bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-port network theory applied to multi-body scattering
Authors: Williams Randall P. , Hall Neal A.
Published: June 2017

We have previously shown how Thévenin’s theorem may be used to help solve problems in linear acoustic scattering from a mobile body, by forming the solution as a superposition of the field scattered from the body when held immobile and the solution for radiation from the body in an otherwise quiescent field. For problems involving acoustic scattering from multiple mobile bodies, the basic approach can be extended by using multi-port network formalism, commonly used in engineering circuit analysis, to decompose the problem into a set of simpler problems. In this presentation we will first review two-port network theory, and then illustrate the approach using the problem of scattering from a pair of mobile, rigid spheres in an ideal plane progressive wave. In addition to solving for the velocities of the spheres, the resultant pressure field will also be determined. Finally, extension to higher-order systems will be discussed.
Estimation of coupling loss factors employed in the statistical energy analysis of kitchen appliances
Authors: Zarate Roberto , Lopez Marcelo , Ortega Martín
Published: June 2017

Statistical energy analysis continues to be an important framework of study that is helping appliance manufacturers to design quieter machines, particularly as household machinery has now moved into the living space with fashionable open kitchens and designs for small apartments. Precise SEA models depend on good estimates of coupling loss factors. There are several analytical, numerical and experimental approaches reported in the literature to help compute these CLFs; published results show good comparison when data are correlated with experimental measurements. Accurate CLFs estimations depend on many factors, amongst them we can mention the geometry of structural components, structure-to-structure type of coupling, material composition, type and number of cavities, quality of the appliance installation and noise source frequency range. This paper presents a survey of different methods that have successfully been used for CLFs estimation. The objective is to help the new product department in the task of defining a procedure to accurately model cabinets that are designed for domestic machinery. The authors layout a procedure that will be used for CLFs calculation of new equipment that is currently being developed by an appliance manufacturer.
The effects of transportation noise on the people’s emotional feelings of the community environment
Authors: Yang Ming , Kang Jian , Hao Yiying , Lavia Lisa
Published: June 2017

A large number of soundscape studies have shown that soundscapes or sound environments affect people's emotional states, behaviors, and performance. This paper studies the effects of community noise, especially noise from transportations, on the residents’ emotional feelings about the environment. Based upon a large-scale questionnaire survey of residents about the community noise such as sounds of traffic and people's activity, it presents the specific relationships between the sound sources and a range of emotional feelings towards the community environment, such as feeling it annoying, calm, pleasant or exciting, using statistical methods including correlation analysis and principal component analysis. It shows that people’s emotional feelings of the sound environment largely depend on the dominant sound sources they hear; also the sound sources in soundscapes (activities in the communities) tend to appear in groups which collectively influence people’s feelings.
Selection of a sound propagation model for noise annoyance prediction: A perceptual approach
Authors: Vallin Pierre-Augustin , Marquis-Favre Catherine , Gille Laure-Anne , Ellermeier Wolfgang
Published: June 2017

The LDEN is widely used to assess transportation noise annoyance, as recommended by the European Commission. However, other signal features (e.g. amplitude modulation) have proven to influence noise annoyance as well. It is not practical to determine the corresponding acoustical and psychoacoustical indices (e.g. roughness) when producing noise maps, since that would require numerous in situ recordings. An alternative might be to estimate the relevant index values knowing the LDEN value at a given receiver point M. To this end, a perceptually relevant sound propagation model needs to be selected. Therefore, ground transportation noises were simultaneously recorded at short (M1) and longer (M2) distances from the source. Three different propagation models were applied to the M1 recordings in order to simulate pass-by noises heard at M2. A simple level decrease based on geometrical divergence was also considered as a fourth model. After a physical comparison of the four models, a listening test was carried out to determine the best propagation model from a perceptual viewpoint. This test consisted of collecting dissimilarity ratings between simulated pass-by noises and a reference noise recorded in situ at M2.
Development of a new smart noise monitoring system for a long-term noise control in the cities
Authors: Borchi Francesco , Governi Lapo , Carfagni Monica , Bartalucci Chiara
Published: June 2017

The paper describes a new smart noise monitoring system designed and implemented into the project named LIFE15 ENV/IT/000586 “Methodologies fOr Noise low emission Zones introduction And management” (MONZA). The prototype system has been designed starting from the state of the art and the monitoring needs of the MONZA project. The designed system can be considered as a prototype according to the necessary customization in the designing of connections among the hardware components and in the definition of protocols to manage and post process of data collected. The designed prototype needs to maintain the original specs over a long time. In fact, the new monitoring system will be used for a long time (at least five years) during and after the MONZA project duration. In this paper, a description related to the designed network are reported as well as the optimized protocol used to check the system performance variation over time.
Simulation of wind turbine noise for community engagement
Authors: Aalmoes Roalt , Boer, den Merlijn
Published: June 2017

The introduction of wind farms on land for the generation of renewable energy often leads to discussion in the surrounding community. Their concerns on impact of Shadow flickering, horizon pollution, and noise levels may postpone or even cancel the construction of a new wind farm. To improve the communication to the public, wind farm simulations, using the Virtual Community Noise Simulator (VCNS), were created for two different wind farm projects in the Netherlands. For this purpose, the primary noise of the wind turbine, the rotor, has been auralized according to the design of the blades. Atmospheric circumstances, including wind direction, were also taken into account to create the propagation through the atmosphere towards the observer location. Finally, 360 degrees video recordings were made and combined with the planned 3D models of the wind turbines to create an appropriate visual experience using Virtual Reality. This was presented to the public during local municipal meetings. Empirical conclusion of these meetings is that the simulation helped to create an objective way to experience the plans, and provided a better understanding and acceptance of the impact of the planned wind farms for the local community.
Sound radiation of a line source moving above an absorbing plane with a frequency-dependent admittance
Authors: Dragna Didier , Blanc-Benon Philippe
Published: June 2017

This paper is concerned with the derivation of an analytical solution for the acoustic pressure field generated by a line source moving at a constant speed and height above an absorbing plane and summarizes the results obtained in a recent article [Dragna and Blanc-Benon, J. Sound Vib. 349, 259-275, 2015]. As an extension of previous studies, the frequency dependence of the admittance is accounted for. First, a Lorentz transformation is used to obtain an equivalent stationary problem. A special attention is paid to the translation of the admittance boundary condition in the Lorentz space. An analytical solution is obtained as a Fourier transform. Excitation of surface waves is investigated depending on the Mach number. In the far field, an asymptotic expression is sought using the modified saddle point method. The solution is expressed under the form of a Weyl-Van der Pol formula, in which the admittance is evaluated at the Doppler frequency. Comparison of the pressure field obtained with the analytical solution and with a direct numerical simulation is performed. Finally, a parametric study is carried out showing that the frequency variations of the admittance must be accounted for if the source is located close to the ground and if its Mach number is greater than 0.2. [This work was supported by the LabEx Centre Lyonnais d’Acoustique of Universit\'e de Lyon, operated by the French National Research Agency (ANR-10-LABX-0060/ANR-11-IDEX-0007.]
Application of the radiative transfer theory to forest acoustics
Authors: Ostashev Vladimir E. , Wilson D. Keith , Muhlestein Michael
Published: June 2017

Although forest acoustics has been studied extensively, there are no established theories or numerical methods for calculating sound propagation and scattering from first principles. A novel approach based on the radiative transfer equation (RTE) overcomes these shortcomings [V. E. Ostashev and D. K. Wilson, J. Acoust. Soc. Am. V. 140 (4), 3194 (2016)]. In this presentation, the RTE as applied to forest acoustics is overviewed and some results are presented. The RTE is an integro-differential equation for the specific intensity (or the radiance) which is the angular Fourier transform of the spatial correlation function of the sound field. This equation correctly describes propagation phenomena such as the transformation of the coherent part of the sound field into the incoherent field, multiple scattering of sound in different directions, and attenuation due to absorption. In this formulation, acoustical properties of a forest are described by the total cross sections and differential scattering cross section of trunks, branches, leaves, and other scatterrers. Analytical solutions of the RTE are considered such as the modified Born approximation and diffusion approximation. Numerical solutions of the RTE are well developed in other fields of physics and can be adjusted to forest acoustics.
Dispersion and acoustic nonlinearity in heterogeneous media containing hyperelastic inclusions
Authors: Konarski Stephanie G. , Haberman Michael R. , Hamilton Mark F.
Published: June 2017

The present work considers the dispersion and quadratic nonlinearity associated with propagation of finite-amplitude acoustic waves through a heterogeneous medium that contains a dilute concentration of hyperelastic inclusions embedded in a nearly incompressible matrix material. The acoustic wave causes the inclusions to oscillate, which are modeled using a volume formulation of a generalized Rayleigh-Plesset equation. The dispersion arises from the inertia of the matrix surrounding the oscillating inclusions, whereas the nonlinearity is primarily due to the stress-strain response of the inclusions. The importance of dispersion relative to nonlinearity is determined by considering the efficiency of second-harmonic generation. The theory is then used to study a specific inclusion, termed a snapping acoustic metamaterial (SAMM). SAMM inclusions are sub-wavelength structures with designed mechanical instabilities resulting in local regimes of positive and negative stiffness. The low-frequency limit of the acoustic nonlinearity for the SAMM inclusion is compared with the quasistatic values previously obtained through a homogenization method. The significance of dynamic effects, such as the behavior near resonance of the SAMM inclusions, can then be quantified. [This work was supported by the Office of Naval Research.]
Diffusive transport and Anderson localization of ultrasonic waves in strongly scattering inhomogeneous media
Authors: Page John H. , Cobus Laura , Hildebrand Kurt , Kerhervé Sébastien O. , Strybulevych Anatoliy , TALLON Benoit , Brunet Thomas , Lemoult Fabrice , Job Stephane , Skipetrov Sergey , van Tiggelen Bart
Published: June 2017

In inhomogeneous media with constituents having very different acoustic properties, very strong multiple scattering of ultrasonic waves can occur, especially when the wavelength is comparable with the length scales over which the constituent properties vary. Such strong multiple scattering can lead to a long “coda” that dominates the observable behaviour in pulsed experiments, and can dwarf the ballistic pulse that travels coherently through the medium. In many cases, the transport of energy by the multiply scattered waves can be well described using the diffusion approximation, which may even seem quite surprising since all interference effects are ignored. An exception occurs when the return probability that the waves scatter back to the same spot becomes enhanced as a result of very strong multiple scattering; then interference plays an important role and can ultimately lead to Anderson localization and the breakdown of wave propagation. Examples of these wave phenomena will be presented in contrasting inhomogeneous materials, ranging from solid or liquid inclusions in a fluid to dry granular media and unusual porous solids. I will describe robust methods for distinguishing between diffusive and localized waves, as well as some of the remarkable properties of localized waves that can be investigated using ultrasound.
Multiple scattering in resonant emulsions: Coherent-ballistic propagation and diffusive transport
Authors: Tallon Benoit , Brunet Thomas , Page John H.
Published: June 2017

Ultrasonic pulse propagation experiments are reported on dilute suspensions of fluorinated-oil droplets immersed in a water-based gel matrix. These resonant emulsions are model systems for studying the effects of scattering resonances on wave transport since the large sound-speed contrast between the scatterers and the surrounding medium enhances the Mie resonances of the liquid particles. Measurements of the coherent-ballistic component reveal that both the scattering mean free path and the group velocity strongly depend on the frequency as predicted by the Independent Scattering Approximation. Scattering resonances are also responsible for very slow diffusivity of the multiply scattered ultrasound. This slowing down of the diffusion process due to resonances is well captured by models that include additional scattering delays of the ultrasonic pulses. The relationship between the diffusion coefficient and the ballistic data allow the frequency dependence of energy velocity of diffusing waves to be estimated, and show that the energy and group velocities are very different in our system. Although our ultrasonic measurements and their interpretation give a complete picture of wave transport in dilute resonant emulsions, the description of the wave transport in concentrated emulsions requires more sophisticated models based on the spectral function approach and the self-consistent theory.
Situational awareness assessment of hearing protection
Authors: Brandewie Eugene , Dittberner Andrew
Published: June 2017

Uncompromised situational awareness has become a critical component of hearing protection devices (HPDs). Situational awareness is a complex psychological phenomenon, which consists of several perceptual and cognitive factors. This study presents data from three experiments designed to analyze the performance of HPDs on measures of situational awareness and determine how multiple factors may impact in-the-field performance. Data are presented for four hearing protection devices on measures of sound localization, distance perception, spatial segregation, speech intelligibility, and dynamic scene analysis. Baseline (open-ear) data is also presented to contrast with the HPDs. Small differences in fine localization-discrimination and the number of large quadrant errors were observed, but these differences between devices were not observed in the more complex scene analysis task. A performance index was developed to determine overall performance of each HPD compared to open-ear performance. This index combined components from each experiment with subcategories of spatial segregation, object segregation, and attention. The index found no major differences between HPDs; however, it may serve as a reliable summary measure in future assessments of situational awareness.
Effects of cochlear-synaptopathy inducing moderate noise exposure on auditory-nerve-fiber responses in chinchillas
Authors: Krishnan Muthaiah Vijaya Prakash , Walls Michael K. , Heinz Michael G.
Published: June 2017

It has been hypothesized that selective loss of low-spontaneous-rate (low-SR) auditory-nerve (AN) fibers following moderate noise exposure may underlie perceptual difficulties some people experience in noisy situations, despite normal audiograms. However, the finding of selective low-SR-fiber loss has not been replicated in an animal model with behavioral thresholds similar to humans. We recently established a behavioral chinchilla model for which neural and behavioral AM-detection thresholds are in line with each other and similar to humans. Here, we report physiological AN-fiber response properties from anesthetized chinchillas exposed to noise that produced cochlear synaptopathy, as confirmed by immunofluorescence histology. Auditory-brainstem responses, distortion-product otoacoustic emissions, and compound action potentials confirmed no significant permanent threshold shift. Stimuli included both simple (pure tones, as studied previously) and complex (broadband noise) sounds. Low-SR fibers were reduced in percentage (but not eliminated) following noise exposure, as shown previously in guinea pigs. Saturated rates to tones were reduced. Similar tuning and temporal coding were observed in broadband-noise responses following noise exposure. Complete characterization of AN-fiber responses to complex sounds in a mammalian behavioral model of noise-induced cochlear synaptopathy will be useful for understanding suprathreshold deficits that may occur due to hidden hearing loss. [Work supported by NIH (R01-DC009838).]
Establishing the presence of cochlear implant related artifact during sound-field recording of the auditory steady state response: A comparison between normal hearing adults, cochlear implant recipients, and a cochlear implanted human cadaver
Authors: Deshpande Shruti B. , Scott Michael P. , Huizenga Jill S. , Samy Ravi N. , Brown David K.
Published: June 2017

The Auditory Steady State Response (ASSR) is an objective technique permitting dichotic, frequency-specific hearing threshold estimation. Electrical ASSR (eASSR) has the potential for auditory assessment in cochlear implant (CI) users through direct CI electrode stimulation. However, sound-field ASSR (sASSR) provides a more natural listening environment for CI users. Electrophysiological recordings could be affected by CI related artifact. The present study investigated the possibility of CI-artifact during sASSR recording in 10 CI subjects at 0.5, 1, 2 and 4 kHz. Results were compared with 15 NH controls. We investigated the mean threshold differences between the sASSR thresholds and the behavioral thresholds for each group at the four frequencies. Correlation between the sASSR thresholds and behavioral thresholds were computed. There were significant differences between the NH and CI groups across the four frequencies indicating the possibility of a CI-related artifact. In order to confirm the presence of the artifact, we recorded the sASSR in a cochlear-implanted human cadaver, six hours post-mortem. This pilot investigation which, is possibly the first sASSR in an implanted human cadaver, confirms the presence of a continuous artifact that “mimics” a true physiological response. Implications and methods to minimize artifacts to potentially increase sASSR utility will be discussed.
Can dual-carrier processing restore masking release in vocoded speech?
Authors: Carter Brittney , Healy Eric , Apoux Frederic
Published: June 2017

Speech processed to replace the original temporal fine structure (TFS) with tones or noise carriers (vocoder processing) are generally less intelligible than natural or unprocessed speech, especially if a background noise is present. Moreover, the poorer intelligibility associated with vocoder processing is typically larger if the background fluctuates over time. This deleterious effect of vocoder processing has led to the postulate that TFS cues play a critical role when listening into the dips in the background. Recently, we have proposed a technique to reintroduce synthetic TFS cues in vocoded speech using one carrier for the target and one carrier for the background. This “dual-carrier” approach allows sentence intelligibility with a speech masker to reach a level almost comparable to that of natural speech. The goal of the present study was to investigate the extent to which dual-carrier processing generally improves speech recognition in various noises or if it truly compensates for the loss of TFS cues, therefore engendering masking release, as does natural speech. Results comparing masking release for three processing conditions (single-carrier, dual-carrier, and natural speech) in five backgrounds (speech-shaped noise, speech-modulated noise, and 1, 2, or 8 talkers) will be discussed.
Influence of limitations from the auditory periphery on across-channel sensitivity to amplitude modulation rate in cochlear-implant users
Authors: Anderson Sean R. , Kan Alan , Litovsky Ruth
Published: June 2017

Individuals with cochlear implants (CIs) attain lower speech reception scores in noise relative to normal-hearing (NH) listeners. Poorer performance in CI users is partly due to reduced access to cues used to segregate sound sources, which may be limited by poor electrode-neuron interface in the auditory periphery. Poor electrode-neuron interface reduces sensitivity to temporal information at specific cochlear sites. This study investigated the influence of the periphery on discriminating differences in amplitude modulation (AM) rates presented simultaneously in two different cochlear channels. In each trial, one interval was presented and subjects chose whether AM rates were the same or different. AM rates were paired within- or across-ears. It was hypothesized that, if sensitivity to AM rate was reduced in one channel due to poor transduction of AM rate, then across-channel sensitivity would decrease. Both CI users and NH listeners participated in this experiment. Results suggest that when temporal encoding in the auditory periphery is poor, sensitivity to differences across-channels decreases. These results may influence CI mapping with respect to which electrode channels are removed to enhance grouping cues important for source segregation. [Work supported by NIH-NIDCD R01-DC003083 to RYL, NIH-NIDCD R03-DC015321 to AK, and NIH-NICHD P30-HD03552 to Waisman Center.]
Specific components of amplitude modulation that enable detection in listeners with cochlear implants
Authors: Bosen Adam K. , Kulkarni Aditya M. , Chatterjee Monita
Published: June 2017

The ability of listeners with cochlear implants to detect amplitude modulation (AM) of stimulation level has been linked to their ability to understand speech, but the specific features of AM stimuli that enable their detection remains unknown. At low modulation rates sensitivity is strongly associated with intensity resolution, but at high modulation rates sensitivity to AM stimuli further degrades, indicating additional temporal limits on detection. The goal of this work is to identify the specific components of AM pulse trains that listeners with cochlear implants use to detect AM. We measured increment and decrement detection thresholds for multiple increment/decrement durations in these listeners and compared these thresholds to their ability to detect sinusoidal AM at different rates. Electrical stimulation also provides a unique opportunity to present arbitrary stimulation waveforms through a single electrode, so we generated additional waveforms that either sharpened or smoothed different portions of each AM period to determine how this altered detectability. Preliminary results suggest that increments in stimulation level are the critical feature that listeners use to detect AM, and that at high AM rates increments are partially masked by preceding stimulation.
Multiple pitch mechanisms revealed by effects of inharmonicity on pitch perception
Authors: McPherson Malinda J. , McDermott Josh
Published: June 2017

Pitch is generally defined as the percept corresponding to a sound’s fundamental frequency (F0). However, there is surprisingly little evidence for the importance of F0-specific mechanisms in pitch perception. To investigate the extent to which pitch perception involves estimating F0, we conducted a battery of pitch-related music and speech tasks using harmonic and inharmonic stimuli, the rationale being that inharmonic stimuli lack a clear F0 and should impair F0-dependent mechanisms. Inharmonic speech was generated with a variant of STRAIGHT analysis/synthesis. We found no difference in performance between harmonic and inharmonic stimuli for basic pitch discrimination, melodic contour discrimination, and speech contour discrimination, but substantial inharmonicity-induced deficits for sour-note detection, interval recognition and discrimination, melody recognition, and voice recognition. Collectively, the results indicate that F0 estimation is not necessary to extract pitch contours in speech or music, but does appear critical for accurate interval perception, and for representing voices. These findings suggest that two or three distinct mechanisms may underlie what has conventionally been couched as pitch perception: one which tracks shifts in fine spectral patterns independent of F0, another that estimates F0 for determining precise interval relationships between notes, and perhaps another associated with voice qualities.
Does a pitch center exist in auditory cortex? A mismatch negativity study
Authors: Gu Feng , Wong Lena
Published: June 2017

Pitch sensation can be evoked by different acoustic cues which should be processed by different strategies for extracting pitch. However, in resent studies a general pitch center was hypothesized exist at some level of the auditory pathway for a general pitch sensation independent of other acoustic features. In this study, the existence of pitch center was examined by testing that whether the mismatch negativity (MMN) response, an index of pre-attentive auditory processing, can be elicited by pitch deviations in a passive oddball paradigm that composed of four different pitch-evoking stimuli (i.e., sinusoidal tone, resolved complex, iterated rippled noise, and pulse train). Although the pitch-evoking cues in these pitch-evoking stimuli were disparate, they evoked a fixed pitch of 200 Hz (or 283 Hz in a reversed oddball paradigm). Occasionally a deviant sound was encountered which evoked a different pitch (283 Hz, or 200 Hz in the reversed oddball paradigm). The results showed no significant MMN response was elicited by the deviant, regardless of the type of pitch-evoking stimuli, suggesting the absence of pitch center in the pre-attentive auditory processing stage.
How susceptibility to noise varies across speech frequencies
Authors: Yoho Sarah E. , Healy Eric , Apoux Frederic
Published: June 2017

It has been long assumed that the corrupting influence of noise on speech is uniform across all frequencies, and that the contribution of each speech frequency decreases at the same rate as noise is added. This assumption is evident in numerous previous works, and is seen clearly in the Speech Intelligibility Index where the contribution of each speech band is scaled in the same way according to the amount of noise present. Here, it is argued that susceptibility to noise may differ across speech bands. To test this hypothesis, the compound method [F. Apoux and E.W. Healy (2012) 132, J. Acoust. Soc. Am.] was modified to evaluate the noise susceptibility of individual critical bands of speech. Noise was added to each target speech band and the signal-to-noise ratio (SNR) required to reduce the contribution of that band by half was estimated. It was found that noise susceptibility varies greatly across speech bands, and that the SNR required to similarly affect each band differed by as much as 12 dB. Interestingly, no obvious systematic relationship appeared to exist between band importance and noise susceptibility.
Differences in speech motor control between bilingual and monolingual speakers—An acoustic study
Authors: Chang Rena K. , Ng Manwa L.
Published: June 2017

The present study attempted to acoustically examine the speech motor abilities associated with English produced by English monolingual speakers (MS), Cantonese-English bilingual speakers with superior (BS-SE) and inferior English (BS-IE). Articulation rate, formant frequencies (F1 and F2), and voice onset time (VOT) obtained from different speech tasks were compared across the three speaker groups to reveal the language influence on their speech motor control. Results indicated that: (1) the MS group exhibited the fastest articulation rate while the BS-IE group the slowest; (2) the three speaker groups had significantly different VOT values for the plosives /b-/, /g-/, /ph-/ and /th-/; and (3) bilingual speakers exhibited larger vowel spaces, demonstrating more posterior tongue position, based on F1 and F2 values of the three corner vowels /-i/, /-a/ and /-u/, than monolingual speakers. No systematic implications were obtained regarding the effect of bilingualism on speech motor control. Despite the inconclusive findings, data from the present study shed light on understanding the effect of bilingualism on speech motor control.
An algorithm to increase intelligibility for hearing-impaired listeners in the presence of a competing talker
Authors: Healy Eric , Delfarah Masood , Vasko Jordan , Carter Brittney , Wang DeLiang
Published: June 2017

Individuals with hearing impairment have particular difficulty perceptually segregating concurrent voices and understanding a talker in the presence of a competing voice. In contrast, individuals with normal hearing perform this task quite well. A machine learning algorithm is introduced here to address this listening situation. A deep neural network was trained to estimate the ideal ratio mask for a target talker in the presence of a single competing talker. The algorithm was found to produce sentence-intelligibility increases for hearing-impaired and normal-hearing listeners at various signal-to-noise ratios. This benefit was largest for the hearing-impaired listeners and averaged 59 %-points at the least-favorable SNR, with a maximum of 87 %-points. The mean intelligibility achieved by the hearing-impaired listeners using the algorithm was equivalent to that of young normal-hearing listeners without processing, under conditions of identical interference. Possible reasons for the limited ability of hearing-impaired listeners to perceptually segregate concurrent voices are also addressed.
Presentation method as air- and bone-conducted speech for delayed auditory feedback
Authors: Toya Teruki , Unoki Masashi
Published: June 2017

Speakers perceive their own voices as “auditory feedback” during speech production. Effects of delayed auditory feedback (DAF) on their speaking styles have been investigated to clarify relationships between speech production and perception. It has been previously investigated whether DAF as not only air-conducted (AC) but also bone-conducted (BC) speech affects speakers’ speaking styles. However, existence of speakers’ own natural voice via bone-conduction could not be ignored. This study investigates the speaking styles under DAF as AC and BC speech in presence of masker, for clarifying the effects of only delayed stimuli as AC and BC speech. Speech duration and the number of dysfluent episodes under delay conditions were measured to quantify the effect of delayed stimuli on the speaking styles. As a result, under noiseless and AC masker conditions, longer speech duration and more dysfluencies were observed under DAF as BC speech than that as AC speech. In contrast, under BC masker condition, opposite trends were observed. Speakers’ introspection suggested that their own natural voices were masked by AC masker better than BC masker. These results indicated that the use of AC masker is effective for masking speakers’ own natural voice during DAF as AC and BC speech.
The independent contribution of glimpse properties to speech recognition in speech-modulated noise
Authors: Gibbs Bobby E. , Fogerty Daniel
Published: June 2017

During fluctuating noise, temporal speech fragments (i.e., glimpses) at sufficient signal-to-noise ratios (SNRs) contribute to speech recognition. Different acoustic properties of these glimpses, related to rate and proportion, reflect the temporal distribution of available speech cues. Glimpse metrics may be used to define different aspects of this temporal distribution. However, these measures are often highly correlated, limiting interpretation of how different glimpse properties contribute independently to speech recognition. The present study investigates how the local SNR cutoff (LC) influences the correlation between glimpse metrics and affects related associations with speech recognition. Speech recognition was assessed in the presence of speech-modulated noise that was temporally manipulated through time compression and presented at different SNRs. Optimization analyses identified LCs that yielded glimpse metrics that were most correlated with the perceptual data. Stimulus manipulations of the noise modulation spectrum and noise level were most related to changes in the glimpse rate and proportion of glimpsed speech, respectively. At an LC of -2 dB, the correlation between these glimpse parameters was minimized while the combined association with speech recognition performance was maximized. Results suggest two glimpse mechanisms, with the relative importance of either mechanism determined by the acoustic noise properties and the analyzed LC.
Articulation and timing in mouse ultrasonic vocalizations
Authors: Castellucci Gregg A. , Calbick Daniel , McCormick David A.
Published: June 2017

Male mice produce ultrasonic courtship vocalizations (UCVs) which have been used as a model in the study of various human social and vocal behaviors. However, little is known about the features of UCVs that are important for their perception, and would therefore be expected to show meaningful variability following experimental manipulations. Here, we show that the temporal structure of UCV bouts are remarkably consistent across C57Bl6/J mice. Specifically, we find that mice produce two UCV subtypes which arise from unique respiratory articulations, and three discrete classes of silent boundaries which also result from distinct respiratory activity patterns. In addition, we demonstrate that these UCV and boundary types occur in a highly consistent pattern across mice, and that UCV temporal structure displays evidence of rudimentary motor planning. Finally, while adult mice produce their UCVs via an egressive pulmonic phonation mechanism, neonatal mice were found to utilize an ingressive pulmonic airstream in the production of their ultrasonic isolation calls. In conclusion, future investigations of mouse UCVs should include analyses of rhythmic structure. Also, the study of adult UCV production may prove to be a useful model for the study of basic aspects of general orofacial coordination and speech motor coordination.
A history of loudness before 1950
Authors: Neely Stephen T.
Published: June 2017

Loudness is a perceptual correlate of the physical intensity of a sound, but the relationship between loudness and intensity is not simple. The derivation from loudness-matching data of equal-loudness contours for tones across frequency was described as early as 1927. However, the most influential work on loudness prior to 1950 was the formulation by Fletcher and Munson (1933) of a method for calculating the loudness of any steady sound from the intensities of its frequency components. In a subsequent publication, Fletcher and Munson (1937) described how the loudness of a tone changes in the presence of another tone, which is a phenomenon known as masking. Stevens (1936) made extensive contributions to the theory of loudness scaling and methods for loudness measurement. Miller (1947) discovered that “just detectable increments in intensity” were of the same order of magnitude for noise as for pure tones.” Dix et al. (1948) suggested a clinical use in differential diagnosis of hearing loss for the phenomenon known as loudness recruitment, which is defined as an abnormally-rapid loudness growth. In part because of its relevance to the remediation of hearing loss, the measurement, quantification, and prediction of loudness continue to be active areas of psychophysical research.
The dawn of psychoacoustics in Japan
Authors: Hirahara Tatsuya , Suzuki Yôiti
Published: June 2017

In the early 1900's, two scholars opened the door of psychoacoustics in Japan. Han'ichi Muraoka was sent to University of Strasbourg in 1878, where he studied physics under August Kundt and received a doctoral degree in 1881. He published his study of the discrimination threshold of Japanese-harp timbre in 1919. Matataro Matsumoto went to Yale University in 1896, studied psychology under Edward Scripture, and received a Ph.D. degree in 1899 with his thesis “Researches on Acoustic Space.” In the 1930s, several psychologists actively conducted psychoacoustical researches and two psychoacoustics textbooks were published. In 1936, the Acoustical Society of Japan was founded. Three years later, Shuji Yagi edited a book titled “Acoustical Sciences,” of which psychoacoustics occupied 23 pages out of 428. Psychoacoustical research, however, gradually became inactive until after WWII. The Journal of the Acoustical Society of Japan was resumed in 1950 and several psychoacoustics textbooks were published in the 1950's. From around 1960, not only psychologists such as of Osaka University but also electrical engineers of Tohoku University, NHK-STRL, and NTT-ECL began psychoacoustical studies, particularly related to timbre, spatial hearing and speech perception. This movement signaled the second down for the current Japanese psychoacoustics; the fusion of psychology and technology.
The German acoustical journal Akustische Zeitschrift (1936-1944)
Authors: Kohlrausch Armin
Published: June 2017

A few years after the foundation of JASA in 1929, the “Akustische Zeitschrift” (Hirzel Verlag, Leipzig) started to appear in 1936. This journal was edited by Martin Grützmacher and Erwin Meyer, on behalf of the German Science Foundation (DFG) and with support from the German Imperial Mail and the Imperial Physical Technical Institute (first director in 1887 von Helmholtz). The motivation for this journal was the explosive growth of acoustics, mainly enabled by the development of electroacoustics, the improved scientific foundations of room- and building acoustics, and the renewal of psychological and physiological acoustics. Right from the beginning, articles from the area P&P had a prominent place. The first article was: Theoretical and experimental comparison of measurements of the absolute threshold of hearing (Waetzmann and Keibs), followed by the first of many articles by Georg von Békésy: On physics of the middle ear and on hearing with a missing tympanic membrane. One important aspect were the regular German summaries of articles from English-language journals, a review of patents and acoustic news. In the first edition, we can read that Erwin Meyer had been invited by the ASA to talk at their annual meeting in New York October 29 to 31.
Exploring auditory frequency selectivity using otoacoustic emissions
Authors: Charaziak Karolina , Siegel Jonathan H.
Published: June 2017

Frequency selectivity—the ability of the auditory system to separate one stimulus out from others on the basis of frequency—originates in the cochlea where outer hair cells (OHCs) provide sharp mechanical tuning at low signal levels. Whether humans have sharper cochlear tuning compared to common laboratory species has been a matter of scientific debate. Whereas cochlear tuning can be measured directly in animal models, similar tests cannot be performed in humans due to their invasiveness. However, cochlear tuning can be gauged from measurements of other OHC-dependent phenomena, such as otoacoustic emissions (OAEs). Here, we compare frequency selectivity derived from stimulus-frequency (SF)OAE suppression tuning curves measured in both humans and chinchillas. SFOAE suppression tuning curves have previously been shown to be as sharply tuned as compound-action-potential tuning curves in chinchillas and behavioral tuning curves in humans (when using simultaneous masking). These earlier findings support the ideas that: (1) OAE tuning curves reflect aspects of cochlear tuning and (2) Sharp frequency selectivity is primarily established at the level of the cochlea. After correcting for interspecies differences in the apical-basal transition frequency and in cochlear lengths, we find that SFOAE tuning curves are twice as sharp in humans as in chinchillas.
Discrimination of Schroeder-phase complex stimuli: Physiological, behavioral, and modeling studies in the Mongolian gerbil
Authors: Carney Laurel H. , Oetjen Henning , Klump Georg
Published: June 2017

Schroeder-phase tone complexes have been studied psychophysically, behaviorally, and physiologically in several species. These stimuli are comprised of equal-amplitude harmonics, defined by fundamental frequency (F0), sign and slope (C) of the phase spectra, and number of harmonics. Perceptual differences between positive (C + ) and negative (C-) phase spectra (time-reversed versions of each other) challenge the power-spectrum model and must be explained by temporal cues, either fine structure or the low-frequency fluctuations of peripherally filtered stimuli. Here, physiological, behavioral, and modeling studies of discrimination of Schroeder complexes in Mongolian gerbil will be presented. Behavioral discrimination of complexes with different C values or signs decreased as F0 increased from 50 to 400 Hz. Here we investigate whether peripheral neural fine structure or changes in low-frequency fluctuations of rate underlie discrimination. Modeling results show that both synaptic adaptation and frequency-dependent asymmetry of tuning create differences in the F0-related vector strength of peripheral responses. Because inferior colliculus (IC) neurons are sensitive to low-frequency fluctuations, we recorded responses in the midbrain to the behavioral stimuli. Discharge rates of many IC cells varied significantly with the value and sign of C. The direction of rate differences depended upon best frequency and type of modulation transfer function.
Near surface ultrasonic imaging
Authors: Croxford Anthony , Potter Jack
Published: June 2017

Ultrasonic phased arrays offer excellent performance for detecting and classifying defects; however when inspecting near the array, there is typically a deadzone where electrical cross talk saturates the response making it impossible to measure. In many situations this can be mitigated through the use of a physical standoff, however for permanently installed systems or in situ inspection of components in access restricted areas such as gas turbines such a solution is impossible. In addition, such a standoff typically reduces the amplitude of the received signals degrading the signal to noise ratio (SNR). This paper reports on an approach that allows ultrasonic measurements to be made of the near surface region. Specifically by measuring the diffuse response of the system it is possible to reconstruct the greens function between any pair of transducers. As this is created from data that is not saturated there is no deadzone in the resulting image. When combined with advanced sampling techniques using hadamard coding the region immediately in front of the array can be imaged with performance similar to that seen in the bulk material despite this reconstruction approach. In this paper, the reconstruction and sampling technique are explained and demonstrated with images shown for defects within 0.5 mm of the sample surface in both aluminium and composite components. The advantages of the sampling approach are shown for immersion coupled measurements to demonstrate the SNR gains achievable.
Estimating the penetration depth of stress corrosion cracks using time-reversal acoustics—A Numerical Study
Authors: Pieczonka Lukasz J. , Remillieux Marcel , Anderson Brian E. , Ulrich Timothy J. , Le Bas Pierre-yves
Published: June 2017

It has been shown experimentally that it is feasible to use time-reversal elastic nonlinearity diagnostics (TREND) to estimate the penetration depth of stress corrosion cracks (SCC) in steel samples. TREND is a method to focus elastic waves energy to a point in space in order to probe that point for damage. High frequencies are used to probe near the surface, while low frequencies are used to probe deeper into the material. Depth estimation of a crack is important to determine when a critical size of defect is reached. This paper aims at a parametric analysis of the time reversal focusing process by means of numerical simulations. The influence of excitation frequency and waveform on the focal spot size and penetration depth are analyzed. An in-house simulation framework based on a commercial Finite Element (FE) solver is used to perform a series of numerical simulations of time-reversal focusing in a steel sample with a curved crack. Results of this study could help to understand the relationship between the vibration responses measured at the sample’s surface and crack-wave integrations at different penetration depths. Ultimately, this knowledge can be used to optimize the experimental setup and facilitate the interpretation of experimental results.
Acoustic surface waves measurements by self mixing array transducers for nondestructive testing and structure health monitoring applications
Authors: Longo Roberto , Adiaviakoye. Ladji , Feron Romain , Feuilloy Mathieu , LeDuff Alain , Plantier Guy
Published: June 2017

In the Non Destructive Testing (NDT) and Structure Health Monitoring (SHM) field, Surface Acoustic Waves (SAWs) are widely employed to detect defects and/ or to monitor the integrity of the structure to test. In this context, SAWs contactless measurements offer several advantages with respect to the traditional use of a recording piezoelectric transducers fixed in the structure to test. They can be easily employed in situations of difficult access to the structure avoiding the generation of undesired reflections due to the presence of a second transducers mass. The gold standard technique for this this kind of measurements is the scanning Laser Doppler Vibrometer (sLDV), which allows to perform contactless measurements with a high spatial resolutions and a good Signal to Noise ratio. The main drawback is the high costs to be supported and the large acquisition time that a 2D grid of measurement points could require. Moreover, to ensure an optimal reflection of the incident light, the surface of the structure under test is often treated with reflective paint or stickers. The purpose of this article is to build a large bandwidth array transducer for NDT/SHM applications overcoming the sLDV measurements disadvantages. This technique is based on the use of Laser diodes. The principle behind this approach is the Self Mixing effect occurring when the optical beam is back-scattered in the active cavity of the diode itself.