency-domain solutions we just derived, i.e., as if you were to perform an actual experiment and just recorded a time-domain waveform.” I will discuss various basic examples covered in the classroom such as modal propagation and dispersion effects in a waveguide.
How is periodicity pitch encoded on basilar membrane of the cochlea?
Authors: Morimoto Takeshi , Kobayasi Kohta I. , Riquimaroux Hiroshi
Published: May 2014

Pitch is the perceptual correlate of periodicity of sound. Even if all the energy at the fundamental frequency (F0) is removed, a periodic complex tone retains the same pitch of missing fundamental frequency. The periodicity pitch has been mostly discussed in the central auditory system while less reported in the peripheral system. The purpose of this study was to investigate how the periodicity pitch is encoded in the cochlea. Cochlear microphonics (CM) was recorded from the round window for confirming frequency characteristics of vibration of the basilar membrane (BM) to periodic complex tones in order to generate F0. The experiments were carried out in the condition which a frequency component corresponding to F0 or frequency components of the sound stimuli were masked by low or high frequency band pass noises respectively. The forward masking did not have temporal overlap of the sound stimuli on the BM. The results showed that the frequency component of F0 existed in the CM. The frequency component of F0 decreased for high frequency band pass masking but little for low frequency band pass masking. The findings suggest that the periodicity pitch is encoded using rates of amplitude modulation rather than the location on the BM.
Real-time implementation of a polyphonic pitch perception model
Authors: Deshpande Nikhil , Braasch Jonas
Published: May 2014

This algorithm is a real-time implementation of a polyphonic pitch perception model previously described in Braasch et al. [POMA 19, 015027 (2013)]. The model simulates the rate code for pitch detection by taking advantage of phase locking techniques. Complex input tones are processed through a filter bank, and the output of each filter is run through its own separate autocorrelation following the Licklider model. After conversion to polar form, analysis is done on the phase output of the autocorrelation, where the algorithm computes the time delay between localized peaks. This gives the fundamental period of the tone within a given filter; these values are then normalized by the magnitude output of the autocorrelation and combined with output data from the other filters to give full spectral information. The algorithm uses an adjustable running frame window to trade off between frequency resolution and rapid changes in pitch. The model can accurately extract missing or implied fundamental frequencies.
Speech, spatial, and qualities of hearing scale (SSQ): Normative data from young, normal-hearing listeners
Authors: Zahorik Pavel , Rothpletz Ann M.
Published: May 2014

The Speech, Spatial, and Qualities of Hearing Scale (SSQ) was developed to assess listeners' subjective sense of listening ability and listening experience in everyday complex situations that often involve spatial hearing. The SSQ is one of the very few instruments designed to measure such quantities and has been used extensively to assess functional hearing impairment and benefit resulting from hearing remediation strategy. Although a recent study examined the psychometric properties of the SSQ with a large sample of hearing-impaired listeners, little published data exist from normal-hearing listeners. The data that have been published suggest that even young normal-hearing listeners do not rate their subjective listening abilities at the most-proficient end of the scale in all the listening situations probed by the SSQ. The goal of this study was to examine this issue more fully, using a sample of 233 young (median age 21.2 years, 3.1-year IQR), normal-hearing listeners (pure tone thresholds ≤ 25 dB HL from 250—8000 Hz). Results provide normative data on each of the (self-administered) SSQ items, and describe the psychometric properties of the SSQ for a young normal-hearing population. These data are intended to aid in the interpretation of SSQ results from other populations.
Defining essential characteristics of reliable spectral properties that elicit spectral contrast effects in vowel identification
Authors: Anderson Paul W. , Stilp Christian
Published: May 2014

Auditory perception excels at extracting reliable spectral properties from the listening environment. Preceding acoustic contexts filtered to emphasize a narrow frequency region (Kiefte and Kluender, 2008 JASA), broad differences between two vowel spectra (Watkins, 1991 JASA), or resynthesized to shift wide ranges of frequencies (Ladefoged and Broadbent, 1957 JASA) all influence identification of a subsequent vowel sound. Spectral differences between filtered contexts and subsequent vowel targets were perceptually enhanced, resulting in contrast effects (e.g., emphasizing spectral properties of [I] in the context produced more [ɛ] responses). Historically, this phenomenon has been studied using filters whose gain was broadband and/or high-amplitude, providing very strong evidence for these reliable spectral properties. Essential characteristics of these filters that are necessary and/or sufficient to elicit spectral contrast effects are unknown. A series of experiments examined relative contributions of filter frequency, amplitude, and bandwidth to reliable spectral properties that elicit contrast effects in vowel identification. Preceding sentence contexts were processed by narrowband, broadband, or spectral envelope difference filters derived from endpoints of a vowel series differing in one frequency region (e.g., F1 in [I] and [ɛ]). Preliminary results suggest complex dependencies on filter amplitude and bandwidth for vowel identification; further results will be discussed.
Acoustic noise interferometry in the Straits of Florida at 100 m depth: A ray-based interpretation
Authors: Godin Oleg A. , Zabotin Nikolay A. , Zabotina Liudmila , Ball Justin S. , Brown Michael G. , Williams Neil J.
Published: May 2014

Cross-correlation function of ambient and shipping noise recorded simultaneously by two hydrophones provides an estimate of the acoustic Green's function, which describes deterministic sound propagation between the hydrophones and can be used to estimate physical parameters of the water column and seafloor. This paper presents results of an experimental investigation of acoustic noise interferometry in 100 m-deep water in the Straits of Florida. Acoustic noise was recorded continuously for about six days at three points near the seafloor. Coherent acoustic arrivals are successfully identified in the 20–70 Hz frequency band for pairs of hydrophones separated by ranges of 5.0 and 9.8 km. The measured noise cross-correlation functions are compared to ray-based simulations of Green's functions, with generally good agreement between correlation functions and simulations. Ray-based simulations are shown to reproduce multipath features of the measured correlation functions, which are due to multiple surface and bottom reflections. The feasibility of passive acoustic remote sensing using a few hydrophones in a shallow-water waveguide will be discussed. [Work supported by NSF, ONR, and NAVAIR.]
Individual differences revealed by the challenges of listening in a complex, crowded scene
Authors: Bharadwaj Hari M. , Shinn-Cunningham Barbara G.
Published: May 2014

To extract content and meaning from a single source of sound in a quiet background, the auditory system can use a small subset of a very redundant range of spectral and temporal features. In stark contrast, communication in a complex, crowded scene places enormous demands on the auditory system. Spectrotemporal overlap between sounds reduces modulations in the signals at the ears and causes masking, with problems exacerbated by reverberation. Often, the more sensitive neurons in the early auditory pathway are driven to saturation, yet precise sensory representation is crucial for the ability to extract spatial, pitch, and cues that support source segregation and selective attention. Consistent with this idea, many patients seeking audiological treatment seek help precisely because they notice difficulties in environments requiring auditory selective attention. Consistent with this, in the laboratory, even listeners with normal hearing thresholds exhibit vast differences in the ability to selectively attend to a target. Here, we highlight the issues faced by the auditory system in a complex scene and describe recent behavioral and electrophysiological findings that hint at the mechanisms underlying individual differences in the ability to communicate in such adverse situations.
Hearing sensation change with loud sound warning in the false killer whale
Authors: Nachtigall Paul E. , Supin Alexander Y.
Published: May 2014

Work on hearing during echolocation has demonstrated that a whale was capable of changing its hearing sensitivity while it echolocated, perhaps to protect its hearing from its own intense emitted pulses. Would a whale similarly change hearing sensitivity when warned prior to receiving a loud sound? Hearing was measured using auditory evoked potentials (AEP). The whale had been trained to station within a hoop while wearing surface electrodes. Baseline AEP dependence on test-sound level and an auditory threshold were first established for a 20 kHz tone. In a second phase, the test sound was followed by a sudden increase in amplitude up to 170 dB re 1 μPa. Thus, the faint test sounds took on the role of a warning signal for the ensuing loud (unconditioned) sound. After a few trials, the test stimuli revealed a substantial reduction of hearing sensitivity before the loud sound. When the delay between the warning tone onset and loud tone was short (varied randomly from 1 to 9 s), the whale increased its hearing thresholds (reduced sensitivity) by around 13 dB. The data indicate that: (1) the whale learned to change hearing sensitivity when warned that the loud sound was about to arrive, and (2) the learning acted only when warnings were immediate.
Reproducibility of high-frequency ultrasonic signals in breast cancer detection
Authors: Breivik A. Mackay , Marshall Andrew J. , Doyle Timothy E.
Published: May 2014

The central question of this project was to determine the reproducibility of high-frequency (HF) ultrasonic signals in breast cancer detection. Previous studies on surgical specimens of breast tissue have shown that HF ultrasound (20–80 MHz) appears sensitive to a range of breast pathologies. A measurement in the ultrasonic signal called the peak density appears most sensitive to the pathology of the breast. The reproducibility of this parameter has not been quantitatively measured in a comprehensive manner. In parallel to a clinical study being conducted at the Huntsman Cancer Institute, the reproducibility of peak density measurements was studied using chicken and bovine tissue. Tissue was cut into 4 × 3 × 0.5 cm and 4 × 3 × 1.5 cm cubes and tested at 23.4°C. Waveforms were obtained for two types of measurements: (1) where the transducer stayed in contact with the tissue, and (2) where the transducer was lifted from the tissue between measurements. Spectral peak densities were obtained from 640 measurements. Type 1 measurements showed high reproducibility. Type 2 measurements displayed greater variability but were consistent with previous measurements on lumpectomy tissue specimens. The variability of the type 2 measurements is believed to be due to transducer-induced pressure differences between each measurement and is currently being studied.
Utah Valley University/Huntsman Cancer Institute Collaborative Breast Cancer Study: High-frequency ultrasound for margin assessments
Authors: Chappell J. Andrew , Stiles Janeese E. , Neumayer Leigh A. , Factor Rachel E. , Doyle Timothy E.
Published: May 2014

In a joint effort between Utah Valley University and the Huntsman Cancer Institute, high-frequency (HF) ultrasound (20–80 MHz) is being studied to determine the pathology of surgical margins from breast conservation surgery. Results from a 2010 NIH R21 study indicated that multiple parameters in the HF ultrasonic spectrum correlate to a range of breast tissue pathologies. This technology promises to provide rapid, intraoperative evaluation of surgical margins, thereby decreasing the number of additional surgeries for patients. A blind study is currently being conducted with conventional pathology as the gold standard for assessing the accuracy of the method. Specimens are delivered by the surgeon's team immediately following resection and ultrasonically tested outside the surgical suite. The margins are approximately 3 × 20 × 20 mm and are oriented using a small staple inserted by the surgeon in one corner and a stitch on one side. The margin is tested at 2–5 locations and then sent to pathology for analysis. Pathology and HF ultrasound results will be compared for correlation at the end of the study, which is expected to last one year. The study will include approximately 80 patients, 360 tissue samples, and 1400 tested locations. If successful, the method will move into clinical trial.
High-frequency ultrasound study of tissue margins from breast conservation surgery: Preliminary results
Authors: Wilson Teresa L. , Fairbrother Amy A. , Cervantes Monica , Doyle Timothy E.
Published: May 2014

A critical issue in breast conservation surgery (lumpectomy) for breast cancer treatment is ensuring the tissue surrounding the excised tumor, the margins, are cancer-free. In collaboration with the Huntsman Cancer Institute at the University of Utah, researchers from Utah Valley University are using high-frequency (HF) ultrasound to test the pathology of lumpectomy surgical margins. This preclinical study is a blind study which will involve 80 patients, approximately 320 specimens, and use traditional pathology as the “gold standard” for measuring the accuracy of the HF ultrasound method. Ultrasonic waveforms of margins were acquired at the Huntsman Cancer Hospital in pitch-catch and pulse-echo modes using 50-MHz transducers with 6.35 mm-diameter active elements. The data were analyzed to obtain ultrasonic parameters such as ultrasonic wavespeed, attenuation, and spectral peak density (the number of peaks and valleys in a HF ultrasonic spectral band). Preliminary results indicate variations in peak density between margin specimens and individual locations on specimens that are indicative of malignant and atypical breast pathologies. The objective of this paper is to search for trends in the data acquired to date to provide an assessment of reliability, stability, and robustness of the study.
An Introduction to the Acoustical Oceanography Technical Committee
Authors: Lavery Andone C.
Published: May 2014

The Acoustical Oceanography (AO) technical committee focuses on the development and use of acoustical techniques to understand the physical, biological, geological, and chemical parameters and processes that occur in the ocean interior and its boundaries. Acoustical techniques are uniquely suited for investigating underwater environments due to the low attenuation of sound relative to other commonly used remote sensing techniques based on electromagnetic radiation. The research encompassed by the AO technical committee is highly inter- and multi-disciplinary, with strong overlap with research addressed in the Animal Bioacoustics, Signal Processing, and Underwater Acoustics technical committees. In this presentation, an overview of recent “hot topics” in Acoustical Oceanography will be given, in addition to embarking on a discussion of the role of the AO technical committee in fostering education and leading the way in determining new and innovative directions in the specialization area.
An introduction to the Physical Acoustics Technical Committee activities
Authors: Garrett Steven L.
Published: May 2014

The primary activity of any ASA Technical Committee is to use collective wisdom of the Committee's membership to determine which research topics within its specialization area are most active and interesting. Based on that assessment, the Committee organizes special sessions at future meetings that will bring together experts from those areas, not necessarily limited to the Society members, who can share interesting results and provide guidance regarding the directions that will lead to further understanding. In Physical Acoustics, that is a particularly daunting challenge given the scope of topics that fall within its purview: use of sound to probe material properties, sound propagation and attenuation mechanisms on this planet and in other parts of the universe, and physical effects of sound and its interaction with other forms of radiation, all of which could also go well beyond the limitations of a linear acoustical theory. Needless to say, involvement in debates about “what's hot” is both interesting and educational. Other activities include proposals for Technical Initiatives that allocate ASA resources. Recently, PATC received funding to co-sponsor the Physical Acoustics Summer School.
Noise and its impact on our world
Authors: Ryherd Erica
Published: May 2014

Noise invades all aspects of our lives. The word noise is actually derived from the Latin word “nausea,” with one possible connection being that unpleasant sounds were made by seasick passengers or sailors in ancient times. In modern times, the demand for noise research and consulting has intensified in concert with rising population densities, growing industrialized societies, escalating demands from consumers, and increasingly common standards and legislation related to noise. The Acoustical Society of America Technical Committee on Noise (TC Noise) is concerned with all aspects of noise, ranging from noise generation and propagation, to active and passive methods of controlling noise, to the effects of noise on humans and animals. This talk will explore the broad topic of noise and its impact on our world.
Investigation of acoustical parameters in the South Indian musical intervals
Authors: Potty Gopu R. , Parameswaran Venkitanarayanan
Published: May 2014

The South Indian musical style is one of the two prominent styles of classical music styles in India whose roots can be traced back to hundreds of years in the past. The South Indian musical scale is said to have evolved from a set of seven primary notes on the basis of 22 intervals. Present day practice is to use 12 intervals in an octave. A scale is divided in to 12 intervals with fixed values that constitute the basis of musical notes. South Indian classical musical intervals are melodic and are therefore flexible. Compared to the twenty two interval scheme, the 12 interval scheme allows the freedom to perturb the fixed frequency values around their defined positions. In this study, pitch analysis of audio samples is carried out to investigate the deviations from fixed frequency values of musical intervals. Departures from theoretically calculated acoustical values will be demonstrated and discussed. The intervals vary dynamically depending on the artistic individuality and the musical context.
Investigating acoustic and electroglottograph features to characterize Passaggio in female singers
Authors: Bernadin Shonda , Morris Richard , Ellerbe Lance , Kessela Demissew
Published: May 2014

The purpose of this study was to examine the acoustic and electroglottographic features in the characterization of passaggio in female singers. Three groups of female singers were instructed to sing the notes of the scale for one octave using an “ah” vowel. When singing this octave they sang through a register shift, which is called “passaggio.” Their singing voices were recorded in a two-channel dataset. The first channel captured the acoustic signal using a microphone, and the second channel captured the electroglottographic (EGG) signal using an EGG instrument. This study used VoiceSauce (Shue, Keating, and Vicenik, 2009) analysis software to analyze the features of the two-channel dataset that contribute to the characterization of the passaggio in female singers. Glottal measurements can give more robust information on precise glottal opening and closing moments using the derivative of the EGG signal (DEGG). The results of this investigation also provide an analytical framework for calculating the DEGG in female singers.
A study of the type and characteristics of relaxing music for college students
Authors: Wang Wei-Chun
Published: May 2014

It is believed that music has the power to soften emotions and alleviate pains. The essence of the power has being encoded by researchers. This study was aimed to explore the effects of music preference and stress-associated responses of college students when they listen to music. The objectives of this study were (1) to survey the music types of relaxing music for college students, and the difference in gender and study majors; (2) to investigate the effects of musical preference, music expertise, and awareness of musical content on their perceptivity of relaxation; and (3) to analyze the relativities of musical emotions with musical characteristics, such as tempo, mode, and dynamic range. Participants were asked to listen to selected music pieces, and to rate their three-dimensional emotional responses, pleasant-unpleasant, calm-arousal, and relaxing-stress, on five-point Likert scales. Data collection of music compositions and personal music taste was acquired using surveys. The findings are expected to (1) understand college students' listening habit, (2) collect repertoire suitable for university students in terms of stress releasing, and (3) offer advices for music appreciation teaching, psychological consultation personnel, and clinical therapist.
Case studies of historic soundscapes with cultural importance
Authors: Lubman David
Published: May 2014

Case studies discussed include Bow Bells, in which the sounds of ringing bells of the East London church of St. Mary Le Bow became a soundmark that defined the ”Cockney” ethnicity. (A “Cockney” is a person born within the sound of Bow Bells.) With London's growth, more churches were built. The combined sounds of their bells became the community soundscape for East London. It inspired beloved children's poetry (Oranges and Lemons … Says the great Bell of Bow). That children's poem was learned by generations of English children, and the poem became the sound symbol for all of England. This became very important in WWII when Nazi arial bombing destroyed Bow Bells creating a serious morale problem for England. To reassure their countrymen that the “home fires” were still burning, BBC used a 1926 sound recording of Bow Bells as an interval signal in their worldwide radio broadcasts. On a smaller scale, accidental whispering arches can give buildings “a sense of place.” A 6th C monastery at Clonmacnoise, Ireland, has a large and elaborately carved door installed that became a storied whispering archway. The storied accidental whispering archways at Grand Central Terminal and Pennsylvania's West Chester University are also described.
Predictions of the magnitude of tonal content on the basis of partial loudness
Authors: Verhey Jesko L. , Hots Jan , Vormann Matthias
Published: May 2014

Environmental sounds containing clearly audible tonal components are considered to be more annoying than sounds without these components. Several standards include sections dedicated to the assessment of tonal components in sound. These standards have in common that they estimate the magnitude of the tonal components (in the following referred to as tonalness) as the level above the noise background. Recent studies indicate that partial loudness of the tonal component determines the tonalness. The present study tests this hypothesis by comparing experimental data on tonalness of sounds with multiple tonal components with predictions of a loudness model. It is shown that partial loudness is a better predictor of the perception of tonal portions of a sound than the intensity. This approach may be useful for future standardization of the perception of clearly audible tonal components in noise.
The role of modulation processing in binaural masking-patterns
Authors: Luebken Bjoern , van de Par Steven , Verhey Jesko L.
Published: May 2014

Binaural masking pattern experiments indicate a continuous decrease in the binaural masking-level difference (BMLD) with increasing spectral distance of a tonal signal to a narrowband noise masker. Previous studies suggested that this decrease in BMLD is due to additional modulation cues in monaural off-frequency masking conditions. An own masking pattern experiment with an additional interferer to mask modulation cues supported this hypothesis. The interferer is positioned spectrally below/above the masker for the signal above/below the masker with a spectral distance equal to the distance between masker and signal. This interference tone has a large impact on the thresholds without a binaural cue, as expected. Such an increase in the diotic thresholds is predicted on the basis of a modulation-filterbank model, but only if an across-channel modulation processing is assumed. The interferer also increases the dichotic thresholds, indicating an influence of modulations processing also in conditions where binaural cues are present. Assuming that modulation cues are masked by the interference tone and thus the detection is based on energy cues, the binaural data indicate effectively wider binaural filter, as previously suggested on the basis of notched-noise experiments.
Resolution and integration within auditory temporal windows
Authors: Teng Xiangbin , Tian Xing , Poeppel David
Published: May 2014

Temporal integration in auditory and speech perception is investigated in a variety of experimental contexts, using different types of signals. How the auditory system manages the tension between resolution, on the one hand, and integration, on the other—and in particular how the system integrates acoustic information over time to form a unitary percept—remains unclear. Using non-speech signals with temporal structure at different scales (30 ms, 200 + ms), we tested in four psychophysical experiments how “local” (shorter-scale) and “global” (longer-scale) auditory information is resolved and integrated. We provide evidence (supported by independent electrophysiological data) that the auditory system extracts temporally detailed acoustic information using small temporal windows, and then integrates that information over approximately 200 ms. Importantly, the fine-detailed information is not fully accessible as sound duration increases to over ~100 ms. Further, we show that representation of acoustic information requires ~150–200 ms, and that the representation of fine-detailed information can compromise temporal integration. The findings demonstrate the time scales over which the integration and resolution of auditory information cooperate and conflict, and thus shed light on the mechanisms of temporal integration.
Aspect-dependent acoustic characterization of an underway autonomous underwater vehicle
Authors: Gebbie John , Siderius Martin , Allen John S.
Published: May 2014

Acoustic emissions emitted by an underway REMUS-100 autonomous underwater vehicle (AUVs) are analyzed with array beamforming. Characterizing emissions of underway AUVs is challenging due to a variety of factors such as low source levels of some vehicle types, continually varying propagation conditions, and inherent uncertainties in vehicle location. While aspect-dependent spectral and source level emissions are available for a wide range of surface craft types, few articles have analyzed these for underway AUVs. Array beamforming is a known method of increasing gain of a weak signal in the presence of interference and noise, and propagation modeling tools can provide estimates of transmission loss between a source and receiver. These techniques are used to measure the aspect-dependent source level and spectral content from the propulsion system of a REMUS-100 AUV deployed near a fixed array near Honolulu Harbor, Hawaii, by fusing measured acoustic data with multi-sensor navigational records recorded on the vehicle. As AUVs become more widely used, characterizing their acoustic radiation will help predict how these platforms interact with and impact the environments in which they are deployed.
Modeling the acoustic color of undersea structures
Authors: Burnett David
Published: May 2014

The Naval Surface Warfare Center Panama City Division has developed a 3-D finite-element computer simulation system, PC-ACOLOR, for modeling the “acoustic color” (target strength as a function of frequency and aspect angle) of single and multiple realistic elastic structures that are near to or straddling the water/sediment interface at the bottom of the ocean. Target strength is a measure of the intensity of scattered fields, but radiated noise can also be modeled, yielding sound pressure level as a function of frequency and aspect angle. PC-ACOLOR employs 3-D continuum mechanics throughout the entire computational domain; no engineering approximations are used anywhere. The talk will give an overview of PC-ACOLOR: important structural acoustic concepts, e.g., the relationship between 3-D modeling and evanescent wave solutions to the Helmholtz pde; modeling techniques; verification and validation; and examples of different types of vehicles and other structures that have been modeled.
A noise robust Arabic speech recognition system based on the echo state network
Authors: Alalshekmubarak Abdulrahman , Smith Leslie S.
Published: May 2014

A major challenge in the field of automated speech recognition (ASR) lies in designing noise-resilient systems. These systems are crucial for real-world applications where high levels of noise tend to be present. We introduce a noise robust system based on a recently developed approach to training a recurrent neural network (RNN), namely, the echo state network (ESN). To evaluate the performance of the proposed system, we used our recently released public Arabic dataset that contains a total of about 10 000 examples of 20 isolated words spoken by 50 speakers. Different feature extraction methods considered in this study include mel-frequency cepstral coefficients (MFCCs), perceptual linear prediction (PLP) and RASTA- perceptual linear prediction. These extracted features were fed to the ESN and the result was compared with a baseline hidden Markov model (HMM), so that six models were compared in total. These models were trained on clean data and then tested on unseen data with different levels and types of noise. ESN models outperformed HMM models under almost all the feature extraction methods, noise levels, and noise types. The best performance was obtained by the model that combined RASTA-PLP with ESN.
Gestural coordination of the velum in singing can be different from coordination in speech
Authors: Blaylock Reed , Lammert Adam , Goldstein Louis , Narayanan Shrikanth
Published: May 2014

Professional singers are trained to maximize vowel duration and minimize consonant interference, while still maintaining intelligibility. The mechanisms by which they do this, however, are unclear. A deeper understanding of the gestural mechanisms utilized during professional-quality singing could be useful to train singers more effectively. It has been well-established that nasal sounds in syllable coda position have longer and larger velum motion in formal speech as compared to casual speech. The hypothesis of this study was that coda velum gestures would be temporally extended proportional to the duration of the entire syllable. To test this, real-time magnetic resonance (rtMR) images of trained soprano singers were used to track the motion of the velum. The boundaries of the vocal tract were mapped to a semi-polar grid, and the velocity of the velum at every frame of its movement was calculated. An important result shows that operatic singing has minimal change in velum gesture duration compared to speech, while a musical theater style can have velum lowering for the duration of a word. Observed gestural kinematics and their implications for speech are discussed from within the framework and perspective of Articulatory Phonology.
Arrays of subcritical width rectangular speech bands maintain intelligibility at high intensities
Authors: Warren Richard , Bashford James , Lenz Peter
Published: May 2014

Speech intelligibility declines at high intensities for both normally hearing and hearing impaired listeners. However, it appears that this rollover can be minimized and intelligibility preserved by reducing speech in high frequency regions to an array of noncontiguous bands having vertical filter slopes (i.e., rectangular bands) and widths substantially narrower than a critical band. Normally hearing listeners were presented with sentences consisting of a 500-Hz lowpass pedestal band and an array of ten 4% bands spaced at 1/3-octave intervals from 1000 Hz to 8000 Hz. The pedestal band was fixed at 70 dB and the subcritical-band array varied from 55 to 105 dB in peak level. Desired sub-ceiling intelligibility ranged from 80 to 89% and was statistically asymptotic for levels from 75 to 105 dB. The largest intelligibility difference across that range, found between 85 and 105 dB, was just 1.6%. For that same contrast in levels, Molis and Summers [ARLO 4, 124–128 (2003)] obtained a significant intelligibility loss of 26.7% for spectrally continuous highpass speech. It is suggested that subcritical-width bandpass filtering reduces rollover by limiting firing rate saturation to a subset of fibers comprising individual critical bands. Implications for hearing aid construction will be discussed. [Work supported by NIH.]
Stream segregation of concurrent speech and the verbal transformation effect: Influence of fundamental frequency and lateralization cues
Authors: Stachurski Marcin , Summers Robert J. , Roberts Brian
Published: May 2014

Listening to a repeating recorded word produces verbal transformations (VTs); perceptual re-grouping of phonetic segments may contribute to this effect. The influence of fundamental frequency (F0) and lateralization grouping cues was explored by presenting two concurrent sequences of the same word resynthesized on different F0s (100 and 178 Hz). In experiment 1, listeners monitored both sequences simultaneously, reporting for each any change in stimulus identity. Three lateralization conditions were used—diotic, interaural time difference (±680-μs ITD), and dichotic. The results were similar for the first two, but fewer forms and later transformations were reported in the dichotic condition. This suggests that large lateralization differences between the two sequences per se have little effect—rather, there are more possibilities for perceptual re-grouping when each ear receives both sequences. For all conditions, VTs reported on one sequence were mainly independent of the other. Experiment 2 investigated the effect of number of sequences presented and monitored. The most forms and earliest transformations were reported when two sequences were presented but only one was monitored, indicating that high task demands reduce reporting of VTs for concurrent sequences. Overall, these findings support the idea that perceptual re-grouping contributes to the VT effect. [Work supported by EPSRC.]
Does a perceived intensity cause pitch change in noise-vocoded vowels?
Authors: Takabayashi Marina , Kobayasi Kohta I. , Riquimaroux Hiroshi
Published: May 2014

Noise-vocoded speech sound (NVSS) is the synthesized speech sound whose frequency information is greatly reduced while the amplitude envelope information remains preserved. In NVSS the fundamental frequency does not exist, and a change in amplitude is perceived as a change in not only loudness but also pitch. Original speech having physically same amplitude is not always identical. The phenomenon might occur also in NVSS. The purpose of this study is to examine whether change in not amplitude but loudness creates pitch change in NVSS. Subjects listened to paired original speech Japanese vowels and judged whether the second vowels were perceived louder or softer than the first ones. And they listened to paired noise-vocoded vowels to evaluate whether pitch of the second sounds rises or falls from the first ones. Results show that changes in loudness seem to cause pitch change in NVSS. After this, loudness perception in NVSS will be investigated. The data will show whether pitch of the second sounds change from the first ones or not when loudness of the first and the second sounds are same. And loudness perception in noise-vocoded vowels will be compared with loudness perception in the original speech.