bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the acoustical properties of sisal and coconut fiber samples based on the flow resistivity experimental assessment
Authors: Lima Key F. , Barbieri Nilson , Barbieri Renato , Grossl Vinicius A.
Published: November 2016

Absorbent materials are fibrous or porous and must have the property of being good acoustic dissipaters. The noise reduction process occurs due to transformation of a part of the sound energy into heat. The attenuation is caused by friction of the viscous air fluid inside the irregular arrangement of fibers during the sound wave propagation. This study assesses the complex wave number and the complex characteristic impedance of two natural fibers with the classical empirical equations of Delany and Bazley (1970). These properties are determined based on experimental evaluation of the flow resistivity of sisal and coconut coir fiber samples. The experimental assessment procedure was performed according to the guidelines of ASTM C522-03 (2009). Samples evaluated have approximately identical densities, different diameters, and thicknesses. The diameters were 62.0, 71.5, and 80.0 mm and thicknesses were 5, 10, 15, and 20 mm. The purpose of testing seven dimensions is to verify the effect of these differences on the flow resistivity experimental measurements. This evaluation is due the standard ASTM does not provide guidelines for the sample dimensions.
Going global with hearing conservation: Regulations and trends
Authors: Wells Laurie
Published: November 2016

Noise is recognized universally as an occupational hazard; however, there is not a globally accepted regulatory approach toward protecting the noise-exposed workforce. The regulatory differences for hearing conservation around the world make it challenging for multinational companies to set policies for corporate hearing loss prevention programs. This presentation compares and contrasts selected aspects of various hearing conservation regulations to the United States Occupational Safety and Health Administration requirements. The following jurisdictions are included: Australia/New Zealand, Brazil, China, European Union, India, Japan, and Mexico. Details were collected from English translations of a country regulation as well as by consultation with an experienced, in-country resident whenever possible. Information includes noise exposure limits, noise control, hearing protection device use, standards, and attenuation derating schemes, audiometric testing and hearing shift criteria, and employee training requirements. Studying these criteria will also spark discussion as to best practices and emerging trends in hearing conservation.
Characterizing impairments in compression and filter shape to establish their role in hidden hearing loss
Authors: Irino Toshio , Matsui Toshie , Patterson Roy D.
Published: November 2016

In the study of hidden hearing loss, it is important to characterize an individual’s peripheral losses accurately while minimizing measurement time for clinical applications. In this talk, we show how peripheral losses involved in compression and auditory filtering can be estimated simultaneously and accurately using the compressive GammaChirp (cGC) filter and notched noise (NN) maskers. Sets of thresholds were gathered with asymmetric maskers and fitted with the cGC filter model using several constraints associated with cochlear filtering. The slopes of the resultant input-output functions were within the range established with temporal masking curves above 1000 Hz. Studies of the fitting process also revealed how to reduce the number of threshold measurements without unduly increasing estimation error. These improvements led to the extension of the cGC filter model to explain hearing impairment of cochlear origin. The model also led to a hearing impairment simulator which can analyze everyday sounds including speech and music with a given individual’s cochlear hearing impairment, and then resythesize the sounds to provide a normal hearing listener with a realistic experience of the sound perception problems facing that hearing impaired individual. By isolating peripheral losses, the simulator will assist the specification of hidden hearing losses.
Conversion of amplitude modulation to phase modulation on the basilar membrane and its implication in the perceptual consequences of disrupted temporal coding
Authors: Otsuka Sho , Furukawa Shigeto
Published: November 2016

Disrupted fidelity of temporal-structure representation by auditory-nerve (AN) firing is a key component of hidden hearing loss. However, impacts of disturbed temporal processing on everyday listening are yet to be identified. Here we propose a new role of the AN’s temporal processing, namely, encoding amplitude modulation (AM). When an AM signal with a constant-frequency carrier is fed to a generic nonlinear amplifier, the carrier phase of the output signal can be modulated, a phenomena referred to as AM-to-PM conversion. By simulating the basilar-membrane (BM) vibration and measuring otoacoustic emissions, we demonstrated that the AM-to-PM conversion takes place on the BM, too. The size of AM-induced PM depends on the stimulus level, which can be accounted for by the characteristics of BM’s compressive nonlinearity. Psychoacoustic measurements further indicated the association between the listener-dependent patterns of the level dependence of AM-induced PM and of AM detection performance. These results imply that the AM-induced PM on the BM can be used as a cue for AM processing in the auditory system and that disrupted AN sensitivity to PM should have negative impacts on AM processing.
Functional hearing impairments in normal-hearing listeners with a history of deployment-related blast exposure
Authors: Brungart Douglas S. , Kubli Lina , Phatak Sandeep , Kokx-Ryan Melissa J. , Bielski Lynn M. , Horvat LeeAnn , Grant Kenneth W.
Published: November 2016

Over the past decade, DoD and VA audiologists have reported large numbers of relatively young adult patients who have normal-audiometric thresholds but who report greater than expected difficulty understanding speech in noisy environments. One common theme in the history of these patients is that they self-report having experienced exposure to explosive blast as part of their military service. Recent studies in our laboratory suggest that some blast-exposed patients with normal-hearing thresholds have greater than expected difficulty in tasks that require spatial sound perception (auditory localization and N0Sπ tone detection) or those that involve the perception of time-compressed speech in reverberant environments. They also tend to report more hearing difficulties compared to non-blast exposed patients on a questionnaire that evaluates spatial perception, speech perception, and perceived sound quality. These laboratory results appear to be confirmed by preliminary results from roughly 2000 active-duty service members who participated in a brief hearing test and questionnaire at the time of their annual hearing test. Within this sample, blast-exposed listeners were 3-4 times more likely to experience subjective or objective hearing deficits than those with no blast history. These results suggest a form of hidden hearing loss that may be associated with exposure to blast. [The opinions presented are the private views of the authors and are not to be construed as official or as necessarily reflecting the views of the DoD.]
Individualized assessment of suprathreshold hearing and relationship to cochlear synaptopathy
Authors: Bharadwaj Hari M. , Varghese Leonard , Mehraei Golbarg , Shera Christopher A. , Shinn-Cunningham Barbara G.
Published: November 2016

Threshold audiometry is currently the foundation of clinical audiology. Yet, many individuals with normal hearing thresholds (NHTs) have difficulty communicating in noisy settings. We previously documented that even among listeners with NHTs and no hearing complaints, large individual differences exist in the ability to perceive subtle temporal features of clearly audible sounds, and to selectively process target speech in the presence of competing sounds. Critically, we find that these suprathreshold differences in individual perceptual sensitivity correlate with physiological measures from the brainstem and auditory nerve. These measures, including brainstem envelope-following responses, auditory brainstem responses, and the middle-ear muscle reflex, show that some perceptually relevant physiological differences arise very early along the auditory pathway. Cochlear synaptopathy—a loss of afferent synapses and nerve terminals innervating the cochlea—is well documented in noise-exposed and aging animals (Kujawa & Liberman, Hear. Res. 2015). Cochlear synaptopathy in humans may account for both large individual differences and hearing difficulties in human listeners with NHTs. This presentation will summarize updated human evidence consistent with cochlear synaptopathy, discuss some of the challenges that remain with this interpretation, and review the search for clinical markers of such damage.
The efficiency of the cytoarchitecture of the organ of Corti for active cochlear amplification
Authors: Motallebzadeh Hamid , Puria Sunil
Published: November 2016

A “Y”-shaped structure of cells formed by the basally tilted force generating outer hair cells (OHC) and apically tilted passive phalangeal process (PhP) connected to a Deiter cell (DC) has been hypothesized to be an essential organ of Corti (OoC) building block for cochlear amplification (Yoon et al., 2011). We developed a COMSOL finite-element model of the mouse cochlea, taking into account the spatial arrangement of Y-shaped elements and the 3-D fluid-structure interaction. The model was validated by comparison with previously reported basilar membranę (BM) displacement for both passive and active cases (Lee et al., 2015). The baseline model can reproduce an increase of 40 dB gain of the BM (re stapes velocity) for low level sounds. However, the absence of the PhP results in an unstable response of the BM for active cases. The model with the roles of the PhP and OHC switched, could not reproduce the active gain. Finally, the model with reversed titling orientation of OHC and PhP cells generated significantly lower gains (specially for lower frequencies), but also results in broader resonance peaks. These results demonstrate the efficiency of the natural cytoarchitecture of the OoC. [Work supported by NIH grant R01 DC 07910.]
Simulating cochlear nonlinearity in an excised, active in vitro segment
Authors: Nankali Amir , Sasmal Aritra , Grosh Karl
Published: November 2016

Hearing relies on a series of coupled acoustical, electrical, and mechanical interactions in the auditory periphery. There exists a distinct nonlinear amplification process inside the cochlea that enables sound processing of a broad range of frequencies and intensities. The precise operating principles of the active mechanics underlying nonlinear cochlear amplifier remains an open question in biophysics. Using the experimental protocol devised by Chan & Hudspeth of an excised cochlear segment as a model problem, we develop a computational model for studying the active in vitro response of the organ of Corti (OoC) to acoustical stimulation. Both experiment and theory show that there exists a traveling wave even for a very small, 700 mm cochlear segment. However, we show that the contribution of the traveling wave on the partition dynamics is insignificant in this preparation as the phase accumulation is less than one-tenth of a cycle. This finding enables us to reduce the macroscopic fluid dynamics of the configuration to a loading added mass on the OoC and study the cochlear local dynamics. The two hypothesized active mechanisms of the cochlea (hair bundle motility and somatic electromotility) are included and the contribution of each mechanism on the cochlear amplifier is investigated. It is observed that in our model the OHC somatic electromotility is sufficient to predict the experimental results. [This work was supported by NIH grants DC-004084 and T32DC-00011.]
Evaluating acoustical features of 3D sound rendering systems by using a visualizing tool of sound intensities
Authors: Nakahara Masataka , Mikami Takashi , Omoto Akira
Published: November 2016

The authors have developed a simple measurement/analyzing tool which visualizes 3D acoustical properties of sound by using sound intensity information. The tool, VSV (Virtual Source Visualizer), has already being used for practical acoustic design works, and the authors have also begun to use it for evaluating acoustical features of 3D sound rendering systems. On the audio industries, various 3D sound reproduction systems have already been commercialized. Therefore, further skill is now required to design acoustic specifications of their production studios. From this point of view, development of a simple method to obtain relationship between loudspeaker positions and source locations rendered by a 3D reproduction system would be helpful. This research introduces analyzing flows of the measurement tool briefly, and shows measured results of physical and/or phantom sound locations detected from sound intensity information in some different 3D reproduction environments including commercial audio strategies such as Dolby Atmos and 22.2ch, and a wave theory based Boundary Surface Control system, BoSC. Verifying differences between target source positions and measured ones, the authors suggest the feasibility of the evaluation method of a rendered 3D sound field by a simple measurement method.
Perceptually plausible acoustics simulation of single and coupled rooms
Authors: Wendt Torben , van de Par Steven , Ewert Stephan D.
Published: November 2016

The fast and perceptually plausible room acoustics simulator [RAZR, see Wendt et al., JAES 62, 11 (2014)] has been optimized and extended to simulate the acoustics of connected rooms. RAZR synthesizes binaural room impulse responses (BRIRs) with high computational efficiency using a hybrid approach: early reflections are calculated as image sources for a shoebox-room approximation up to a low order, and the later reverberation is generated by a binaurally extended feedback delay network (FDN). For the extension toward two coupled rooms, validity, visibility, and diffraction of the image sources in the two rooms were taken into account, as well as different reverberation properties and the opening angle of the door to the neighbor room seen from a specific receiver position. The suggested method was evaluated by comparing measured and synthesized BRIRs for several rooms differing in size and reverberation time. For room acoustical parameters such as early decay time, late decay time, definition, and clarity a good agreement in terms of the Pearson correlation coefficient (0.86—0.99) was achieved between measured and simulated BRIRs. Subjective listening tests showed a good agreement of ratings of perceptual attributes (e.g., tone-color, reverberation time, envelopment, and naturalness) for the measured and synthesized BRIRs.
Simultaneous recordings of marine mammal calls by a glider, float, and cabled hydrophone array
Authors: Fregosi Selene , Klinck Holger , Matsumoto Haru , Turpin Alex , Martin Stephen W. , Matsuyama Brian M. , Helble Tyler A. , Henderson E. Elizabeth , Moretti David J. , Morrissey Ronald P. , Mellinger David K.
Published: November 2016

Recent advances in passive acoustic monitoring (PAM) technologies have led to development of mobile autonomous platforms for recording marine mammals. These instruments may allow greater spatial and temporal sampling than traditional towed or bottom moored systems. However, comparison of recording abilities of these instruments to traditional methods has yet to be performed. We deployed two types of commercially available platforms at the Southern California Offshore Range (SCORE) complex in late December 2015 through early January 2016. The QUEphone, based on the APEX float (Teledyne Webb Research, Falmouth, MA, USA), is a buoyancy driven device capable of descending to 2000 m where it drifts horizontally with the currents. The Seaglider (Kongsberg Underwater Technology, Lynwood, WA, USA) is also buoyancy driven, but dives repeatedly up to 1000 m following a flight path controlled via satellite. We deployed one glider and two floats, each equipped with identical acoustic sensors developed by Oregon State University, sampling at 125 kHz. Each instrument recorded 250-300 hours of data over 13 days. Marine mammal detections included beaked whales, Risso’s dolphins, and fin, blue, and humpback whales. We utilized known marine mammal locations derived from the SCORE hydrophone array to compare PAM capabilities of these novel mobile platforms.
Multipath propagation of sound in a shallow tidal channel and its implications on tomographic current measurements
Authors: Razaz Mahdi , Zedel Len , Hay Alex , Kawanisi Kiyosi
Published: November 2016

A pilot observational experiment with Fluvial Acoustic Tomography (FAT) system was conducted in the Grand Passage, Nova Scotia, Canada, in 2014, to assess the capabilities of FAT in continuous monitoring of transport in a tidal channel. To implement the tomographic measurements, two broadband FAT transceivers operated at 7 kHz central frequency were positioned in both sides of the channel emitting a pulse every 30 s for 4 days. Three coherent arrivals were identified in the acoustic receptions. This paper investigates the influence of physical characteristics of water and current shear on multipath propagation of sound in well-mixed conditions of the channel. At the end, we report the comparison between FAT and reference velocity data collected by a moving-boat ADCP.
A method for estimating the 3-D structure function from 2-D histology sections
Authors: Han Aiguo
Published: November 2016

Understanding the fundamental scattering mechanism(s) in tissues is critical to the success of Quantitative Ultrasound (QUS) imaging. From a discrete scatterer point of view, the ultrasound scattered power depends not only on the properties of the individual scatterers (modeled by the form factor) but also on the spatial correlation among the scatterers (modeled by the structure function). Previously, the structure function was obtained from the ultrasound backscatter data for dense cell pellet biophantoms. This study introduces a method for obtaining the 3-D structure function from the digitized hematoxylin & eosin (H&E) stained histology images. The method starts with calculating the 2-D pair correlation function using the scatterer positions determined from a histology image. Assuming isotropic media with spherical scatterers, the 3-D pair correlation function is then estimated by numerically solving a stereological function that relates the 3-D pair correlation function with the 2-D pair correlation function. The 3-D structure function is finally calculated through a Fourier-Bessel transformation of the 3-D pair correlation function. The proposed method was validated through computer simulations and cell pellet biophantom experiments. Using this method to estimate 3-D structure functions may lead to improved understanding of acoustic scattering in biological media. [Support : R01CA111289 and R01DK106419.]
Multi-parameter analysis of bladder mechanical properties using ultrasound bladder vibrometry
Authors: Huber Matthew T. , Signh Aparna , Cheong Mathew , Urban Matthew , Bayat Mahdi , Fatemi Mostafa
Published: November 2016

Bladder wall mechanical properties are important indicators of bladder compliance. This study compares the effectiveness of the Kelvin-Voigt, Maxwell, and fractional Kelvin-Voigt rheological models in capturing the mechanical properties of normal (compliant) and aberrant (non-compliant) ex-vivo pig bladder walls. Bladders were filled to different volumes, varying their thickness and internal pressure, and excited by the acoustic radiation force. Pulse-echo ultrasound imaged anti-symmetrical Lamb waves traveling along the bladder wall. Two-dimensional Fourier analysis generated velocity-frequency dispersion curves for the Lamb wave propagation. Fitting these experimental curves against theoretical curves from the models yielded values for bladder elasticity and viscosity. Pressure, measured simultaneously, was used as a point of comparison with elasticity. Our findings indicate an increasing trend in both elasticity for the rheological models and recorded pressure with increasing volume. This rate was observed to be significantly higher in aberrant bladders than intact bladders for the Maxwell and fractional Kelvin-Voigt models (p-value of 0.0082). Additionally, all three models showed a similar strong correlation (greater than 0.9) between pressure and elasticity. These findings provide a foundation for selecting an appropriate bladder wall rheology model which can potentially be used in evaluation of human bladder mechanical properties. [Work supported by NIH grant DK99231.]
Design of transmission-mode measurements for estimating ultrasound attenuation and nonlinearity in liver
Authors: Kreider Wayne , Hunter Christopher , Sapozhnikov Oleg A. , Maxwell Adam D. , Khokhlova Vera A. , MacConaghy Brian , Wang Yak-Nam
Published: November 2016

Previously, it has been shown that ultrasound measurements of sound speed and nonlinearity can be used to quantify the fatty and non-fatty components of liver tissue. In addition, it has been proposed that ultrasound attenuation measurements can be used to distinguish fatty components comprising either sub-micron lipid droplets (microsteatosis) or much larger cell-sized droplets (macrosteatosis). To perform all of these measurements, a caliper device is being developed based on a transmission-mode approach. Design challenges are posed by competing requirements: sub-megahertz frequencies for optimal detection of microsteatosis and nonlinearity estimation based on waveform distortion over relatively short distances. To meet these challenges, a design is proposed in which ultrasound at 667 kHz is generated by a 50 mm piezoceramic disk and all measurements are made in the plane-wave regime. Given geometrical and physical constraints, all analysis was performed in the time domain. The nonlinearity coefficient was accurately estimated from a quasi-linear approximation to the lossless Burgers equation for pressure amplitudes less than 1 MPa and propagation distances from 15 to 50 mm. An analogous time-domain approach was implemented for determining attenuation at the fundamental frequency and several odd harmonics. [Work supported by NIH grants EB017857, EB007643, EB016118, and DK104854.]
Finite-difference time-domain simulations of piezoelectric effect in bone under ultrasound irradiation
Authors: Hosokawa Atsushi
Published: November 2016

To understand the piezoelectricity in bone at ultrasound frequencies, numerical simulations of piezoelectric effect under ultrasound irradiation was performed using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, the effect of piezoelectricity on ultrasound wave propagation in a piezoelectric material was investigated with consideration of conductivity. Ultrasound pulsed waveforms propagating through piezoelectric ceramics, whose piezoelectric parameter values were known, were investigated by the PE-FDTD simulations. In the simulated results, the ultrasound speed in the ceramics increased with piezoelectricity, and the ultrasound attenuation caused by the piezoelectricity increased with conductivity. The simulated waveforms were in good agreement with the experimental waveforms, which demonstrated the validity of the PE-FDTD simulations. Next, the piezoelectric effect on ultrasound wave propagation in cortical bone was simulated. The piezoelectric effect on ultrasound wave propagation in the bone was scarcely observed because of the very low piezoelectricity. Finally, the piezoelectric potential induced in cortical bone by ultrasound irradiation was simulated. The simulated results showed that the piezoelectric potential decreased with conductivity. Moreover, using the cortical bone specimen, on the surfaces of which positive and negative electrodes were deposited, the piezoelectric potential was experimentally observed to compare with the simulated results.
Effect of intracortical bone properties on the guided wave propagation using low-frequency axial transmission technique: Simulation study
Authors: Pereira Daniel , Haïat Guillaume , Fernandes Julio , Belanger Pierre
Published: November 2016

In this work, a semi-analytical finite-element method was on the propagation of acoustic guided wave. The simulations were performed with a realistic bone cross-sectional geometry by considering an axial transmission configuration. A point source excitation was applied using a toneburst centered at 35 kHz as the input signal. The propagating waves were monitored using out-of-plane displacement in the axial direction at 32 positions separated 4 mm apart. The properties of the endosteal region of cortical bone were varied from healthy to early osteoporotic conditions. The use of the two-dimensional Fourier transform (2DFFT) allowed the measurement of individual mode velocity, which was compared to the velocity typically measured using first arrival signal (FAS). The results have shown that variations in the velocity measured using 2DFFT were mainly associated to a low order flexural-like mode among the eight modes supported by the waveguide. Furthermore, the measured velocity decreased approximately 10/% due to a degradation of 20/% of the biomechanical properties in the endosteal region. In contrast, the FAS velocity has shown to be affected by four modes, showing a non-linear variation on the velocity. The flexural mode measured using 2DFFT can therefore be considered promising to monitor changes in the endosteal region.
Detection and evaluation of airborne ultrasound passed through a heel for non-contact bone assessment
Authors: Hirata Shinnosuke , Hachiya Hiroyuki
Published: November 2016

Ultrasonic bone assessment by quantitative ultrasound (QUS), measurement of ultrasonic propagation characteristics, is one of the diagnosis methods of osteoporosis. In typical QUS devices, opposed ultrasonic transducers are brought into contact with tissue surfaces through an ultrasonic gel to effectively propagate ultrasound. We have proposed non-contact measurement of propagation characteristics using airborne ultrasound passed through a heel. Generally, airborne ultrasound which passed through a tissue is extremely attenuated due to large reflections at boundaries between air and the tissue. In the proposed method, therefore, the signal-to-noise ratio of pass-through ultrasound is greatly improved by pulse compression using a higher-order M-sequence. Furthermore, each side of a heel is inclined to the direction of the ultrasonic beam. Pass-through ultrasound cannot fully be received by opposed transducers, because the ultrasonic beam inflects at each surface. Therefore, inclination of each heel side is measured by the pulse-echo method. Then, each transducer is inclined with considering the surface inflection. The propagation speed of ultrasound in the heel is estimated from the time of flight of pass-through ultrasound, the length of the propagation path, and the propagation speed of ultrasound in air.
Acceleration of critical bone defect healing by guided low-intensity ultrasound in a rat tibial model
Authors: Qin Yi-Xian , Liu Jingbo , Zhang Dongye , Li Xiaofei
Published: November 2016

Bone defects, caused by trauma, inflammation, and tumors, may lead to loss of limb functions and substantially affect the quality of patients’ life. Low-intensity ultrasound (LIUS) can transmit through and into living tissues as acoustic pressure waves, and generate dynamic acoustic radiation force in the local region to induce stem cell recruitment, and mineralization. The aim of this study was to evaluate the effect of LIUS induced healing in a rat tibial critical defect. A total of 40 skeletally mature female Lewis rats were used in this study with a surgical bone defects of 2 mm in-diameter at proximal tibia. The defects of the left tibia (LIUS group) received daily treatment of ultrasound, and the defects in the right tibia (Control) received sham stimulation. A modified repetitive frequency at 100 Hz, characteristic frequency of 1 MHz at an intensity of 30 mW/cm2 were used for the stimulation for 20-min/day. After 2 weeks, the μCT images showed that trabecular bone formed in the defect area of both LIUS and control groups. LIUS treated tibia showed more increased in BV/TV, Cont.D, Tb.N, and BMD, and significant decrease in Tb.Sp compared to control. Four-point bending testing showed LIUS treatment significantly increased the bone stiffness (kN/mm) relative to control group. The histological analysis and μCT data revealed that LIUS therapy can significantly increase new trabecular bone volume, so as the stiffness and ultimate stress of LIUS treated group with two-week as optimized treatment period for healing.
Irregular qualities of sound sources appeared at the input of the outdoor emergency mass notification sound system
Authors: Kurisu Kiyohiro , Matsumoto Yasushi , Matsuishi Ryota
Published: November 2016

In order to obtain an intelligible speech at a listening point addressed by the mass notification sound system, not only high transmission quality of the system, but also a sufficiently clear speech sound source is needed. However, the qualities of speech sources may not be constant because they are supplied by different types of production and transmission methods, e.g., the variety of speech source production methods causes various specifications and irregular qualities of sources, and some types of transmission methods between the parent station (speech production system) and children stations (acoustic amplification system) cannot convey the source signal with sufficient quality. In this presentation, the authors showed examples of irregular source quality appeared at the input of the acoustic amplification system and discussed the necessity of verifying the signals at several points in the total system (i.e., the system between the speech source and the listening point) to regulate their qualities. Then, the guidelines for the performance verification of the outdoor emergency mass notification sound systems which was published by the Acoustical Society of Japan was introduced.
Subwoofer array modeling and optimization
Authors: Ahnert Wolfgang , Feistel Stefan
Published: November 2016

In the last few years, configuring subwoofer arrays in order to achieve a desired sound radiation pattern has become one of the most discussed topics in the sound reinforcement industry. The directivity of such arrays of low-frequency loudspeakers can typically be controlled by means of delay, gain, and polarity settings applied to the individual elements. A new software solution is presented that allows modeling and optimizing such setups, including various cardioid configurations as well as end-fire and steered setups. Frequencies down to 20 Hz can be investigated. It is also explained how coherent sound superposition at low frequencies and incoherent interaction of sound waves at high frequencies can be simulated consistently by means of a cross-over frequency band. Finally, an optimization method is presented that allows computing elemental delays automatically based on a user-defined coverage angle for the array.
Applying the cellular automaton model in speech production process simulation
Authors: Taka Koji
Published: November 2016

This study investigates the dynamic simulation of the speech production process. When an utterance occurs, the sound pressure and the particle velocity distribution of the vocal tract space changes from word to word. The author examined and visualized this change to illustrate how it happens. The author used the cellular automata as a model to calculate the acoustic characteristics of the vocal tract in each region. This study takes a different approach from the traditional z-transform to the cellular automata to calculate the dynamic sound pressure at each site of the vocal tract space. To simplify the calculation, an acoustic cylindrical tube model was used. Dynamic calculations were made even more manageable by changing the physical model from a three-dimensional to a one-dimensional cellular automaton model. Consequently, this study demonstrates that the relationship between the words and the sound pressure distribution can be examined dynamically using the cellular automata model.
“A record without (or with) prior acoustic information” and “Given: 1.Manet, 2.Coil—Oscillation from a minimum unit of speaker”
Authors: Jo Kazuhiro , Smith John
Published: November 2016

In this demonstration, we’d like to introduce two of our work, “A record without (or with) prior acoustic information” and “Given: 1.Manet, 2.Coil—Oscillation from a minimum unit of speaker.” The first one is a work in which we computationally draw a groove of a record as a vector graphic (with Adobe Illustrator or other tools) by calculating frequencies with a number of zigzags and engrave the groove on diverse materials on diverse material including paper, wood, or acrylic with laser cutter or cutting plotter to produce sounds. Through the demonstration, we show a process of making the record with a cutting plotter on the spot. The result and other examples would be played on a standard analog record player. The second one is a work in which we split a unit of a speaker into a magnet and a coil. We demonstrate an example of the work by Johnsmith as a cartilage conduction hearing with a set of neodymium magnets and a pair of coils with stereo mini jack. Through the demonstration, people could listen the sound from her/his portable audio player by directly vibrating her/his cartilages. Both of the work would present alternate embodiments of matured audio technologies (i.e., vinyl record and headphone) with a help of later technological developments. The demonstration shows basic principles of how audio technologies work. Through our practices at the intersection of media archeology and personal fabrication, we’d like to reconsider the ordinariness of acoustic media technologies.
Factors influencing students’ choice of musical instruments: A case study of Tertiary Institutions in South-Eastern Nigeria, a survey of University of Nigeria, Nsukka, College of Education Eha-Amufu Nsukka and Nnamdi Azikiwe University, Awka
Authors: Onwubiko Stephen G.
Published: November 2016

The choice of musical instruments is among the most important factors in determining the course of students’ music education. Instruments and its/their selection can be a challenging process with attendant factors. Musical acoustics which falls into intrinsic-extrinsic motivating factor and gender stereotyping of instruments are among those factors. The association of musical acoustics with particular instrument can significantly influence students’ choice of musical instrument, thereby resulting in numerous negative-hatred consequences, including fewer instrument choices, limited ensemble participation, and peer disapproval. The findings show that musical acoustics reliably predicted the choice of musical instrument. In order for students to make the right instrument choice, musical acoustics should be encouraged, not the family (parents) forcing their children into musical instrument choice careers. Teachers, like parents, work very closely with learners in schools and they know the abilities of their students in various instruments. Therefore, teachers should guide their students in their musical instrument acoustics before their choice and aspirations in line with their abilities in various instruments. Musical acoustic guidance and counselling at tertiary entry level will enable the students learn about and explore careers that ultimately lead to career choice of the musical instrument; questionnaires as a means of data collection.
Acoustic characteristics of respirators
Authors: Sakuma Takao , Inoue Jinro , Yokoya Toshitaka , Endo Yukimi
Published: November 2016

In some workplaces, employees are obliged to wear a respirator to protect them from harmful substances. However, an acoustical problem with respirator design is that respirators diminish the voice. Frequency analysis of sound through respirators could help tackle the problems associated with this design. We used a mannequin with a loudspeaker attached to its mouth and emitting pink noise. We measured the noise with 59 combinations of respirators and filters. For half-face masks with one or two filters, attenuation of the noise under 1 kHz was relatively small. The attenuations over 1 kHz varied widely among the tested respirators. With full-face masks, the attenuated frequency was lower than with the half-face masks. Respirators with a speaking diaphragm conducted louder sound over 3 kHz than did respirators without a speaking diaphragm. Among disposable masks, the attenuations were smaller than with half-face masks. We discuss the requirements for smooth communication among workers using respirators in light of the attenuation values of respirators at different frequencies.
Watching gigahertz acoustic waves confined in cavities
Authors: Wright Oliver B.
Published: November 2016

Surface-acoustic and bulk-acoustic-wave wave devices based on waves in resonators have found extensive application in high-frequency signal processing. In particular, phononic crystals, metamaterials, and micron to sub-micron structures exhibit interesting physical properties, such as omnidirectional stop bands or tight wave confinement, that allow potential improvements to these devices. Here, we present results of real-time imaging and tracking of laser-excited acoustic waves at frequencies from 100 MHz up to ~100 GHz in various novel micron-scale cavity geometries: phononic-crystal slab cavity structures, metamaterial extraordinary-transmission structures and sub-micron fibres. Applications include gigahertz sound control and nanoscale acoustic imaging. [1] T. Dehoux et al., Light Sci. Appl. 5, 16082 (2016). [2] O. B. Wright and O. Matsuda, Philos. Trans. Roy. Soc. A 373, 20140364 (2015). [3] J. J. Park et al., Phys. Rev. Lett. 110, 244302-1-5 (2013).
From MHz to THz: How ultrasound and inelastic scattering see lattice dynamics
Authors: Hermann Raphael
Published: November 2016

Resonant ultrasound spectroscopy and direct phonon spectroscopy methods based on inelastic scattering of x-rays or neutrons provide complementary but also sometimes apparently contradicting pictures of the lattice dynamics. In order to resolve these apparent contradictions, the probe energy and length scales must be considered. I will review results for a few classes of energy material, such as bulk [Sergueev et al., Phys. Rev. B 91, 224304 (2015)] and nanostructured [Claudio et al. PCCP 16, 25701 (2014); pss B 251, 919 (2014); 213, 515 (2016); Klobes et al., Nanoscale 8, 856 (2016)] thermoelectric materials, magnetic and magnetocaloric materials [Herlitschke Phys. Rev. B 93, 094304 (2016); Klobes Phys. Rev. B 92, 014304 (2015)], or rutile oxides [Budai et al., in preparation]. [Work at Oak Ridge National Laboratory was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division; work at Forschngszentrum Jülich was supported by the Helmholtz Association VH-NG-407, HRJRG-402, DFG SPP-1386, and BMBF 03X3540. The European Synchrotron Radiation Facility, Advanced Photon Source, Petra III at DESY, and Institut Laue Langevin are acknowledgment for beam time allocation. The invaluable contributions of all collaborators are grateful acknowledged.]
Rapid wave velocity measurement by Brillouin scattering using artificially induced phonon
Authors: Shibagaki Yoshiaki , Kawabe Masahiko , Takayanagi Shinji , Mori Kazuma , Yanagitani Takahiko , Matsukawa Mami
Published: November 2016

Brillouin light scattering enables measurements of hypersonic longitudinal and shear velocities in the small area (diameter about 50 μm). One problem of the conventional Brillouin technique is the weak Brillouin scattering peak from thermal phonons and this results in the longer measurement time. To overcome this problem, we have proposed measurements of strong coherent phonons by fabricating a high frequency transducer on the sample surface. However, the fabrication of the transducer is not suitable for simple and nondestructive measurements. In this study, a small glass device with a ZnO piezoelectric thin film was used as a hypersonic transducer around 1 GHz. By attaching this transducer to the sample with coupling liquid, artificial coherent phonons were successfully induced in a sample. In the case of a quarts sample, strong Brillouin scattering peaks were observed using a tandem Fabry-Perot interferometer. The measured frequency shift of the peaks was equal to the excitation frequency of the ZnO piezoelectric film (resonance frequency: 822 MHz). The intensity of Brillouin peak from the induced phonons was about 375 times as strong as the peak from the thermal phonons. The technique of induced phonons can realize nondestructive and rapid velocity measurements in the small area.
Stimulus phase locking of cortical oscillation for perceptual organization
Authors: Takahashi Hirokazu
Published: November 2016

The phase of cortical oscillations contains rich information and is valuable for encoding sound stimuli. We tested whether and how spatial patterns of oscillatory phase locking within the auditory cortex better predicted perceptual organization than those of response amplitude. A high-density microelectrode array with 10 × 10 sites within 4 × 4 mm2 mapped LFPs at the 4th layer of auditory cortex in rats. First, in response to ABA-sequences with different inter-tone intervals and frequency differences, neurometric functions based on stimulus phase locking in the gamma band could better describe van Noorden’s perceptual boundary than the LFP amplitude. Second, when a random tone sequence was switched to a regular tone sequence, the gamma-band phase locking increased immediately after the transition from random to regular sequences. The amplitude of the tone-evoked response, on the other hand, increased with frequency separation with respect to the prior tone, irrespective of putative organization of auditory objects. These results suggest that the evoked-response amplitude encodes the local order of tones, while the phase locking better predicts the perceptual organization.
Investigating bottom-up auditory attention
Authors: Elhilali Mounya
Published: November 2016

In everyday life, we are surrounded by a cacophony of sounds that our brain has to sort through in order to focus on important information. The conspicuity of certain sounds allows them to grab our attention and “stand out” relative to the soundscape. In this work, we hypothesize that as sound statistics change over time, variance from these statistics drive bottom-up attention processes that direct our focus to certain objects in the scene. We investigate the perceptual space that renders certain sounds salient relative to their context, and examine neural underpinnings of emergence of these salient sounds using complex acoustic scenes as stimuli. Results reveal adaptive neural representations of the context and salient objects reflecting deviations from the statistical structure of the scene. We speculate that principles of predictive coding could explain a number of observed neural and perceptual findings and discuss relevance of such framework in understanding processes of auditory scene analysis.
Estimation of material properties using vibration magnification
Authors: Liem Alyssa T. , McDaniel J. G.
Published: November 2016

This presentation describes the use of video magnification to estimate material properties of a structure within a region of interest. Video magnification is a recently introduced technique that magnifies motions which are mathematically present in a video but often not visible to the human eye. Several recent papers have shown that this technique may be used to derive quantitative information about vibration without contacting the structure. Furthermore, the technique amplifies all components of the three-dimensional vibration field that are present in the plane of the video. In the present work, a mechanical excitation is applied to the center of a region of interest on a structure. The excitation is concentrated in space and time. The response of the structure is captured at high temporal and spatial resolution by a video camera focused on the area of interest. Material properties are then estimated by adjusting values in a model of the region until agreement is obtained throughout the temporal and spatial responses in the video. The present work allows one to understand physical mechanisms and improve numerical models. Use of an impulsive excitation limits the extent of testing to a region of interest. Experimental results will be presented.
The effect of semantic predictability on word intelligibility in natural and spectrally degraded sentences
Authors: Shahsavarani Bahar S. , Carrell Thomas , Samal Ashok
Published: November 2016

One of the most consistent findings across a wide range of methodologies and stimuli is the positive effect of semantic context and predictability on speech intelligibility. However, there is evidence that this may not be true for a limited range of stimuli. The present study investigated how sentences with spectrally-limited acoustic information constrained the use of semantic predictability in speech perception. This was studied by presenting listeners with spectrally-degraded and natural-speech sentences with high- and low-predictability words. The SPIN sentence lists and the associated multi-talker babble was used (Bilger, 1984). The results demonstrated that listeners benefited from high predictability in both cases but the degree of this effect was not equal. High predictability aided the perception of natural and 8-band speech equally. In contrast high predictability had a significantly smaller effect on speech intelligibility for 4-band speech. These findings are of special interest to investigations of speech perception in individuals with poor frequency representation such as those with cochlear implants.
Integration and maintenance of gradient acoustic information in spoken language processing
Authors: Falandays James B. , Toscano Joseph , Brown-Schmidt Sarah
Published: November 2016

Models of speech processing seek to explain how continuous acoustic input is mapped onto discrete symbols at various levels of representation, such as phonemes, words, and referents. While recent work has supported models that posit maintenance of fine-grained information, it is not clear how continuous, low-level information in the speech signal is integrated with discrete, higher-level linguistic information. To investigate this, we created acoustic continua between the pronouns “he” and “she” by manipulating the amplitude of frication in the initial phoneme. Using the visual world eye-tracking paradigm, listeners viewed scenes containing male and female referents and heard sentences containing a pronoun, which later disambiguated to a single referent. Measures of eye-gaze revealed immediate sensitivity to both graded acoustic information and discourse-level information. Moreover, when listeners made an initially incorrect interpretation of the referent, recovery time varied as a function of acoustic step along the pronoun continuum, showing that graded acoustic information was maintained over at least a five-word delay. The results suggest that not only are listeners highly sensitive to fine-grained acoustic information in the speech signal but also that non-categorical representations are used to guide linguistic interpretation for extended periods of time.