bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiences on noise in Argentina.
Authors: Vechiatti Nilda , Gavinowich Daniel
Published: October 2010

It is well known that as the number of people living in an urban core increases, the consumption and production of goods and services and, proportionally, the waste generated, including noise as a common pollutant, increases. At the beginning, it might seem that noise pollution is associated with the high level of life in developed countries, but reality shows that exposure to noise in developing countries is not less, because the lack of demand in the quality of the buildings and a suitable framework of the law bring as a consequence that millions of people have no guaranteed good sound quality in their environment and suffer adverse effects on their health. Several decades before many institutions in our country conducted research works, provided services to the community, and participated in the development of standards and laws to prevent and correct noise pollution. But while the authorities of some countries have taken full awareness of the necessity to ensure the acoustic comfort of the people, in Argentina we still have much to do.
Measurement schemes for resonant ultrasound spectroscopy experiments at high temperatures.
Authors: Gladden J. R. , Li G. , Adebisi R. , Male S.
Published: October 2010

The heart of any acoustic measurement is the conversion of vibrational energy into electrical energy. One of the most common and efficient methods of this energy transduction is the use of piezoelectric elements such as PZT or lithium niobate. At temperatures above about 600 °C, all traditional piezoelectric materials lose their piezoelectric properties, requiring the use of buffer rods to separate the sample in the hot zone and the transducers. Buffer rods introduce experimental difficulties such as reduced signal to noise, sample loading effects, and extraneous buffer rod resonances. We will report on experimental details of RUS measurements at temperatures up to 1000 °C including the development of a noncontact optical lever system of resonance detection. Data showing the acoustic signature of phosphorus pre-cipitation in silicon germanium and phase transitions in Zintl phase YMS thermoelectric materials will be presented.
Elastic rays and coda wave interferometry.
Authors: Gorin Thomas , Ortega Adrian
Published: October 2010

We apply the concept of rays, well known from geometric optics, to elastic waves traveling in a finite solid. Ray splitting and mode conversion between compressional P-waves and transversal S-waves are taken into account by using a random walk procedure and Monte-Carlo integration. In addition, we use the diagonal approximation from semi-classical theory to take the interference between rays traveling along different paths into account. Our approach allows us to simulate interference effects in the propagation of diffuse Coda waves in isotropic solids of different geometric shapes. We use that method to describe recent experiments by Lobkis andWeaver [Phys. Rev. E 78, 066212 (2008)] on the scattering fidelity in elasto-dynamic systems.
Experimental measurement of the elastic tensor of single crystal rare earth scandates utilizing resonant ultrasound spectroscopy.
Authors: Scott Eric , Pestka Kenneth
Published: October 2010

Using resonant ultrasound spectroscopy (RUS) in combination with ab initio calculations, the complete elastic tensor of four rare earth scandates, SmScO3, TbScO3, NdScO3, and EuScO3, was determined. These recently developed materials are useful for a variety of novel applications including strain-induced thin film growth of superlattices used in sonic lasers. In these applications, the dynamic lattice properties are of importance and are directly related to the elastic constants. The RUS method for determining the elastic constants is accomplished by iteratively comparing the experimentally determined resonant frequencies of a sample with a set of calculated frequencies. These calculated frequencies are generated from an assumed set of elastic constants. In order for the RUS method to reproduce the elastic tensor of the sample, reasonable initial elastic constants are required. For these newly developed materials, the initial elastic constants were obtained using ab initio calculations. Utilizing RUS, the experimentally determined elastic constants differed, on average, by less than 10% from the theoretical values.
Temporal fine structure for sequential segregation.
Authors: Grimault Nicolas , Gaudrain Etienne
Published: October 2010

Pitch based sequential segregation is reputed to benefit from spectral cues and temporal envelope cues. However, some previous results with hearing impaired listeners raised the possibility that other cues could promote segregation. These other cues could be responsible for the high inter-subject variability across hearing impaired listeners in streaming experiments. Temporal fine structure cues appeared then to be a valuable candidate. The current study is dedicated to assess the potential benefit from temporal fine structure cues for sequential segregation. Unresolved complex tones (A) and unresolved complex tones with the same F0 in which all components were shifted upward by the same number of Hertz (B) were presented in ABA-ABA- sequences. Using these stimuli, a rhythm discrimination task was used to estimate the amount of primitive segregation. Cochlear models will be applied first to the stimuli to establish the respective amount of spectral, temporal envelope and temporal fine structure cues. The results from the discrimination task will then be discussed at the light of the outputs of the models.
The role of spectral cues and minimum bandwidth in the auditory perception of distance.
Authors: Vergara Ferrari Ramiro Oscar , Calcagno Esteban , Eguia Manuel C.
Published: October 2010

Little is known about the strategies that humans use to estimate the distance of a sound source. Variations in the sound pressure level and changes in the sound induced by its relationship with the acoustic environment have been proposed as important cues in the judgment of the apparent distance of a sound source. However, relatively little attention has been given to the role of frequency spectrum in the determination of auditory distance. In this work, psychophysical experiments on distance perception using auditory stimuli with different spectral characteristics are performed. The first series of experiments show that subjects perceive better the changes in the distance of the source for spectrally complex auditory stimuli compared to pure tones. In the second set of experiments, noise bands with bandwidths located on different parts of the frequency spectrum were used. From this experiment, the minimum bandwidth required for a sound signal in order to preserve information on the distance to the acoustic source is obtained as a function of frequency. These results show that the spectral characteristics of sounds can significantly influence the perception of the distance to a sound source.
Avoiding measurement artifacts in assessing the detection of “expected” and “unexpected” signals.
Authors: Henry Molly J. , McAuley J. Devin , Hartmann William M. , Pleskac Timothy J.
Published: October 2010

Auditory perception studies using the probe-signal method [Greenberg and Larkin (1968)] have demonstrated greater detection sensitivity for tones occurring at “expected” frequencies relative to tones occurring at “unexpected” frequencies. An important, but largely overlooked, methodological issue in studies using the probe-signal and related methods is that measured sensitivity (d́) can underestimate true sensitivity for conditions with relatively few observations, implying that enhanced sensitivity observed for “expected” conditions with more observations compared to “unexpected” conditions with fewer observations can potentially be due to a measurement artifact. To address this possibility, the current research combines results of two behavioral studies with a set of simulations and finds that heightened sensitivity to an expected signal relative to an unexpected signal can be observed when there are no differences in true sensitivity across conditions. Specifically, enhanced detection sensitivity for more frequent signals attributable to a measurement artifact is more likely when true detection sensitivity is high, the number of stimulus presentations is relatively low, and a correction for response proportions of 0 and 1 is required to calculate d’. Implications are discussed for psychoacoustics research using the probe-signal method and more broadly for psychological studies examining effects of listener expectations on perception.
Modulation of phonetic duration by morphological and lexical predictors.
Authors: Sims Michelle , Tucker Benjamin V. , Baayen Harald
Published: October 2010

This study investigates how the duration of the stem vowel of regular and irregular English verbs is modulated by tense (present and past), regularity, lexical frequency, gang size of the vocalic alternation, imageability ratings, and vowel quality. The vocalic durations of 48 monosyllabic irregular verbs and 171 regular verbs were extracted from the Buckeye Corpus of spontaneous speech. A linear mixed effects regression model revealed that vowels of past tense forms tend to have longer durations than vowels of present tense forms, that vowels of words that are less imageable are realized with shorter durations, and that tense vowels are longer than lax vowels. Surprisingly, higher frequency irregular past tense forms were produced with longer vowels, contradicting Aylett and Turk [(2004); (2006)] and Bell et al. [(2003); (2009)]. Further, vowels were shorter for irregular verbs with larger vocalic alternation gangs, contradicting the predictions of Kuperman et al. [(2007)] but supporting hypotheses that units with a smaller information load have shorter durations. This pattern of results is interpreted as a consequence of the pressure for regularization during the production of irregular past tense forms.
Perceptual evidence for allophonic variation of the palatal fricative /ç/ in spontaneous Berlin German.
Authors: Jannedy Stefanie , Weirich Melanie , Brunner Jana , Mertins Micaela
Published: October 2010

Auer (2004) postulates that the multi-ethnolect Kiezdeutsch (Berlin, Germany) differentiates three realizations of /ɪç/: [ɪç]; [ɪ∫]; [ɪφ]. Acoustic analyzes of 1192 tokens of /ç/ from the ZAS-spontaneous speech database (collected from nine adolescent speakers of the Kiezdeutsch multi-ethnolect as spoken in Berlin) showed no reliable differences in kurtosis, skewness, cog, or peak between items impressionistically categorized into these three groups. Further, in the spontaneous speech of middle-aged monolingual speakers of the local Berlin dialect [∫] variants of /ç/ were also detected, although here this alternation is not attested. The hypotheses are (1) that Berlin-German also has [∫] as an allophonic variant of /ç/ and (2) that Kiezdeutsch has a 3-way-split of this category. To evaluate the perceptual validity of these assumptions, tests are being conducted asking native Berliners to rate the category membership of excised variant realizations of /ç/ and /∫/ from the Kiezdeutsch- and Berlin-database on a scale from 1 (/ç/) to 7 (/∫/), with 4 indicating no real preference for either one. First results point to a two-way perceptual split for the older Berlin speakers and a more fuzzy category boundary between [ç] and [∫] for the Kiez data, suggesting a third intermediate perceptual category. [Work supported by a grant from the German Ministry of Science and Education (BMBF).]
Visual influences on interactive speech alignment.
Authors: Dias James W. , Rosenblum Lawrence D.
Published: October 2010

Speech alignment describes the tendency to produce speech that shares characteristics with a perceived speech signal. Visual speech information has also been found to modulate speech alignment [R. M. Miller et al., Attention, Perception, & Performance (in press)]. The present study evaluated whether visual speech information enhances alignment over auditory-alone information in a live context. Pairs of subjects performed an interactive search task for which they were required to utter nine key words multiple times. Half of the subjects performed the task while interacting face-to-face, while the other half performed the task separated by a cloth preventing them from seeing each other without inhibiting the heard speech. Subjects also uttered the key words before and after the interaction. Alignment was evaluated using an AXB matching task in which raters judged whether post-interaction or pre-interaction utterances of a word spoken by a subject were more similar to the post-interaction word spoken by that subject’s partner. Raters also judged similarity between partner utterances from early and late in the interaction. Evidence showed that visual information did enhance interactive speech alignment. These findings add to the evidence that amodal, gestural properties of perceived speech can induce alignment.
Interpretation of the compressed pulse output for broadband acoustic scattering from inhomogeneous weakly scattering objects.
Authors: Lee Wu-Jung , Lavery Andone C. , Stanton Timothy K.
Published: October 2010

Pulse compression signal processing techniques are commonly used to identify dominant scattering features for weakly scattering marine organisms. In cases where the organism can be accurately represented as homogeneous (e.g., eupausiids), the separation of two distinct peaks in the compressed pulse output (CPO) envelope produced by the front and back water-tissue interfaces can be used to estimate the size of the organism at some angles of orientation. In order to investigate the effect of internal inhomogeneities on the scattering, a 3-D distorted-wave Born approximation-based numerical model has been used to model the CPO due to scattering from weakly scattering inhomogeneous objects. It has been found that when the organism is highly inhomogeneous (e.g., sea-water filled cavities in squid), the CPO envelope does not provide an accurate estimate of size. Characteristics of the replica signal can further complicate the issue by introducing spurious peaks with high side lobes or smearing out the CPO peaks from internal inhomogeneities when the main lobe is wide.
Detection of a target in shallow water using the feedback phenomenon: A small-scale experimental demonstration.
Authors: Marandet Christian , Roux Philippe , La Rizza Patrick , Nicolas Barbara
Published: October 2010

We experimentally demonstrate the detection of a wavelength-size target in a shallow ultrasonic waveguide between two source-receiver transducers using acoustic feedback. The waveguide represents a 1-km-long, 50-m-deep ocean acoustic channel at the 1/1000 scale. People are familiar with the feedback phenomenon that results in the loud sound heard when a musician plays an electric instrument directly into a speaker. Feedback occurs when a source and a receiver are connected both acoustically through the propagation medium and electrically through an amplifier in such way that the received signal is simultaneously and continuously added to the emitted signal. A resonance is then obtained when the emitter and the receiver are in phase. The resonant frequency appears to be highly sensitive to fluctuations of the propagation medium. During the crossing of the target trough the waveguide, fluctuations inferred by the target allow the detection. Experimental results are presented with target of different sizes in the presence of surface fluctuations.
Tomography of the surface elevation in shallow water between two source-receiver ultrasonic arrays: A small scale experiment demonstration.
Authors: Marandet Christian , Roux Philippe , Nicolas Barbara
Published: October 2010

Based on single-scattering effects, the diffraction-based sensitivity kernels which make the link between the acoustic perturbations and the medium fluctuations have been extensively studied. We propose a similar study for perturbations at the air-water interface in an ultrasonic waveguide that scales down with a 1-km-long, 50-m-deep ocean acoustic channel in the kilohertz regime. Using array processing between two source-receiver arrays, the sensitivity kernel for both time and amplitude has been experimentally inferred for each acoustic echo reverberated in the waveguide to a small surface elevation. We demonstrate a good agreement between experimental and theoretical sensitivity kernels. Finally, using theoretical sensivity kernels for both amplitude and time ultrasonic fluctuations, we give a real-time estimation of the surface elevation at any point between the source and receiver arrays.
Enhancing resonant features in the aspect dependence of target spectra by reversible imaging filtration techniques.
Authors: Marston Timothy M. , Marston Philip L. , Williams Kevin L.
Published: October 2010

The aspect dependence of the spectral response of simple objects is sometimes examined in scattering research. The use of reversible imaging algorithms for the approximate de-coupling of the impulse response and associated spectral-responses of two adjacently located targets with overlapping signals was previously demonstrated [T. M. Marston, P. L. Marston, and K. L. Williams, J. Acoust. Soc. Am. 127, 1749 (2010)]. The current research concerns how resonant features of targets can be enhanced by using related imaging and filtering algorithms. When resonant targets are imaged using synthetic aperture techniques, the resonant portion is often distinct enough from specular or edge-diffraction portions so that it is possible to design spatial filters that isolate the resonant from the non-resonant portions of the signal in the image domain. The filtered image is then returned to the original domain, and frequency response is plotted with the non-resonant portions of the data filtered out. The resulting plots show enhanced resonant features. Demonstrations using line-scan SAS and circular SAS data will be shown. [Work supported by ONR.]
Measured acoustic scattering from a water-filled aluminum pipe in contact with various interfaces.
Authors: Espana Aubrey L. , Williams Kevin L. , Kargl Steven G. , Marston Timothy M. , Marston Philip L.
Published: October 2010

Detection and classification of objects on or imbedded in the ocean sediment are difficult problems due to the complexity of the sediment. The measured scattering will include interactions of the incident sound with the sediment interface as well as the possibility for multiple interactions between the target and sediment. Recent experiments conducted in the test pond at the Naval Surface Warfare Center, Panama City Division, investigated the impact the environment has on the measured acoustic response from various targets. A particular subset of these experiments is presented, focusing on the acoustic scattering from a water-filled aluminum pipe having length-to-diameter ratio equal to 2. Initial measurements examined the scattering from the pipe in a proud configuration on the flattened sand sediment. Subsequent measurements placed the pipe in contact with interfaces with known reflection coefficients, including suspending the pipe just below the air/water interface and placing it in a proud configuration on a flat acrylic panel on the sand sediment. Acoustic templates depicting the absolute target strength as a function of azimuthal angle over the frequency range 1–30 kHz are compared for the three different configurations. [Work supported by the Office of Naval Research.]
High fidelity noise and reverberation waveforms for sonar stimulators.
Authors: Harrison Chris
Published: October 2010

A stimulator produces multiple hydrophone signal, noise, and reverberation waveforms sophisticated enough to produce a realistic behavior in the output displays of a sonar system run on the bench. These waveforms need to be able to deceive the sonar’s given signal processing, detection and tracking algorithms, etc. This talk focuses on the difficult problem of reproducing the directionality, spatial and temporal coherence, statistics, and spectra in ambient noise and reverberation, and instilling this into the channels of a hydrophone array. Frequency domain approaches work well for noise where directionality hardly changes in time. Time domain approaches work better for reverberation where the directionality changes as the arrivals come from longer and longer ranges. Since the aim is real-time operation, the level of fidelity is an important consideration; one needs correct mechanisms for the sonar system under consideration, although they can often be crudely, rather than exactly, modeled. For instance, simulating noise for a single hydrophone system would be much simpler than for a vertical array system intended for beam-cross-correlation and passive fathometry; nevertheless, both simulation approaches are possible. Examples of noise and reverberation will be shown.
Model-based estimation and uncertainty characterization of modal arrival times and amplitudes in ocean acoustics.
Authors: Michalopoulou Zoi-Heleni
Published: October 2010

A Bayesian approach is proposed for modal arrival time and amplitude estimation from short-time Fourier transforms of broadband acoustic signals in the ocean. The goal is to obtain accurate estimates of arrival times of propagating modes and corresponding amplitudes using a physical model to describe short-time Fourier transform slices and a signal processing method to estimate parameters that are integrated in the physical modeling. The method provides uncertainty information on both modal arrival time and amplitude estimates, which is desirable in ocean acoustic inversion that utilizes a combination of modal information and sound propagation models. [Work supported by ONR.]
Cotton, cryptology, and acoustics.
Authors: Moyer David
Published: October 2010

Established as the first laboratory dedicated to architectural acoustics, Riverbank Acoustical Laboratories has been providing reliable, independent, third party results since 1918. Founded by Wallace Clement Sabine, the laboratory is entrusted by the acoustical community at large to provide results for the seasoned manufacturers of acoustical products or the novice noise control entrepreneur. The author will provide a brief overview of improvements made through the history of architectural testing and particularly at this historic laboratory.
State-of-the-art in determining absorption, diffusion, and scattering coefficients.
Authors: D’Antonio Peter
Published: October 2010

Absorption, scattering, and diffusion coefficients characterize surfaces in architectural acoustics and are also used in computer models. Absorption coefficients, determined by ISO 354, have been used for over 100 years and yet improvements in their measurement are continually being evaluated to address the factors causing coefficients to exceed unity. Scattering, s, and diffusion, d, coefficients described in ISO 17497-1 and -2 are relatively newcomers. While absorption coefficients are typically experimentally measured at full scale, s and d have the advantage of being able to be both predicted and experimentally measured in full-scale or with scale models. In this presentation a description of the state-of-the-art of both the predictive and experimental methods for s and d as well as comparison examples between full-scale and scale models will be presented. The accuracy needed for a and s in computer models and the reproducibility and accuracy of d will also be discussed.
Shallow water acoustic propagation in West Indian manatee habitats.
Authors: Gur Berke M. , Niezrecki Christopher
Published: October 2010

As part of the Manatee Avoidance Technology program of the Florida Fish and Wildlife Conservation Commission, several experiments were conducted between the years 2004 and 2008 in the coastal waters of Florida within typical West Indian manatee (Trichechus manatus latirostris) habitats. The primary purpose of these experiments was to evaluate several vocalization enhancement and noise suppression algorithms. Most of the experiments were conducted in brackish waters having depths less than 30 ft with silt and grassy seabeds. The analysis of the data collected during these experiments revealed certain phenomena pertinent to manatee communication. This talk will focus on the acoustic propagation characteristics observed at these manatee habitats. More specifically, the repetitive loud and fading patterns due to Lloyd’s mirror effect measured from opportunistic sources and the results of controlled transmission loss experiments will be detailed. The effects of such phenomena on manatee communication will be discussed. [This research was supported by Florida Sea Grant, Florida Fish and Wildlife Conservation Commission, University of Florida Marine Mammal Program, and the University of Massachusetts Lowell Provost’s Office.]
Acousticians abuse Darwin: Multipath propagation of seismic airgun signals and bowhead whale calls in the Arctic Ocean, with evolutionary implications.
Authors: Thode Aaron
Published: October 2010

Evolutionary biologists have long noted that animals attempting long-range communication often adjust their acoustic signals to compensate for or even exploit features of the acoustic propagation path. Here we present recordings of long-range seismic exploration signals and bowhead whale calls detected on directional autonomous seafloor acoustic recorders deployed in the Beaufort Sea in 2008. Seismic signals that begin as broadband impulses geometrically disperse into FM downsweeps as they propagate over several kilometers range in shallow water waveguides parallel to the Alaskan coast, eventually becoming similar to bowhead FM sweeps in bandwidth and modulated structure, creating headaches for unfortunate scientists trying to create automated bowhead whale acoustic detectors. It is suggested that the similarity in structure between long-range seismic signals and bowhead whales is not coincidental, but provides an enlightening example of how marine mammals, over evolutionary time scales, have optimized their acoustic signals to propagate long distances while retaining information. A broadband harmonic bowhead whale call is analyzed to examine the speculation. In general, stereotyped baleen whale calls might serve purposes beyond simple species identification in complex waveguide environments.
Ocean environmental effects on low-frequency sound propagation in shallow water with application to marine mammals.
Authors: Newhall Arthur E. , Lin Ying-Tsong
Published: October 2010

In shallow ocean areas (less than 100 m), the water-column and seafloor structure play a critical role in sound propagation and can influence many different applications of shallow water acoustics including source detection and localization. While the seafloor and subbottom effects on sound propagation are relately well known, water-column variability, especially that of internal wave activity, thermohaline intrusions, and fronts, are only beginning to be understood, but should be considered when predicting sound propagation in shallow water. For example, termination of the mid water-column duct by a shelfbreak front or the appearance of an internal wave duct can change acoustic channels which may hinder marine mammal communication or may be exploited by the animals. In this paper, we will examine the effects of the ocean environment on sound propagation in shallow water in the presence of these features in a continental shelf region. Specifically, we will use field data and numerical acoustic simulations to study low-frequency sound propagation in a dynamic ocean and how it relates to marine mammal vocalization, communication, and localization. [Work supported by ONR.]
Sound propagation modeling of right whale calls in Cape Cod Bay.
Authors: Lin Ying-Tsong , Newhall Arthur E. , Parks Susan E.
Published: October 2010

Numerical simulations of underwater sound propagation for right whale calls in the Cape Cod Bay are presented. Whale calls recorded by the acoustic tags attached on the whales in the region are used in the model. The tag records show that whales made sweeps in a fundamental frequency band from 80 to 200 Hz, along with harmonics of higher frequency up to 4 kHz. The acoustic modeling is performed for both fundamental and harmonic sweeps. The acoustic normal mode propagation of lower-frequency fundamental sweeps will be examined, as well as the acoustic ray path of higher frequency harmonic sweeps. The real bathymetry and water-column stratification are considered in the model to study the environmental effects on sound propagation. Applications to passive acoustic monitoring of whales in the Cape Cod Bay are then discussed.
Auditory brainstem recordings during echolocation at an aluminum cylinder in a harbor porpoise (Phocoena phocoena).
Authors: Linnenschmidt Meike , Hoejer Kristensen Jakob , Beedholm Kristian , Nachtigall Paul , Wahlberg Magnus
Published: October 2010

Cetacean hearing during echolocation has only been studied in the false killer whale. A male harbor porpoise was successfully trained to perform an echolocation task while acoustic brainstem response (ABR) suction cup electrodes were attached to its body surface. The project was set up to be as similar as possible to the false killer whale studies to make results directly comparable. The porpoise was trained to position itself in a hoop 80 cm below surface. A visual screen of 1-mm opaque plastic at 30 cm prevented the animal from using visual cues. Echolocation viewing time was controlled by an acoustical shield of neoprene foam between two aluminum plates. The shield was raised for 3 s to allow the animal free access for echolocation. An aluminum cylinder was presented at 2 m distance to the hoop 80 cm below surface in a random order 50% of the time, and the animal responded whether it detected a cylinder (GO trial) or not (NOGO trial). The ABR recordings show a clear response to the outgoing click and echoes from the target and obstacles in the near surroundings. The initial results are directly comparable to the false killer whale studies. [Work Supported by the Danish Research Council.]
Comparison of A-weighted sound pressure level (dB(A)), loudness-level weighted sound pressure level (dB(EQL)), and loudness with respect to environmental noise assessment.
Authors: Genuit Klaus , Bray Wade , Caspary Georg
Published: October 2010

A pair of related tools useful for environmental noise assessment are time-varying psychoacoustic loudness, and an expression of sound pressure level in dB[SPL] weighted dynamically according to the contours of equal loudness rather than the static A-weighting. Conventional weightings applicable to sound pressure (dB[A], etc.) are fixed in spectral shape and intended for use over certain ranges of unweighted sound pressure level. Particularly for sounds with tonal content and within the general level range of the A-weighting, the authors propose a new spectral sound pressure weighting assembled from the Phon values of the complete set of equal-loudness contours calculated for each frequency within the human auditory range. It will be shown that although giving values numerically similar to those of the A-weighting, the dB[EQL] or Equal-Loudness weighting is situation-dependent rather than fixed, and better-represents subjective impressions at all frequencies. Although based on perceived loudnesses, the dB[EQL] sound pressure weighting is not a specific loudness measurement, does not consider critical band formation nor yield masking or psychoacoustic loudness data. Developed from the same basis as psychoacoustic loudness of sounds at different frequencies, the dB[EQL] and time-varying loudness together provide a bridge between conventional and psychoacoustic techniques.
A physiologically constrained van Bergeijk model of interaural time difference coding predicts bandwidth-dependent lateralization.
Authors: Hancock Kenneth E.
Published: October 2010

Recent physiological data have revived the notion that ITD is encoded centrally by the relative activity of coarsely tuned channels that pool the firing rates of many neurons [McAlpine et al., Nat. Neurosci. 4, 396–401 (2001), van Bergeijk, J. Acoust. Soc. Am. 34, 1431–1437 (1962)]. Here we implement a model of the van Bergeijk-type and demonstrate that it predicts the dependence of perceived laterality on stimulus bandwidth [Stern et al., J. Acoust. Soc. Am. 84, 156–165 (1988)]. Each model channel comprises a large number of neurons, whose characteristic frequencies and best ITDs (BDs) are distributed to mimic physiological data from cat inferior colliculus. Each neuron cross-correlates the bandpass-filtered stimuli to the two ears, and the channel output is simply the summed firing rate of its neurons. The model predicts lateralization as a function of bandwidth, if four channels are used, one representing each medial and lateral superior olive. The outputs of the van Bergeijk-type code are appropriate for controlling phonotaxis. Its lack of labeled lines minimizes the precision required in the BD distribution and may explain how a viable ITD representation is formed despite the existence of several factors that determine the BD of individual neurons.
Psychophysical evidence for internal delays in binaural detection.
Authors: van der Heijden Marcel
Published: October 2010

The availability of an internal delay line has major consequences for performance in binaural detection tasks. It is well known that binaural thresholds vary with the interaural correlation of a noise masker, and the detrimental effect of noise decorrelation is well described by many models. When a delay line is present, however, the exact nature of the decorrelation of the noise becomes crucial. Decorrelation originating from an external delay can be compensated by internal delays, but other sources of decorrelation (e.g., mixing) cannot be undone. The special status of decorrelation from interaural delay is supported by psychoacoustic evidence. The quantitative analysis of such data, which requires a careful consideration of peripheral frequency selectivity, indicates the existence of a delay line in human listeners that can compensate accurately for external delays of up to ∼750 μm. Larger internal delays, i.e., up to 2–3 ms, are probably also operative, but performance using such large internal delays is degraded as if their application introduces noise in the internal stimulus representation. I will review the psychoacoustic evidence for internal delays, discuss the assumptions underlying their interpretation, and rebut a recent attempt to dismiss this evidence.
Optimal codes for processing interaural time differences.
Authors: Brette Romain
Published: October 2010

It has been argued that a graded code with two populations of neurons tuned at two symmetrical delays is optimal for ITD estimation. However, this theoretical result critically relies on the assumption that the only source of uncertainty is the randomness of spiking, while the source signal is fixed (a pure tone). With this assumption, information about ITD is equivalent to sensitivity to ITD. If this assumption is relaxed, for example, if the sound is unknown, it turns out that the two-channel model is not optimal anymore for ITD estimation. In particular, place codes (e.g., Jeffress model) give better estimates. The two-channel model, on the other hand, is optimal for categorical decisions (left/right). Finally, I will discuss the distribution of natural ITDs. Theory, computational models, and measurements show that ITDs are larger at low frequencies (wavelength larger than head width). I will also suggest that natural ITDs should include reflections (e.g., on the ground) when their delay is comparable to or smaller than the signal period. This results in larger ITDs in low frequencies than expected from wide band measurements in anechoic rooms.
The processing of interaural difference information in binaural models: Relation to physiological data.
Authors: Colburn H. Steven
Published: October 2010

This paper addresses the role of the binaural displayer in the modeling of binaural psychoacoustical abilities and the relation of proposed displayers to available physiological data. The roles of the binaural displayer and the binaural analyzer in forming model decision variables are defined and described. Explicit attention is given to simplicity as a fundamental goal in the formulation of psychoacoustical models, especially the ability of a single model to relate disparate types of behavioral experiments. When the internal processes within models are compared to physiological data, with the goal of finding models that are compatible with both types of data, conflicts and trade-offs arise and the challenge becomes much greater. Ultimately, we are searching for psychophysical models that are consistent with physiological data related to the coding of information about interaural differences, and we all agree that conflicts between psychophysical models and physiological data must be resolved. With this in mind, the immediate goal of this paper is to clarify points of agreement and disagreement in conceptualizations about the binaural displayer and in the interpretation of available neural data. [Work supported by NIH: 5 R01 DC000100.]
Stress relaxation in human true and false vocal folds.
Authors: Alipour Fariborz
Published: October 2010

Stress relaxation behavior of the human true and false vocal folds were measured in vitro and modeled for viscoelastic parameter determination. Vibrations of the vocal folds are greatly influenced by the elasticity and viscosity of its mucosal layer. When there is a change in the viscoelastic properties of vocal fold tissue due to disease or trauma such as scarring, voice change may occur. Voice simulation models are in need of viscoelastic properties of human vocal folds for more reliable results. Due to the shortage of human data, these properties have been extrapolated from animal data such as canine vocal fold tissues. In this study, samples are made from human larynges acquired from NDRI, which were snap frozen 24–48 h post mortem and stored in −82 °F. Samples were made from medial portion of true and false vocal folds without any muscle, with a piece cartilage at each end for mounting. Stepwise elongation of 20 and 30% stretch was applied the force response was measured with an ergometer and modeled with a quasi-linear viscoelastic model. The preliminary results suggest the strong relaxation behavior in both true and false vocal folds are indicative of abundant collagen material. [Work supported by NIDCD Grant # DC00956.]
Using systematic synthetic voice differences to probe the perception of mixed-talker vowels.
Authors: Barreda Santiago , Nearey Terrance M.
Published: October 2010

Many experiments have reported a perceptual advantage for vowels presented in blocked versus mixed speaker conditions. Nusbaum and colleagues [Nusbaum and Morin (1992); Magnuson and Nusbaum (2007)] found that the size of this advantage varies with aspects of the similarity of the voices involved. The largest performance difference occurs when voices are of intermediate similarity (e.g, two similar sounding female voices with incongruent vowel spaces). Difference are smaller when voices are either very similar or very different. The current study will explore some potentially relevant dimensions of similarity using vowels from a set of synthetic virtual talkers whose voice characteristics differ in formant ranges, f0, and/or source characteristics. Perceptual accuracy and response times will be collected using a speeded monitoring task in which participants are asked to respond as soon as they hear a specific target vowel. Results will be evaluated in light of current theories of vowel normalization and speaker adaptation.
Phonetic correlates of vocal attractiveness in American English.
Authors: McGuire Grant L. , Babel Molly , Miller Teresa , King Joseph
Published: October 2010

This study explores fine-grained phonetic vocal characteristics that underpin vocal attractiveness. In general, while it is well known that F0 plays a major role in such judgments [see, e.g., Riding et al. (2006)] there is a distinct lack of more detailed examinations of the phenomenon [see Zuta (2007) for a notable exception]. Moreover, the term “attractiveness” is generally ill-defined and conflated with other terms (such as “pleasantness”). Therefore, the specific goal of this study is to replicate and extend such studies by including a large number of talkers, more detailed acoustic measures, and better definition the term “attractiveness”. Specifically, 60 talkers from California (30 female) produced isolated words controlled for phonetic content. These voices will be played to listeners who will judge the attractiveness of each talker. Ratings of these talkers will be compared against these acoustic measures: duration, average F0, F0 variation, spectral tilt, jitter, vowel space area, long term averaged spectrum, VOT, spectral mean of frication, and spectral peak of frication. The semantic value of “attractiveness” will be explored in follow-up questionnaires asking more detailed questions. Results will be compared against previous studies and will be discussed in terms of possible universal and culture-specific features.
Voiced laughter elicits more positive emotion in listeners when produced with the mouth open than closed.
Authors: Owren Michael J. , Riede Tobias
Published: October 2010

Laughter is ubiquitous in human interaction, but little is known about the communicative mechanisms involved. In previous work, listeners hearing laughter in isolation experienced positive emotion in response to voiced laughs, but showed neutral or negative reactions to unvoiced versions—even though all sounds had originally been recorded in positive circumstances. Current work compared ratings of open- versus closed-mouth voiced laughter, again from positive circumstances. Participants were 28 university students (14 female) hearing a total of 48 different laughter bouts presented in two randomized blocks (96 total trials). Listeners rated how positive each bout sounded using a 4-point scale ranging from “neutral” to “very positive.” Laughter included 24 open-mouth and 24 closed-mouth bouts, with 12 of each type from males and females. Mean ratings did not differ by listener-sex or stimulus-block. However, female laughter was rated significantly higher than male laughter, replicating previous results. Furthermore, ratings for open-mouth laughter were significantly higher than for closed-mouth sounds, both across and within laugher sex. Results suggest that a higher positive arousal in vocalizers is associated with a greater likelihood of laughing with the mouth open, and that listeners hearing this laughter experience more positive emotion than for closed-mouth versions.
The role of perceptual learning in emotional vocalizations.
Authors: Sauter D. A. , Crasborn O. A. , Haun D. B. M.
Published: October 2010

Vocalizations like screams and laughs are used to communicate affective states, but what acoustic cues in these signals require vocal learning and which ones are innate? This study investigated the role of auditory learning in the production of non-verbal emotional vocalizations by examining the vocalizations produced by people born deaf. Recordings were made of congenitally deaf Dutch individuals and matched hearing controls, who produced non-verbal vocalizations of a range of negative and positive emotions. Perception was examined in a forced-choice task with hearing Dutch listeners (n = 25), and judgments were analyzed together with acoustic cues, including envelope, pitch, and spectral measures. Considerable variability was found across emotions and acoustic cues, and the two types of information were related for a sub-set of the emotion categories. These results suggest that auditory learning is less important for the acquisition of certain types of vocalizations than for others (particularly amusement and relief), and they also point to a less central role for auditory learning of some acoustic features in affective non-verbal vocalizations. The implications of these results for models of vocal emotional communication are discussed.
Pitch accent on [il] in Seoul Korean.
Authors: Jun Sun-Ah , Cha Jihyeon
Published: October 2010

A Sino-Korean morpheme il is lexically ambiguous, referring to (1) “one” and (2) “day.” As Standard Korean does not use pitch accent or tone lexically, these morphemes are expected to be pronounced the same regardless of their meaning, if they are produced in the same prosodic condition. However, informal observation reveals that certain speakers pronounce il with a high pitch in accentual phrase—initial position when meaning “one” (e.g., /il-pun/ “one minute”), but with low pitch in the same position when meaning “day” (e.g., /il-ki/ “diary”). According to the intonation system of Seoul Korean, vowel-initial syllables such as [il] should bear low pitch phrase-initially. [S.-A. Jun, Phonology 15, 189–226 (1998).] We have examined the pitch of [il] in various prosodic and semantic conditions, produced by several speakers of different age groups, dialects, and gender. Preliminary results show that a high pitch on [il] is observed only among Seoul speakers, in particular, among young generation when the numerical meaning (“one”) is salient and the phrase is short. Furthermore, this phenomenon seems to extend to other morpheme or words beginning with [il] among female speakers. We will discuss factors affecting this phenomenon and possible triggers of this sociolinguistic variation.
Effects of linguistic experience and speaking style on pitch alignment in focus syllables.
Authors: Rogers Catherine L. , Zasimovitch Jennifer
Published: October 2010

The location and realization of any pitch accents associated with utterance focus can vary across languages. The present study compared the relative locations of fundamental frequency (F0) maxima and minima in monosyllables produced by native English speakers and non-native English speakers with Spanish as their first language. Ten monolingual English speakers, 15 early learners of English (age of immersion 12 years or earlier), and 10 later learners of English (age of immersion 15 years or later) produced target monosyllables in the carrier phrase “Say ______ again” in conversational and clear speech styles. The relative locations of F0 maxima and minima were computed for each target syllable. Results for the conversational speech tokens showed significant differences in peak (F0 maximum) alignment for the monolingual and early learner groups compared to the later learners and significant differences in alignment of F0 minima among all three talker groups. Early learner average values fell between those for the monolinguals and later learners in both cases. Ongoing analysis suggests a switch to more native-like patterns for the early but not the later learners in the clear speech style, suggesting a nuanced awareness and control of second-language prosodic features by the early learners. [NIH-NIDCD #1R03DC005561-01A1]