bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study of the influence of the mouth-flue-foot geometry on sounding mechanism of an “air-jet” instrument model
Authors: Tateishi Shuhei , Tsutsumi Genki , Kobayashi Taizo , Takami Toshiya , Takahashi Kin’ya
Published: November 2016

The geometry of flue and foot influences the stability of jet oscillation, which products aerodynamic sound as the sound source of “air-jet instruments. Thus, we numerically study the influence of mouth-flue-foot geometry on the stability of jet oscillation with compressible LES. We introduce a 2D flue organ pipe model terminated with a closed end. We investigate the influence of the length of the flue, the existence of chamfers at the flue exit and the volume of the foot. As a result, eliminating the chamfer makes the jet oscillation unstable, while adding the chamfer stabilizes the jet oscillation and sound generation. A long flue makes the jet motion stable and robust, so that it spends a long time to reach a stable oscillation and cannot response quickly to the change of the air supply. Thus a relatively short flue with the chamfers is suitable for a performance. This result qualitatively agrees with the experimental result reported by Segoufin et al.. We also found that the existence of foot stabilizes the sound oscillation in the pipe: the pressure oscillation in the foot synchronizes with that in the pipe with a phase delay, but eliminating the foot rather makes the sound oscillation unstable.
Effect of accuracy of digital map data on predicting road traffic noise in Japan
Authors: Hiraguri Yasuhiro , Fujimoto Kazutoshi
Published: November 2016

Use of GIS for evaluating the Environmental Quality Standards for Noise is established at local authorities in Japan. A digital map on a scale of 1/2,500 is generally used. However, it has not been clarified yet whether the digital map with such a scale has an accuracy to apply for the estimation of environmental noise. A ground plan of buildings on the digital map is a roof plan, because the digital map data are made on a basis of an aerial photograph. It is feared that the noise estimated by using such a map may have some differences in the effects of buildings on the noise propagation from reality. In spite of the fact that the propagation of road traffic noise is highly affected by whether a road is visible from receiving point or not, when the roof plan is used as the floor plan, the road is sometimes visible from the receiving point on the digital map, though it is invisible in practice. The aim of this study is, therefore, to reveal the effect of accuracy of the digital map in GIS on the estimation of road traffic noise for evaluation of the Environmental Quality Standards for Noise.
Sound source identification on automotive muffler surface using single explosion excitation and near-field acoustic holography method
Authors: Matsumoto Ryota , Seo Takehiko , Mikami Masato , Esaki Takashi
Published: November 2016

Recent automobiles tend to have larger interior space, resulting in the smaller space for arranging the muffler. Flat shape mufflers are required for this reason but cause relatively large radiation noise from the surface. In order to improve understanding of radiation noise generation mechanism of flat shape muffler, we tried to identify the noise sources using the near-field acoustic holography (NAH) method on muffler surface excited by a single explosion pulse, which simulates a single pulsation in the exhaust system,. Two types of mufflers were tested with different shapes. Results show that some areas had large vibration velocity at specific frequencies depending on the muffler shape. The flat muffler tends to generate large radiation noise and vibration velocity as compared with a conventional one. In the front and rear outer plates of the muffler, large vibration velocity exists within a certain range of frequency. Within the same frequency range, the flat muffler has more number of the peak of radiation noise as compared with the conventional one.
Determining average flow speed in a scale model smokestack by measuring correlated noise through a long-wavelength acoustic flow meter
Authors: Abbott JohnPaul R. , Gillis Keith A. , Moldover Michael R. , Gorny Lee J.
Published: November 2016

As part of its Greenhouse Gas and Climate Science Measurements Program, the National Institute of Standards and Technology (NIST) has successfully developed long-wavelength acoustic flowmeters (LWAFs) to measure the average flow speed, V, and the speed of sound, c, for a fluid passing through 1:100 scale test model of a coal-burning power plant smokestack with standard measurement uncertainties of less than 1% and 0.1%, respectively. This improves upon the estimated 5-20% standard measurement uncertainty for existing technologies. With this success NIST has constructed a 1:10 scale test model for further investigation. Current LWAF measurement techniques are reliant on a good signal-to-noise ratios (SNR), which may be problematic for the 1:10 scale test model since the amount of turbulence and difficulty generating high-amplitude low-frequency excitation signals at larger scales increases. Anticipating poorer SNRs for larger scale test models, NIST is investigating the use of the LWAF to correlate low-frequency acoustic noise, flow noise, and other excitation signals as an alternative technique to measure V and c with the goal of obtaining the same standard measurement uncertainties of less than 1% and 0.1%, respectively. The latest results of this ongoing investigation are presented.
Cut-off frequency criterion for wind noise contributions for wind noise reduction enclosures
Authors: Abbott JohnPaul R. , Raspet Richard , Collier Sandra , Alberts W. C. K. , Noble John
Published: November 2016

A cut-off frequency criterion for contributions for the wind noise generated from the undisturbed and surface regions for a wind noise reduction device, such as wind fence enclosures and semi-porous fabric domes, is given. The calculations of the measured wind noise inside an enclosure assume that contributions from the undisturbed region and the surface region dominate and are physically restricted to turbulence wavelengths that are larger than the enclosure and the same size or smaller than the enclosure, respectively. The cut-off frequency criterion defines the wavelength where the dominant source of wind noise transitions from interactions in the undisturbed region to the surface region. The transition point is determined by considering when a volume enclosed by a wavelength, Vλ, is equal to 100 times the volume enclosed by the reduction device, VE. Wind noise calculations following this criterion are presented for a set of semi-porous fabric domes that are 4 m wide and 2.1 m tall, and three cylindrical wind fences that are 5 m wide and 2.9 m tall, 5 m wide and 5.8 m tall, and 10 m wide and 2.9 m tall.
Acoustic-vortex interaction in reacting wakes near the global hydrodynamic stability limit
Authors: Emerson Benjamin , Lieuwen Tim
Published: November 2016

This study experimentally characterizes the effect of acoustics on the vortex dynamics in reacting wakes. This work is motivated by the problem of combustion instabilities, where the natural combustor acoustics excite hydrodynamic instabilities of the flow that, in turn, induce heat release oscillations. Time resolved PIV, Mie scattering, and chemiluminescence imaging measurements are obtained in a reacting wake facility with acoustic excitation. Measurements and analysis are performed where the acoustic frequency is varied relative to the global mode frequency. We observe that the acoustic waves excite a varicose mode of vortex shedding, which is locked into the acoustic frequency. When the acoustic frequency is close to the natural global hydrodynamic frequency of the wake, we observe resonance, which manifests as very rapid amplification of these shed vortices as they convect downstream. Interestingly, in the resonant case, the vortices stagger from the varicose structure deposited by the acoustic waves and assume a sinuous structure that resembles the hydrodynamic global mode. A linear, local stability analysis, together with a nonlinear analysis, help elucidate the physics that govern the vortex staggering. The study counterintuitively concludes that the resonance, due to the change from varicose to sinuous structure, may help alleviate combustion instability.
Chaos in a stadium-shaped acoustic cavity
Authors: Yu Roger
Published: November 2016

A numerical scheme has been developed to solve wave equations for chaotic systems such as stadium-shaped cavity. The same numerical method can also be used for finding wave properties of rectangle cavities with randomly placed obstacles. About 30,000 eigenvalues have been obtained accurately on a normal circumstance. For comparison, we also initiated an experimental study which determines both eigenfrequencies and eigenfunctions of a stadium-shaped cavity using pulse and normal mode analyzing techniques. The acoustic cavity was made adjustable so that the transition from nonchaotic (circle) to chaotic (stadium) waves can be investigated.
Behavioral and electrophysiological evidence for backward masking
Authors: Sears Robert , Smith Silas , Galvin Brittany , Yonovitz Al
Published: November 2016

Backward Masking (BM) functions have been shown to relate to age, lead toxicity, and are differentiated in children with language disorders. These functions may be indicative of auditory processing deficits. This study compared BM functions obtained from Evoked Potentials (EP) to behaviorally obtained functions. A stimulus followed by an ISI and a noise masker were presented. All were studied individually in the appropriate temporal alignment. The design of this study allowed observation of the early, middle, and late auditory evoked potentials. For the behavioral task, stimuli were presented with a method of adjustment. This study randomly presented four different stimulus conditions: 1) stimulus alone, 2) noise alone, 3) stimulus and noise, and 4) silence. With a long inter-trial interval (1 s) and high sample rate (25,600 Hz) EP’s were obtained for 4000 trials. The stimuli were pure-tones (1000 Hz, 10 ms duration with a Blackman function and brief 100 microsecond clicks of varying intensity and varied ISI. Older and younger subjects were tested. Results indicated that EP’s could be arithmetically combined to observe the differential electrophysiological responses and were highly correlated with the behaviorally obtained BM functions.
Relationship between the frequency asymmetry of across-frequency gap detection and the temporal asymmetry of cochlear responses
Authors: Takamura Akihide , Ito Kazuhito , Mori Shuji
Published: November 2016

Gap detection is often used to estimate the temporal resolution of the human auditory system. Gap detection performance becomes worse when the frequency difference between the leading and trailing markers that delimit a silent gap gets larger. In addition, the across-frequency gap detection threshold is not always constant when the presentation order of the two markers is altered, even if the frequency difference remains unchanged. We suspect that these inconsistencies in gap detection performance are partly caused by cochlear delay; i.e., low frequency signals reach the responding areas of the cochlea later than higher frequency signals. To examine whether across-frequency gap detection thresholds increase when the leading marker is higher in frequency than the trailing marker, as would be expected if the above mentioned hypothesis is correct, we conducted across-frequency gap detection tasks by altering the presentation order of the two markers (marker frequency: from 250 to 8000 Hz). The gap detection thresholds appeared to vary irrespective of the presentation order of the two markers, which does not support the cochlear delay hypothesis.
Predicting the characteristics of wideband absorbance in ears with middle-ear pathologies
Authors: Kei Joseph , Aithal Venkatesh , Aithal Sreedevi , Anderson Shane , Wright David
Published: November 2016

Wideband absorbance (WBA), a measure of the proportion of energy absorbed by the middle ear, is an emerging technology to detect middle-ear dysfunction. WBA results in display absorbance as a function of frequency. WBA characteristics in adults with normal middle-ear function show a broad peak between 2 and 4 kHz. While changes in WBA results in patients with middle-ear dysfunction have been described previously, the acoustical properties accounting for those changes have not been investigated. This study investigated the wideband acoustical properties of the middle ear using a spring-mass-friction mechanical system modeling technique. When the system undergoes simple harmonic motion with damping, its frequency of vibration is given by f =1/2π√(k/m), where k and m represent stiffness and mass of the system, respectively. In the presence of middle-ear dysfunction, the k to m ratio changes, resulting in reduced WBA amplitude and a change of the frequency of vibration as shown by a shift of the broad peak of WBA. This study demonstrated the applicability of this modelling technique to account for the changes in acoustical properties of the middle ear in the presence of middle ear dysfunction arising from Eustachian tube dysfunction, otosclerosis, ossicular-chain discontinuity, and cholesteatoma.
Flexibility of ossicular joints reduces damaging impulse peaks
Authors: Gottlieb Peter K. , Vaisbuch Yona , Puria Sunil
Published: November 2016

The presence of three distinct middle-ear ossicles is a uniquely mammalian trait whose benefits are still debated. One hypothesis is that the flexibility afforded by the two synovial joints connecting the ossicles provides a protective advantage by dispersing potentially damaging impulsive stimuli before they reach sensitive cochlear structures. The 3D velocity of points along the ossicular chain in unaltered cadaveric human temporal bones (N = 9), stimulated with acoustic impulses, was measured in the time domain using a Polytec CLV-3D laser Doppler vibrometer. The measurements were then repeated after fusing one or both of the ossicular joints. Sound transmission was characterized by measuring the amplitude, width, and delay of the impulsive velocity profile as it traveled from the eardrum to the cochlea. In most cases, a delay was noted across either or both of the ossicular joints, and the velocity profile at the stapes was lower in amplitude and broader than at the umbo. Typically, fusing the incus-stapes joint had a small effect, while fusing the incus-malleus joint both significantly increased the amplitude and decreased the width of the velocity profile at the stapes relative to the unaltered case. [Work supported by NIH grants R01 DC 05960 and F31 DC 013943A.]
Identifying conductive conditions in neonates using wideband acoustic immittance
Authors: Myers Joshua , Kei Joseph , Malicka Alicja N. , Aithal Sreedevi , Aithal Venkatesh , Driscoll Carlie , Khan Asaduzzaman , Manuel Alehandrea , Joseph Anjali
Published: November 2016

Wideband acoustic immittance (WAI) is an innovative method of middle ear assessment with significant advantages over currently available clinical tests. Previous large-scale studies in neonates have assessed accuracy against evoked otoacoustic emissions but further research is needed using a more stringent gold standard. The aim of this study was to evaluate the test performance of WAI in neonates against a composite reference standard consisting of distortion-product otoacoustic emissions (DPOAEs) and high-frequency tympanometry (HFT). Five hundred and five neonates were recruited from the maternity ward of the Townsville Hospital to participate in the study. DPOAEs and HFT were performed on each neonate to assess outer and middle ear function. Wideband absorbance and complex admittance (magnitude and phase) were measured from 226 to 8000 Hz in each neonate at ambient pressure using a click stimulus. Best separation between groups that passed and failed the reference standard occurred at frequencies from 1500 to 3000 Hz for absorbance, 1000-2000 Hz for admittance magnitude, and 2000-4000 Hz for admittance phase. The WAI response was modelled using multivariate logistic regression and the model validated with bootstrap resampling. The WAI model accurately identified conductive conditions with an area under the receiver operating characteristic curve of 0.89.
Toward an evidence-based taxonomy of everyday sounds
Authors: Bones Oliver C. , Cox Trevor J. , Davies William J.
Published: November 2016

An organizing account of everyday sounds could greatly simplify the management of audio data. The job of an audio database manager will typically involve assigning a combination of textual descriptors to audio data, and perhaps allocation to a predefined category. Retrieval is likely achieved by matching the descriptor to keyword search terms or by browsing through categories. While classification of musical instruments using this type of approach is relatively simple by virtue of the fact that a predefined taxonomy can follow a signal-related hierarchy, non-musical sounds do not necessarily follow such a hierarchy. In addition, classification is made more problematic by the ambiguity of words used to describe everyday sounds. Another area in which the issue of establishing a taxonomy of everyday sounds is particularly pertinent is that of soundscape research; research into soundscapes—acoustic environments as they are perceived—is a relatively new and multidisciplinary area, and as such descriptive terms for everyday sounds are currently used inconsistently. Many existing attempts to taxonomize everyday sounds prescribe categories that are not mutually exclusive, in that everyday sounds could exist in a number of categories; moreover, many are not based on empirical evidence. Here, we present a robust method for creating an evidence-based taxonomy of everyday sounds, involving hierarchical clustering from dimensions generated by correspondence analysis of data from a simple card-sorting and naming procedure.
A research on understanding of piano players’ control of performance behavior in brushing up processes of music piece using Near-infrared spectroscopy
Authors: Matsuo Ayako , Akita Takeshi , Sano Naoko
Published: November 2016

In this paper, we are studying about the method in which we could catch the relationship between players’ perception of sonic field environment and the following control of playing behavior characteristically. Based on the above way of thinking, we made some measuring experiments on some actual performances in brushing up processes, and analyzed and considered about the difference between experimental results from the view point of the perception and behavior control. Already, it has been shown that measuring the change in frontal lobe brain blood flow using Near-infrared spectroscopy (NIRS) Brain-measuring-apparatus and comparative-analyzing the measured data was different by a variety of psychological conditions. In this paper, adopting the above method, we measured subjects’ frontal lobe brain blood flow on two actual performance of the early stage “performance of playing at sight” and the final stage “performance of automated levels” in proficiency-process. After some supplementary interviewing to subjects about their measured practices, we analyzed about control of performance behaviors in some sonic environment. The analysed results show that we could measure two each status of “the perception and behavior control” on actual performance of “performance of playing at sight” and “performance of automated levels” in proficiency-process characteristically.
Effects of spectral gaps on the contribution of specific frequency bands to the loudness of broadband sounds
Authors: Jesteadt Walt , Wróblewski Marcin , Thrailkill Katie
Published: November 2016

Contributions of individual frequency bands to judgments of total loudness can be assessed by varying the level of each band independently from one presentation to the next and determining the relation between the change in level of each band and the loudness judgment. Recent studies using stimuli consisting of 15 bands of noise, each two critical bands wide, have shown that frequencies near the lower and upper edges of a broadband noise make a greater contribution to overall loudness than frequencies in the center of the spectrum. In the present study, eight listeners with normal hearing compared the loudness of two 15-band stimuli with average levels of 59 dB SPL per band and of stimuli where 1, 3, 5, or 7 bands were missing from the center of the spectrum. Listeners placed greater weight on the bands at the edges of the spectral gap and the effect was larger for greater gap widths. Edge bands received more weight regardless of absolute frequency and the high-frequency edge of the low bands received greater weight than the low-frequency edge of the high bands. These effects are not predicted by loudness models. [Work supported by NIH.]
Auditory training and subsequent generalization with speech and non-speech stimuli
Authors: Spencer Nathaniel , Thompson Eric R. , Wisniewski Matthew G. , Simpson Brian D. , Iyer Nandini
Published: November 2016

Auditory training studies have varied in degree-of-similarity between the training and testing conditions. Some focused testing on the trained task (e.g., Sweetow and Henderson Sabes, 2007), while others addressed whether the training effects generalize to other tasks. The current study used speech and non-speech stimuli to explore how much training in a specific analytical listening task would generalize to performance improvements for another. Naïve listeners participated. Percent correct was measured as a function of signal-to-noise ratio (SNR) in pre- and post-tests with the “multiple-bursts same” (MBS) paradigm (Kidd et al., 1994) and the speech-target/speech-masker Coordinate Response Measure (CRM) paradigm. There were three training groups in a between-groups design: 1) training in a masked speech identification task (the CRM) with the competitors varying in f0 separation (Darwin et al., 2003); 2) training in the MBS task with the protected-region (frequency region with no maskers) bandwidth around the target varying; and 3) no training. Preliminary data describe individual-subject variability in pre-test performance and indicate performance improvements with auditory training. The degree of generalization will be explored for the trained sub-groups. 1) Int J. Audiol. 46. 374. 2) J. Acoust. Soc. Am. 114, 2913. 3) J. Acoust. Soc. Am. 95, 962.
On the color of speech: The effect of speaking styles on speech recognition by cochlear-implant users
Authors: Tamati Terrin N. , Janse Esther , Başkent Deniz
Published: November 2016

Speaking styles are a common source of real-life variability that may affect cochlear implant (CI) speech communication. Speech transmitted via a CI is heavily degraded in acoustic-phonetic cues. Therefore, the extent to which (and for what conditions) individual CI users benefit from carefully articulated speech (or are hindered by casually articulated/reduced speech) is unclear. First, we examined the impact of speaking styles on CI speech recognition in favorable listening conditions. CI users and normal-hearing (NH) listeners tested with 8- and 4-channel acoustic CI simulations completed a sentence recognition task with casual and careful sentences (with similar lexical and semantic content) in the quiet. Second, we explored individual performance on this task and its relation with standard speech recognition scores and self-reported real-life hearing abilities. Listeners were overall more accurate on careful sentences than the casual sentences, but casual sentences were disproportionately more difficult than careful sentences for 4-channel stimulations (simulated “poor” CI users) and some CI users. Additionally, CI users with lower self-reported real-life hearing abilities and with lower standard sentence recognition scores were also less accurate on the casual sentences. The results suggest that speaking styles can challenge CI speech recognition, especially for listeners with poor overall recognition skills.
Modeling the effect of olivocochlear efferents on the subcortical envelope following response in humans
Authors: Smalt Christopher J. , Heinz Michael G. , Strickland Elizabeth A.
Published: November 2016

The medial olivocochlear reflex (MOCR), a feedback mechanism that controls outer-hair-cell gain, is thought to provide protection and signal enhancement for a listener in background noise. This listening advantage can be attributed to reduced auditory-nerve firing to noise, which results in an increased dynamic range for encoding signals of interest. The computational model presented here updates the modeling work of Smalt et al. (2014) by adding dynamic MOCR characteristics to the more recent “humanized” model version (Zilany, et al., 2014). This MOCR implementation effectively reduces outer-hair-cell gain depending on the stimulus frequency, level, and timing. Human Envelope Following Responses (EFRs; Bharadwaj, 2015) were compared to outputs of the Nelson and Carney (2004) Inferior-Colliculus (IC) model combined with the MOCR auditory-nerve model. Adding simultaneous contralateral noise did not significantly affect the model IC modulation-filter energy at the stimulus frequency, while a 500-ms contralateral noise precursor increased the output by ~3 dB consistent with the human data. Further study of the auditory-nerve model with the MOCR may help to understand human susceptibility to noise-induced hearing loss, the impact of damage to low-spontaneous rate auditory-nerve fibers, as well as to develop new algorithms for hearing aids to restore normal speech perception in noise.
Dimensional interactions in the perception of frequency and bandwidth
Authors: Silbert Noah H. , Lentz Jennifer
Published: November 2016

As part of a project to develop efficient techniques for measuring the characteristics of tinnitus percepts, multiple listeners exhibited difficulties accurately perceiving the bandwidth of stimuli. Frequency perception seems to dominate bandwidth perception and relative bandwidth judgments seem to interact with frequency judgments in complex ways. In the present work, we use general recognition theory (GRT) to directly probe perceptual interactions between center frequency and bandwidth in noise stimuli. GRT is a multidimensional generalization of signal detection theory, and it allows us to simultaneously model within-category and between-category interactions between dimensions, as well as dimension-specific patterns of response bias. The most common stimulus set for GRT experiments consists of the factorial combination of two levels on each of two dimensions. In order to more fully investigate the perception of frequency and bandwidth, we extend this standard approach to encompass multiple factorial sets of stimuli spanning a larger region of frequency-by-bandwidth space. We will present multilevel Bayesian GRT models fit to frequency-by-bandwidth perception data.
Experimental examination of acoustic sensing using super-directivity speaker and super-resolution signal processing with pulse compression technique
Authors: Asakura Yuya , Okubo Kan , Tagawa Norio
Published: November 2016

Acoustic sensing technology in the air is a promising method to acquire shapes and/or position of a target object. Universal and smart technology in Acoustic sensing, however, cannot be sufficiently established because of various acoustic environmental noises, attenuation effect, etc. Normally, pulse transmission using higher frequency cannot obtain high SNR images due to the atmospheric attenuation, whereas the spatial resolution becomes lower by use of signals in lower frequency range. That is, there is the tradeoff between frequency and spatial resolution of transmission signal. In recent years, with the development of computer technologies, a single processing method becomes important for the real-time sensing in air. To overcome these problems, therefore, in this study, we propose and examine acoustic sensing in the air using the super-directivity speaker, super-resolution signal processing, and pulse compression technique (PCT). By applying the super-resolution signal processing and called SCM-MUSIC (FM-chirp based Super resolution Correlation Method—MUltiple SIgnal Classification) method, we can improve the SN ratio and spatial resolution in acoustic sensing. Our experimental results suggest that combination of super-directivity speaker and super-resolution signal processing with PCT enables high-resolution acoustic imaging. Additionally, we discuss the feasibility of far-field high resolution imaging by the proposed method.
What is the impact of individualizing head-related transfer functions used for sound externalization?
Authors: Leclère Thibaud , Lavandier Mathieu , Perrin Fabien
Published: November 2016

Natural listening can be reproduced via headphones by introducing head-related transfer functions (HRTFs) which represent the temporal and spectral modifications occurring when a sound travels from the source to the listener’s ears. HRTFs are individualized, they differ from one listener to the other and strongly depend on their morphology. For practical reasons, it might be complicated to measure HRTFs from each listener and, as a result, non-individualized HRTFs (e.g., measured using a manikin) are sometimes preferred. This study investigated the consequences of this non-individualization on perceived sound externalization. First, individualized HRTFs were measured for a set of listeners in different rooms for sources at different azimuths. Non-individualized HRTFs were also measured at the same positions using a manikin. In a first experiment, listeners evaluated the perceived degree of externalization of sounds convolved with their own HRTFs (individualized condition) or with those measured using the manikin (non-individualized condition). In a second experiment, the effect of equalizing the frequency-response of the headphones was investigated by using either the headphones (equalized or not) or (non-equalized) earphones to deliver the convolved signals. The results of this study are used for a preliminary quantification of the differences between individualized and non-individualized sound externalization.
Auditory evaluation of head-related transfer functions from multiple databases
Authors: Zhong Xiao-li
Published: November 2016

In order to rationalize the combined utilization of multiple databases of head-related transfer functions (HRTFs), this work investigates the influence of different HRTF measuring conditions on auditory perception. First, the HRTFs of KEMAR artificial head from five databases were selected, and the diffusion-field equalization was applied to the original HRTFs as a pre-processing method to reduce the differences from different measuring conditions. Then, the spectral deviations among the equalized HRTFs were calculated to objectively evaluate the HRTF’s differences from different measuring conditions. Finally, a series of listening experiments (including localization and discrimination experiments) were conducted to subjectively evaluate different HRTF measuring conditions on auditory perception. Results indicate that the different measuring conditions has less influence on the localization performance of HRTFs, suggesting the auditory consistency among multiple HRTF databases in terms of localization; however, only part of HRTF databases are consistent in terms of indiscernibility which is a stricter metric. [Work supported by National Natural Science Foundation of China, No.11474103.]
Emphasizing interaural level difference corrects the shift of perceived direction of sound for consumer-grade bone-conduction headphones
Authors: Iwaki Mamoru , Chigira Yoshiki
Published: November 2016

Sounds are perceived not only in air-conduction (AC) manner but also in bone-conduction (BC) one. According to our investigation [Autumn Mtg Acoust. Soc. Japan, 3-1-18, pp. 865-866, 2013; IEEE Int’l Conf. GCCE, pp. 194-197, 2014] about the discrepancy of perceived directions of sound through a BC headphone (TEAC Filltune HP-F200) and an AC headphone (SONY MDR-Z900), the perceived direction through a BC headphone inclined toward the center. In this report, we examined a correction of the shift of perceived direction of sound by emphasizing interaural level difference (ILD). Seven students with normal audibility participated in our experiment. It was carried out in a sound proof room. Sound stimuli were pure-tones of 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz, with 11 different directions for each stimulus. The sound level through AC headphone was 70 dB. That through BC headphone was adjusted to have the same loudness, for each participant. As a result, the perceived direction through BC headphones was improved. Although the BC headphone used in our experiment produced about 20 dB of ILD in the external auditory meatus, it is difficult to explain that in terms of cross hearing and trans-cranial attenuation, but cartilage conduction hearing. Emphasizing ITD had little improvement of perceived direction.
Investigating integration between auditory and visual location information presented in an augmented-reality device
Authors: Okumura Hiraku , Sushrut Khiwadkar , Kim Sungyoung
Published: November 2016

Effective rendering technique of auditory information for an augmented reality (AR) device has been investigated. Researchers and industries are searching for new applications incorporating AR and Virtual Reality (VR) technologies, which provide enhanced user-experience of interactivity and intimacy. To utilize these benefits best, homogeneous integration between visual and auditory information is important. To date, the binaural technology based on head-related transfer function (HRTF) has been used to create immersive and three-dimensional audio objects for VR and AR devices. In this study, we compared the HRTF method with a stereophonic panning method that only controls Inter-aural Level Difference (ILD) for an AR device (a smart see-through glass) and investigated the precision of auditory information required for a coherent representation with a target visual image at the locations of 0 degree, -5 degrees, and -10 degrees in a counter clockwise. Auditory stimuli were rendered to have target locations in the horizontal plane from + 45 degrees to -45 degrees with a 5-degree interval. In the subjective evaluation, each participant answered whether a randomly given auditory location was matched to a target location of the visual image. The results showed that two audio rendering methods did not produce significant difference in creating integrated perception in an AR device.
INCE/J Vibration Measurement Manual for Buildings—Part 2: On the assessment based on the vibration
Authors: Matsumoto Yasunao
Published: November 2016

This paper discusses the assessment of building vibration in terms of human responses based on vibration measurements specified by the Vibration Measurement Manual for Buildings developed by the Technical Subcommittee on Environmental Vibration Evaluation of the Institute of Noise Control Engineering of Japan. As stated in some of the current international and national standards, building vibration could cause adverse comments from occupants when the vibration magnitude is in excess of human perception only slightly. For the assessment of building vibration based on the measurement manual, therefore, a range of human vibration perception threshold was derived from the previous studies that determined the perception thresholds in experiment involving human subjects. The vibration perception threshold range implies a range of vibration magnitude for different frequencies that may correspond to lowest vibration magnitudes people with different sensitivities to vibration can detect. The vibration magnitude within or in excess of the perception range may be assessed as a magnitude that can be perceived by occupant at different possibilities. The assessment with the vibration perception threshold range does not necessarily show if the building vibration to be assessed has a magnitude high enough to cause adverse comment.
Isolation of residential buildings from ground vibration from railroad
Authors: LoVerde John , Dong David W.
Published: November 2016

For residential developments near railroad tracks, ground vibration due to train movement is often a concern. Although there are usually no code requirements for vibration levels, ground vibration levels are often compared to the criteria recommended by the FTA; these criteria are sometimes explicitly included as part of the Conditions of Approval or other governing documents required for the development of the site. These criteria are often exceeded when the development is in proximity to the tracks, but experience has provided limited practical applications for reducing the vibration. Some of the methods suggested include isolating the building on elastomeric bearings, digging a wave barrier trench, increasing the mass of the foundation, and stiffening the joist structure. However, these measures have been rarely employed, and little data are available on the objective effects of the mitigation, correlated with the benefit to occupants. Despite this, such methods are sometimes required on a project without analysis of efficacy or even an understanding of the anticipated result. The authors have compiled the results of recent measurements on several buildings that employed some these measures, and discuss the benefits of the mitigation measures and their application to building construction strategy.
Processing of aircraft signatures with significant Doppler, simultaneously observed on microphones and distributed underwater sensors
Authors: Hursky Paul
Published: November 2016

An experiment was performed with a source mounted on an aircraft with a microphone array rigidly mounted on a research vessel, and with sonobuoys and a vertical line array deployed in the ocean underneath. Programmed waveforms, including tones, linearly frequency modulated tones, and m-sequences, were transmitted from the airplane. The Doppler in this configuration was substantial, due to the sound speed in air being 1/5 that of water, with much of the acoustic path passing through the air. We will present results of matched filtering the transmitted waveforms, using various combinations of observed signals, including using replicas augmented by modeling, to compensate for the Doppler in order to enhance the coherent integration gain in this configuration.
Paradigm shift of underwater echo sounding technology I—Principle and algorithm
Authors: Matsuo Ikuo , Sasakura Toyoki
Published: November 2016

Underwater echo sounding technology was developed 65 years ago and has been applied in various systems such as fishfinder, bathymetry, sonar, side scanning sonar, multi beam echo sounding system, and synthetic aperture sonar. Here, we proudly suggest a new concept that may change the history of underwater echo sounding technology, the “Paradigm Shift.” In the conventional system, the transmitting signal is transmitted after receiving the target signal, e.g., a bottom echo. Therefore, the transmission intervals are always longer than the time of the round trip distance to the target divided by the underwater sound velocity. On the other hand, by adapting our new “Paradigm Shift” into the system, the transmission intervals can be decided without depending on a target and it will be possible to conduct a bathymetry survey that transmits 100 times per second. The system was tested and confirmed in the actual sea trial. This new concept, the “Paradigm-Shift-Echosounder” ( PSE ), utilizes the 7th order and 127 kinds of Gold code sequence signals. Different code of Gold code signals will be transmitted in each transmission, and receiving signals will be identified by the correlation of the 127 kinds of Gold code sequences of different transmission signals.
Paradigm shift of underwater echo sounding technology II—Experiment and actual sea trial
Authors: Sasakura Toyoki , Matsuo Ikuo
Published: November 2016

The newly suggested “Paradigm-Shift-Echosounder” (PSE) for bathymetry survey was tested in a sea trial experiment using a prototype. Experiment was conducted at the depth of 30-80 m using 200 kHz signals transmitted 100 times per second and succeeded to obtain continuous bottom echo data. We also conducted a side scanning sonar experiment using 88 kHz signals, at a site with a depth more than 500 m and succeeded to obtain the echo of a 2 m x 5 m artificial reef moored at the depth of 50 m. Correlation processing was done and we managed to reconstruct a high-resolution echogram of the artificial reef. The prototype used in the trial experiments utilizes the 7th order Gold code sequence. Four cycles of carrier signals as 1 bit, the transmission signals are all phase-modulated. The pulse length of transmission signal is 2.54 ms for 200 kHz. As there are 127 Gold codes, transmission signals of the same code are repeated every 1.28 seconds. The receiving signals are then processed by the correlator, with a shift register length of 4064 stages by 8-times sampling frequency for carrier frequency. There are 127 kinds of replicas of correlator, and the numbers of “Exclusive OR + Summation” circuits are also 127.
Three-dimensional acoustic modeling of a complex harbor environment
Authors: Porter Michael B. , Henderson Laurel J. , Duda Timothy F. , Newhall Arthur E.
Published: November 2016

Typically, we model sound propagation in the ocean viewing it as an “open” environment where the sound propagates outwards from the source. Of course, targets are reflectors, and other features such as islands and seamounts have been of interest as false targets. However, the standard acoustic models based on rays, normal modes, spectral integrals, and parabolic equations generally consider outgoing energy confined to a single bearing line. In contrast, constrained or partially closed environments such as harbors introduce special issues. Obviously, the sound can be reflected back by seawalls and ship hulls, to mention just a couple of features of harbors environments. Considering coastal environments more broadly, sound reflections also may be caused by wharves, docks, piers, boat landings, quays, floats, groins, and jetties as well as natural features such as submarine canyons. In short, we have sound refracted in the latitude/longitude plane and reflected by a variety of features. In terms of computational ocean acoustics there are few options for modeling such problems. We discuss a comprehensive 3D beam tracing approach implemented in a model called BELLHOP3D that can handle 3D effects including complete reversal of the sound. It is also capable of handling narrowband waveforms (tonals) as well as full broadband timeseries. We will demonstrate and test the model using an example location that is expected to become the site of a future sea test.
Underwater sound propagation and scattering in Ports and Harbors
Authors: Badiey Mohsen
Published: November 2016

Ports and Harbors are crucial life lines in our economy and commerce. To ensure safe and efficient utilization of these important facilities, a thorough understanding of underwater sound propagation and scattering in very shallow water regions is critical. These regions however, present a challenging waveguide for underwater acoustics. Weather the goal is active acoustics (such as underwater communication) or passive acoustics (such as source detection and localization), detailed understanding of channel response function is necessary in order to develop and apply proper security measures. Several studies in recent years have addressed interesting results in acoustic signal propagation and scattering. These include effects of sound speed profile in water column, sea surface dynamic behavior, and seafloor attenuation. Signal coherence, and spatial and temporal variabilities due to environmental parameters have all been examined and to some extent modeled. Deterministic features due to interaction of broadband acoustic signals with the dynamic environment are shown. These results have been incorporated in development of robust underwater communications that can also be utilized for Harbor security implementation. In this paper, we present results of several recent experiments and modeling using Ray and Parabolic Equation approaches to understand this problem. [Work supported by ONR 322 OA.]
Acoustics for amplified music and a new, variable acoustics technology
Authors: Adelman-Larsen Niels W.
Published: November 2016

Surveys among professional musicians and sound engineers reveal that a long reverberation time at low frequencies in halls during concerts of reinforced music such as pop and rock is a common cause for an unacceptable sounding event. Mid- and high-frequency sound is seldom a reason for lack of clarity and definition due to a 6 times higher absorption by audience compared to low frequencies, and a higher directivity of speakers at these frequencies. Lower frequency sounds are, within the genre of popular music, rhythmically very active and loud, and a long reverberation leads to a situation where the various notes and sounds including vocals cannot be clearly distinguished. This reverberant bass sound rumble often partially masks even the direct higher pitched sounds. A new technology of inflatable, thin plastic membranes presents a solution to this challenge of needed low-frequency control. It is equally suitable for multipurpose concert halls that need to adjust their acoustics by the push of a button and for halls and arenas that only occasionally present amplified music and need to be treated just for the event. The technology, permanently mounted, is being projected in various concert halls around the world and is being installed in the new Dubai Opera and the Sheik Jaber Al Ahmad Cultural Center, Kuwait during spring 2016. This paper presents the authors’ research of also large venues as well as the technology showing applications including on/off measurements of reverberation time versus frequency.
Proposed design schemes for vineyard concert halls with subjective test of solo singing
Authors: Chiang Weihwa , Chen Yi-Run , Tanadi Melisa Rosiana
Published: November 2016

Although a vineyard hall has both acoustical and architectural merits associated with its short source-receiver distance, attention to acoustical design needs to be placed upon the terrace seating that primarily governs the energy distribution in such a hall, in particular when listening to the vocal sound where both acoustic and visual deprivation exists. Design schemes were developed sequentially with an emphasis on seating division and evaluated by computer modeling using Odeon 9.2 acoustic software for a hall with approximately 1/4 of the seats surrounding the stage. The effect of solo singing was evaluations by listeners representing musicians and the general public based on pair comparison. Anechoic soprano and baritone singing segments with calibration information were recorded. Side terraces, preferably stepped back or splayed toward both ends of the hall, are essential for controlling the overall energy distribution. 3-dB high-frequency energy compensation can be provided for the terrace seats surrounding the stage by introducing a frontal terrace and terraces near the corners of the hall. The improvement in objective measures was verified by subjective evaluation where the perceived quality at a terrace seat surrounding the stage was not significantly less than the ones facing the stage.