bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and tracking of fluttering moths by echolocating bats
Authors: Lee Wu-Jung , Moss Cynthia F.
Published: May 2015

Aerial-hawking echolocating bats present an interesting model for studying how a moving listener interacts with moving sound sources. During foraging, relative movements between the bat and its prey introduce echo variation, which is further influenced by the timing of biosonar emissions with respect to insect wingbeats. Through systematic characterization of echoes from fluttering moths, this study aims at understanding how intermittent and highly variable echo information may be perceived and integrated by foraging bats for prey detection, tracking, and discrimination. Calibrated broadband echoes from frequency-modulated linear sonar sweeps were measured from live, fluttering moths of different morphological features with concurrent high-speed video recordings. The measurements are used to estimate the probability distribution of echo amplitudes as a function of moth morphology, wingbeat phase, and body orientation, as well as to predict changes of echo characteristics as the bat approaches the prey. Signal detection theory is then applied to model the bat’s perception of prey presence as influenced by changes in biosonar emission rate in different phases of the foraging process. These results can be further integrated with neurophysiological findings on the bat’s internal representation of space for a better understanding of this agile and efficient biosonar system.
On the role of visual information about head motion in the interpretation of dynamic interaural cues for front/back sound localization
Authors: Macpherson Ewan A.
Published: May 2015

The dynamic interaural cues generated by listener head rotation specify the front/back location of a sound source only when coupled with information about the head motion that produced them. Potential sources of this information are vestibular, proprioceptive, and visual inputs. To investigate the influence of these extra-auditory modalities on the interpretation of dynamic acoustic cues, we use real-time motion tracking and dynamic virtual auditory space synthesis in conjunction with an oscillating chair apparatus that permits dissociation of head-on-body and head-in-space motion. The results of a previous study conducted in darkness [Kim, Barnett-Cowan, & Macpherson, ICA 2013], suggest that vestibular (head-in-space) information is necessary and sufficient for accurate interpretation of dynamic cues, whereas proprioceptive (head-on-body) information is neither necessary nor sufficient. In the present study, active (providing vestibular and proprioceptive information) or passive (providing primarily vestibular information) head-in-space rotations at 50°/s were combined with congruent or incongruent visual motion information in a task requiring the identification of the front/back location of 200- or 400-ms low-pass noise targets. Experiments were conducted in a lighted room, and incongruent visual stimuli were produced with left/right-reversing prism glasses providing ~30° field of view. We found that this visual input had little or no influence on listeners’ interpretation of the dynamic auditory cues.
The three-dimensional morphological database for spatial hearing research of the BiLi project
Authors: Rugeles Ospina Felipe , Emerit Marc , Katz Brian F.
Published: May 2015

The BiLi Project is a French collaborative project concerned with binaural listening and improved rendering for the general public. One of the goals of this project is to develop simple methods to personalize head-related transfer functions based on people's morphology. In order to accomplish this, it is necessary to study the links between an individual’s HRTF and their corresponding morphology. As a resource for studies relating these parameters, two databases have been created: a database of high resolution measured HRTFs and an accompanying database of 3-D morphological data. This work presents the details of the creation of the morphological database. The prerequisites for such a database are presented. Various technical solutions are proposed and evaluated. Resulting accuracies of the methods are compared using extracted morphological parameters as defined in the CIPIC database with those measured directly on the individuals.
A study on sound contents development based on analysis a Foley sound and a real sound of thunder
Authors: Iksoo Ahn , Seong Geon Bae , Myungjin Bae
Published: May 2015

This study focuses on verifying possibility of developing Foley sound of thunder, one of the tools of Foley sound used to make sound effect required for story making of radio drama in early period broadcasting as a sound content by examining it. The purpose of this research is to make its creativity and uniqueness into sound content by proving similarities between thunder Foley sound made by tools and actual Foley sound based on their comparison and analysis and studying its production principles and usage.
An analysis the actual sound and Foley sound at stepping on dead leaves
Authors: Iksoo Ahn , Bae Myungjin , Bae Seonggeon
Published: May 2015

The purpose of this research is to prove similarity between imitation sound of stepping on dead leaves used in media and actual sound of stepping on dead leaves and based on the result applying it to sound contents. By comparing imitation and actual sound, this research proves that imitated sound and the tools used for this are useful as sound contents. Also, it concludes that imitation sound of stepping on dead leaves has big potential to be developed as sound contents for not only performance, exhibition, and experience contents but also for treating spiritual health of people.
Analytic and divided listening in normal-hearing and hearing-impaired listeners measured in a nonspeech pattern identification task
Authors: Roverud Elin , Best Virginia , Mason Christine R. , Kidd Gerald
Published: May 2015

In multisource listening environments, it is important to be able to attend to a single sound source (analytic listening) while concurrently monitoring unattended sources for potentially useful information (divided listening). Previous studies have indicated that hearing-impaired (HI) listeners have more difficulty with analytic listening than do normal-hearing (NH) listeners. Although central factors (e.g., selective attention and memory) clearly play a role, the extent to which differences in peripheral factors (e.g., auditory filter characteristics) contribute to this effect is not clear. In this study, performance in a closed-set nonspeech tonal pattern identification task was measured in NH and HI listeners for patterns centered at 850 and 3500 Hz. The frequency spacing among the tones forming the patterns was adjusted to equate performance across listeners at each center frequency separately to control for peripheral frequency resolution. Patterns were then played at both frequencies concurrently. Listeners were instructed to attend to either the low or high frequency and identify the pattern. In a second condition, patterns were randomly presented at one frequency with a foil at the other frequency, requiring the listener to monitor both frequencies to identify the pattern. Preliminary findings suggest that peripheral and central factors contributed to performance. [Support: NIH-NIDCD.]
Voice emotion recognition and production by individuals with normal hearing and with cochlear implants
Authors: Chatterjee Monita , Kulkarni Aditya M. , Christensen Julie A. , Deroche Mickael L. , Limb Charles J.
Published: May 2015

Children and adults with normal hearing (NH) as well as those who use cochlear implants (CIs) were tested on a voice emotion recognition task. The materials were child-directed sentences, and acoustic analyses showed that features such as voice pitch range were exaggerated relative to earlier reports in the literature with adult-directed materials. The NH participants achieved ceiling-level performance in the task, while the children and adults with CIs had lower, and highly variable, scores. In a parallel study, we have also collected complex pitch discrimination thresholds in many of these participants. In a new preliminary study, we are analyzing the acoustic features of voice emotion production by these populations. The task involves reading simple sentences in a happy and a sad way. In this presentation, we will report on relationships between the perceptual data on voice emotion recognition and complex pitch discrimination by child and adult NH and CI participants. In addition, we will report on our initial acoustic analyses of voice emotion production by participants with NH and those with CIs.
Priming gestures with associated sounds
Authors: Lemaitre Guillaume , Navolio Nicole , Heller Laurie M.
Published: May 2015

Hommel (1996) established that sounds artificially associated with key presses could prime key presses. The goal of the current study was to explore the nature of the link between auditory perception and manual actions by comparing the priming of manual actions by naturally and artificially associated sounds. We report three experiments. The procedure in each experiment consisted of cueing participants to perform manual gestures. Executing the gestures produced feedback sounds; those sounds were also used as primes before the response cues. Experiment One replicated Hommel’s procedure: participants lifted keys that triggered artificial sounds. Experiment Two used sounds naturally produced by tapping or scraping wooden dowels on a custom interface. Experiment Three replicated Experiment Two with the sounds of the dowels muffled. The priming effect was observed on reaction times in Experiments One and Two but not in Experiment Three. These results show that long-term associations between sounds and gestures created in memory by repeated experience throughout life are not sufficient to prime the gestures. Instead they suggest that auditory-motor priming may be mediated by associations between sounds and gestures that are created on-line by the experiment via associative learning, and which are short-lived and can be readily reconfigured.
Evaluation of a navigational application using auditory feedback to avoid veering for blind users on Android platform
Authors: Wersényi György
Published: May 2015

Assistive technologies incorporate various applications and devices to assist handicapped people. This includes areas such as user interface design, sound design, mapping of visual and spatial information, sonification, etc. Visually impaired people also use state-of-the-art solutions especially for safe and independent navigation with the help of electronic travel aids (ETAs). Smartphones and tablets offer new possibilities in creating applications using the in-built sensors and open-source development platforms such as Android. This paper presents a short overview of recent technical approaches to assist users with visual impairment focusing on mobile applications for the Android platform. Evaluation of a navigational assistant using the magnetic sensor and tactile/auditory feedback to avoid veering is presented. Users can use the application after a short training time and keep straight walking path in outdoor and indoor tests using different sounds and vibration of the smartphone.
Speech experience and cue trading in budgerigars
Authors: Flaherty Mary M. , Sawusch James R. , Dent Micheal L.
Published: May 2015

The current project investigates how experience with human speech can influence speech perception in budgerigars. Budgerigars are vocal mimics and speech exposure can be tightly controlled in a laboratory setting. The data collected include behavioral responses from 30 budgerigars, tested using a cue-trading paradigm with synthetic speech stimuli. Prior to testing, the birds were divided into three exposure groups: Passive speech exposure (regular exposure to human speech), no speech exposure (completely isolated), and speech-trained (using the Model-Rival Method). After the exposure period, all budgerigars were tested using operant conditioning procedures. Birds were trained to peck keys in response to hearing different synthetic speech sounds that began with either “d” or “t.” Sounds varied in VOT and in the frequency of the first formant. Once training performance reached 80% on the series endpoints, budgerigars were presented with the entire series, including ambiguous sounds. The responses on these trials were used to determine which speech cues the birds use, if cue trading behavior was present, and whether speech exposure had an influence on perception. Preliminary data suggest experience with speech sounds is not necessary for cue trading by budgerigars.
Individual differences in auditory brainstem response wave-V latency in forward masking: A measure of auditory neuropathy?
Authors: Mehraei Golbarg , Gallardo Andreu P. , Epp Bastian , Shinn-Cunningham Barbara , Dau Torsten
Published: May 2015

A recent animal study suggests that noise exposure causes a preferential loss of low-spontaneous rate (low-SR) auditory nerve fibers (ANFs). This loss may leave detection thresholds normal yet degrade temporal encoding of supra-threshold sounds. Differences in the rate of recovery from forward masking in ANFs with different spontaneous rates may allow one to assess the state of different ANF populations. To test this, we measured auditory brainstem response (ABR) in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals (MPI). We expected that (1) loss of ANFs increases wave-V latency and forward masking thresholds, and (2) a preferential loss of low-SR fibers results in faster recovery time of wave-V latency. To test our hypotheses, we presented listeners with a broadband noise masker at two levels followed by a chirp probe at various MPIs. Initial results show that normal hearing threshold (NHT) listeners with delayed wave-V latency exhibit higher behavioral detection thresholds. Additionally, the listeners with the poorest behavioral thresholds had the fastest threshold recovery as a function of MPI. These results are consistent with the hypothesis that a preferential loss of low-SR fibers explains differences in NHT listeners.
Dual-carrier vocoder: Effect on streaming in a cochlear implant simulation
Authors: Apoux Frederic , Carter Brittney , Healy Eric W.
Published: May 2015

Recently, it has been suggested that temporal fine structure (TFS) cues play a critical role in streaming while providing little speech information. To take advantage of this role of TFS, a coding strategy for cochlear implants (CIs) has been developed involving two independent carriers, one for the target and one for the background. The so-called dual-carrier coding can help to provide awareness of the background sounds to CI users while improving speech intelligibility. Two experiments evaluated the ability of normal-hearing (NH) listeners to process a target sentence and a “competing background” sentence and their ability to switch from one sentence to the other when presented with dual-carrier stimuli. The first experiment showed that NH listeners can deliberately focus their attention and successfully process the target or the background sentence. It also showed that this capability is not greatly affected by the addition of a 500 ms sentence fringe at the beginning of one of the sentences. Similarly, the second experiment showed that NH listeners could understand both sentences when presented with the same stimulus more than once. This last result confirms, if needed, that the target and background signals are both intelligible in dual-carrier stimuli. [Work supported by NIH.]
The role of age and executive function in auditory category learning
Authors: Reetzke Rachel , Maddox Todd , Chandrasekaran Bharath
Published: May 2015

Auditory categorization is a natural and adaptive process that allows for the organization of high-dimensional, continuous acoustic information into discrete representations. The aim of this study is two-fold: (a) to examine the developmental trajectory of rule-based auditory category learning from childhood through early adulthood, and (b) to examine the extent to which individual differences in rule-based category learning relates to individual differences in executive function. Sixty participants with normal-hearing, 20 children (age range, 7–12), 20 adolescents (age range, 13–19), and 20 young adults (age range, 20–23), learned to categorize novel spectrotemporally modulated sounds using trial-by-trial feedback. The experimental design included six blocks of 100 stimuli for a total of 600 trials. Results revealed that auditory categorization accuracy improved with age, with young adults outperforming children and adolescents. Computational modeling analyses indicated that the use of the task-optimal strategy (i.e., multidimensional learning strategy) improved with age. Further, correlational analyses revealed that the use of optimal multidimensional learning strategies was strongly correlated with individual differences in executive function, even when age was partialed out. The current findings demonstrate the protracted development of rule-based auditory categorization. The results further suggest that executive function strongly relates to successful strategy use during auditory category learning.
Effect of age and hearing loss on intelligibility enhancement in a loudspeaker-based simulated reverberant environment
Authors: Srinivasan Nirmal Kumar , Zahorik Pavel , Jakien Kasey M. , Gordon Samuel , Kampel Sean D. , Stansell Megan , Gallun Frederick J.
Published: May 2015

The ability of the human auditory system to adapt to changes in the modulation spectrum of a reverberant signal has been documented (Zahorik et al., 2012). Previously, results were presented examining the effects of age and hearing loss on adaptation to reverberation in an anechoic chamber with spatially separated speech with monaural distortions only. The results indicated that older listeners obtained decreased benefit from prior exposure to listening environments. However, in a realistic reverberant environment, both monaural distortions and spatial cues are present and it is important to analyze the effects of reverberation in the presence of spatial cues. In this experiment, a more spatially realistic sound field using 24 speakers separated by 15° in azimuth was created in an anechoic chamber by calculating the directions, attenuations, and delays of the reflections from a sound source. An impulse response for each loudspeaker that has the appropriate delays and attenuations for all reflections in its spatial vicinity was created. Speech was convolved with individual speakers’ impulse responses for different spatial separations between target and maskers before presenting to the listeners. Effects of age and hearing loss on intelligibility enhancement due to prior exposure to a realistic listening environment will be discussed. [Work supported by NIH R01 DC011828.]
When a competing talker is easy to ignore: The elusive nature of informational interference
Authors: Mattys Sven
Published: May 2015

A competing talker can impair speech processing through both energetic masking and informational, cognitive aspects of the competing utterance. We refer to the latter as informational interference. We hypothesized that handling informational interference depletes processing resources that could otherwise be allocated to recognizing the target speech. As a consequence, informational interference should be particularly pronounced for target sentences with high processing demands (syntactically complex sentences) than for sentences with low-processing demands (syntactically simple sentences). Using a speeded picture selection task, we assessed native and non-native listeners’ understanding of subject-relative (simple) and object-relative (complex) sentences played against a competing talker vs. a matched energetic mask. While object-relative sentences were more difficult to process than subject-relative sentences, there was no effect of masker type, and this pattern was comparable for native and non-native listeners and across various SNRs. Thus, contrary to prior research, we found no evidence that a competing talker requires greater processing resources than energetic masking alone. Ongoing eye-tracking and pupillometric versions of this experiment will establish the nature of the discrepancy and the conditions under which informational interference is absent.
The relationship between phonetic cue weighting and listening effort in listeners with cochlear implants
Authors: Winn Matthew , Edwards Jan , Litovsky Ruth
Published: May 2015

In the study of speech perception, measures of cognitive load are especially useful because speech intelligibility performance results from a wide variety of auditory and cognitive processes that might demand different amounts of effort. The experience of elevated effort is an important part of hearing impairment and could be the target of audiological outcome measures. Listeners demonstrate different cue-weighting strategies when identifying phonemes, which is especially apparent for cochlear implant patients, who receive a highly degraded signal. This study explored whether changes in signal processing that affect phonetic cue weighting are also associated with changes in listening effort. Using both a conventional and an experimental speech processing strategy in alternating blocks, listeners completed tests of basic intelligibility, cue weighting for the /b/-/d/ contrast, and listening effort indicated by pupil dilation. Listeners for whom the experimental strategy promoted increased weighting of formant transition cues generally also showed reduced effort when using that strategy to listen to complete sentences, compared to listening with their basic strategy. Intelligibility scores generally did not show much change across both strategies. Results suggest that intelligibility measures can be complemented by other measures that tap into the mechanisms of perception and the effort demanded by the process.
Factors that increase processing demands when listening to speech
Authors: Johnsrude Ingrid , Rodd Jennifer M.
Published: May 2015

Listening effort is an increasingly important concept for applied hearing researchers, but it has not been well elaborated in the cognitive literature. We propose that listening effort is the product of two factors: the processing demands imposed by the listening situation, and the cognitive resources that an individual brings to bear, to compensate for demands. Whereas cognitive resources differ markedly among individuals, processing demands are generally constant in a given listening situation, at least for normal-hearing individuals, and fall into at least three different categories: (i) perceptual demands, (ii) linguistic demands, and (iii) concurrent task demands. Perceptual demands are increased when the speech is degraded, when concurrent interfering sounds are present, or when the listener is hearing impaired. Linguistic demands are increased, for example, when speech is semantically or syntactically complex, or when meaning is ambiguous. Finally, when a listener is performing another task (such as driving) while hearing speech, additional demands are present. A series of behavioral and neuroimaging experiments reveals the nature of these different demands, which appear to be largely independent but to interact in left inferior frontal cortex; fMRI activity in this area may serve as an objective, quantifiable, measure of listening effort. Interactions among different types of demand imply that they cannot be fully understood by studying them in isolation.
Recruitment of the speech motor system in adverse listening conditions
Authors: Alain Claude , Du Yi
Published: May 2015

Background noise is detrimental to speech comprehension. The decline-compensation hypothesis posits that deficits in sensory processing regions caused by background noise can be counteracted by compensatory recruitment of more general cognitive areas. We are exploring the role of the speech motor system as a compensatory mechanism during impoverished sensory representations in the auditory cortices. Prior studies using functional magnetic resonance imaging (fMRI) have revealed an increase in prefrontal activity when peripheral and central auditory systems cannot effectively process speech sounds. Our research using event-related fMRI revealed a negative correlation between brain activation and perceptual accuracy in speech motor regions (i.e., left ventral premotor cortex (PMv) and Broca’s area), suggesting a compensatory recruitment of the motor system during speech perception in noise. Moreover, multi-voxel pattern analysis revealed effective phoneme categorization in the PMv and Broca’s area, even in adverse listening conditions. This is in sharp contrast with phoneme discriminability in auditory cortices and left posterior superior temporal gyrus, which showed reliable phoneme classification only when the noise was extremely weak. Better discriminative activity in the speech motor system may compensate for the loss of specificity in the auditory system by forward sensorimotor mapping during adverse listening conditions.
Blind deconvolution of simple communication signals recorded in laboratory water tank
Authors: Kim Jane , Douglass Alex , Choi Paul , Dowling David R.
Published: May 2015

Overlapping synthetic time reversal (OSTR) is a technique for estimating the original source signal from acoustic array recordings in an unknown, multipath, time-varying sound channel without using a channel probe or calibration pulse. The OSTR technique applies synthetic time reversal (STR) to short-duration overlapping time segments of the received signal and then stitches the sequences of signal estimates together to blindly recover the original long-duration signal. Previous shallow ocean simulations of OSTR with a 2 kHz center frequency were successful. This presentation describes experimental results for OSTR in the reverberant environment provided by a laboratory water tank with 1.07-m diameter and filled to 0.80-m depth. Here, a variable-duration 50 kHz center frequency communication signal modulated with binary phase shift keying and four carrier cycles per bit was broadcast from an omnidirectional source to either a 1-by-16 or 4 × 4 receiving array that was 30 to 50 cm away. The nominal multipath reverberation time was varied from 10 ms to 4 ms by adding absorption material to the walls of the tank. Experimental signal reconstruction results are promising and demodulation diagrams are shown for 8, 64, 512, and 4096-bit signals. [Sponsored by the ONR and NAVSEA.]
Multichannel blind deconvolution of sound source of opportunity in ocean waveguide
Authors: Byun Sung-Hoon , Sabra Karim G. , Tian Ning , Romberg Justin
Published: May 2015

Signals that travel through an ocean waveguide are typically distorted when they are received by a remote receiver because of interference and distortion arising from multiple propagation paths. This presentation investigates the applicability of a physics-based blind-deconvolution technique proposed by Sabra et al. (JASA 127, EL42, 2010) to sound sources of opportunity such as randomly radiating ships. Using only the noisy recorded signals from an underwater receiver array, this blind deconvolution provides a means to estimate the Green's functions between the source of opportunity and the elements of the receiver array as well as the original signal radiated by the source of opportunity. These estimated Green's functions can then be used for acoustic characterization of the ocean waveguide parameters which is typically done using controlled sources only. We will discuss the performance of the proposed approach using both numerical simulations and at-sea data using discrete shipping events recorded on a vertical array as sources of opportunities.
Statistical characterization of biologic clutter from the shallow water TREX13 reverberation experiments
Authors: Preston John R.
Published: May 2015

A large experimental effort called TREX13 was conducted in April–May 2013 off Panama City, Florida. As part of this effort, reverberation and clutter measurements were taken in a fixed-fixed configuration in very shallow water (~20 m) over a 22 day period. Results have been presented previously characterizing reverberation, clutter and noise in the 1800–5000 Hz band. The received data are taken from the triplet sub-aperture of the Five Octave Research Array (FORA). The array was fixed 2 m off the sea floor and data were passed to a nearby moored ship (the R/V Sharp). An ITC 2015 source transducer was fixed 1.1 m off the seafloor nearby. Pulses comprised of gated CWs and LFMs were used in this study. Matched filtered plots of the reverberation and clutter along particular bearings are presented using the FORA triplet beamformer. There are clear indications of biologic scattering. Statistical characterization of the biologic components of the reverberation are presented using K-distribution based algorithms to note differences in the estimated shape parameter. Help from the Applied Physics Laboratory at the University of Washington was crucial to this effort. [Work supported by ONR code 322OA.]
The effect of internal waves on the ambient noise vertical directionality in deep ocean
Authors: Farrokhrooz Mehdi , Wage Kathleen E.
Published: May 2015

Vertical array measurements of low-frequency ambient noise in the mid-latitudes indicate that distant shipping noise has a flat angular distribution concentrated around broadside, e.g., [Wales and Diachok, JASA, 1981]. Ships cannot directly excite the lowest modes (associated with broadside angles) since those modes are trapped near the sound channel axis. Dashen and Munk [JASA, 1984] considered three mechanisms that could transfer shipping noise into the low modes: (1) downslope conversion on the continental slope, (2) volume scattering due to internal waves, and (3) direct excitation of the low modes at high latitudes where the sound channel intersects the surface. Dashen and Munk conclude that the first mechanism is the most likely since the second requires impractically large propagation ranges and the third requires unrealistic shipping densities at high latitudes. A limitation of Dashen and Munk's internal wave analysis is that it does not consider the effect of bottom loss. This talk adapts the transport theory approach of Colosi and Morozov [JASA, 2009] to study the effect of internal waves on the vertical directionality of distant shipping noise in the presence of seafloor attenuation. Initial results indicate that internal waves may have a significant effect at shorter ranges than previously thought.
Differential pattern time delay shift coding underwater acoustic communication using parametric array
Authors: Yin Jingwei , Zhang Xiao , Zhou Yiming
Published: May 2015

The long range and high data rate communication are two main targets of point to point underwater acoustic communication (PPUAC). In order to achieve the longer communication range, low frequency is the best choice. However, the data rate is limited by narrow available bandwidth at low frequency. So, the system band select must compromise between the data rate and communication range according to the application scenarios. Parametric array can achieve considerable bandwidth at the low frequency band with narrow beam pattern by nonlinear acoustics conversion. These characteristics meet the requirements of both data rate and communication range to a certain extent, and make the channel equalization more simple and effective. A PPUAC scheme based on differential pattern time delay shift coding using parametric array has been proposed. The system employs a 150 kHz primary frequency then get a 10 kHz secondary frequency wave. A proof test has been carried out under ice in SongHua River, HeiLongjiang Province, China. The error free communication was achieved in the trial. The communication scheme is expected to been used in underwater platform directional remote control and other scenarios.
A review of academic research and data related to laboratory testing for sound transmission loss
Authors: Shafer Benjamin
Published: May 2015

The building noise control design and manufacturing industry currently relies heavily on laboratory-tested sound transmission loss data for the design and implementation of noise control treatments in buildings. Although most sound transmission loss laboratories achieve acceptable measurement repeatability, the reproducibility of this test data has recently fallen under scrutiny and is currently unknown for common building noise control partition designs. Key academic articles will be discussed that provide a fundamental understanding of how laboratory sound transmission loss measurement procedures and laboratory facilities may affect reproducibility. A review of comparative sound transmission loss data for various laboratories will also be provided in an effort to clearly illustrate why sound transmission loss testing reproducibility has come under scrutiny. It is essential that organizations for standards and design professionals become more aware of these realities.
Status report on the planned intra-laboratory study to improve American Society for Testing and Materials E90’s precision and bias statement
Authors: Golden Matthew V.
Published: May 2015

The ASTM E33 Committee on Building and Environmental Acoustics has recently undertaken an effort to improve the precision and bias statements of all of the standards under its purview. Based on an analysis of the current state of the precision and bias statements and each standards importance to the industry, ASTM E90 was chosen as the standard to focus on first. Improving the precision and bias statements requires an intra-laboratory performance study, also known as a round robin, to be performed. Previous round robins for ASTM E 90 used relatively low performing specimens, Sound Transmission Class (STC) 24-32. The current proposed round robin is planned to use specimens with a STC in the high 40’s to low 50’s. Details of these efforts will be shared.
Reproducibility and repeatability of measuring noise level reduction using an artificial noise source
Authors: Robert Rene , Cunefare Kenneth , Ryherd Erica , Irizarry Javier
Published: May 2015

Buildings that are subjected to aviation noise require extra sound isolation measures in order to keep the indoor noise levels below a certain threshold. The difference in sound pressure from outside to inside a building is often quantified as a single number known as the noise level reduction (NLR). Generally, the procedures described in ASTM E966-10 are followed in determining this number for a façade, which is then used to determine the modifications required. The standard allows testing with one of two noise sources: an actual traffic source or a loudspeaker. An investigation is underway to statistically evaluate the repeatability and reproducibility of measurements taken on a façade for a “test house” with a loud speaker. The test house is a single-room structure that was designed and constructed with materials and methods of a residence in a mixed-humid climate. The repeatability is defined as the ability for a specific test to be implemented multiple times with comparable results, while the reproducibility is the ability for various test configurations allowed within the standard to yield comparable results. The results of this analysis can be used to improve testing parameters, further validate the procedure, and provide an estimate of confidence bounds.
Discrimination of frequency-modulated sweeps by laboratory mice
Authors: Screven Laurel A. , Dent Micheal L.
Published: May 2015

Mice often produce ultrasonic vocalizations (USVs) that sweep upwards in frequency from around 60 kHz to around 80 kHz, and similarly sweep downwards in frequency from 80 kHz to 60 kHz. Whether or not these USVs are used for communication purposes is still unknown. Determining the ability of mice to discriminate between synthetic upsweep and downsweep frequency-modulated stimuli will expand the current knowledge about acoustic communication in mice. Mice were trained and tested using operant conditioning procedures and positive reinforcement to discriminate between upsweeps and downsweeps. The stimuli varied in bandwidth, duration, and direction of the sweep. The animals responded when they heard a change in the repeating background, indicating that they could discriminate background from target. The mice performed significantly worse discriminating between background and targets when the stimuli occupied the same bandwidths. Further, the mice’s discrimination performance became much worse when the duration approached that of their natural vocalizations. When the sweeps occupied different frequency ranges and longer durations, discrimination performance improved. These results collected using artificial stimuli created to mimic natural USVs indicate that the bandwidth of vocalizations may be much more important for communication than the frequency contours of the vocalizations. [Work supported by NIH DC012302.]
Automatic manatee count using passive acoustics
Authors: Castro Jorge M. , Camacho Arturo , Rivera Mario
Published: May 2015

The West Indian manatee is a threatened species throughout its known range. To improve its conservation, it is necessary to locate and count the individuals. This is a very difficult task due to the cryptic behavioral characteristics of the species and the environmental constrains, particularly in the Central American region, where muddy waters produce limited visibility. A method to estimate manatee population through vocalizations is a reliable, inexpensive, non-invasive, and novel option in the region. Digital signal processing techniques are proposed to identify individuals in field recordings of manatee vocalizations. The proposed methods for signal denoising and vocalization recognition have produced promising results. Further work needs to be done to identify individuals.
Localization of individual call among croakers’ chorus using a stereo recording system
Authors: Ito Masanori , Matsuo Ikuo , Imaizumi Tomohito , Akamatsu Tomonari
Published: May 2015

Passive acoustic monitoring (PAM) is widely used in cetacean census in the ocean. In these years, PAM has been applied for various species out of mammals such as fish and crustaceans. For detection, classification and density estimation in PAM, isolation of each biological sound and reliable detection is essentially needed. Choruses of fish sounds were recorded by a stereo sound monitoring system on the seafloor in off Choshi, Chiba prefecture, Japan in May 2013. Numbers of croaker sounds were recorded and the simple separation in time domain was not possible in chorus situation. A blind source separation method based on independent component analysis was applied to separate mixed sounds in order to obtain individual sounds and to localize them. The directions of sound arrivals could be estimated by using the cross correlation function of the separated signals and the estimated directions were plotted. Using proposed methods, individual call sounds could be localized and inter-pulse intervals could be accurately estimated. Using separated sequence of sounds from an individual, the movement of phonating fish could be measured using PAM. [This study was supported by CREST, JST.]
Surface acoustic wave microfluidics: Thin films and drop splitting
Authors: Friend James
Published: May 2015

A renaissance in surface acoustic waves (SAW) has occurred, due mainly to their enormously powerful ability to manipulate fluids and colloids for microfluidics. Beyond the routine manipulation of drops, mixing, and separation and concentration of colloids using SAW, we have found fascinating behavior in the formation and propulsion of thin fluid films from a few tens to less than a micrometer thick in various directions, either with or against the acoustic wave propagation. Furthermore, we have seen—and been able to control through careful input conditions—the splitting of fluid drops. Both have a broad range of applications that will be briefly discussed, but more important is the underlying physics that illustrates the rich interaction of the acoustics, fluid dynamics, and free fluid interface in these systems.
Examples of viscous phenomena relevant to second-order responses to ultrasound
Authors: Marston Philip L. , Zhang Likun
Published: May 2015

It has long been realized that viscosity strongly affects the response of drops and bubbles to the radiation pressure of modulated ultrasound. See for example an analysis of the viscous damping of bubble and drop shape oscillations and related experiments [T. J. Asaki and P. L. Marston, J. Fluid Mech. 300, 149–167 (1995)]. There has been some recent interest in the importance of the viscosity of the fluid surrounding objects of interest when considering other second-order responses. These include the following quantities or responses associated with scattering by spheres and other objects: radiation force of progressive plane waves and Bessel beams [P. L. Marston, Proc. Meet. Acoust. 19, 045005 (2013)]; power extinction of acoustic beams [L. Zhang and P. L. Marston, Bio. Opt. Express 4, 1610–1617 (2013); (E) 4, 2988 (2013)]; and the radiation torque of vortex beams and orthogonal standing waves [L. Zhang and P. L. Marston, J. Acoust. Soc. Am. 131, 2917–2921 (2014)]. The underlying assumptions and limitations of some current and prior approaches will be noted along with some applications to acoustophoresis. [Work supported by ONR (Marston) and by the 2013-14 F. V. Hunt Postdoctoral Fellowship (Zhang).]
U
nderstanding the fluid dynamics associated with macro scale ultrasonic separators
Authors: Lipkens Bart , Chitale Kedar , Presz Walter , Desjardins Olivier
Published: May 2015

Acoustic standing wave fields are widely used in MEMS applications to separate micron sized particles from fluids. However, the use and understanding of macro scale ultrasonic separators are still limited and challenging. These systems rely on acoustic radiation forces for trapping and clumping of dispersed phase particles. The clumps of particles then continuously separate out due to enhanced gravity or buoyancy in a flowing system. Typical flow Reynolds numbers are less than 50, particle concentrations up to 20%, ultrasonic standing wave fields at frequencies of 2 MHz, and acoustic pressure amplitudes of about 1 MPa. At such small Reynolds numbers, the flow is dominated by shear forces and the drag on clumps of particles is significantly lower than Stokes drag on a single particle. The fluid dynamics associated with these systems is extremely complex due to the coupling between the fluid flow field, suspended particles, and acoustic radiation forces. This work discusses the key physics involved and explains our current understanding of operation of macro scale acoustic separators. The status of CFD efforts to predict the flow fields and particle clumping in such systems is presented and compared to experimental results.
Experimental and numerical acoustofluidics in bulk acoustic wave devices at ETH Zurich
Authors: Hahn Philipp , Leibacher Ivo , Lamprecht Andreas , Reichert Peter , Dual Jurg
Published: May 2015

Ultrasonic fluid cavity resonances in acoustofluidic micro-devices can be exploited to miniaturize important operations for the handling of beads, cells, droplets, and other particles. With a growing number of experimentally tested unit operations, acoustofluidics holds increasing promise for emerging applications in bio- and microtechnology on lab-on-a-chip systems. We provide an overview of our research activities during the last years with a focus on the latest experimental setups and advances in the numerical simulation. Specifically, we present micro-devices with impedance matched cavity walls that allow a more flexible device design. Further, we show devices for the handling of fluid droplets and report on a method for the direct measurement of the acoustic radiation force on micro-particles. Due to the rapidly growing computational capabilities, numerical simulation has become a valuable tool in acoustofluidics research. We present a numerical model that accurately mimics the boundary layer damping inside the fluid cavity, allowing to make predictions of the attainable acoustic amplitudes and radiation forces. Furthermore, we demonstrate how numerical optimization of the device geometry is used to design new devices in an automatic fashion. Finally, we show how the radiation forces and torques can be deduced from the simulated acoustic fields to compute trajectories of complex shaped particles.
On the extent of head motion in listening tests and individual measurements using different head-tracking sensors
Authors: Wersényi György , Wilson Jeff
Published: May 2015

Measurements and applications in spatial hearing research, virtual auditory displays, etc., often rely on head-related transfer functions (HRTFs) of human subjects. Individually measured HRTFs have the advantage of being more accurate in virtual localization tasks. On the other hand, the measurement and recording procedure raise several new problems such as signal-to-noise ratio issues and subject comfort. For measurements with human subjects, lots of methods are used from free heads to different head fixations methods. This study analyses the extent of head movement during measurements using different sensors and environmental conditions based on the circular angle variance, errors in yaw-pitch-roll directions and magnitude of standard deviation. Conclusive results indicate magnitudes of standard deviation of 2–8 cm and errors about 2 degrees depending on the situation as well as a preference for sitting instead of standing posture.
Pitch perception and frequency-following responses elicited by lexical-tone chimeras in American and Chinese adults
Authors: Jeng Fuh-Cherng , Chou Meng-Shih , Lin Chia-Der , Sabol John , Hollister Grant , Chen Ching-Hua , Kenny Jessica , Tsou Yung-An
Published: May 2015

Objective: Previous research has shown the usefulness of utilizing auditory chimeras (i.e., interchanging the envelope and fine structure of two different sounds) in assessing a listener’s perception of the envelope and fine structure for an acoustic stimulus. However, research comparing and contrasting behavioral and electrophysiological responses to this stimulus type is scarce. Design: Two sets of chimeric stimuli were constructed by interchanging the envelopes and fine-structures of the rising /yi2/ and falling /yi4/ Mandarin pitch contours that were filtered through 1, 2, 4, 8, 16, 32, and 64 frequency banks. Behavioral pitch-perception tasks (through a single-interval, two-alternative, forced-choice paradigm) and electrophysiological responses (through the frequency-following response to voice pitch using validated scalp-recorded potential methods) were obtained from two groups of participants (native speakers of a tonal or nontonal language). Study Sample: Thirteen American and 13 Chinese adults were recruited. Results: A two-way analysis of variance showed significance (p<0.05) within and across the filter bank and language background factors for the behavioral measurements to the lexical-tone chimeras, while the frequency-following response demonstrated a significance across filter banks, but not for language background. Conclusions: Frequency-following responses to voice pitch provide supplementary information on how chimeric stimuli are processed at the brainstem level.