bluuebunny/crossref_metadata_2025 huggingface dataset:
Miniature acoustic prime mover operating at 10 kHz
Authors: Flitcroft Myra L. , Symko Orest G.
Published: October 2013

A miniature thermoacoustic prime mover was developed for interfacing with electronics and microcircuits where it will be used for thermal management. It operates at approximately 10 kHz; heat is injected to the hot part of the device, the cold part is thermally anchored at room temperature. It consists of a quarter wave resonator of cylindrical geometry, 9 mm long. It has a stack of random porous material between two heat exchangers and it operates with air at one atmosphere. Preliminary results show that this oscillator produces a sound intensity at 110 dB, 1 m away from the open end of the resonator. This level can be raised substantially by careful alignment of the hot and cold parts of the resonator, and by reducing the heat losses along the stack and supporting structure between the hot and cold side of the stack. Based on the high operating frequency, a high power density is expected; such device can be used as the basic unit in an array of acoustic prime movers. This work provides a new functional miniature element that can lead the technology toward even smaller devices and well into the ultrasonic range.
Absolute-detection results with a Bayesian adaptive tracking procedure using simulated and human subjects
Authors: Stiefenhofer Georg , Woods William , Edwards Brent
Published: October 2013

Adaptive tracking procedures are widely used in psychophysics. The common, fixed step-size, up-down procedures are known to be biased and yield convergence dependent upon the step-size used [e.g., B. W. Edwards and G. H. Wakefield, J. Acoust. Soc. Am. 83, S17 (1988)], provide an estimate of only one parameter of the psychometric function, and in general make nonoptimal use of information (a priori and a posteriori) concerning a given subject’s psychometric function. Recently introduced Bayesian adaptive procedures [e.g., L. L. Kontsevich and C. W. Tyler, Vision Res. 39, 2729–2737 (1999)] make optimal use of all information in both the estimation of parameters of the psychometric function, as well as in stimulus placement via a minimum-entropy rule. No direct comparison of the up-down and Bayes procedures has been carried out, however. We present results of Monte Carlo simulations that demonstrate the Bayes procedure is as efficient, and often more efficient, than common up-down procedures, even when estimating more parameters than the up-down procedures. We will also present results from absolute-detection experiments with human subjects (with and without hearing loss) that demonstrate the Bayes procedures behavior outside the simulation environment. These experiments used a priori information derived from an audiogram database.
An examination of the relation between reaction time and loudness using perceptual weights
Authors: Leibold Lori J. , Buss Emily
Published: October 2013

The relation between reaction time and loudness was examined by comparing the perceptual weights listeners assign to the individual components of a multi-tone complex during a reaction time task and a magnitude estimation task. Stimuli were 300-ms, five-tone complexes centered on 1000 Hz, with a logarithmic frequency spacing ratio of 1.586. Levels of the individual components of the complex were selected at random on each trial from a rectangular distribution with a range of 43–63 dB SPL. For the reaction time task, listeners initiated trials. The complex was presented following a random delay (500–4000 ms) to guard against anticipation effects. The subject was instructed to press a button on the response box as quickly as possible upon hearing a stimulus. All aspects of the magnitude estimation task were the same as described for the reaction time task, except that listeners gave absolute magnitude estimates for the loudness of the complex on each trial. Subjects performed 20 blocks of 50 trials each for the reaction time and the magnitude estimation tasks. Perceptual weights were computed by calculating the point-biserial correlation between the level of each component and the subjects response. Results support the feasibility of obtaining reliable perceptual weights during both tasks.
The significance of offset transients in listener identification of pipe organ stops
Authors: Disley Alastair C. , Howard David M.
Published: October 2013

Onset transients have been demonstrated to have a significant effect on listener identification of pipe organ stops and have been widely studied (Disley, A. C., and Howard, D. M., (2006). Onset transient significance in listener identification of pipe organ stops, J. Acoust. Soc. Am. 119, 3333, abstract only). Offset transients in contrast are frequently ignored, but the authors’ previous research suggests that for certain stops, in particular reed stops, the offset transient is a significant cue in correct listener identification. Eight samples of individual pipes, covering most common stop types, were presented to trained organists in a listening test. Each sample was presented with and without its offset transient, the transient being replaced by an amplitude ramp in the latter case. To avoid an obvious curtailment of a reverberant tail, all samples were recorded within a closed swell box, and then had reverberation added using impulse responses of real churches to preserve the impression of a real and typical listening environment. The results demonstrate that offset transients are important in listener identification of some stops, but the significance varies between different classes of stop.
The effect of voicing, pitch, and vocal tract length on the recognition of concurrent speech
Authors: Vestergaard Martin D. , Fyson Nicholas R. C. , Patterson Roy D.
Published: October 2013

In natural speech, the pitch of the voice can be varied by the speaker, but they cannot vary their vocal tract length (VTL), so VTL would seem to be a logical choice of tracking variable for listening in multispeaker environments. Experiments with concurrent speech have shown that differences in pitch and VTL make it possible for listeners to attend to a particular speaker in a multi-speaker environment, but the relative contribution of pitch and VTL is not clear. A series of experiments was conducted to investigate the extent to which differences in vocal characteristics contribute to the recognition of concurrent speech, using syllables with matched temporal envelopes to preclude glimpsing. Syllable pairs were synthesized with a vocoder to simulate different speakers. We measured the recognition of whispered and voiced syllables masked by syllables that varied in voicing, pitch, and/or VTL. The results show that differences in any of the vocal characteristics improve recognition performance. Voiced speech was more recognizable than whispered speech at the same SNR when it was the target speaker. When the distracter was whispered speech, it produced lower recognition scores than voiced speech. [Research supported by the UK-MRC (G0500221, G9900369).]
The voice use profile; illustrating actual voice use from long term monitoring from the National Center for Voice and Speech voice dosimeter
Authors: Hunter Eric , Titze Ingo , Titze Ingo
Published: October 2013

The Voice Range Profile (VRP) is a map of the dynamic and fundamental frequency ranges of a voice and is often used by both the voice clinicians and coaches to show improvements in therapy and/or training. However, although the VRP may accurately capture the extreme range of the voice, it does not represent actual patient/student voice use which is where the therapy and training hope to improve. Using the National Center for Voice and Speech voice dosimeter, the actual voice use of 60 teachers was captured over two weeks per subject (average of 160 hours of recording per subject). The result is an entirely new method of examining voice; the Voice Use Profile (VUP). The VUP enhances the VRPs 2-D representation of vocal frequency and intensity by adding a third dimension, that of normalized incidences of occurrences. Using the VUP, intensity-frequency area where a voice user spend most of his/her time can be quantified and tracked, allowing for metrics for patient improvements. The presentation of this abstract will illustrate the VUP of several subjects showing how the addition of this third-dimension gives a detailed look of the topography of the subjects voice use through computer animation.
Coherent-broadband, white noise constraint, matched-field processing
Authors: Debever Claire , Kuperman William A.
Published: October 2013

Coherent-broadband matched-field processing takes advantage of the temporal complexity of the signal and, therefore, offers an increased gain over narrowband processing. However, the problem of mismatch is aggravated in adaptive versions such as the MVDR. One constraint is not enough to achieve robustness in such high-dimensional spaces. Some coherent algorithms also require a large number of snapshots, leading to ill-conditioned cross-spectral density matrices in the context of the required MVDR matrix inversions. The white noise constraint algorithm developed by Cox et al. [IEEE Trans. on Acoustics, Speech, and Sig. Proc. 35, 1365–1376 (1987)], and typically used for narrowband processing, is applied to some previously derived broadband processors to enhance their robustness. The broadband white noise constraint theory is presented and validated through simulation and experimental data. [Work supported by ONR.]
Array gain of vector sensors in ocean noise
Authors: Poulsen Andrew J. , Baggeroer Arthur B.
Published: October 2013

By measuring acoustic particle motion, vector sensors provide important capabilities to ocean sensing systems, such as the elimination of left/right ambiguity for towed arrays, the ability to ‘‘undersample’’ an acoustic wave without spatial aliasing, and improved detection performance and array gain in ocean noise fields. Several different ocean noise models exist, including isotropic noise, directional noise (both point and spatially spread directional noise sources), and realistic surface noise in a stratified ocean environment [W. A. Kuperman and F. Ingenito, J. Acoust. Soc. Am. 67, 1988–1996 (1980)]. Theoretical expressions are derived for array data covariance matrices under different noise models, then used with optimal MVDR beamforming weights to analyze array gain. In order to better understand the advantages of vector sensor arrays, this paper also includes a performance comparison between vector and hydrophone arrays. Of further interest is array sensitivity and performance in the presence of system imperfections and mismatch between the assumed and actual array configurations, or in the snapshot deficient regime. All arrays are susceptible to perturbations in array element locations, however vector sensor arrays are also sensitive to changes in sensor orientation. [Work supported by the PLUSNet program of the Office of Naval Research.]
Acoustic design in small performance venues: “Unplugged” amplification, spatial presentation of dance, unamplified loudness control.
Authors: Pfeiffer Scott
Published: October 2013

Facilities for the 150-seat S.N. Shure Theatre and 400-seat MUNTU Dance Theatre and for a small family of 500-seat high school auditoria all employ techniques particular to the venue size. At Shure, an emphasis on an “unplugged” sound led to a room design that is intimate and controlled. Architectural features that would be cost prohibitive on a larger scale are implemented gracefully here. The MUNTU Dance Theatre is small enough to allow for the audience to be convincingly provided with directional realism. Area microphones on stage directly feed left, center, and right clusters to allow the acoustic sounds made by the dancers to be naturally “panned” to their actual location on stage, allowing for a seamless placement of the performer. Lastly, “one-room” design approaches for schools at Nazareth Academy, Marengo High School, and Benet Academy allowed for a basic theatrical function while at the same time linking the stage volume to the house. Absorption on the tops of the ceiling system and in the materials selected for basic finishes controls loudness for circumstances where ensembles are large when compared to the audience size. Variations in approach to these similar-sized venues are discussed.
Who cares if small high school auditoria sound any “good” for music?
Authors: Dohn Bill
Published: October 2013

High school music instructors, high school music students, and acoustical consultants certainly care if their auditoria sound good for music, but not all high school districts or architects appear to be all that interested. Examples of some recently completed small high school (multipurpose) auditoria are presented. Some of these have not proven particularly satisfactory for music, and (thankfully) some have. Basic programming and design criteria to achieve satisfactory music performance and listening environments in small mulitpurpose auditoria are suggested.
Two new terms for the comparison between acoustical measurements, calculations (ray or image models), and subjective impressions.
Authors: Duty Jason R. , Savitala Hari V. , Schwind David R.
Published: October 2013

The sound energy growth (SEG) curve is a new parameter depicting the growth in sound energy during the first 200–300 ms. An instantaneous sound envelope (ISE) is a new parameter yielding the sound amplitude and arrival time of individual reflections. ISE is especially useful for comparison with calculated reflectograms generated in computer models. ISE shows the contribution of individual reflections to the SEG. The two new terms provide a better comparison between measurements (ISE), calculations (from ray or image computer models), and subjective impressions (SEG) based on energy parameters.
Case study of measurement results for medium-sized multipurpose halls.
Authors: Savitala Hari V. , Duty Jason R.
Published: October 2013

This case study focuses on presenting measurement results for medium-sized multipurpose halls (400–600 seats). Objective acoustical parameters, such as Reverberation Time (T20) and Clarity (C80), were correlated to subjective impressions of the spaces by the end users. The results are presented to better understand how to design medium-sized multipurpose halls.
Audibility of absorption, diffusion, or a specular reflector on the first lateral reflection.
Authors: Bridgewater Benjamin
Published: October 2013

To better understand the importance of treatment on the first reflection in a small room, a study of the audibility of the treatment of the first lateral reflections in a small room was conducted. Subjects completed the ABX tests comparing the different treatments of the first lateral reflection to determine if there was a noticeable difference between the treatments of the first lateral reflection.
New approaches in soundscapes: About the triangulation of measurements.
Authors: Schulte-Fortkamp Brigitte
Published: October 2013

A procedure is developed following the soundscape approach, which will provide acoustical indicators and parameters describing urban and other outdoor living areas with respect to physical conditions and their relevance for life. In particular, the contribution of important sources like traffic noise to the overall sound exposure and its influence on the evaluations by humans has to be determined. Moreover, the question is to which degree does a single source determine the soundscape of the environment with respect to the perception and evaluation? Qualitative evaluations have been conducted introducing the concept of new experts with respect to data triangulation.
Spatial variation in marine mammal habitat soundscapes within one coastal region.
Authors: Miksis-Olds Jennifer L. , Nystuen Jeffrey A.
Published: October 2013

Manatees and dolphins inhabit coastal waterways in which they are constantly exposed to sound produced by physical processes, biological activity, and human activities. Ambient sound levels can change rapidly on the scale of minutes to hours, but variability in sound level is the only one component of the acoustic environment that has the potential to impact marine mammals. Soundscapes, or acoustic footprints, of a region provide a visual snapshot of the acoustic components contributing to the ambient sound level. Acoustic footprints provide information on the identity of sound sources as well as sound levels. A passive aquatic listening instrument was deployed in 24 sites around Sarasota Bay, FL. Recordings were made in 24 sites frequented by manatees and dolphins. Generation of acoustic footprints from each site illustrates the temporal and spatial variabilities of source components within and between the habitat types. Vessel noise is a more dominant sound source in sites used less frequently by manatees compared to more frequently used sites. Sites used most heavily by manatees tended to be dominated by biological activity or wind.
Results of giving a bottlenose dolphin control over exposure to a net alarm: Implications for the measurement of aversion and detection thresholds.
Authors: Bowles Ann , Anderson Rindy
Published: October 2013

When exposed to pings from a Dukane Netcom 1000 net alarm, bottlenose dolphins responded with avoidance and aggression. These species-typical behaviors were tested as a tool for measuring the threshold for aversion. Two bottlenose dolphins were exposed to pings with varying signal-to-noise ratios (SNRs of 5–70 dB) in randomized order. Trials were terminated when the dolphins exhibited any agonistic behavior. Sixty-nine animal trials were terminated by the avoidance or aggressive approach. Seventy-seven trials were terminated by fluke-slapping, for which latency could be measured precisely. At SNR of 10 dB or below, the dolphin did not fluke-slap. Above 10 dB SNR, the probability of response increased and latency to slap decreased rapidly. The shape of the latency-SNR curve was similar to equal latency curves measured in audiometric studies using operant conditioning, suggesting that control over pings was intrinsically rewarding. Cessation of pings may have been the reward, but because the dolphin chose to terminate stimuli at levels just above the limit of detection, another possibility should be considered: control over the stimulus could reinforce itself. If so, conditioning experiments could be designed for audiometric research on wild cetaceans [Work supported by NMML and SeaWorld San Diego; NMFS Permit 1016.]
The impacts of energy development noise playback on lek attendance and behavior in greater sagegrouse.
Authors: Blickley Jessica , Blackwood Diane , Patricelli Gail
Published: October 2013

The spread of human development has caused a dramatic increase in noise across the landscape. Recent studies suggest that noise may negatively impact wildlife, yet little is known about the causes and consequences of this impact. Furthermore, most previous studies have not been designed to isolate noise impacts from other confounding factors. This study is investigating the impacts of energy development noise on greater sage grouse (Centrocercus urophasianus), a species of management concern across western North America. Sage grouse are declining in areas of energy development and circumstantial evidence suggests that noise is a cause of this decline. To test this hypothesis, control leks and leks with experimentally-introduced energy development noise were monitored. Results from three seasons of experimental noise playback will be presented, comparing lek attendance, territory selection, and display behavior between noise and control leks. This is the first long-term playback experiment investigating the chronic impacts of noise on any wild population, offering a unique opportunity to experimentally address noise impacts on avian behavior and breeding site selection while informing conservation efforts for this species.
Effects of varying levels of noise and vibration on behavioral and physiological stress responses in two species of freshwater aquarium fish: Fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus).
Authors: Rose Alexandra , Thomas Jeanette , LaPointe Allen
Published: October 2013

Aquariums provide beautiful underwater environments for an array of fish species, but to maintain optimum water quality and aesthetically pleasing displays, a variety of mechanical systems that unintentionally produce noise, including pumps, filters, skimmers, bubblers, etc., are necessary. The objectives of this study are to measure the acoustic properties of noise in an aquarium and examine the effects of different noise levels on the stress experienced by two species of freshwater fishes: fathead minnows (Pimephales promelas), hearing specialists, and bluegill sunfish (Lepomis macrochirus), hearing generalists. We conducted a noise mapping of several fish galleries at the Shedd Aquarium using a BK 2560 SPL meter; Leq, SEL, and minimum & maximum decibel levels were measured up to 2 kHz using a DolphinEar hydrophone. We then tested the effects of four noise levels on the stress experienced by these two fish species by measuring oxygen consumption/respiration rates with Loligo respirometry chambers and cortisol release rate with a noninvasive radioimmunoassay that measures free cortisol in water samples [Ellis et al. 2004]. These measurements will help to evaluate the effects of noise in standard aquarium settings on fish welfare and may aid in the determination and regulation of acceptable anthropogenic noise levels in aquariums.
Identification of transition-only and steady-state vowels by young and older normal-hearing listeners.
Authors: Talmage Elizabeth , Donaldson Gail , Rogers Catherine
Published: October 2013

Normal-hearing listeners can identify vowels on the basis of either dynamic or steady-state (SS) cues. To determine which cues are more effective, vowel identification was measured for full, transition-only (TN) and SS versions of naturally produced exemplars of the syllables “beeb, bib, babe, beb, bab, and bob.” TN stimuli retained 10, 20, 30, 40, 60, or 80 ms of the consonant-vowel and vowel-consonant transitions and were neutralized in overall duration. SS stimuli retained 10, 20, 30, 40, 60, or 80 ms of the vowel center but eliminated transitions. Young normal-hearing (YNH) and older normal-hearing (ONH) listeners were assessed. Performance declined as the duration of acoustic information decreased. On average, decrements were similar for TN and SS stimuli except at the shortest duration (TN10 and SS20), where average performance was poorer for the TN stimulus. However, relative performance for short-duration TN and SS stimuli varied substantially across vowels. TN and SS stimuli produced similar performance for some vowels, but TN stimuli produced much poorer performance than SS stimuli for other vowels. Preliminary findings indicate a trend for slightly lower performance among ONH listeners relative to YNH listeners but suggest similar patterns of performance across groups. [Work supported by NIH-NIDCD 5R03DC005561.]
The role of speech-specific signal characteristics in vowel normalization.
Authors: Sjerps Matthias J. , McQueen James M. , Mitterer Holger
Published: October 2013

Listeners adjust their vowel perception to the characteristics of a particular speaker. Six experiments investigated whether speech-specific signal characteristics influence the occurrence and amount of such normalization. Previous findings were replicated with first formant (F1) manipulations of naturally recorded speech; target sounds on a /pIt/ (low F1) to /pt/ (high F1) continuum were more often labeled as /pIt/ after a precursor sentence with a high F1, and more often labeled as /pt/ after one with a low F1 (Experiment 1). Normalization was also observed, though to a lesser extent, when these materials were spectrally rotated, and hence sounded unlike speech (Experiment 2). No normalization occurred when, in addition to spectral rotation, the silent intervals and pitch movement were removed and the syllables were temporally reversed (Experiment 3), despite spectral similarity of these precursors to those in Experiment 2. Reintroducing only pitch movement (Experiment 4), or silent intervals (Experiment 5), or spectrally rotating the stimuli back (Experiment 6) did not result in normalization, so none of these factors alone accounts for the effect’s disappearance in Experiment 3. These results show that normalization is not specific to speech but still depends on more than the overall spectral properties of the preceding acoustic context.
Perceptual compensation for /u/-fronting in American English.
Authors: Kataoka Reiko
Published: October 2013

Listener’s identification of speech sounds are influenced by both perceived and expected characteristics of surrounding sounds. For example, Ohala and Feder (1994) demonstrated that American listeners judge a vowel stimulus which is ambiguous between /i/ and /u/ more frequently as /u/ in alveolar context than in bilabial context, and do so both in cognitively “restored” contexts as well as acoustic contexts. This paper reports the results of three-part perception experiments with 31 native speakers of American English, aiming to confirm and extend these results. Experiment 1 replicated the findings of Ohala and Feder. Furthermore, it shows that reaction time (RT) for /u/ judgment is shorter in alveolar than in bilabial context. Experiment 2 showed that perceptual compensation became greater as the speech rate of the precursor sentence increased. The results from experiments 1 and 2 might indicate that listeners use both cognitively based categorical compensation and mechanically based gradient compensation. Experiment 3 investigated the role of speech production in perceptual compensation. Moderate correlation between the degree of /u/-fronting in production and the perceptual boundary of /i/-/u/ categories was obtained, suggesting a link between speech production and speech perception.
The impact of caregivers’ speech on infants’ discrimination of a speech sound contrast.
Authors: Cristià Alejandrina
Published: October 2013

The acquisition of speech perception has aimed primarily to detect variation across linguistic populations, assuming that the linguistic input to infants within a given linguistic community is essentially the same. In this presentation, individual differences due to variability within a linguistic community are investigated using a contrast that is phonemic in the language, but which is produced with a great deal of variation across speakers. English-learning 5-month-old and 13-month-old infants were tested for their ability to discriminate English sibilants, and the variance in their performance was correlated with the acoustic characteristics of the speech of their caregivers in order to investigate some of the possible sources of individual differences in speech perception.
Infants’ perception of non-native sibilants following different distributions of frication and vocalic cues.
Authors: Cristià Alejandrina , McGuire Grant , Seidl Amanda , Francis Alexander
Published: October 2013

Previous work suggests that learning to perceive speech categories in infancy may be influenced by the distributions of acoustic cues that underlie them. However, studies on this topic have focused on distributions of single cues, especially voice onset time (VOT), whereas natural phonetic categories are typically defined according to multiple cues and, moreover, VOT may constitute a special case as nonhuman animals are known to exhibit categorical perception of this cue. In order to explore the role of cue distributions in a more natural context, and to extend this research beyond the domain of VOT, in this study we exposed infants to different distributions of cues to a non-native contrast of place of articulation in fricatives. Results suggest that young infants are indeed able to track multiple acoustic cue distributions at once, and that these distributions shape infants’ perception after a brief exposure, possibly by enhancing the perceptual similarities between acoustically similar tokens.
Transmission and reception of visual speech signals produced by cued speech transliterators.
Authors: Pelley Katherine , Krause Jean C.
Published: October 2013

Although it is common practice for deaf individuals to use interpreters as a means of accessing spoken information, few investigations of interpreter skills have been reported and virtually none have focused on interpreter intelligibility [Kluwin and Stewart, Odyssey 2, 15–17 (2001)]. In order to begin quantifying the contribution of factors affecting interpreter (transliterator) intelligibility for one English-based communication mode (cued speech), two experiments were conducted. In the first experiment, 12 cued speech transliterators were asked to transliterate materials at three different speeds (slow, normal, fast). Two characteristics of the visual speech signal produced by these transliterators were then examined: (1) accuracy, measured as a percent-correct score based on the target cue sequence, and (2) lag time, reported as the average delay between the spoken and transliterated messages. In the second experiment, eight to ten expert receivers of cued speech were presented with visual stimuli excised from the transliterated messages and asked to transcribe the stimuli. Intelligibility of the visual speech signals was measured as the percentage of words correctly received. Results show that accuracy is inversely related to lag time and accounts for roughly 25% (on average) or more (when transliterator experience is controlled) of the variance in intelligibility. [Work supported by NIH/NIDCD Grant 5-R03-DC007355.]
From production to acoustics to perception: The case of fricatives.
Authors: McMurray Bob , Jongman Allard
Published: October 2013

Although the acoustics of speech mediate production and perception, few studies have examined the entire chain. English fricatives present an interesting case because they are realized by multiple cues. Previously, 20 speakers were recorded producing the eight English fricatives with six vowels. Twenty-one cues were measured [Jongman et al., J. Acoust. Soc. Am. 108, (2000)]. Fricatives were presented (with and without the vowel) to 20 listeners for identification. Listeners were better at identifying fricatives in context (M=91%) than isolation (M=75%), and sibilants (M=94%) than nonsibilants (M=72%). Acoustic measurements were analyzed with a regression model of cue-parsing [McMurray et al. (unpublished)]. The model approximated listeners' performance in context (M=87%). However, this was only true when speaker-specific variance could be parsed out; significant speaker variation was observed in every cue. Thus, vowel context may aid perception by helping listeners identify the speaker. While parsing speaker and vowel from the cues was helpful, this was not true for voicing. Voicing and place cues overlapped, but knowing the voicing did not improve identification of place (and vice versa). Finally, when cue weightings based on perception and articulation were computed independently, subtle differences emerged, suggesting that perception is similar, but not isomorphic, to production
Perceptual sensitivity to within-category acoustic variation by language impaired and typically developing adolescents.
Authors: Munson Cheyenne , McEchron W. Dan , McMurray Bob , Tomblin J. Bruce
Published: October 2013

Perceptual deficits have been suggested as an underlying cause of language impairment, and language impaired (LI) listeners sometimes show less categorical perception than normal listeners (Tallal & Piercy, 1974, Neuropsychologia, 12; Sussman, 1993, J. Speech Language Hearing Research, 36). This suggests that LI listeners might be extrasensitive to acoustic details. This issue was addressed using the visual world paradigm. Participants (32 TD, 37 LI, 14–20 years old) saw pictures on a computer screen, including a minimal pair differing in VOT (e.g., beach/peach). Auditory stimuli were six 9-step VOT continua constructed from natural speech. Participants heard a stimulus and clicked the referent. Eye movements were monitored to measure lexical activation. Both groups showed identical categorization functions (mouse clicks). Looks to competitor objects (peach when they clicked beach) increased as a function of VOT for both groups with no group interaction on either side of the boundary (B: p<.001; P: p<.001). Results were identical when the step closest to the boundary was removed, indicating sensitivity to within-category acoustic details. However, the LI group showed a heightened competitor activation overall (P: p<.01; B: p=.06). Thus, problems inhibiting lexical competitors, not perceptual differences, may be an underlying cause of language impairment.
Categorization, category goodness, and psychophysical difference in perceptual assimilation.
Authors: Silver Jenna , Wayland Ratree , Harnsberger James D.
Published: October 2013

Two experiments were conducted to investigate the relative importance of three factors that influence the perceptual assimilation (i.e., identification and discrimination) of non-native speech contrasts: the categorization of non-native speech sounds with native speech sounds, the goodness of fit in such categorization judgments (or category goodness), and the phonetic differences between non-native stimuli. These factors were examined in a series of categorial AXB discrimination and forced-choice identification tests (which included goodness ratings) involving the perception by 80 native speakers of American English of 2 Hindi voicing contrasts, /tS/-/dZ/ and /k/-/g/, produced by three talkers in initial position in three different vowel contexts. The discrimination scores were correlated with (1) categorization scores based on the proportions of different responses in identification, (2) mean difference in goodness ratings, and (3) the results of an analysis of multiple acoustic cues for the Hindi stimuli (representing phonetic difference). Overall, the categorization factor showed the strongest correlation with discrimination scores (r=0.87**), relative to phonetic difference (r=0.57*), which was accounted for exclusively by measures of voice onset time. For non-native contrasts that were identified with single native categories, category-goodness difference was a more important factor in discrimination (r=0.61**) relative to phonetic difference (r=0.50*).
New home buyer noise reduction listening study.
Authors: Alter Harry A.
Published: October 2013

In 2007 Owens Corning Science Technology in Granville, Ohio built a comparative wall assembly listening facility called the Acoustic Research Experience Laboratory (AREL) Annex. Within this listening facility, approximately 100 perspective new home buyers were selected to listen and evaluate various sound clips when played through wall assemblies at varying levels of noise reduction. Jurors responded to perceptual and lifestyle questioning. The building of the AREL Annex and listening study results will be discussed.
Incorporating acoustically challenging functions into single family residences.
Authors: Berger Russ
Published: October 2013

Recording and broadcast studios, screening theaters, music performance venues, and other acoustically challenging functions have been successfully incorporated into single family residences. Several examples will be discussed illuminating concerns beyond normal sound isolation and acoustical performance requirements.
Sound in a single family house.
Authors: Beristain Sergio
Published: October 2013

Apart from road and air traffic noise, and some noise from neighbors, the most important noise in single family residences usually is the noise generated within the residence itself, such as music, general activities, operating machinery for the house and people comfort, and the sound isolation characteristics of the different partitions within the house. Mexican single family residences are usually made out of brickwork, but some inner walls are nowadays changing from brickwork to rocksheet and similar materials, which reduces noise attenuation from kitchens, washing rooms, and living spaces. Home theaters are usually installed at will, and the resulting sound has limitations. A case is presented where family relations started to deteriorate due to the low isolation capabilities of the inner walls.
Who pays? Defining construction defects and assigning blame in borderline acoustical assemblies.
Authors: LoVerde John , Dong Wayland
Published: October 2013

It is often the case when performing field noise isolation testing that some assemblies will meet the relevant statutory requirements and other nominally identical assemblies will fail. Sometimes this can be attributed to errors in construction materials and/or methods. However, when an assembly is “borderline,” that is, only just meets the requirements based on historical or laboratory data, it can be expected that a certain percentage will fail even when constructed without error. This is due to the variation in construction procedures and materials as well as the inherent uncertainties in acoustical measurements. As a result, it is often not clear whether any particular assembly failed because of construction error or inadequate design and, by extension, whether the contractor or the designer bears the responsibility and resultant financial liability. The definition of construction defects in acoustical assemblies and the resultant division of responsibility are discussed and illustrated with actual cases.
Characterization of airborne sound transmission and impact isolation in floor/ceiling assemblies with structural cementitious floor sheathing and cold formed steel framing.
Authors: Tonyan Timothy D. , Payne Stephen W. , Elfering Robert
Published: October 2013

There is growing demand for floor/ceiling assemblies that combine noncombustible structural cementitous floor sheathing panels with cold-formed steel (CFS) framing. The combination being light in weight and possessing high stiffness makes these floor systems particularly advantageous in seismic zones, where reduction in building mass can translate into structural efficiencies and cost savings. However, as a result of their relatively low mass appropriate design strategies must be used to control airborne sound transmission and impact noise. This paper presents research conducted to characterize the acoustical behavior of floor/ceiling assemblies using structural cementitious floor sheathing combined with CSF framing. A variety of isolation and damping strategies are described and tested. The influence of the use of different underlayments and acoustical mats on STC and IIC values in the floor/ceiling assemblies is documented and evaluated. Isolation approaches, including the use of drywall suspension systems for ceiling attachment, are also presented. The results demonstrate that, by using the appropriate damping and isolation strategies, floor/ceiling assemblies combining structural cementitious floor sheathing with CFS framing can provide excellent acoustical performance. Recommendations for further research are also provided.
Nonlinear internal wave parameter extraction from images synthetic aperture radar.
Authors: Boughan C. Chaya , Duda Timothy F. , Lynch James F. , Newhall Arthur E. , Siegmann William L.
Published: October 2013

Enhancement of satellite synthetic aperture radar (SAR) ocean images is needed for improved predictions of nonlinear internal wave effects on acoustic amplitude, phase, and coherence. Their effective use in acoustic applications can be hampered by the false negative problem of SAR images that fail to reveal internal wave presence. Our aim is a largely automatic extraction of nonlinear internal wave features such as wave amplitude, wave front width, wave front separation, and longwave correlation length. A complex discrete wavelet transform is used to denoise contrast-enhanced SAR images, and a fingerprint recognition algorithm is applied to extract edges. The image is segmented into connected components that are analyzed to obtain estimates for nonlinear internal wave parameters. To evaluate the process, estimates are compared with temperature and other data from moorings positioned approximately 100 miles east of the New Jersey coast. Extensions of the procedure may give an acoustically useful description of nonlinear internal waves in SAR images. Assimilation of parameter estimates with volume data offers a new approach to appraising internal wave effects on propagation. [Work supported by the ONR.]
Acoustic wave scattering from submerged turbulent wakes.
Authors: Yamamoto Tokuo
Published: October 2013

Acoustic wave scattering in submerged turbulent wakes has been solved on the assumption of small and smooth turbulent fluctuations. The turbulent fluctuations are modeled by the Kolmogorov spectrum. The turbulence in the submarine wakes is modeled by a MIT Ocean Model by pat.gallacher@nrlssc.navy.mil. The effect of turbulent velocity fluctuation and the effect of turbulent temperature fluctuation are roughly equal on the scattering of acoustic wave from turbulent wakes (1 Hz–1 MHz). Acoustic scattering by a turbulent wake is very strong in the forward direction while it is small in the backward direction. The scattering from internal waves is modeled using the Garret–Monk spectrum. Since the frequency spectrum (1 Hz–1 MHz) of wake turbulence and that of internal waves (0.0138 Hz–10 MHz) do not overlap the two scattering mechanisms do not interact. The two mechanisms of scattering can be treated separately and then added linearly. [Work supported by ONR Code 321 OA.]
A mathematical model of very soft tissue for acoustics applications.
Authors: Sassaroli Elisabetta , O' Neill Brian E. , Li King C.P.
Published: October 2013

A theoretical model of very soft tissue is presented. The soft tissue is considered to be composed of two continuum homogeneous media: the fluid medium and the solid medium. The average pressure, the velocity in the fluid, and the average displacement in the tissue can be obtained by averaging the equations of continuum mechanics over a scale that is large compared with the mean spacing between the solid and liquid regions but small compared to the length scale of the sample considered and also smaller than the ultrasound wavelength. The biphasic model presented here is inspired by the one originally proposed by Pride et al. who used it to model fluid-saturated porous materials, but here it is altered to suit the conditions for ultrasound propagation in a very soft tissue. The phase-averaged equations of continuity and momentum, as well as the stress-strain relations in the quasistatic limit, are discussed. In linear approximation, the averaged momentum equation for the liquid phase gives rise to a generalized Darcy’s law.
Computational models of aberration in ultrasound breast imaging.
Authors: Shen Yi-Ting , Lacefield James C.
Published: October 2013

Two methods are proposed for simulation of distributed aberration. One method models aberration as a superposition of five parallel time-shift screens with 8–11 irregularly shaped strongly scattering inclusions. The second method employs an anatomically realistic three-dimensional model of breast anatomy that includes lobular ducts, periductal and intralobular loose fibrous tissue, interlobular dense fibrous tissue, Cooper's ligaments, fat, and skin. Simulations of two-dimensional linear ultrasound propagation in the two model media and digitized breast tissue specimens were performed using a first-order k-space ultrasound simulator [Tabei et al., J. Acoust. Soc. Am. 111, 53–63 (2002)]. The initial field was a planar pulse wavefront with a 7.5-MHz center frequency and a 5-MHz −6-dB bandwidth. Propagation was computed over 25-mm paths. Both of the proposed models reproduce two characteristics of aberration observed in simulations using digitized breast specimens that are not included in conventional aberration models: non-Gaussian first-order statistics of arrival-time fluctuations and sharp changes in root-mean-square arrival-time fluctuation as a function of propagation distance. The two models, respectively, represent a relatively simple and a detailed approach in simulating realistic challenging aberration for in-silico testing of adaptive focusing techniques. [Research supported by an NSERC Discovery Grant.]
Dynamics of thalamocortical circuits for sound processing revealed by magnetoencephalography.
Authors: Ross Bernhard , Fujioka Takako
Published: October 2013

Music perception and cognition involves multi-modal processing within a wide range of neural networks working in concert. Rhythmic brain activities, or neural oscillations, are thought to play an important role in such long-range communication. How are related networks established and dynamically reconfigured in order to adapt to the ever changing auditory environment? Oscillations in the 40-Hz range (gamma band) in thalamocortical connections are proposed as a key mechanism. A common problem to delineate the behavior of 40-Hz oscillatory activity, however, is the small effect size and unknown time, courses when using noninvasive megnetoencephalography (MEG) recording. To overcome this problem, auditory stimulation with sounds containing a strong 40-Hz rhythm can be used to drive neural networks into a state of high synchrony. These areas are successfully identified by beamforming techniques, which transform MEG signals to voxel-based source images. Phase lags between primary auditory cortices and thalamus and auditory association areas suggest the information flow across the regions. Moreover, changes in the sound stimulus were observed as temporal changes of synchrony reflecting dynamic reconfiguration of neural networks. The relevance of these observations for detecting changes in sound localization will be demonstrated.
Effects of sounds from seismic exploration on the calling behavior of bowhead whales.
Authors: Blackwell Susanna B. , Nations Christopher S. S. , McDonald Trent L. , Greene Charles R. , Thode Aaron , Macrander A. Michael
Published: October 2013

The westward migration of bowhead whales (Balaena mysticetus) was studied during summer and autumn of 2007 to examine the effects of airgun sounds on the whale calling behavior. Whale calls were recorded by 35 directional autonomous seafloor acoustic recorders (DASARs), placed in groups of seven recorders at five locations in the Beaufort Sea covering an east-west span of 280 km. The directional capability of DASARs allowed triangulation of an estimated whale position for about 130 000 calls. Call detection rates and call locations were compared to the timing of seismic operations—which took place in the center of the study area—and the estimated received levels of airgun sounds at the whale call locations. The analyses showed that seismic operations led to a significant decrease in call detection rates used as a proxy for calling rates. Within about 30 km of the seismic activities, received sound pressure levels from airgun pulses at call locations were greater than 140 dB re 1 μPa for about 20%–40% of calls. Quantile regression analyses showed that seismic activities were correlated to statistically significant shifts in the whales’ distance from the shore, either offshore or inshore. [Study funded by Shell Exploration and Production Company, Alaska.]