bluuebunny/crossref_metadata_2025 huggingface dataset:
Distortion-product otoacoustic emission generator and reflection components in newborns, infants, and adults
Authors: Prieve Beth , Long Glenis , Talmadge Carrick
Published: May 2013

Glenis Long and colleagues (Talmadge et al., J. Acoust. Soc. Am. 105, 275) were among the first to model and describe the characteristics of distortion-product otoacoustic emissions (DPOAEs) using two sub-components from different, cochlear sources. It is now accepted that there is a generator component that results from inter-modulation distortion created by nonlinearity in the outer hair cell near the f2 place. The reflection component predominantly arises from coherent reflection near the characteristic place corresponding to the frequency of the distortion product. Because the two components are generated through different mechanisms, it has been hypothesized that they may be differentially affected by human development. The goal of this presentation is to discuss ongoing research of DPOAE components in newborns, infants and adults. Analysis of the components indicates that the relationship between growth rates for generator and reflection components are significantly different between infants and adults. Furthermore, the phase functions for both components are different among groups. Possible sources for these differences will be discussed. [Funded by the March of Dimes Birth Defects Foundation].
Auditory influence on tactile perception changes with age
Authors: Landry Simon P. , Guillemot Jean-Paul , Champoux François
Published: May 2013

Characteristics of auditory interaction with vision have been extensively studied. However, auditory system integration with other sensory modalities, such as the tactile system, lacks such thorough investigations. The objective of this study was to examine the effects of age on audiotactile integration in humans. Thirty-one participants between the ages of 20 and 65 were divided into three groups according to their age. Audiotactile integration was assessed using the “auditory flash illusion” in which 1, 2, 3, or 4 tactile stimuli were accompanied with 0, 1, 2, 3, or 4 auditory stimuli. Participants were asked to ignore auditory stimulations and report the number of tactile stimulations perceived. All participants were tested with task relevant auditory and tactile stimuli as a control measures and were shown to have similar abilities. However, groups differed during the experimental conditions. The youngest group reported a greater number of tactile stimuli than actually presented during the illusory experimental conditions. Participants in the middle and older age groups did not report this illusory tactile perception. These results suggest that age reduces predisposition to audiotactile integration. These results are consistent with developmental studies for multisensory integration in other sensory modalities.
Talker effects in speech band importance functions
Authors: Healy Eric W. , Yoho Sarah E. , Youngdahl Carla L. , Apoux Frederic
Published: May 2013

The literature is somewhat mixed with regard to the influence of (a) the particular speech material (e.g., sentences or words) versus (b) the particular talker used to create the recordings, on band-importance function (BIF) shape. One possibility is that previous techniques for creating BIFs are not sensitive enough to reveal these influences. In the current investigation, the role of talkers was examined using the compound technique for creating BIFs. This technique was developed to account for the multitude of synergistic and redundant interactions that take place among various speech frequencies. The resulting functions display a complex microstructure, in which the importance of adjacent bands can differ substantially. It was found that the microstructure could be traced to acoustic aspects of the particular talkers employed. Further, BIFs for IEEE sentences based on ten-talker recordings displayed less microstructure and were therefore smoother than BIFs based on one such talker. These results together suggest that the compound technique is sensitive enough to reveal acoustic aspects of the particular talker employed. It is further suggested that multiple talkers, rather than smoothing of the functions, be used if the goal is to describe speech more generally.
Complementary correlation may offer a new approach to better understand temporal fine structure coding
Authors: Lee Adrian KC , Atlas Les E. , Li Xing
Published: May 2013

Historically, sound has been separated into a slow-varying envelope and a component that rapidly varies, called the temporal fine structure (TFS). Perceptual studies suggest that users of cochlear implants can benefit from better TFS coding strategies, as they lead to improved speech understanding in noise. Yet given the standard signal processing methodology used in the auditory neuroscience community, namely the Hilbert transform, findings in such prior studies have been limited by their use of the heavily distorted estimates of the TFS information (through the Hilbert phase of the related analytic signal). Complementary correlation is a new mathematical tool with potential to advance our understanding of temporal coding in neuroscience. This new mathematical formulation can be defined simply by dropping the usual complex conjugation operation from the canonical definitions of correlation, coherence, variance, magnitude-squared estimators of power, and other similar common second-order statistical quantities and their estimators. We will show that a complementary correlation approach, which provides a more complete characterization of TFS information, will provide measurable perceptual benefits by reducing distortion in the original speech signal.
The roles of temporal envelope and temporal fine structure in speech synthesis for cochlear implants for tonal language speakers
Authors: Saimai Nantaporn , Tantibundhit Charturong , Onsuwan Chutamanee , Wutiwiwatchai Chai
Published: May 2013

Since most cochlear implants (CIs) have been developed for non-tonal languages, their level of hearing improvement is significantly decreased when used by speakers of tonal language, e.g., Thai. Temporal envelope (TE) and temporal fine structure (TFS) are important acoustic cues for languages with lexical tones. Specifically, TE is shown to carry manner and voicing cues for consonants, while TFS correlates with vowel formant transitions. Therefore, TFS and TE are expected to enhance intelligibility of lexical tones for CI patients. We proposed the use of six-channel bandpass filters to extract spectral information. Then, TE is extracted by half-wave rectification and smoothed by lowpass filler at 500 Hz cutoff frequency. TFS is extracted by the Hilbert transform to construct carrier signals. TE from each channel is modulated with its corresponding carrier signal and then combined to generate synthesized speech. Synthesized speech tokens from this study and two others [Fu et al. (1998) and Chen and Zhang (2008)] are evaluated by 16 Thais with normal hearing. The results showed that the intelligibility scores from the proposed algorithm are significantly higher than the other two for initials (by 32.2%) and final consonants (by 16.7%) and significantly higher for tones (by 48.8%) than Fu et al.
The role of peripheral spectro-temporal coding in congenital amusia
Authors: Cousineau Marion , Oxenham Andrew J. , Peretz Isabelle
Published: May 2013

Congenital amusia, a neurogenetic disorder, affects primarily pitch and melody perception. Here we test the hypothesis that amusics suffer from impaired access to spectro-temporal fine-structure cues associated with low-order resolved harmonics. The hypothesis is motivated by the fact that tones containing only unresolved harmonics result in poorer pitch sensitivity in normal-hearing listeners. F0DLs were measured in amusics and matched controls for harmonic complexes containing either resolved or unresolved harmonics. Sensitivity to temporal-fine-structure was assessed via interaural-time-difference (ITD) thresholds, intensity resolution was probed via interaural-level-difference (ILD) thresholds and intensity difference limens, and spectral resolution was estimated using the notched-noise method. As expected, F0DLs were elevated in amusics for resolved harmonics; however, no difference between amusics and controls was found for F0DLs using unresolved harmonics. The deficit appears unlikely to be due to temporal-fine-structure coding, as ITD thresholds were unimpaired in the amusic group. In addition, no differences were found between the two groups in ILD thresholds, intensity difference limens, or auditory-filter bandwidths. Overall the results suggest a pitch-specific deficit in fine spectro-temporal information processing in amusia that cannot be ascribed to defective temporal-fine-structure or spectral encoding in the auditory periphery. [Work supported by Fyssen Foundation, Erasmus Mundus, CIHR, and NIH grant R01DC05216.]
Comodulation masking release and monaural envelope correlation perception in listeners with cochlear hearing loss
Authors: Porter Heather , Grose John H. , Hall Joseph W. , Buss Emily
Published: May 2013

This study investigated the comparative dependence of comodulation masking release (CMR) and monaural envelope correlation perception (MECP) on the degree of envelope similarity in pre-senescent adult listeners with normal hearing (NH) or mild-to-moderate cochlear hearing loss (CL). A 1600-Hz pure-tone signal was used to measure CMR as a function of degree of envelope correlation in 100-Hz-wide noise bands centered at 727, 1093, 1600, 2300, and 3268 Hz. The same noise band configuration was used to measure MECP thresholds for both comodulated and independent standards. Envelope correlation was adjusted by mixing comodulated and independent maskers at variable intensity ratios. The five-band complex was 85 dB SPL. Signal thresholds improved monotonically (i.e., CMR increased) with increasing degrees of envelope correlation for all listeners. Results for CL listeners were most similar to data from previous NH listeners at a 72 dB SPL masker level. For MECP, performance patterns for the two conditions were uniform across NH listeners, whereas those for CL listeners exhibited greater individual differences. Finally, CMR and MECP performance appeared to be related in listeners with CL. The pattern of results will be discussed in terms of the effects of CL on sensitivity to envelope similarity. [Work supported by NIDCD R01DC001507.]
Dividing attention between two segregated tone streams
Authors: Demany Laurent , Semal Catherine
Published: May 2013

Listeners were presented with pure-tone sequences which had a high speed (25–50 tones/s) and consisted of two interleaved melodies, M1 and M2, spanning separate frequency ranges (624–786 Hz and 1483–1869 Hz). M1 and M2 were renewed from sequence to sequence and could be either (1) perfectly correlated, or (2) perfectly anticorrelated, or (3) independent of each other. The main task, performed in a 2I-2AFC paradigm, was to discriminate sequences of type 1 (perfect correlation) from sequences of type 2 or 3. This appeared to be relatively easy when, in the type-1 sequences, each note of M2 immediately preceded or followed the corresponding note of M1. In that case, however, listeners were unable to tell whether M2 preceded or followed M1, which shows that the two melodies were perceptually segregated. In another series of experimental sessions, listeners knew that M2 would always follow M1 after a fixed delay, corresponding to one tone in some sessions and three tones in other sessions. The main discrimination task was performed better for the one-tone delay, but performance was still well above chance for the three-tone delay. Overall, the data suggest that two segregated tone streams can be attended to simultaneously.
Selective auditory or visual attention reduces physiological noise in the ear canals of human subjects
Authors: Walsh Kyle P. , Pasanen Edward G. , McFadden Dennis
Published: May 2013

A nonlinear version of the stimulus-frequency OAE (SFOAE), called the nSFOAE, was used to measure cochlear responses from human subjects while they simultaneously performed behavioral tasks requiring selective auditory attention (dichotic or diotic listening), selective visual attention, or relatively little attention. The auditory- and visual-attention tasks both were digit-recall tasks, where the nSFOAE-stimuli were interleaved with seven spoken (or displayed) digits. Unlike many previous studies, the required motor behavior always was the same across all tasks, including the inattention tasks. A 30-ms recording in the quiet followed every nSFOAE-eliciting stimulus to provide an estimate of the magnitude of each subject’s physiological noise in each experimental condition. For every subject, physiological-noise magnitudes were higher (noisier) in the inattention tasks, and lower (quieter) in the selective auditory- and visual-attention tasks. The differences in noise levels were about 3–6 dB, on average, and the effect sizes for those differences all were greater than 2.5. Our interpretation is that the efferent innervation of the cochlea is activated maximally during selective attention (be it auditory or visual), potentially to the benefit of the observer. [Work supported by NIDCD grant DC00153.]
Build-up of auditory stream segregation induced by tone sequences of constant or alternating frequency and the resetting effects of single deviants
Authors: Haywood Nicholas R. , Roberts Brian
Published: May 2013

Three experiments investigated the dynamics of auditory stream segregation. Experiment 1 used a 2.0-s constant-frequency inducer (10 repetitions of a low-frequency pure tone) to promote segregation in a subsequent, 1.2-s test sequence of alternating low- and high-frequency tones. Replacing the final inducer tone with silence reduced reported test-sequence segregation substantially. This reduction did not occur when either the 4th or 7th inducer was replaced with silence. This suggests that a change at the induction/test-sequence boundary actively resets build-up, rather than less segregation occurring simply because fewer inducer tones were presented. Furthermore, experiment 2 found that a constant-frequency inducer produced its maximum segregation-promoting effect after only three tone cycles—this contrasts with the more gradual build-up typically observed for alternating sequences. Experiment 3 required listeners to judge continuously the grouping of 20-s test sequences. Constant-frequency inducers were considerably more effective at promoting segregation than alternating ones; this difference persisted for ~10 s. In addition, resetting arising from a single deviant (longer tone) was associated only with constant-frequency inducers. Overall, the results suggest that constant-frequency inducers promote segregation by capturing one subset of test-sequence tones into an on-going, pre-established stream and that a deviant tone may reduce segregation by disrupting this capture.
Acoustic correlates of tinnitus-like sounds
Authors: Lentz Jennifer , He Yuan
Published: May 2013

Although many people describe their tinnitus using complex terms (such a tea-kettle, crickets, and roaring), past studies of tinnitus have focused using pure tones and noises as stimuli. Therefore, this study was developed to begin to address the usefulness of using complex, dynamic sounds in the assessment of tinnitus. In a previous study, a free-classification task was used to ascertain the perceptual dimensions of tinnitus-like sounds in normally hearing listeners. Sounds were representative of those commonly used to describe tinnitus (e.g., ringing, tonal, noisy, pulsing, and clicking sounds). Listeners placed icons associated with each sound on a grid and placed similar sounds in clusters. Multi-dimensional scaling conducted on the classification data revealed three different perceptual dimensions. This study evaluated the acoustics of the stimuli to determine the nature of the perceptual dimensions. These analyses estimated a variety of temporal and spectral stimulus properties (e.g., autocorrelation statistics, spectral statistics, envelope characteristics, etc.). The acoustic characteristics were then correlated with the ordering along the three perceptual dimensions. Results suggest a noisy versus tonal dimension, an envelope-based dimension stimulus (choppy versus smooth), and a dimension related to dynamic stimulus characteristics.
Assessing the contribution of spectral cues to recognition of frequency-lowered consonants
Authors: Fitz Kelly , Micheyl Christophe , Valentine Susie , Zhang Tao
Published: May 2013

Commercially available strategies for restoring audibility of critical high frequency cues to patients with severe high frequency hearing loss translate information from high-frequency regions with unaidable hearing to lower-frequency regions with aidable hearing. Methods for synthesizing lowered spectral features, rather than generating them from the signal, have been proposed, though no commercially available hearing aid uses such a method. We assessed consonant discrimination under three configurations of a spectral feature synthesis method intended for use in frequency lowering. Lowered consonants were rendered using one or two narrowband noise components presented in a low frequency region with aidable hearing. Different configurations conveyed different spectral cues intended to distinguish among lowered consonants. In a short pilot study, preliminary analysis found no significant difference in consonant matching accuracy between the different configurations, suggesting that listeners were not making use of additional spectral cues when they were available. However, there were some observable trends in the data, as well as open questions about the possible impact of training and acclimatization on listener performance. We will present the findings of a more extensive study to determine whether listeners with training can make use of enhanced spectral cues to distinguish among frequency-lowered consonants.
Poisson coupling in the in vacuo dynamics of an infinite cylindrical shell
Authors: Martinez Rudolph
Published: May 2013

This paper applies a perturbation analysis to the “n = 0” in vacuo dynamics of an infinite cylindrical shell as presented in their exact form by Junger and Feit in Sound, Structures, and Their Interaction. The small parameter in the asymptotic theory is the square of the Poisson ratio ν. Two sets of results emerge: (1) Relating to the system’s dispersion relation and therefore irrespective of the type of loading, the approximate roots of the governing cubic polynomial display explicitly the mutual contamination and influence of axial compression and latent skin flexure, the latter becoming actual past the ring frequency ωra/cp = 1. (2) In the parametric range of small values of ωa/cp, and for a radial ring force, our asymptotic expansions establish that the shell’s normal-to-surface response is one of local reaction to zeroth order in ν2. It is not until the analysis is carried out to O(ν2) that wave propagation from axial compression and nearfield skin flexure begin to assert themselves away from the driven station.
Cooperating with Miguel on improvements of the acoustical product - SOUNDBLOX
Authors: Kleinschmidt Klaus
Published: May 2013

Some 15 years after joining Miguel’s consulting firm Cambridge Acoustical Associates around 1960 he asked me to help him with improving the sound absorbing quality of a patented slotted concrete block. The original concept of the block, sold under the trademark, SOUNDBLOX, was create a Helmholtz resonator by providing a slot in one face of a standard concrete block whose natural frequency would match the fundamental frequency of a common noise source, transformer hum. A broader absorption spectrum was desired to expand the rather limited applications of the original design to compete with certain acoustical materials widely used in schools, gymnasiums, auditoriums, and swimming pools. This presentation will describe the nature of our cooperation and the successes and failures of various concepts. The fact that the product, first introduced in the late 1950’s, is still on the market speaks well of our collaboration.
Modal contributions to sound radiated from a fluid loaded cylinder
Authors: Peters Herwig , Kessissoglou Nicole , Marburg Steffen
Published: May 2013

A modal decomposition technique to compute the individual modal contributions to the sound radiated from a cylindrical shell submerged in water is presented. The wet structural modes are calculated by means of a polynomial approximation and symmetric linearization of the underlying nonlinear eigenvalue problem. A Krylov subspace technique is used to reduce the model size of the structural domain, while the fluid domain remains unchanged. Results for the radiated sound power and sound pressure directivity are presented for groups of circumferential modes with common mode number. Under axial and transverse excitation, the cylinder breathing and bending modes are respectively the major modes contributing to the radiated sound at low frequencies. The contribution of the rigid body modes to the radiated sound is also observed.
Acoustic radiation mode shapes for control of plates and shells
Authors: Johnson William R. , Aslani Pegah , Hendricks Daniel R.
Published: May 2013

During the advent of active structural acoustic control, attempts were made to target and control structural vibration mode shapes to reduce radiated sound power. In the late 1980s and early nineties work on acoustic radiation mode shapes developed an alternative way to target structural acoustic radiation. By attempting to control the radiation mode shapes, contributing structural modes could be more easily targeted. Radiation mode shapes have been examined previously for rectangular plates. The method has been extended to demonstrate radiation mode shapes of circular plates and cylindrical shells. Certain spatial derivatives of plate vibration have been found to be highly correlated with the most efficiently radiating radiation mode shapes at low frequencies. A weighted sum of these spatial derivatives is proposed as a new, generalized control metric.
On the tolerance of spectral blur in the perception of spoken words
Authors: Remez Robert E. , Cheimets Chloe B. , Thomas Emily F.
Published: May 2013

How does a listener resolve linguistic properties conveyed by speech? Many descriptions of perception attribute a causal role to brief spectral details in narrow frequency ranges. Perceptual standards allow far more variety, revealed by the robustness of perception of many kinds of distorted speech. The present study considered the effects of spectral blur on the recognition of spoken words. Listeners heard successive presentations of noise-vocoded easy and hard words. The number of spectral channels composing the word increased with each presentation, reducing blur within a trial. Four conditions counterbalanced the number of presentations of each word in a trial, 3 or 5, and the severity of initial blur, either 1 or 5 channels. In all conditions, the final presentation had 9 bands, yielding a net blur reduction of 4 or 8 bands. These conditions were also tested with the instruction that the words would become clearer during each trial. A control used two repetitions of each word at 9 spectral bands. Across the tests, exposure to spectral blur impaired the recognition of easy and hard words alike regardless of the listener’s belief during presentation. However, intelligibility of hard words declined sharply when subjects were instructed to attend to the continuity and successive decrease in blur within a trial. The pattern of results exposes the role of attention, uncertainty, and spectral resolution in the phonetic contribution to word identification.
Cortical responses to degraded speech are modulated by linguistic predictions
Authors: Peelle Jonathan E.
Published: May 2013

Our perceptual experience is formed by combining incoming sensory information with prior knowledge and expectation. When speech is not fully intelligible, non-acoustic information may be particularly important. Predictions about this degraded acoustic signal can be provided intrinsically (if the speech is still partially intelligible) or extrinsically (for example, by presenting a written cue). I will discuss results from studies in which the neural response to speech was measured using magnetoencephalography (MEG), with speech clarity parametrically manipulated using noise vocoding. In one study, we found that during sentence processing the phase of ongoing cortical oscillations is matched to that of the acoustic speech envelope in the range of the syllable rate (4–8 Hz). Critically, this phase-locking was enhanced in left temporal cortex when speech is intelligible. In a separate study of single word listening, accurate predictions provided by written text enhanced subjective clarity and changed the response in early auditory processing regions of temporal cortex. Both experiments thus highlight neural responses in brain regions associated with relatively low-level speech perception. Together these findings support the ability of linguistic information to provide predictions that shape auditory processing of spoken language, particularly when acoustic clarity is compromised.
Effect of speech clarity on perception of interrupted meaningful and anomalous sentences
Authors: Smiljanic Rajka , Shaft Stan , Chandrasekaran Bharath , Shafiro Valeriy
Published: May 2013

The influence of speech clarity on the perception of interrupted speech was examined for sentences distinguished by the presence of semantic-contextual cues. Semantically meaningful and anomalous sentences produced in either conversational or “clear” speech were periodically interrupted at gating rates ranging from slow (0.5 Hz) to fast (24 Hz) and presented to 32 native English listeners. At slow rates, speech perception may be based on integration of whole syllables and words, with “glimpsing” of (sub)phonemic segments playing a role at faster rates. Our results show that semantic context and speech clarity had a significant rate-dependent impact on the intelligibility of interrupted speech. At the lowest rates, intelligibility differences between conditions were minimal. Overall, interruption was most deleterious for anomalous conversational sentences. Such effects were seen even at the highest gating rate of 24 Hz for which interruption effects are generally minimal. The magnitude of the clear-speech benefit varied with gating rate for the two types of sentences, starting at 1 Hz for meaningful and 2 Hz for anomalous sentences. Acoustic-phonetic enhancements of clear speech thus “shifted” contextual benefit to lower gating rates. The implications of these results for our understanding of different time scales of speech processing will be discussed.
The effects of temporal envelope confusion on listeners’ phoneme and word recognition
Authors: Nie Yingjiu , Svec Adam , Nelson Peggy B. , Munson Benjamin
Published: May 2013

Broadened auditory filters in listeners with hearing loss may result in listeners’ increased reliance on temporal envelope cues for understanding speech. Previous data have shown that background noise may affect hearing-impaired (HI) listeners by negatively affecting the temporal envelope cues in speech. The current study investigates additional HI listeners’ understanding of vocoded spondees in the presence of fluctuating and stationary background noise. Stimuli were 8- and 32-channel noise vocoded double spondees, high-pass filtered at 1426 Hz. New data confirmed the previous finding that temporal envelope confusion in HI listeners resulted in speech understanding that is poorer in fluctuating noise (at a rate of 4 Hz) than in stationary noise. Preliminary analysis suggests HI listeners experience significant envelope confusion for both 8- and 32-channel vocoded stimuli. Additional analysis of phoneme errors suggests that envelope confusion affects HI listeners’ perception of both consonants and vowels. Further analysis of j-factors will indicate the relationship of phoneme to whole word understanding for vocoded speech in noise. Results confirm the importance of temporal envelope cues for phoneme and syllable recognition for listeners with hearing loss. [Work supported by NIH DC008306 to PB Nelson.]
Effects of semantic predictability and dialect variation on vowel production in clear and plain lab speech
Authors: Turnbull Rory , Clopper Cynthia G.
Published: May 2013

Speech addressed to a non-native or hearing impaired listener features longer, more peripheral vowels. In addition, more extreme dialect-specific forms are produced in semantically predictable contexts, and less extreme forms (more standard forms) in unpredictable contexts. This study investigated the interactions between predictability and speaking style on Southern American English monophthongization of the vowel /aj/. The Midland dialect of American English served as the comparison. Participants read a set of sentences with monosyllabic target words in sentence-final position. Target words varied in semantic predictability based on the preceding sentential context. Each set of sentences was produced twice by each participant—first as if talking to a friend (“plain” speech) and again as if talking to a non-native or hearing impaired listener (“clear” speech). The duration, dispersion, and trajectory length of the vowel in each target word were measured. Preliminary results suggest that, as expected, Southern /aj/ has a shorter trajectory length than Midland /aj/, and in both dialects, /aj/ has a shorter trajectory length in clear speech than plain speech. However, these processes do not interact with each other or with semantic predictability, suggesting that style and predictability effects are independent of the realization of some dialect variants.
The effects of surgical masks on speech perception in noise
Authors: Wittum Kelsi J. , Feth Lawrence L. , Hoglund Evelyn M.
Published: May 2013

Surgical masks and blood shields worn by anesthesiologists and surgeons in hospital operating rooms may negatively impact speech communication and put patients at needless risk. Young adult subjects listened to sentences from the Speech Perception in Noise Test (SPIN) recorded by a male and female talker. All eight SPIN lists were recorded under three different speaking conditions: (1) speaking normally without any obstruction, (2) wearing a typical surgical mask, and (3) wearing a surgical mask with an attached blood shield. Multi-talker babble was mixed with the SPIN sentences at several signal-to-noise ratios to simulate conversation in noisy environments. Speaker gender and recording conditions were counterbalanced across listeners to control for learning and fatigue effects. SPIN test scores for each of the three types of recordings and both talker genders were compared in order to determine the degradation that blood-shields and surgical masks may have speech communication in the operating room. [Research supported by research grants from the Division of Social and Behavioral Sciences and a scholarship from the College of Arts and Sciences at The Ohio State University.]
Wind noise reduction using empirical mode decomposition
Authors: Yatabe Kohei , Oikawa Yasuhiro
Published: May 2013

One common problem of recorded sound outdoors is interfusion of wind noise, which has highly non-stationary characteristics. Although there are a lot of noise reduction methods which produce good results for general kinds of noises, most methods perform worse for wind noise due to its non-stationary nature. Therefore, wind noise reduction need special technique to overcome this non-stationarity. Empirical mode decomposition (EMD) is a relatively new method to decompose a signal into several nonlinear and non-stationary bases which are modeled as amplitude and frequency modulated sinusoids that represent wind noise well. Thus, EMD has a possibility to reduce wind noise from recorded sounds in entirely different way from ordinary methods. In this paper, a preliminary discussion of applying EMD to wind noise reduction is presented. Since EMD decomposes a signal into monocomponent bases, it is easier to treat them as analytic signals via Hilbert transform. Our method utilize this characteristics in order to reduce wind noise. The experiment is performed on female voice superimposed with wind noise and shows it possibility and effectiveness.
Seabed characterization using ambient noise and compact arrays on an autonomous underwater vehicle
Authors: Nielsen Peter L. , Siderius Martin , Miller Jim , Crocker Steven , Giard Jennifer
Published: May 2013

Estimating the seabed geoacoustic properties at various fidelity levels has been a research topic for several decades. The majority of the applied seabed characterization techniques often require significant involvement of surface vessels, complex experimental setup, and human interaction. Technical advances in underwater autonomy and the development of energy efficient electronics provide new opportunities to optimize underwater environmental surveys in particular of the seabed. In 2012, the CMRE conducted the GLASS’12 experiment in the Mediterranean Sea with the objective to investigate the feasibility of utilizing a hybrid autonomous underwater vehicle equipped with a compact nose array for long-duration seabed characterization over large areas. The vehicle has the capability of operating in traditional propulsion and glider mode, and the nose-mounted array consists of a 5-element vertical and 4-element tetrahedral array. The sound sources used as information carrier were ambient noise, e.g., sea surface generated noise and loud distant sources of opportunity. The experimental setup together with the newly developed autonomous equipment will be presented and examples of inferred reflection loss and sub-bottom profiling from the ambient noise are compared to ground truth measurements. [Work supported by the STO-CMRE, ONR-G Grant No. N62909-12-1-7040, the ONR N-STAR/ILIR program.]
Synthetic-array beamforming for bottom-loss estimation using marine ambient noise
Authors: Muzi Lanfranco , Siderius Martin
Published: May 2013

Previous studies have shown that, using a vertical line array, the bottom loss can be estimated in an ambient-noise field from the output power of beams steered toward the sea surface and beams reflected off the seabed. With short arrays, the low angular resolution of the bottom-loss estimate is one of the main limitations of the approach. Synthetic-array processing is proposed as a technique that can improve the angular resolution of the bottom-loss estimate to a level comparable to that of an array with twice as many physical sensors (at equal inter-sensor spacing). The proposed technique follows naturally from a new derivation in frequency-wavenumber domain of the bottom-loss estimation procedure. The conditions under which the approach can be successfully applied are analyzed, with particular regard to the need for the array cross spectral density matrix to be “close” to Toeplitz. A metric is proposed for assessing this particular circumstance in practice. The technique is illustrated using synthetic data from simulations and then applied to data from several experimental campaigns. Results show that a 16-element synthetic array can achieve an angular resolution comparable to that of a 32-element array.
Analysis of the vertical structure of deep ocean noise using measurements from the SPICEX and PhilSea experiments
Authors: Wage Kathleen E. , Farrokhrooz Mehdi , Dzieciuch Matthew A. , Worcester Peter F.
Published: May 2013

There are open research questions about the vertical structure of low-frequency ambient noise in deep water. For example Gaul et al.'s [IEEE JOE (2007)] analysis of the Church Opal data set showed that noise decreases substantially (on the order of 20 dB) below the critical depth, whereas other researchers have reported more modest reductions [Morris, J. Acoust. Soc. Am. (1978)]. Two deep water experiments provided a unique opportunity to measure ambient noise using large vertical arrays. In 2004–2005, SPICEX used two arrays to sample a North Pacific environment. One array was centered on the sound channel axis, and the other array had hydrophones above and below the critical depth. In 2010–2011, the PhilSea experiment deployed a single array with 150 hydrophones spanning the full water column. Both experiments made repeated short measurements (each 2–3 min long) of the field at the arrays. This talk compares the ambient noise observed during SPICEX and PhilSea with results reported in the literature. Since these data sets contain receptions over the period of a year, we focus on the seasonal dependence of the noise field. In addition to investigating noise level as a function of depth, we consider wind dependence and vertical directionality.
Modeling of underwater piling noise mitigation using an array of soft spheres in the ocean
Authors: Lee Keunhwa , Baik Kyungmin , Seong Woojae
Published: May 2013

The ocean noise generated by marine piling affects severely fish, other marine life, and fishery activities. Accordingly, a few kind of noise mitigation system are presented. Among them, the noise mitigation system using soft scatterers such as air bubbles or rubber spheres is reported to show higher noise reduction than the classical cofferdam system composed of mass-absorbing materials. In this proceeding, a numerical scheme is developed to model and design the noise mitigation system using an array of soft spheres. This scheme is originally based on self-consistent equation of Zhen Ye for multiple scattering [Z. Ye and A. Alvarez, Phys. Rev. Lett. 80, 3503 (1998)]. We generalize the original self-consistent equation for the oceanic waveguide using the waveguide green function. This generalized self-consistent equation is useful to model the noise propagation through an array of soft spheres in the ocean and assess the ability of the noise mitigation system. The effect of the oceanic waveguide on the noise reduction is studied and the validity of effective medium approach for a bubbly layer is also analyzed numerically.
Spatial filtering in ambient noise crosscorrelation
Authors: Carriere Olivier , Gerstoft Peter , Hodgkiss William S.
Published: May 2013

Ambient noise crosscorrelation is an attractive approach for estimating the properties of a propagation medium (presence of scatterers, wave propagation speed, etc.) without having to deploy active acoustic source. According to the theory, Green's function between pair of receivers can be extracted from the crosscorrelation of the received signals, given that the noise source is diffuse. In practice, this ideal condition is rarely met in the ocean and directional sources, often related to human activity in the vicinity of the receivers, may bias the travel time estimates. Using array processing, matrix spatial filters can be built independently from the environment properties (as opposed to model-based techniques) to filter specific directions of arrival. Such filter might be useful to remove an interferer or to restrict the effective source distribution to a reduced cone area. Here we study the use of matrix spatial filters for removing unwanted contributions in the crosscorrelations. Based on theory and simulations, we discuss the effect of array size, dimension and geometry, processed frequency band, and environmental conditions in the filtered crosscorrelations. An example of application to real data from the Shallow Water '06 experiment further illustrates the potential of the method.
Acoustic manifestations of frozen bubbles
Authors: Maksimov Alexey
Published: May 2013

The hydrocarbon seeps emitting buoyant bubble plumes from seafloor vents have been actively investigated in different regions of the World Ocean. In winter, rising bubbles, which have reached the sea surface, freeze in ice. These clouds of the frozen bubbles are observed in Arctic seas and represent a common element of an ice cover of lakes. Deposits of gas hydrates were discovered in many marginal seas of the World Ocean. The nature of the relationship between the acoustic and physical properties of gas hydrates is still under debate for both saturated sediments and sediment containing free-gas bubbles. Acoustic manifestations of bubbles frozen in ice and gas hydrate are the subjects of the current study. On the basis of the general solution of the elastic wave scattering problem for the sphere, the scattering cross section for a bubble frozen in an ice has been found. The derived expressions coincide in the limiting cases with known results: a bubble in a rubber-like media, where the longitudinal wave speed is significantly faster than the transverse wave speed and an empty cavity in the elastic media. The structure of low-frequency resonances of bubbles clouds of the simplest geometry has been investigated.
Measurements and modeling of transmission loss variability in Barrow Strait
Authors: Pecknold Sean , Pelavas Nicos , Heard Garry
Published: May 2013

During the summer of 2012, a field trial was held in Barrow Strait, south of Devon Island in the Canadian Arctic. The trial included a set of acoustic transmission loss experiments recorded on Starfish Sensor Cubes, which include a 1-m cube of seven hydrophones operating in the frequency range of 5–750 Hz. The transmission loss runs consisted of 10-min and 20-min duration transmissions of 400 and 500 Hz tones made at a discrete set of distances up to 60 km from the recorders. Supporting environmental measurements included sets of CTD (conductivity-temperature-depth) profiles and bathymetric measurements. The effects of the measured environmental properties and variability are investigated via propagation modeling, and compared to the experimental data acquired during these experiments.
Evaluation of stage acoustics preference for a singer using oral-binaural room impulse responses
Authors: Miranda Jofre Luis A. , Cabrera Densil A. , Yadav Manuj , Sygulska Anna , Martens William L.
Published: May 2013

There are two main objective measurement methods in current practice that can be used to evaluate the stage acoustic conditions for singers. One is the stage support metrics (STEarly and STLate, included in the standard ISO 3389-1), and the other is the voice support metrics proposed by Pelegrín-García (room gain (GRG) and voice support (STV)). All of these metrics use energy integration from impulse responses to derive the acoustic descriptors. This overlooks two potentially important features of the responses: the temporal distribution of the impulse response within the evaluation period, and the directional distribution for the spatial impulse response within the evaluation period. In this paper, a method to study the effect of these features is proposed and tested. This method is based on the auralization of ones’ own voice in rooms using oral-binaural room impulse responses (OBRIRs). The OBRIRs used are created by combining synthesized early reflections with a recorded reverberant tail. The early reflections are manipulated in their arrival time, arrival direction, and strength. Results of a pilot study indicate that a wide range of on-stage acoustic quality can be achieved for responses showing a given STEarly value due to variation in the temporal and spatial distribution of reflected energy.
Augmented stage support in ensemble performance using virtual acoustics technology
Authors: Ko Doyuen , Woszczyk Wieslaw , Hong Jonathan
Published: May 2013

Perceptual evaluation of electronically varied acoustic conditions has been perfomed with 15 musicians in a chamber orchestra rehearsal. Using Virtual Acoustics Technology (VAT), a room impulse response based active acoustic enhancement system, four different acoustic conditions were presented to the musicians. Condition 1 was the natural room itself without the VAT system. Condition 2 had a moderate level of VAT enhancement with approximately 10% increased EDT value from the condition 1. Condition 3 duplicated the condition 2 except for another 10% rise of EDT, and condition 4 offered enhancement utilizing multiple early reflections IRs without extending the reverb time of the space. The conditions were presented to the ensemble in random order and the loudness of all four conditions was carefully matched within 1 dB variance. Evaluation results indicated that 65% of participating musicians prefered condition 4 and their preference was highly correlated with perceptual attributes such as “feeling of stage support,” “feeling of intimacy,” and “quality of reverberation.” The objective measurements also confirmed the improvements in stage acoustics support parameters (ST1 and ST2) in condition 4.
Exploring the capacity of neural networks to recognize objects from dolphin echoes across multiple orientations
Authors: Wisniewski Matthew G. , DeLong Caroline M. , Heberle Amanda L. , Mercado Eduardo
Published: May 2013

Dolphins naturally recognize objects from multiple angles using echolocation. With training, humans can also learn to accurately classify objects based on their echoic features. In this study, we used neural networks to identify acoustic cues that enable objects to be recognized from varying aspects. In simulation 1, a self-organizing map was able to differentiate a subset of objects using only amplitude and frequency cues, but it classified some echoes from different objects as being from the same object. In simulation 2, a multilayer perceptron was trained through error correction to identify objects based on echoes from a single aspect, and then tested on its ability to recognize those objects using echoes from different orientations. Overall, perceptrons performed similarly to trained undergraduates. Analysis of network connection weights revealed that both the amplitude and frequency of echoes, as well as the temporal dynamics of these features over the course of an echo train, enabled perceptrons to accurately identify objects when presented with novel orientations. These findings suggest that learning may strongly impact an organism’s ability to echoically recognize an object from any viewpoint.
Polyplex-microbubbles for improved ultrasound-mediated gene therapy
Authors: Borden Mark , Sirsi Shashank , Hernandez Sonia , Homma Shunichi , Kandel Jessica , Yamashiro Darrell
Published: May 2013

Sonoporation is an established method whereby acoustically stimulated microbubbles create pores in the endothelium to promote the delivery of nucleic acids and other macromolecules through the vasculature. In this presentation, we describe the development of polyplex-microbubbles to enhance delivery and intracellular trafficking to target cells beyond the endothelium following sonoporation. Our design combines the tissue targeting capability of microbubbles with the cellular targeting capability of polyplexes, which are self-assembled particles comprising nucleic acids and a cationic polymer. The first purpose of the cationic polymer (polyethylenimine, PEI) is to condense and protect the nucleic acids on the microbubble surface as it travels in circulation from the site of injection to the target tissue. Polyethylene glycol (PEG) is conjugated to the PEI to reduce immunogenicity. Ultrasound is applied to the target tissue to fragment the microbubbles and release the polyplexes and to porate the endothelium, allowing the polyplexes to extravasate. The second purpose of PEI is to promote endocytotic uptake and subsequent endosomal escape of the nucleic acids into the cytoplasm by the so-called “proton-sponge” effect. Here, we will describe polyplex-microbubble fabrication and characterization, as well as in vivo testing. Our results indicate that this is a promising design for cancer gene therapy.