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Music is an important signal class for hearing aids, and musical genre is often used as a descriptor for stimulus selection. However, little research has systematically investigated the acoustical properties of musical genres with respect to hearing aid amplification. Here, extracts from a combination of two comprehensive music databases were acoustically analyzed. Considerable overlap in acoustic descriptor space between genres emerged. By simulating hearing aid processing, it was shown that effects of amplification regarding dynamic range compression and spectral weighting differed across musical genres, underlining the critical role of systematic stimulus selection for research on music and hearing aids. [ABSTRACT FROM AUTHOR]

The paper presents the velocity-pressure and quality factor-pressure dependences of a sandstone sample, using the Fourier spectra of the complete waveforms of the P waves measured in laboratory. Measurements were performed on sandstone and (a reference) aluminum sample at 40 different pressures. The professional literature uses approximate methods to determine the value of the quality factor. The spectral ratio method was used to evaluate our measurements. The measured velocity and quality factor data were processed using inversion methods. The results showed that both the velocitypressure and the quality factor pressure dependence can be well-described utilizing the double relaxation model in forward modeling. [ABSTRACT FROM AUTHOR]

The Mayan city of Chichen Itza is full of legends and mysticism. There, in the temple of Kukulkan, in front of a great pyramid with 91 central staircases, an interesting physical-acoustic phenomenon occurs that has fed mythical stories attributed to the Mayas. When clapping your hands in front of the steps, the echo sounds very different from the sound emitted: The echo presents a ‘tonality’ that resembles a kind of bird chirping (chirp) which is said to be the response of the Quetzal, sacred bird of the Mayas. Earlier work has discussed the convolution method to find a simulation of the spectrum of the echo sound captured at Kukulkan. In this article we are going to present an analysis of the reflected sound using the wave superposition method, and thus obtain a sound with musical ‘Pitch’ as a result of the superposition of multiple reflections of a percussive sound, using the AUDACITY audio software, as demonstrated in the supplementary material. [ABSTRACT FROM AUTHOR]

This paper analyses the acoustic behaviour of the Palace of Charles V from a room acoustics perspective but also ponders the uniqueness of the space and its ability to engage and enhance the audience experience. The Palace of Charles V is a relevant part of the historical heritage of Granada. It has an architectural but also an acoustic uniqueness that deserves research. A measurement campaign was made to calculate parameters such as T30, IACC, C80 or Gm, and to explain the behaviour of the Palace. The BQI is quite high, but the late part of the impulse response (t > 80 ms) has strong unwanted reflections causing low clarity (C80) and listener envelopment (LEV). Nevertheless, the Palace is a successful concert venue with good feedback from musicians and the audience. [ABSTRACT FROM AUTHOR]

Introduction: An evaluation was conducted to measure the impact of noise from air operations at El Dorado International Airport on the productivity and health of dairy cattle in the municipality of Funza, Colombia. This experimental study sought to determine if aircraft noise significantly affected milk production, considering various factors such as health and animal welfare. Justification: The evaluation conducted arises from the need to understand how this factor can influence key aspects of dairy production. Given the importance of the livestock industry in the region and the proximity of the airport, it is crucial to understand if aircraft noise significantly affects productive, sanitary, and welfare variables of cattle. Objective: To evaluate the effect of aeronautical noise on productivity and sanitary condition in dairy herds in the municipality of Funza. Methods: The study was conducted in the rural area of the International Airport, in the municipality of Funza, at an altitude of 2,548 meters above sea level. There were 18 stratified dairy farms in 3 groups according to exposure levels (n=6 farms per group): Low (0%-33.3%), Medium (33.3%-66.6%), and High (66.6% -100%), corresponding to low, medium, and high levels of noise exposure, respectively. The evaluated variables were: acoustic measurement, blood count, milk production, and somatic cell count for 5 months. The treatments evaluated were the exposure levels; data were analyzed using ANOVA. Results and Discussion: Higher grazing noise (dB) was observed in the medium and high treatments (68.47 dB - 69.20 dB). Meanwhile, the noise recorded in the milking facilities was higher in the medium treatment (78.67 dB). Milk production was higher in the ranges classified as high and low exposure levels (17.09 L and 15.7 L), respectively, unlike the medium level where the recorded production was lower (10.30 L). The variables red blood cells, hemoglobin, hematocrit, and platelet variables showed no differences between treatments; the total protein variable showed statistical differences between medium and low treatments. Likewise, the somatic cell content was not affected by noise exposure. Conclusion: It is concluded that exposure to noise during milking may lead to a decrease in milk production; however, it was evidenced that it does not directly affect the health of the cattle, considering the sanitary variables evaluated in the dairy herds. [ABSTRACT FROM AUTHOR]

Quantifying and characterizing suspended sediment is essential to successful monitoring and management of estuaries and coastal environments. To quantify suspended sediment, optical and acoustic backscatter instruments are often used. Optical backscatter systems are more sensitive to mud particles (<63 μm) and flocs, whereas acoustic backscatter systems are more responsive to larger sand grains (>63 μm). It is thus challenging to estimate the relative proportion of sand or mud in environments where both types of sediment are present. The suspended sediment concentration measured by these devices depends on the composition of that sediment, thus it is also difficult to confidently measure concentration with a single instrument when the composition varies and extensive calibration is not possible. The objective of this paper is to develop a methodology for characterizing the relative proportions of sand and mud in mixed sediment suspensions by comparing the response of simultaneous optical and acoustic measurements. We derive a sediment composition index (SCI) that is used to directly predict the relative fraction of sand in suspension. Here, we verify the theoretical response of these optical and acoustic instruments in laboratory experiments and successfully apply this approach to field measurements from Ameland ebb‐tidal delta (the Netherlands). Increasing sand content decreases SCI, which was verified in laboratory experiments. A reduction in SCI appears during more energetic conditions when sand resuspension is expected. Conversely, the SCI increases in calmer conditions when sand settles out, leaving behind mud. This approach provides crucial knowledge of suspended sediment composition in mixed sediment environments. Plain Language Summary: Sand and mud particles are the building blocks of our coastlines. Counting and describing sand and mud particles floating through the water is essential to managing coasts. We commonly do this with devices that send out a sound (acoustic) or light (optical) signal into the water. The sensors measure the strength of the signal reflecting back off of any sand and mud particles passing by. Optical instruments are better at "seeing" mud than sand, and acoustic instruments are better at "hearing" sand than mud. If both sand and mud are present, a single instrument will not accurately estimate the total amount of sediment because of these different sensitivities. Instead, we can use both types of instrument together and compare what we "see" with what we "hear." This comparison allows us to estimate whether there are more sand or mud particles floating through the water. The relationship between "seeing" and "hearing" can be described in a single number, the sediment composition index (SCI). We successfully tested this approach in laboratory experiments and then applied it to a site on the coast of the Netherlands. This approach gives us a new way to understand environments that are both sandy and muddy. Key Points: Suspended sand and mud can be distinguished by their different optical and acoustic backscatter signaturesWe define a sediment composition index (SCI) from relative optical and acoustic backscatter and verify it with lab and field measurementsSCI can be used to estimate the fraction of suspended sand, adding interpretive value to measurements in mixed sediment environments [ABSTRACT FROM AUTHOR]

The United States and Canada employ dynamic management strategies to improve conservation outcomes for the endangered North Atlantic right whale (Eubalaena glacialis). These strategies rely on near real‐time knowledge of whale distribution generated from visual surveys and opportunistic sightings. Near real‐time passive acoustic monitoring (PAM) systems have been operational for many years but acoustic detections of right whales have yet to be incorporated in dynamic management because of concerns over uncertainty in the location of acoustically detected whales. This rationale does not consider whale movement or its contribution to location uncertainty following either visual or acoustic detection. The goal of this study was to estimate uncertainties in right whale location following acoustic and visual detection and identify the timescale at which the uncertainties become similar owing to post‐detection whale movement. We simulated whale movement using an autocorrelated random walk model parameterized to approximate three common right whale behavioral states (traveling, feeding, and socializing). We then used a Monte Carlo approach to estimate whale location over a 96‐hr period given the initial uncertainty from the acoustic and visual detection methods and the evolving uncertainties arising from whale movement. The results demonstrated that for both detection methods the uncertainty in whale location increases rapidly following the initial detection and can vary by an order of magnitude after 96 hr depending on the behavioral state of the whale. The uncertainties in whale location became equivalent between visual and acoustic detections within 24–48 hr depending on whale behavior and acoustic detection range parameterization. These results imply that using both visual and acoustic detections provides enhanced information for the dynamic management of this visually and acoustically cryptic and highly mobile species. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present study was to evaluate the acoustic activity of Litopenaeus vannamei of different size classes during feeding in captivity, as well as describe the sound generation mechanism and main associated acoustic variables. The structure responsible for sound emission was identified based on simultaneous audio and video recordings during the consumption of feed pellets. Eighteen animals divided into three size classes (small: 13.03 ± 1.87 g; medium: 22.09 ± 2.20; large: 35.31 ± 3.20 g) were used for the acoustic characterization of feeding activity. The animals were fed three pellets (48 ± 4 mg) individually and offered in sequence. The recording of each pellet offered lasted 10 min, beginning with the point at which the animal took the pellet. The number of sound pulses ("clicking" sound) per pellet ingested was counted and related to food intake. L. vannamei emits sound during the feeding process, which is associated with the closing of the mandibles during the shredding of the food. The average values for the acoustic variables were a minimum frequency of 3.47 ± 0.32 kHz, maximum frequency of 37.75 ± 2.44 kHz, frequency peak of 11.1 ± 3.39 kHz, maximum energy of 83.55 ± 3.39 dB and sound duration of 4.7 ± 0.2 ms. No statistically significant differences in the acoustic variables were found among the different size classes or in the sequence of the pellets offered. The number of clicks per pellet ranged from 121 to 154 for all size classes. However, the number of clicks generated in the large class was significantly higher during the first minute after the capture of the pellets, dropping significantly after five minutes in comparison to the other size classes. The findings demonstrate that L. vannamei is acoustically active and the sounds generated can be used as an indication of feeding activity in captivity. The click rate per pellet or particular period of time, combined with the maximum energy generated at a specific frequency (frequency peak) can be used as an indication of the quantity of feed consumed by the animals. Highlights • The Pacific white shrimp L. vannamei is acoustically active and emits sound (clicks) during the process of feeding. • The click rate per pellet or time, and the energy at a specific frequency can be related to feeding activity of L. vannamei. • The acoustic parameters evaluated are useful to apply Passive Acoustic Monitoring (PAM) in feeding management of L. vannamei. [ABSTRACT FROM AUTHOR]

Combined laboratory experiment and numerical simulation are conducted on bubble clouds nucleated on the surface of a model kidney stone to quantify the energy shielding of the stone caused by cavitation during burst wave lithotripsy (BWL). In the experiment, the bubble clouds are visualized and bubble-scattered acoustics are measured. In the simulation, a compressible, multi-component flow solver is used to capture complex interactions among cavitation bubbles, the stone, and the burst wave. Quantitative agreement is confirmed between results of the experiment and the simulation. In the simulation, a significant shielding of incident wave energy by the bubble clouds is quantified. The magnitude of shielding can reach up to 90% of the energy of the incoming burst wave that otherwise would be transmitted into the stone, suggesting a potential loss of efficacy of stone comminution. There is a strong correlation between the magnitude of the energy shielding and the amplitude of the bubble-scattered acoustics, independent of the initial size and the void fraction of the bubble cloud within a range addressed in the simulation. This correlation could provide for real-time monitoring of cavitation activity in BWL. [ABSTRACT FROM AUTHOR]

Highlights • The role of spectral tilt in sentence prominence was investigated. • Estimators for tilt of glottal source spectrum and surface spectrum were compared. • Multidimensional representations for spectral tilt were also investigated. • Robustness of different tilt estimators was tested for noisy and coded speech. • Experiments were conducted on both French and Dutch speech data. Abstract Linguistic prominence in speech is known to correlate with the acoustic measures of energy, F0, and duration. In contrast, the role of spectral tilt in the realization of prominence has remained more inconsistent between previous empirical investigations. This may be partially due to the lack of a standard method for quantifying spectral tilt or due to difficulties in estimating the acoustical source of spectral tilt, the glottal flow, from continuous speech. These issues have rendered interpretations and comparisons between studies difficult. In addition, (i) little is known about the robustness of tilt estimators for prominence detection in the case when speech is not clean but corrupted, as in real life, by environmental noise or telephone transmission (i.e. degradation caused by bandpass filtering and quantization noise). Moreover, (ii) little attention has been paid to multidimensional representations of source spectrum that can potentially incorporate more information about the phonation style than purely scalar measures. In this work, we study spectral tilt in signaling prominence in spoken Dutch and French under different levels of additive noise, and for telephone-band coded speech, and compare several one-dimensional tilt measures that have been previously encountered in the literature as well as multidimensional tilt measures. We also compare spectral tilt measures with other standard acoustic correlates for prominence, namely, energy, F0, and duration. Our results provide further empirical support for the finding that tilt is a systematic correlate of prominence in Dutch, that the role is smaller in French, and that energy, F0, and duration appear still to be the most robust features for discriminating prominent and non-prominent words. In addition, our results show that there are notable differences between different tilt measures at different levels of noise, and that multidimensional representations for tilt improve class separability from the scalar measures. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to give an integrative answer on which speech stereotypes exist toward German gay and straight men, whether and how acoustic correlates of actual and perceived sexual orientation are connected, and how this relates to masculinity/femininity. Hence, it tests speech stereotype accuracy in the context of sexual orientation. Method: Twenty-five gay and 26 straight German speakers provided data for a fine-grained psychological selfassessment (e.g., masculinity/femininity) and explicit speech stereotypes. They were recorded for an extensive set of read and spontaneous speech samples using microphones and nasometry. Recordings were analyzed for a variety of acoustic parameters (e.g., fundamental frequency and nasalance). Seventy-four listeners categorized speakers as gay or straight on the basis of the same sentence. Results: Most relevant explicitly expressed speech stereotypes encompass voice pitch, nasality, chromaticity, and smoothness. Demonstrating implicit stereotypes, speakers were perceived as sounding straighter, the lower their median f0, center of gravity in /s/, and mean F2. However, based on actual sexual orientation, straight men only showed lower mean F1 than gay men. Additionally, we found evidence that actual masculinity/femininity and the degree of sexual orientation were reflected in gay and straight men's speech. Conclusion: Implicit and explicit speech stereotypes about gay and straight men do not contain a kernel of truth, and differences within groups are more important than differences between them. Supplemental Material: https://doi.org/10.23641/asha.6484001 [ABSTRACT FROM AUTHOR]

In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum Length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method -- FEM, showing a good agreement. [ABSTRACT FROM AUTHOR]

An on-site system for measuring low-frequency noise and complainant's responses to the low-frequency noise was developed to confirm whether the complainant suffer from the environmental noise with low-frequency components. The system suggests several methods to find the dominant frequency and major sound pressure level spectrum of the noise causing annoyance. This method can also yield a quantified relationship (correlation coefficient and percentage of response to the noise) between physical noise properties and the complainant's responses. The advantage of this system is that it can easily find the relationship between the complainant's response to the acoustic event of the houses and the physical characteristics of the low-frequency noise, such as the time trends and frequency characteristics. This paper describes the developed system and provides an example of the measurement results. [ABSTRACT FROM AUTHOR]

We propose a system that controls the spatial distribution of odors in an environment by generating electronically steerable ultrasound-driven narrow air flows. The proposed system is designed not only to remotely present a preset fragrance to a user, but also to provide applications that would be conventionally inconceivable, such as: 1) fetching the odor of a generic object placed at a location remote from the user and guiding it to his or her nostrils, or 2) nullifying the odor of an object near a user by carrying it away before it reaches his or her nostrils (Fig. 1). These are all accomplished with an ultrasound-driven air stream serving as an airborne carrier of fragrant substances. The flow originates from a point in midair located away from the ultrasound source and travels while accelerating and maintaining its narrow cross-sectional area. These properties differentiate the flow from conventional jet- or fan-driven flows and contribute to achieving a midair flow. In our system, we employed a phased array of ultrasound transducers so that the traveling direction of the flow could be electronically and instantaneously controlled. In this paper, we describe the physical principle of odor control, the system construction, and experiments conducted to evaluate remote fragrance presentation and fragrance tracking. [ABSTRACT FROM PUBLISHER]

After the publication of NBR 15575 (ABNT, 2013) standard, it became necessary that the constructive systems used in residential buildings go through verification processes concerning the performance requirements. Considering the security requirements, it is necessary to evaluate the fire resistance of vertical sealing systems. Within the scope of habitability, the standard specifies that these systems must have an adequate acoustic performance. Regarding this scenario, this study has the purpose of evaluate the performance of two non-structural vertical sealing systems in ceramic bricks by comparing two different layouts of horizontal air gaps. Therefore, laboratory tests were performed, following the prescriptions of NBR 10636 (ABNT, 1989) and ISO 10140-2 (ISO, 2010). It was verified that the system with higher air gaps number had a better performance on fire resistance, and that the acoustic performance was very similar between the two systems. [ABSTRACT FROM AUTHOR]

Acoustic variation in expressive speech at the syllable level is studied. As emotions or attitudes can be conveyed by short spoken words, analysis of paradigmatic variations in vowels is an important issue to characterize the expressive content of such speech segments. The corpus contains 160 sentences produced under seven expressive conditions (Neutral, Anger, Fear, Surprise, Sensuality, Joy, Sadness) acted by a French female speaker (a total of 1120 sentences, 13 140 vowels). Eleven base acoustic parameters are selected for voice source and vocal tract related feature analysis. An acoustic description of the expressions is drawn, using the dimensions of melodic range, intensity, noise, spectral tilt, vocalic space, and dynamic features. The first three functions of a discriminant analysis explain 95% of the variance in the data. These statistical dimensions are consistently associated with acoustic dimensions. Covariation of intensity and F0 explains over 80% of the variance, followed by noise features (8%), covariation of spectral tilt, and F0 (7%). On the basis of isolated vowels alone, expressions are classified with a mean accuracy of 78%. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to address the reported inconsistencies in the relationship between objective acoustic measures and perceptual ratings of vocal quality. Method: This tutorial moves away from the more widely examined problems related to obtaining the perceptual ratings and the acoustic measures and centers in less scrutinized issues regarding the procedure to establish the correspondence. Expressions for the most common measure of association between perceptual and acoustic measures (Pearson's r) are derived using a multiple linear regression model. The particular case where the multiple linear regression involves only roughness and breathiness is discussed to illustrate the issues. Results: Most problems reported regarding inconsistent findings in the relationship between given acoustic measures and particular perceptual ratings could be linked to sample properties not directly related to the actual relationship. The influential sample properties are the collinearity between the regressors in the multiple linear regression and their relative variances. Recommendations on how to rule out this possible cause of inconsistency are given, varying in scope from data collection, reporting, manipulation, and results interpretation. Conclusions: The problems described can be extended to more general cases than the exemplified roughness and breathiness sample's coverage. Ruling out this possible cause of inconsistency would increase the validity of the results reported. [ABSTRACT FROM AUTHOR]

This article reports the first use of the pressure reciprocity technique to calibrate a micro-electromechanical system (MEMS) microphone. This standardized primary calibration method is conventionally used to calibrate laboratory standard microphones. Results for the pressure reciprocity calibration of a MEMS microphone and two laboratory standard microphones are presented for the frequency range 100–10 000 Hz. Because the amplifier in the MEMS microphone package prevents reciprocal operation, this microphone was used only as a receiver of sound. A description of the procedure is presented along with checks of the measurement results and data regarding the uncertainties of these results. [ABSTRACT FROM AUTHOR]

A characteristic surface duct beneath the sea-ice in the Marginal Ice Zone causes acoustic waves to be trapped and continuously interact with the sea-ice. The reflectivity of the sea-ice depends on the thickness, the elastic properties, and its roughness. This work focuses on the influence of sea-ice roughness on long-range acoustic propagation, and on how well the arrival structure can be predicted by the full wave integration model OASES. In 2013, acoustic signals centered at 900 Hz were transmitted every hour for three days between ice-tethered buoys in a drifting network in the Fram Strait. The experiment was set up to study the signal stability in the surface channel below the sea-ice. Oceanographic profiles were collected during the experiment, while a statistical description of the rough sea-ice was established based on historical ice-draft measurements. This environmental description is used as input to the range independent version of OASES. The model simulations correspond fairly well with the observations, despite that a flat bathymetry is used and the sea-ice roughness cannot be fully approximated by the statistical representation used in OASES. Long-range transmissions around 900 Hz are found to be more sensitive to the sea-ice roughness than the elastic parameters. [ABSTRACT FROM AUTHOR]

The article offers news briefs on the American National Standards (ANSI) for acoustics. News-related topics, including the use of sound pressure to determine sound power levels of noise, the Acoustical Society of America's (ASA's) volunteers, machinery sound measurement, measuring mechanical properties through resonance and mechanical vibration, are discussed.

The present study provides an evaluation of cabin noise inside a passenger car cabin for two types of roads in tropical environmental conditions in Malaysia. Tropical weather conditions are hot and humid, with rain also giving effect to the road surface condition. Noise exposure was measured using a DuO sound level meter, which is capable to record sound pressure in unit of Pa, and comparisons were made between the two types of roads; tarmac and dirt. The data was analysed using Integrated Kurtosis-based Algorithm for Z-notch Filter (I-kazTM) in relation to varying speeds of the car, in order to determine the degree of data scattering for the noise signals. Based on the results obtained, noise exposure levels can be presented using sound pressure, sound pressure level (SPL), I-kazTM coefficient (Z∞) and I-kazTM display. Test comparisons were made between the two types of roads in the same test speed, which showed that the values of Z∞ and SPL were higher, and the size for I-kazTM display was larger for the dirt road as compared to the tarmac road. It was found that rough roads exhibit higher noise exposure variation as the vehicle speed changes in the tropical environmental condition. [ABSTRACT FROM AUTHOR]

For online monitoring of complex temperature distributions, an acoustic tomography system based on sound travel‐time measurement is developed. For coping with the reverberation phenomenon in actual measurement, an anti‐reflection interference measurement method for sound travel‐time is proposed based on cross‐correlation and peak recognition. In view of the fact the pixel number provided by commonly used reconstruction algorithms, such as least‐squares methods, is very limited, radial basis function approximation and regularisation technique are used, which leads to the pixel number of the reconstruction image increasing dramatically. Mixed programming with LabVIEW and MATLAB is used. Queue structure is adopted to make data acquiring program and data processing program parallel. Test results show that the system can run normally as designed. The measurement values of sound travel‐time acquired by the proposed method are stable even in strong reflection interference. Test results show that the system can run normally as designed. The measurement values of sound travel‐time acquired by the proposed method are stable even in strong reflection interference. The temperature fields reconstructed are coincided with actual fields, and correctly reflect the temperature changes in the measured area with the heater number, heater location and heating time. [ABSTRACT FROM AUTHOR]

Partial discharges (PDs) are a cause of degradation of insulation system and its permanent activity monitoring is used as a tool for insulation condition assessment in power transformers. Information on PD position can be used by plant monitors to diagnose the cause of PD and can help to identify type and severity of an insulation fault for maintenance strategies. The acoustic PD detection system, with great advantages relative to other methods, contains inaccuracies in PD localisation, such as the multipath interferences due to reflections within transformer tank, improper acoustic coupling between sensor and tank surface, mechanical vibrations and inherent sensor inaccuracies, which can severely limit the accuracy of the positioning system and make locating the exact positions of PD difficult. In this study, a method has been proposed for calculation of position measurement sensitivity for different PD origins within transformer tank. Different possible cases have been considered for placement of acoustic emission (AE) sensors. For each case, sensitivity of PD location to the time measurement errors has been calculated. The optimum arrangement of AE sensors has been chosen as the configuration yielding lowest error in the PD localisation. A test setup has been organised and the experimental results have justified the theoretical analysis. [ABSTRACT FROM AUTHOR]

We consider the quasilinear wave equation $a,b>0$ , associated with initial and Dirichlet boundary conditions at one part and acoustic boundary conditions at another part, respectively. We prove, under suitable conditions on α, β, m, p and for negative initial energy, a global nonexistence of solutions. [ABSTRACT FROM AUTHOR]

A method for estimating the sound transmission loss of partitions in coupled reverberant-anechoic rooms is proposed, using two sound intensity measurements made before and after a test specimen is installed between the two rooms. Laboratory tests performed following a standard procedure and the suggested method with three different panels provide comparable transmission loss values. [ABSTRACT FROM AUTHOR]

Nowadays, the finite element method (FEM) - boundary element method (BEM) is used to predict the performance of structural-acoustic problem, i.e. the frequency response analysis, modal analysis. The accuracy of conventional FEM/BEM for structural-acoustic problems strongly depends on the size of the mesh, element quality, etc. As element size gets greater and distortion gets severer, the deviation of high frequency problem is also clear. In order to improve the accuracy of structural-acoustic problem, a smoothed finite-element/boundary-element coupling procedure (SFEM/BEM) is extended to analyze the structural-acoustic problem consisting of a shell structure interacting with the cavity in this paper, in which the SFEM and boundary element method (BEM) models are used to simulate the structure and the fluid, respectively. The governing equations of the structural-acoustic problems are established by coupling the SFEM for the structure and the BEM for the fluid. The solutions of SFEM are often found to be much more accurate than those of the FEM model. Based on its attractive features, it was decided in the present work to extend SFEM further for use in structural-acoustic analysis by coupling it with BEM, the present SFEM/BEM is implemented to predict the vehicle structure-acoustic frequency response analysis, and two numerical experiments results show that the present method can provide more accurate results compared with the standard FEM/BEM using the same mesh. It indicates that the present SFEM/BEM can be widely applied to solving many engineering noise, vibration and harshness (NVH) problems with more accurate solutions. [ABSTRACT FROM AUTHOR]

Increasingly powerful and noisy military aircraft have generated the need for research leading to the development of supersonic jet noise reduction devices. The hot, high speed supersonic jets exhausting from military aircraft during takeoff present a most challenging problem. The present study extends prior research on two methods of noise reduction. The first is the internal nozzle corrugations pioneered by Seiner et al. and the second is the beveled exit plane explored most recently by Viswanathan. A novel research idea of creating fluidic corrugations similar to the nozzle corrugations has been initiated by Penn State. To further the understanding and analysis of the fluidic corrugations, the present study focuses on the flow field and acoustic field of nozzles with two, three, and six conventional, hardwalled corrugations. The effect of the combination of the internal corrugations with a beveled nozzle is explored. The results show that significant noise reductions of over 3 dB of the mixing noise and the broadband shock-associated noise can be achieved. The combination of the beveled nozzle and the internal nozzle corrugations showed that there is less azimuthal dependence of the acoustic field than for the purely beveled nozzle. The combination nozzle was shown to reduce the noise over a wider range of polar angles and operating conditions than either the purely beveled nozzle or the purely corrugated nozzle. [ABSTRACT FROM AUTHOR]

Scaled acoustic laboratory experiments are used to develop a methodology for obtaining the acoustic characteristics of different barrier top designs and for identifying geometries that may have advantages over the traditional thin vertical screen. The idea is to use a short impulsive spherical sound pulse possessing a broad frequency spectrum. If the duration of the pulse is sufficiently short, the entire primary signal, which travels by the shortest direct route diffracting at the top of the barrier, arrives at the receiver much earlier than any secondary signals reflected from the surroundings. Secondary signals may therefore be ignored and only the information from the primary signal can be analyzed. When the typical frequency band of the sound pulse is about an order of magnitude higher than typical traffic noise spectra, then scaled acoustic modeling using the same scaling factor for lengths and distances is possible. The results of such experiments are reported here for barriers with six different geometries. Using spectral analysis, insertion losses as functions of frequency were calculated for different source-receiver positions and barrier tops. The results were then rescaled for full-size traffic barriers and, using a typical traffic noise spectrum, single number ratings of barrier performance were obtained. [ABSTRACT FROM AUTHOR]

Doppler current profilers on autonomous underwater gliders measure water velocity relative to the moving glider over vertical ranges of O(10) m. Measurements obtained with 1-MHz Nortek acoustic Doppler dual current profilers (AD2CPs) on Spray gliders deployed off Southern California, west of the Galápagos Archipelago, and in the Gulf Stream are used to demonstrate methods of estimating absolute horizontal velocities in the upper 1000m of the ocean. Relative velocity measurements nearest to a glider are used to infer dive-dependent flight parameters, which are then used to correct estimates of absolute vertically averaged currents to account for the accumulation of biofouling during months-long glider missions. The inverse method for combining Doppler profiler measurements of relative velocity with absolute references to estimate profiles of absolute horizontal velocity is reviewed and expanded to include additional constraints on the velocity solutions. Errors arising from both instrumental bias and decreased abundance of acoustic scatterers at depth are considered. Though demonstrated with measurements from a particular combination of platform and instrument, these techniques should be applicable to other combinations of gliders and Doppler current profilers. [ABSTRACT FROM AUTHOR]

A novel panel-form loudspeaker in which the panel of the speaker is excited by the forces generated through the flat voice coil of a rectangular electro-magnetic type exciter for sound radiation is presented. The exciter when properly designed has the advantage of exerting appropriate loads to the panel so that the major sound pressure level (SPL) dips of the speaker can be suppressed or even eliminated. For designing such panel-form speaker, a method formulated on the basis of the classical plate theory (CPT), Ritz method, and first Rayleigh integral is proposed for predicting the SPL curve of the speaker. An experimental investigation was performed to verify the feasibility of the proposed method. The effects of some system parameters on the major SPL dips of the proposed panel-form speakers are investigated by means of several numerical examples. The optimal locations of flat voice coils for exciting several panel-form speakers are determined to illustrate the important role of excitation location for enhancing sound quality of such speakers via the removal or suppression of the major SPL dips. [ABSTRACT FROM AUTHOR]

The subjective evaluation of noise perception is a very broad topic that has many applications in the field of acoustics. Large variability is usually associated with a subjective evaluation that appears in the standard deviation. This is due to a small amount of subjects (the outliers), who had different responses compared to most of the other subjects. By using the Bootstrap statistical method, this paper shows how to identify the outliers and quantify the contribution to the final results with and without considering the outliers in the calculation. [ABSTRACT FROM AUTHOR]

Purpose. Since human voice characteristics are specific to each individual, numerous anthropological studies have been oriented to find significant relationships between voice and morpho-functional features. The goal of this study was to identify the correlation between seven morpho-functional variables and six voice acoustic parameters in sportsmen. Methods. Following the protocols of the International Biological Program, seven morpho-functional variables and six voice acoustic parameters have been measured in 88 male professional athletes from Kosovo, aged 17-35 years, during the period of April-October 2013. The statistical analysis was accomplished through the SPSS program, version 20. The obtained data were analysed through descriptive parameters and with Spearman's method of correlation analysis. Results. Spearman's method of correlation showed significant negative correlations (R = -0.215 to -0.613; p = 0.05) between three voice acoustic variables of the fundamental frequency of the voice sample (Mean, Minimum, and Maximum Pitch) and six morpho-functional measures (Body Height, Body Weight, Margaria-Kalamen Power Test, Sargent Jump Test, Pull-up Test, and VO2max.abs). Conclusions. The significant correlations imply that the people with higher stature have longer vocal cords and a lower voice. These results encourage investigations on predicting sportsmen's functional abilities on the basis of their voice acoustic parameters. [ABSTRACT FROM AUTHOR]

In this paper, we studied the thermodynamic behavior of generalized warp factor for the corresponding AdS metric background. To discuss the stability of the theory we studied thermodynamical properties of generalized metric background. Here also to obtain the quantity of sound for the measure of stability of the system, we need to calculate the energy density and pressure. Such parameters of sound for the properties of stability constrain some conditions on the corresponding theory as θ. We used the corresponding conditions and rewrite the action of theory. The new action give us opportunity to study the AdS black hole and thermally charged AdS black hole. [ABSTRACT FROM AUTHOR]

This follow-up study examines the accuracy of selected smartphone sound measurement applications (apps) using external calibrated microphones. The initial study examined 192 apps on the iOS and Android platforms and found four iOS apps with mean differences of ±2 dB of a reference sound level measurement system. This study evaluated the same four apps using external microphones. The results showed measurements within ±1 dB of the reference. This study suggests that using external calibrated microphones greatly improves the overall accuracy and precision of smartphone sound measurements, and removes much of the variability and limitations associated with the built-in smartphone microphones. [ABSTRACT FROM AUTHOR]

A simple and inexpensive approach to acquiring signals in the megahertz frequency range using a smartphone is described. The approach is general, applicable to electromagnetic as well as acoustic measurements, and makes available to undergraduate teaching laboratories experiments that are traditionally inaccessible due to the expensive equipment that are required. This paper focuses on megahertz range ultrasonic resonance spectra in liquids and solids, although there is virtually no upper limit on frequencies measurable using this technique. Acoustic resonance measurements in water and Fluorinert in a one dimensional (1D) resonant cavity were conducted and used to calculate sound speed. The technique is shown to have a precision and accuracy significantly better than one percent in liquid sound speed. Measurements of 3D resonances in an isotropic solid sphere were also made and used to determine the bulk and shear moduli of the sample. The elastic moduli determined from the solid resonance measurements agreed with those determined using a research grade vector network analyzer to better than 0.5%. The apparatus and measurement technique described can thus make research grade measurements using standardly available laboratory equipment for a cost that is two-to-three orders of magnitude less than the traditional measurement equipment used for these measurements. [ABSTRACT FROM AUTHOR]

Environmental noise is a risk factor for human physical and mental health, demanding an efficient large-scale noise-monitoring scheme. The current technology, however, involves extensive sound pressure level (SPL) measurements at a dense grid of locations, making it impractical on a city-wide scale. This paper presents an alternative approach using a microphone array mounted on a moving vehicle to generate two-dimensional acoustic tomographic maps that yield the locations and SPLs of the noise-sources sparsely distributed in the neighborhood traveled by the vehicle. The far-field frequency-domain delay-and-sum beamforming output power values computed at multiple locations as the vehicle drives by are used as tomographic measurements. The proposed method is tested with acoustic data collected by driving an electric vehicle with a rooftop-mounted microphone array along a straight road next to a large open field, on which various pre-recorded noise-sources were produced by a loudspeaker at different locations. The accuracy of the tomographic imaging results demonstrates the promise of this approach for rapid, low-cost environmental noise-monitoring. [ABSTRACT FROM AUTHOR]

Address-level estimates of exposure to road traffic noise for epidemiological studies are dependent on obtaining data on annual average daily traffic (AADT) flows that is both accurate and with good geographical coverage. National agencies often have reliable traffic count data for major roads, but for residential areas served by minor roads, especially at national scale, such information is often not available or incomplete. Here we present a method to predict AADT at the national scale for minor roads, using a routing algorithm within a geographical information system (GIS) to rank roads by importance based on simulated journeys through the road network. From a training set of known minor road AADT, routing importance is used to predict AADT on all UK minor roads in a regression model along with the road class, urban or rural location and AADT on the nearest major road. Validation with both independent traffic counts and noise measurements show that this method gives a considerable improvement in noise prediction capability when compared to models that do not give adequate consideration to minor road variability (Spearman’s rho. increases from 0.46 to 0.72). This has significance for epidemiological cohort studies attempting to link noise exposure to adverse health outcomes. [ABSTRACT FROM AUTHOR]

An efficient acoustic events detection system EAR-TUKE is presented in this paper. The system is capable of processing continuous input audio stream in order to detect potentially dangerous acoustic events, specifically gunshots or breaking glass. The system is programmed entirely in C++ language (core math. functions in C) and was designed to be self sufficient without requiring additional dependencies. In the design and development process the main focus was put on easy support of new acoustic events detection, low memory profile, low computational requirements to operate on devices with low resources, and on long-term operation and continuous input stream monitoring without any maintenance. In order to satisfy these requirements on the system, EAR-TUKE is based on a custom approach to detection and classification of acoustic events. The system is using acoustic models of events based on Hidden Markov Models (HMMs) and a modified Viterbi decoding process with an additional module to allow continuous monitoring. These features in combination with Weighted Finite-State Transducers (WFSTs) for the search network representation fulfill the easy extensibility requirement. Extraction algorithms for Mel-Frequency Cepstral Coefficients (MFCC), Frequency Bank Coefficients (FBANK) and Mel-Spectral Coefficients (MELSPEC) are also included in the preprocessing part. The system contains Cepstral Mean Normalization (CMN) and our proposed removal of basic coefficients from feature vectors to increase robustness. This paper also presents the development process and results evaluating the final design of the system. [ABSTRACT FROM AUTHOR]

Passive Acoustic Mapping (PAM) enables real-time monitoring of ultrasound therapies by beamforming acoustic emissions emanating from the ultrasound focus. Reconstruction of the narrowband or broadband acoustic emissions component enables mapping of different physical phenomena, with narrowband emissions arising from non-linear propagation and scattering, non-inertial cavitation or tissue boiling, and broadband (generally, of significantly lower amplitude) indicating inertial cavitation. Currently, accurate classification of the received signals based on pre-defined frequency- domain comb filters cannot be guaranteed because varying levels of leakage occur as a function of signal amplitude and the choice of windowing function. This work presents a time-domain parametric model aimed at enabling accurate estimation of the amplitude of time-varying narrowband components in the presence of broadband signals. Conversely, the method makes it possible to recover a weak broadband signal in the presence of a dominant harmonic or other narrowband component. Compared to conventional comb filtering, the proposed sum-of-harmonics method enables PAM of cavitation sources that better reflect their physical location and extent. [ABSTRACT FROM AUTHOR]

The acoustic signature of a controlled-diffusion airfoil immersed in a flow is experimentally characterized. Acoustic measurements have been carried out in an anechoic open-jet-wind-tunnel for low Reynolds numbers (from 5×104 to 4.3×105) and several angles of attack. As with the NACA0012, the acoustic spectrum is dominated by discrete tones. These tonal behaviors are divided into three different regimes. The first one is characterized by a dominant primary tone which is steady over time, surrounded by secondary peaks. The second consists of two unsteady primary tones associated with secondary peaks and the third consists of a hump dominated by several small peaks. A wavelet study allows one to identify an amplitude modulation of the acoustic signal mainly for the unsteady tonal regime. This amplitude modulation is equal to the frequency interval between two successive tones. Finally, a bispectral analysis explains the presence of tones at higher frequencies. [ABSTRACT FROM AUTHOR]