bluuebunny/crossref_metadata_2025 huggingface dataset:
Resonant ultrasound spectroscopy of sandstone.
Authors: Pantea Cristian , Sturtevant Blake T. , Sinha Dipen N.
Published: October 2010

Sandstones are typically found in geothermal and oil and gas reservoirs. A precise determination of the elastic moduli of sandstone is very important toward understanding the reservoir properties, especially when hydro-fracturing needs to be performed. Hydro-fracturing consists of injecting high-pressure water in the bedrock formation to create bedrock fractures that connect to existing fractures in the formation, resulting in an increased flow of water, oil, or gas. Elastic properties of various types of sandstones are investigated in this work using resonant ultrasound spectroscopy (RUS). The porosity and very low elastic moduli of sandstones introduce additional challenges in the determination of the elastic moduli when compared to materials previously investigated by this technique. Conventional RUS experiments are difficult to perform on such porous, brittle, and attenuating samples, and a re-designed experimental setup is required that can deliver more acoustical energy to the sample. A detailed description of the approach will be discussed, including transducer selection, experimental setup materials, and sample geometry. Temperature dependence of sandstone elastic moduli for temperatures typical of geothermal and oil and gas reservoirs is investigated. In addition, high pressure–high temperature determination of the elastic moduli will be described.
The effects of ear of stimulus presentation on pitch discrimination abilities of young adult females.
Authors: Gaal Ashley R. , Moore Robert E. , Estis Julie M.
Published: October 2010

Previous research has examined various factors that influence pitch discrimination abilities in normal-hearing listeners [Deutsch (1970); (1978)], including the influence of spatial location of input stimuli. Separating the input location of interference tones from the initial (reference) and final (comparison) tones leads to better pitch discrimination accuracy (PDA) than when all tones are presented to the same ear, but the effects of the relationships between these three tone types have not been explored. This study examined the impact of ear of stimulation in 20 conditions: 5 containing no interference and 15 containing 4 interference tones. Twenty-four non-musician females (age 19–30) with normal hearing participated. Results showed that performance was significantly better when (a) no interference was present, (b) the comparison tone was presented contralaterally to reference and interference tones, (c) the comparison tone was presented to the left ear, and (d) the reference and comparison tones were the same frequency. Overall, the comparison tone seems to play a key role in PDA. These findings should be further explored, as they could be utilized in aural training and therapy programs to strengthen pitch discrimination in musicians and clinical populations, such as individuals with prosodic language or auditory processing deficits.
A role for low-frequency sensitive neurons in the auditory brainstem in the encoding of source location distance-dependent interaural level difference cues.
Authors: Tollin Daniel J. , Jones Heath G. , Thornton Jennifer L. , Koka Kanthaiah
Published: October 2010

The duplex theory posits that low- and high-frequency sounds are localized using two different acoustical cues, interaural time delays (ITDs) and interaural level differences (ILDs), respectively. Psychophysical data have generally supported the theory for pure tones. Anatomical and physiological studies have revealed two parallel brainstem pathways that appear to encode ITDs and ILDs separately. ITDs are extracted by medial superior olive neurons. ILDs are extracted by lateral superior olive (LSO) neurons. ILD-sensitive neurons are also found in the inferior colliculus (IC). ILDs are a complex function of both source location and frequency such that lower and higher frequencies exhibit smaller and larger ILDs, respectively. LSO and IC neurons encode ILDs for high-frequency sounds where the cues are physically available, but there are discrepancies regarding low-frequency neurons. Although acoustically, low-frequency ILDs are small, humans are sensitive to them and physiological studies have found low-frequency neurons in the LSO and IC that could encode them. Here the hypothesis that low-frequency ILDs are useful when sound source distance is varied is explored. These data demonstrate that a population of IC neurons is sufficient to encode the range of acoustic ILDs that would be experienced as a joint function of source location and distance.
Sensitivity to characteristics of Gaussian-shaped stimulus distributions in auditory categorization.
Authors: Sullivan Sarah C. , Kittleson Megan M. , Lotto Andrew J. , Diehl Randy L.
Published: October 2010

The purpose of this experiment was to further investigate the role that distributional information plays in auditory categorical decision tasks. Participants were presented non-speech sounds randomly sampled from two overlapping, Gaussian-shaped distributions. The sounds consisted of 27 narrow-band noise bursts varying in center frequency from 985–1375 Hz. Each of the four conditions was composed of a distribution with a relatively large variance and one with a relatively small variance, resulting in different distributional cross-over points or ideal boundaries. Participants were presented the stimuli over headphones as part of a computer game in which they navigated through 3-D space, reacting to animated alien characters along the way. Each distributional sound category corresponded to a specific character; either a blue alien or a green alien. The participants were asked to use a keyboard to identify the alien best associated with the sound they heard. Performance was tracked by plotting identification functions and noting boundary placement for each individual block. After only six blocks of training (approximately 25 min), most subjects had established boundaries near the distributional cross-over points (i.e., optimal category boundaries). The present experiment lays the foundation for a distributional approach to auditory categorization. [Work supported by NIH.]
Generalized transformation acoustics for material design.
Authors: Cipolla Jeffrey , Gokhale Nachiket , Norris Andrew
Published: October 2010

Norris [“Acoustic cloaking theory,” Proc. R. Soc. London, Ser. A 464, 2411–2434 (2008)] presented a theory of transformation acoustics that enables the realization of pentamode acoustic materials having anisotropic density and finite mass. The design of acoustic materials for 3-D objects composed of combinations of simple geometric shapes, e.g., a cylinder with spherical end-caps, is considered. Certain classes of transformations which are well-suited for the design of such shapes are described and conditions under which these transformations result in materials which minimize acoustic reflections are proposed. The concept is validated using 3-D explicit transient finite element simulations, which closely emulate the physics of wave propagation in the proposed materials.
Acoustic characterization of magnetorheological fluids.
Authors: Fratantonio Frank , Howarth Thomas R. , Boisvert Jeffrey E. , Bruno Anthony , Scandrett Clyde L. , Wynn William M.
Published: October 2010

Magnetorheological (MR) fluids contain magnetic particles dispersed within a host fluid. These materials are considered a type of “smart” fluid in that their viscoelastic properties can be controlled by varying the magnetic field intensity. MR fluids have found favor in high-end automobile applications such as the General Motors dynamic MR suspension system which has been in Corvettes (and other GM products) since 2005. Recently there has been interest in understanding the acoustic properties of MR fluids. In particular, the ability to control the radial and orthogonal bulk moduli suggests that MR fluids are a potential candidate for acoustic metamaterial applications. This presentation will discuss MR fluids and a method for the acoustic characterization of these fluids as functions of frequency and magnetic drive levels. [Work supported by the Office of Naval Research.]
Use of linguistic knowledge in the recognition of reduced words: Effects of age and high-frequency hearing loss.
Authors: Janse Esther , Ernestus Mirjam
Published: October 2010

Older adults have more language experience than young adults and may therefore rely more strongly on transitional probabilities between words for spoken word recognition. We investigated recognition of acoustically reduced words (such as “promised”) that were followed by a word with which it either formed a fixed expression (“promised land”) or not (“promised lamp”). Our research questions were (a) whether older adults show a greater following-word context effect on target word recognition than young adults; (b) whether low-pass filtering the stimuli would bring about a stronger reliance on following context in young adults; and (c) whether there are any interactions with the morphological complexity of the target word (e.g., “promised” versus “fat”), because complex and longer words can be more reduced. Data analysis (recognition accuracy and RTs) showed that words were better recognized when part of a fixed expression, and that older adults benefited more in RT than young adults (equal benefit in accuracy), but only for the morphologically complex target words. The young adults with simulated hearing loss, however, benefited less than the other two groups (both in accuracy and RT). These results suggest that signal degradation does not immediately lead to greater reliance on following-word context.
Gesture reorganization in Mandarin tone 3 Sandhi.
Authors: Hsieh Fang-Ying
Published: October 2010

This study hypothesizes that the tone 3 Sandhi rule in Mandarin Chinese results from a change in organization of tone gestures. Tone 3 in pre-pausal position has a low falling-rising pitch contour, but when it precedes another tone 3 in the same domain, it becomes a derived tone 2 (rising contour). It is hypothesized that tone 3 is composed of sequential L(ow) and H(igh) tone gestures; since tone 2 is composed of synchronous L and H [Gao (2008)], the derived tone 2 results from shifting the sequential relationship to be synchronous. This hypothesis is tested by a production experiment in which speakers repeated phrases that include a pre-pausal tone 3 followed by another tone 3 in a separate domain. Production rate was gradually increased since it has been shown that increasing speech rates could induce gestural synchrony. Results indicate that the H gesture becomes more synchronous with the L gesture as has been predicted by the hypothesis.
Prosodic and segmental convergence in spontaneous German conversations.
Authors: Lewandowski Natalie , Schweitzer Antje
Published: October 2010

Phonetic convergence is the process of adapting one’s speech to that of an interlocutor and is hence seen as a dynamic process causing continuous updates in multiple speech parameters. Current methods of measuring phonetic convergence are often impressionistic or perceptual, or have only been tested in limited scenarios. The aim of this ongoing project is to investigate convergence in German in a natural open scenario and to develop computational objective methods of accounting for it. A variety of phonetic parameters with respect to their relevance for convergence will be examined. On the prosodic level, one goal is to examine phonological features such as the prosodic inventory or distribution of prosodic events as well as the detailed phonetic implementation of prosodic events. The latter can be measured by the PaIntE F0 parametrization method. Convergence effects have been shown to be very subtle; thus large amounts of data are required in order to obtain statistically valid and robust results. Developing and implementing a new automatized procedure allows us to use a large corpus of spontaneous speech without foregoing the chance of capturing fine phonetic detail.
Speech articulator movements recorded from facing talkers using two electromagnetic articulometer systems simultaneously.
Authors: Tiede Mark , Bundgaard-Nielsen Rikke , Kroos Christian , Gibert Guillaume , Attina Virginie , Kasisopa Benjawan , Vatikiotis-Bateson Eric , Best Catherine
Published: October 2010

Two 3-D electromagnetic articulometer systems, the Carstens AG500 and Northern Digital WAVE, have been used simultaneously without mutual interference to record the speech articulator movements of two talkers facing one another 2 m apart. A series of benchmark tests evaluating the stability of fixed distances between sensors attached to a rotating rigid body was first conducted to determine whether the two systems could operate independently, with results showing no significant effect of dual operation on either system. In the experiment proper, two native speakers of American English participated as subjects. Sensors were glued to three points on the tongue, the upper and lower incisors, lips, and left and right mastoid processes for each subject. Independent audio tracks were recorded using separate directional microphones, which were used to align the kinematic data from both subjects during post-processing. Data collected were of two types: extended spontaneous conversation and repeated incongruent word sequences (e.g., talker one produced “cop top...;” talker two “top cop...”). Both talkers show strong positive correlations between speech rate (in syllables/s) and head movement. The word sequences also show error and rate effects related to mutual entrainment. [Work supported by ARC Human Communication Science Network (RN0460284), MARCS Auditory Laboratories, NIH.]
Analyses of fundamental frequency in infants and preschoolers with hearing loss.
Authors: VanDam Mark , Moeller Mary Pat , Tomblin Bruce
Published: October 2010

Technological advances in the last 15 years have resulted in earlier identification of children with mild and moderate hearing loss. Little is known about the impact of early provision of amplification on the development of prosodic speech characteristics such as fundamental frequency (F0). This study aims to address that gap. Children enter this study at 12–36 months of age and contribute 1 whole-day audio recording each month for one year. The wearable recorder and associated software (LENA Foundation) output (i) a continuous (PCM) audiofile of the whole day and (ii) a time-aligned, XML-coded file at millisecond resolution identifying periods of speech (adult female or male, other children, target child) and other acoustic events (overlapping vocals, noise, silence, etc). In this study, children’s F0 is examined directly and in response to certain talkers or in selected turn-taking relationships (e.g., child-directed speech, father-child turn-taking exchanges). This work includes a detailed methodological description of the use of the LENA system and the customization of that technology relevant to speech and language science. Data from F0 analyzes are interpreted in descriptive and theoretical terms, complementing an ongoing, multi-center study investigating outcomes of children with mild and moderate hearing loss. [Work supported by NIH/NIDCD Grant Nos. DC009560 and DC009560-01S1.]
The development of temporal structure in mother-child speech.
Authors: Smith Nicholas A.
Published: October 2010

The present study examined age-related changes in the timing of mothers’ and children’s utterances during free interaction. Using a longitudinal database of recordings of mother-child speech between 4 and 48 months of age, the onset and offset times of maternal and child utterances were coded and analyzed. The goal of the analysis was to use changes in the temporal intervals between adjacent utterances as a measure of mutual responsiveness and coordination. Although considerable individual variation was found across mother-child dyads between 4 and 18 months of age, at 24 months both mothers and children showed tighter temporal coupling, indicated by consistently shorter latencies in their responses to each other’s utterances. This change in the temporal pattern likely corresponds to the emergence of turn-taking and reciprocity in dialogue. This study is part of a large project examining the effects of hearing loss on mother-child vocal interaction, and a parallel analysis of dialogue between mothers and their hearing-impaired children is currently underway. [Work supported by NIH Grant R03DC009884.]
Cross-correlation based detection of self-vocalization for the purpose of minimizing the perceived effects of occlusion.
Authors: Green Matthew , Burns Thomas
Published: October 2010

Partial or complete occlusion of the ear canal by an assistive listening device results in an unnaturalness in the sound of a person’s own voice, known as the occlusion effect. When the occlusion effect is present, if the sound presented to the eardrum is dominated by the amplified output of the assistive listening device, then the frequency response of the device could be adjusted in order to minimize the perceived effects of occlusion. Such an alteration of the frequency response must be applied during self-vocalization and at no other time. A robust and accurate method for detecting self-vocalization will be presented, consisting of a MEMS accelerometer and a cross-correlation based signature detection algorithm. The requirements for signature capture and selection will be discussed, as well as detection performance by gender. Results for detection accuracy, immunity to tasks other than self-vocalization, and binaural agreement will be presented.
Echo statistics due to a randomly rough, randomly oriented prolate spheroid that is randomly located in a directional active sonar beam.
Authors: Bhatia Saurav , Stanton Timothy K.
Published: October 2010

The statistical characteristics of sonar echoes from a randomly rough, randomly oriented prolate spheroid are studied through the use of a previously published exact analytical formula by Ehrenberg, which involves a convolution between the probability density functions (PDFs) associated with the sonar beam-pattern and scatterer. This is a direct-path scattering geometry in which only the echo from the scatterer is involved (no reflections from boundaries, such as in a waveguide). The scattering by the rough prolate spheroid is modeled approximately through the use of the Rayleigh PDF for each orientation angle with the mean value at each angle determined by the high-frequency (Kirchhoff) solution to a smooth prolate spheroid. Once the orientation is randomized, the echo from the rough spheroid (without beam-pattern effects) is non-Rayleigh. It had previously been established that random location in the beam pattern causes strongly non-Rayleigh echoes for resolved scatterers whose echoes were otherwise Rayleigh distributed (such as a rough spherical scatterer) before beam-pattern effects. The presence of the randomly rough, randomly oriented prolate spheroid that is randomly located in the beam increases the degree to which the echoes are non-Rayleigh beyond non-Rayleigh effects from the beam pattern.
Analysis of mixed assemblages of fish using the statistics of echoes from a single beam broadband echosounder.
Authors: Lee Wu-Jung , Stanton Timothy K.
Published: October 2010

Broadband echoes (30–70 kHz) were collected from fish aggregations with a downward-looking single beam echosounder over Georges Bank near Cape Cod, MA in the fall of 2008. The echoes were collected in a short-range, direct path geometry. Echoes from sequential pings occurring within sampling windows that lie entirely in a given patch were grouped to obtain the distribution of the magnitude of matched filtered echoes. Non-Rayleigh distributed echoes were observed in patches both near the surface and bottom. Two-component mixed probability density functions (pdf’s) were formed by accounting for beampattern effects and assuming various proportions of sizes of fish with correspondingly different scattering strengths and are used to fit the measured echo distribution. For each patch, parameters of the best fitting pdf’s for a series of sampling windows within the given patch were used to infer the fish size composition of the patch. The best-fit parameters for the surface patches were different from those from near the bottom. Results of the acoustically inferred fish assemblages are compared with the net-tow data and are used to investigate the biological significance of the fish aggregations.
The interplay of acoustic signals with boundary and volume scattering phenomena: An overview.
Authors: Gauss Roger C.
Published: October 2010

Active sonar systems use acoustic sources and receivers coupled with signal processing to detect, classify, localize, and track undersea targets. The limiting influence of scattering phenomena, manifesting as reverberation and clutter, on sonar performance has long been recognized, with acoustic echoes from the waveguide boundaries and biologics capable of both masking desired signals and creating false targets/tracks. This talk provides a broad overview of reverberation and clutter phenomena in both deep and shallow water in the context of their impact on sonar performance for frequencies of 50 Hz to 5 kHz. The interplay of system (geometry, transmitter/receiver design, frequency, waveform, and signal processing) and environmental (oceanography, geology, ice, and biology) factors will be discussed, with a series of data and model examples demonstrating the importance of using high-fidelity, physics-based approaches to both characterize the acoustic field and guide the signal processing. While the environment presents many challenges to active sonar systems because of its spatiotemporal variability and strong coupling between scattering and propagation structures, it should also be viewed as both potentially manageable and presenting opportunities. If the mechanisms are understood, they can be dealt with, and even exploited. [Work supported by ONR.]
Tracking sperm whales with a towed acoustic vector sensor using physics-based noise analysis.
Authors: Thode Aaron M. , Skinner Jeff , Scott Pam , Roswell Jeremy , Straley Janice , Folkert Kendall
Published: October 2010

Passive acoustic towed linear arrays are increasingly used to detect marine mammal sounds during mobile anthropogenic activities. However, these arrays cannot resolve between signals arriving from the port or starboard without vessel course changes, and their performance is degraded by vessel self-noise and non-acoustic mechanical vibration. In principle, acoustic vector sensors can resolve these directional ambiguities, as well as flag the presence of non-acoustic contamination, provided that the vibration-sensitive sensors can be successfully integrated into compact tow modules. Here a vector sensor module attached to the end of an 800-m towed array is used to detect and localize 1813 sperm whale clicks off the coast of Sitka, AK. Three physics-based methods are used to identify frequency regimes relatively free of non-acoustic noise contamination, and then the active intensity of the signal was computed between 4 and 10 kHz along three orthogonal directions, providing unambiguous bearing estimates of two sperm whales over time. These bearing estimates are consistent with those obtained via conventional methods, but the standard deviations of the vector sensor bearing estimates are twice those of the conventionally derived bearings. The resolved ambiguities of the bearings deduced from vessel course changes match the vector sensor predictions.
Experimental quantification of a novel reverberation chamber diffusing panel.
Authors: Diaz Candido , Bradley David T.
Published: October 2010

In this project, a 1:5 scale reverberation chamber was designed, built, and tested. The envelope geometry of the chamber was chosen to produce an isotropic sound field and uniform modal response. To further scatter the sound energy, several randomly placed reflective panels were installed in the room. Additionally, a novel diffuser panel with resonating properties was characterized and utilized in the chamber design. The properties of this diffuser/resonator will be discussed. Objective data from measured impulse responses for several configurations of the reflective panels and diffuser/resonators will be presented. These data will be compared with minimum reverberation time (RT) values specified in ISO 345. The level of diffusivity will be shown using the RT standard deviation between receivers as specified in ASTM C423. Finally, the modal response of the chamber will be discussed. These data were analyzed to determine the appropriate number of reflective panels and optimum panel configuration. An overview of this optimization process will be presented. A computer model of the chamber was also analyzed in ODEON; computational and measured results will be compared and contrasted. [Work partially funded by the ASA Diversity in Acoustics Committee and the National Society of Black/Hispanic Physicists.]
Latest development in modern measurement tools.
Authors: Ahnert Wolfgang , Feistel Stefan
Published: October 2010

Although personal computer-based and hardware-based acoustic measurement solutions are already available for decades, recently a new, significant development direction emerged. The abundant availability of computing power on personal computers and on mobile devices, such as cell phones, has enabled new ways of making and evaluating measurements. We introduce a set of new tools that exploit these possibilities. The spectrally selective accumulation filter provides a robust means to work in noisy measurement environments or with discontinuous excitation signals such as speech and music. Transferring measurement results to a handheld device, like the Apple iPhone, allows for walking through a venue and evaluating electro-acoustic and room acoustic quantities easily and at any position. Nowadays, software-based measurement tools also increasingly replace proprietary hardware-based solutions, such as for determining the absorption, transmission, and scattering properties of acoustic materials as well as for processing measurements taken in physical scale models.
A revised scale model reverberation chamber for measurements of scattering coefficients.
Authors: Müller-Trapet Markus , Vitale Renzo , Vorlaender Michael
Published: October 2010

For measurements of random-incidence scattering coefficients according to ISO 17497-1, scale models have proven to yield results with reasonable time and effort. Especially, handling the samples becomes much easier so that several measurements, which may be difficult or even unfeasible in a full-scale reverberation chamber, turn out to be possible. Despite these advantages, using a scale model environment poses other difficulties that are related to the extended frequency range. In order to achieve a better repeatability and stability of the measurements, a revised scale model room is proposed. As a further development from the ordinary scale model rooms, the turntable can now be lowered so that the rotating base plate is mounted flush with the floor. The previously used hanging panels have been replaced with wall-panel diffusers. Furthermore, the chamber includes temperature and humidity sensors to enable correction for air absorption. Measurements in the new model room are performed to evaluate the quality of the results compared with reference data from calculation and the repeatability of the measurements. Results will be compared for different room setups.
Measurement uncertainty of scattering coefficients in scale models.
Authors: Vitale Renzo , Dietrich Pascal , Vorlaender Michael
Published: October 2010

The measurement of the scattering coefficient is defined in ISO 17497-1. The method evaluates random-incidence absorption coefficients obtained from measured reverberation times for four different configurations. Measurements in a scale model reverberation chamber are preferred to real scale chambers for several reasons. Requirements in terms of time invariance are easier to fulfil and the handling of samples is simpler. Although the use of a scale model renders the measurements easier, results are still affected by an uncertainty that is currently not considered when using these results for ongoing simulations or predictions. Moreover, air absorption at very high frequencies causes the measured reverberation times to be very similar, thus influencing the validity of the results in this frequency range. This paper aims to determine the measurement uncertainty of the scattering coefficients in a scale model reverberation chamber. A simplified uncertainty model will be presented taking into account the uncertainty contribution of the reverberation times. In a first stage, analysis both of the measurement chain and of the measurement techniques will be performed. Afterward, determination of scattering coefficients under several variable conditions will be carried out. Finally, results in terms of comparisons and uncertainty evaluation will be presented and discussed with regard to the relevance of the auditory effect of scattering.
Manatee hearing and communication shaped by boundaries of their shallow water habitats.
Authors: Gerstein Edmund R. , Gerstein Laura A.
Published: October 2010

How well manatees hear and transmit biologically significant sounds is inextricably bound to the spectral characteristics and subsequent propagation of these acoustical signals in their shallow water habitats. Sensory adaptations, particularly auditory abilities, and subsequent call characteristics have been shaped by shallow water boundary effects over evolutionary time. Gerstein and colleagues defined the audiogram, critical ratios, and directional hearing of West Indian manatees and argued that shallow water propagation limits and Lloyd’s mirror effect shaped manatee hearing and their subsequent vocalizations. The social utility and context of calls are influenced by transmission losses. In addition to monitoring manatee communication in various shallow habitats, extended ambient noise surveys and active propagation tests with calibrated tonal sources and vocalizations were conducted using synchronized GPS instrumented buoys. Site-specific bathometry and sound speed profiles revealed diffraction was negligible with respect to manatee reception at 100 m distances; however, directly measured transmission losses revealed 2 kHz as an idealized cutoff frequency for typical manatee habitats. While adapted to detect and locate their own calls, shallow water low-frequency cutoffs, near surface interaction, and their evolved auditory constraints have placed them at a sensory disadvantage dealing with the new ecological challenges posed by low-frequency watercraft.
The case for a duration-adjusted loudness metric to assess transportation noise.
Authors: Schomer Paul D. , Fidell Sanford , Mestre Vincent
Published: October 2010

Heretofore, noise has been assessed using a “black box” approach: input DNL, output percent highly annoyed, infer/output relationship. It has long been assumed under this mode of inference that annoyance was primarily a reaction to noise, and that scatter to the data was due to measurement error, an imperfect noise metric, and some degree of non-acoustic factors. Recently the authors have developed a theoretical model for annoyance with transportation sources based on Green and Fidell [J. Acoust. Soc. Am. (1991)]. This model posits that the level of annoyance in a community is a function of the DNL and the community tolerance (to noise) index (CTI). Specifically, it posits that annoyance is proportional to DNL raised to the 0.3 power and to CTI. Since DNL is time integrated and the 0.3 power is indicative of the loudness function, this functional relationship is indicative of time-integrated loudness. This paper shows the excellent fit to data obtained with this theoretical approach and that it explains about 2/3 of the variance, far more than has ever been explained before. Finally, this paper provides an indication that conversion from A-weighting to true, log 10 time-integrated loudness may significantly further reduce the variance.
Comparative study of a proposed time varying loudness standard.
Authors: Novak Colin , Ule Helen , Letowski Tomasz
Published: October 2010

While noise levels are most often quantified using physical quantities including A-weighted sound pressure level, these metrics do not adequately represent the human perception of the noise. For this, loudness is a more appropriate acoustic metric as it describes the perceived acoustic intensity of a sound. Given that real sounds are often unsteady, a most useful loudness calculation will also account for the perceptional phenomena of time and temporal masking. One such model is the DIN 45631-A1. However, this standard takes a less common approach in that it does not fully describe a methodology to calculate the unsteady loudness. It instead offers a more general procedure along which it provides open-ended checks and balances for verifying the progress through the various calculation steps. The caveat of this is that while conditions specified by this standard may be satisfied, it has been suggested that varying results may be achieved due to the procedure’s open architecture. Using several commercial software applications which purport to follow the DIN standard, this study investigated several of these commercial applications and compared the calculated results for several common time varying inputs to determine the extent to which compliance with DIN 45631-A1 results in identical loudness scores.
Spatial resolution and the binaural display.
Authors: Wiegrebe Lutz
Published: October 2010

An important feature of a Jeffress-type binaural display is that it not only allows for localization of a single sound source but it also allows for resolution of multiple sound sources. Here an experiment is reported which directly addresses spatial resolution with a paradigm similar to the notched-noise paradigm which quantifies spectral resolution. Listeners are required to detect a band-pass signal at a frontal position in the presence of two independent band-stop maskers symmetrically arranged around the signal in space and frequency. Data show that signal detection does not improve when the spatial separation between the signal and the maskers is increased from ± 10 to ± 90 deg. When listeners are turned by 90 deg, i.e., the signal is presented from the left, release from masking is only observed when the maskers are moved into the right hemisphere, an effect closely related to BMLDs observed under headphones. The current data show that auditory spatial resolution of simultaneous sound sources is very bad and in line with a “two channel model,” which allows for spatial acuity but not for spatial resolution. Follow-up experiments quantify the extent to which this can be compensated for by the recently shown high binaural temporal resolution.
The impact of the distribution of internal delays in binaural models on predictions for psychoacoustical data.
Authors: Stern Richard M.
Published: October 2010

Jeffress’s theory of binaural interaction has played a dominant role in the modeling of binaural phenomena since its introduction more than 60 years ago. Central to most binaural models is a network of binaural coincidence-counting units that respond to simultaneous excitation from each of the two ears after a fixed internal delay. The predictions of these models for a broad range of binaural phenomena, including subjective lateral position, interaural discrimination, binaural detection, and dichotic pitch, are critically dependent on the shape of the function that describes the distribution of the binaural units with respect to their internal delays and best frequencies. In recent years new theories have challenged the traditional notion that the distribution function that best describes the widest variety of perceptual data is a broadly tapered function that decreases monotonically with increasing internal delay. Most arguments in support of the new theories have been based on physiological evidence or on the results of a limited set of psychoacoustical experiments. In this paper, we will compare the extent to which the new theories as well as the traditional binaural models are able to describe and predict experimental results for the broadest set of binaural perceptual phenomena, independently of physiological considerations.
Influence of classroom acoustics on the voice levels of teachers with and without voice problems: A field study.
Authors: Pelegrin-Garcia David , Brunskog Jonas , Lyberg-Åhlander Viveka , Rydell Roland , Lofqvist Anders
Published: October 2010

Many teachers suffer from voice problems, and classroom acoustics has been considered as one of the potential hazards for this. The present study examines how classroom acoustics interacts with the voices of 14 teachers without voice problems and 13 teachers with voice problems. The assessment of the voice problems was made with a questionnaire and a laryngological examination. During teaching, the sound pressure level at the teacher’s position was monitored. The teacher’s voice level and the activity noise level were separated using mixed Gaussians. In addition, objective acoustic parameters of reverberation time and room support (based on early reflections) were measured in 30 empty classrooms of the study. An empirical model shows that the measured voice levels depend on the activity noise levels and the support. Teachers with and without voice problems were differently affected by the support of the classroom. The results thus suggest that teachers with voice problems are more aware of classroom acoustic conditions than their healthy colleagues and make use of the more supportive rooms to lower their voice levels. This behavior may result from an adaptation process of the teachers with voice problems to preserve their voices. [Work supported by AFA.]
Comparison of vocal characteristics between Cantonese and English produced by Cantonese-English bilingual adult speakers.
Authors: Ng Manwa L. , Chen Yang
Published: October 2010

Previous studies have revealed vocal differences in speakers of different ethnic groups [e.g., Andrianopoulos et al., (2001)]. While some researchers attributed such differences to the physical variation associated with different ethnicities/races, others argued that the different languages being used contributed to the discrepant acoustic findings, especially when tonal and non-tonal languages were used for comparison [Altenberg and Ferrand, (2006)]. As such, it seems that both ethnicity/race of speakers and the language being used may simultaneously affect vocal quality. To study how language alone affects speaking voices with the effect of race/ethnicity being excluded, examining the vocal output from bilingual speakers appears to be a feasible approach. The present study examines the vocal characteristics of Cantonese and English produced by Cantonese-English adult speakers by using long-term average speech (LTAS) spectra. Continuous speech samples produced in Cantonese and English were obtained from 40 (20 male and 20 female) Cantonese-English bilingual speakers and used to generate LTAS spectra. First spectral peak, mean spectral energy, and spectral tilt derived from the LTAS spectra associated with Cantonese and English were compared. Results should reveal if the same vocal apparatus is used differently by Cantonese-English bilingual speakers when speaking different languages.
Learning of adjectival word meaning through tone of voice.
Authors: Jesse Alexandra , Reinisch Eva , Nygaard Lynne C.
Published: October 2010

Speakers express word meaning through systematic but non-canonical acoustic variation of tone of voice (ToV), i.e., variation of speaking rate, pitch, vocal effort, or loudness. Words are, for example, pronounced at a higher pitch when referring to small than to big referents. In the present study, we examined whether listeners can use ToV to learn the meaning of novel adjectives (e.g., “blicket”). During training, participants heard sentences such as “Can you find the blicket one?” spoken with ToV representing hot-cold, strong-weak, and big-small. Participants’ eye movements to two simultaneously shown objects with properties representing the relevant two endpoints (e.g., an elephant and an ant for big-small) were monitored. Assignment of novel adjectives to endpoints was counterbalanced across participants. During test, participants heard the sentences spoken with a neutral ToV, while seeing old or novel picture pairs varying along the same dimensions (e.g., a truck and a car for big-small). Participants had to click on the adjective’s referent. As evident from eye movements, participants did not infer the intended meaning during first exposure, but learned the meaning with the help of ToV during training. At test listeners applied this knowledge to old and novel items even in the absence of informative ToV.
On the perception of tones in Fuzhou.
Authors: Donohue Cathryn J.
Published: October 2010

The Fuzhou dialect of Chinese has seven citation tones. Three of these tones are considered phonologically level. An acoustic quantification revealed consistent changes in pitch contour in addition to pitch height for these tones, with the highest tone rising slightly and the lower two tones dropping slightly. Moreover a non-modal phonation was found to occur consistently with the lowest of these “level” tones. This study focuses on the role of pitch height versus contour and phonation as relevant for tonal identification. Actual tokens were altered to modify the pitch height of these tones, maintaining their inherent contours and phonation. Native speakers were then asked to identify the “word” that they heard (from a list). The results show that both contour and phonation, in addition to pitch height, play a role in tonal perception.
The challenge of learning new highly variable prosodic categories: Training English listeners on pitch accent in Tokyo Japanese.
Authors: Shport Irina A. , Guion-Anderson Susan
Published: October 2010

The high-variability multi-talker paradigm has been successful for perceptual training of segments and tones. Here, it is extended to training native English listeners on Tokyo Japanese pitch accent using multiple lexical items, talkers, and sentential contexts. Native English listeners were randomly assigned to control or training groups. Their test task was to categorize pitch patterns of two syllable words as first syllable accented, second syllable accented, or unaccented. The same 3AFC identification task, but with feedback, was used in three training sessions (one hour total duration) over a course of one week. The identification accuracy scores of Japanese native speakers and the control group were used to assess the trainees’ improvement. Preliminary results showed a small effect of training that was also generalized to new stimuli in new sentential contexts spoken by a familiar talker. The non-native listeners tended to misidentify the unaccented pattern as second syllable accented, and the native Japanese listeners also often confused these two pitch patterns. The results suggest that learners of Japanese are challenged by the unaccented lexical pitch pattern, which is a new prosodic category for them and which also exhibits high variability in native speech production.
Grammaticalized syntactically disambiguating prosody.
Authors: Choe Wook Kyung , Redford Melissa A.
Published: October 2010

Suprasegmental temporal patterns can be used to reliably disambiguate syntactically ambiguous sentences in English [e.g., Price et al. (1991)], but the extent to which speakers reliably produce these patterns appears to vary with training [Albritton et al. (1996)]. This study investigated whether the production and perception of disambiguating temporal patterns also vary with the type of structure being disambiguated. Five speakers produced five different types of ambiguous sentences with disambiguating prosody after having been explicitly instructed in the different meanings that the sentences could convey. Despite equivalent instruction, acoustic analyzes revealed that only some types of sentences were consistently disambiguated by temporal patterns. Same-different judgments by 14 listeners revealed that speakers employed additional prosodic cues to distinguish meaning; however, a question-answer task indicated that the accuracy with which listeners were able to pair a sentence rendition with its intended meaning varied extensively with type. Consistency in production mostly overlapped with accuracy in perception, but in one case a consistent prosodic distinction failed to yield accurate meaning judgments. Overall, the results suggest that disambiguating prosody is only grammaticalized for certain types of syntactically ambiguous sentences. [Work supported by NIH Grant 1R01HD061458.]
Application of a three-dimensional coupled-mode model for acoustic propagation in shallow water.
Authors: Ballard Megan S. , Knobles David P. , Sagers Jason D.
Published: October 2010

The goal of this work is to understand the physics of propagation in continental shelf areas, specifically horizontal refraction and mode coupling induced by 3-D inhomogeneities in the waveguide. Of particular interest is an environment off the coast of southern Florida for which significant horizontal multipath arrivals have been observed [K. D. Heaney and J. J. Murray, J. Acoust. Soc. Am. 125, 1394–1402 (2009)]. A two-way coupled-mode approach is chosen for this work because of its high accuracy and because the outputs of such a model (modal eigenvalues and modal amplitudes) can be used to understand the effects of environmental inhomogeneities on the acoustic field. The technique used in this work involves transforming the differential coupled-mode equations into an integro-differential form [D. P. Knobles, J. Acoust. Soc. Am. 96, 1741–1747 (1994)]. Initial modeling results will be presented from coupled-mode and adiabatic models which are applicable to laterally range-invariant environments. The importance of mode coupling will be demonstrated by comparing the coupled-mode and adiabatic solutions. [Work supported by ONR.]
Absorption edge effects: Comparing the results of measurements in different test environments.
Authors: Sauro Ronald
Published: October 2010

This paper is a follow up to two previous papers on absorption coefficients presented at the 2009 Portland ASA meeting and the 2009 Ottawa INCE meeting. Data will be presented using the same samples that were originally measured in the laboratory at the Western Electro-Acoustics Laboratory and then subsequently measured in the new NWAA Labs, Inc. reverberation chambers. The intention is to show that although the absolute data measured may be different depending on the different environments, the r2 regression slope will be the same for both sets of data measured. A suggestion to revise the measurement standards will also be presented based upon these collected results.