As one of the most important physical phenomena of underwater acoustics, ocean reverberation is a common and strong interference which significantly degrades the performance of target bearing estimation. Meanwhile, sensor failure is inevitable in actual sonar deployment as the underwater scene is complicated. Therefore, it is a challenge for acoustic localization in the ocean reverberation with sensor

Background Pinpointing the noise-induced psychological effects in workplace is difficult due to the wide variance of individual responses. The aim of this study was to investigate the role of individual and personality traits in occupational noise-induced annoyance, mental work load, and fatigue. Methods Thirty-one male participants with normal hearing and good general health were recruited. They were

Cavities with asymmetrical walls exist in many industrial applications and its acoustic properties are crucial to noise and vibration control. However, traditional methods are complex and time-consuming such as finite element method (FEM). Given the problems existing in traditional methods, the ISM-TM algorithm which combined the image source model (ISM) with the transformation matrix (TM) is proposed

The resonance characteristics of elastic acoustic scattering play an important role for buried target detection and identification. Taking a stainless steel sphere as the target, the acoustic scattering of the target under free-field and buried conditions are calculated using the corresponding COMSOL models. The influences of the burial layer on the Rayleigh wave and Whispering-Gallery wave are analyzed

Surrounded by low SNR, how to make the voice faster and better recognize the owner has become a heated research topic. The human auditory system can accurately acquire the characteristics of acoustic events in complex systems or low SNR noise environment, which is of significance in the research of bionic hearing of human ear. The response curve of human ear output is obtained by bionic technology

This study explores a modified active noise control (ANC) system using a Bayesian inference approach as a pre-processing method. The key aspect of low-frequency noise attenuation is investigated with the existing control algorithms, the conventional filtered-x least mean square (FxLMS) algorithm and a new convex structure via an FxLMS/F algorithm (C-FxLMS/F), that combine Bayesian inference with a

The low identification rate of the Orthogonal frequency division multiplexing (OFDM) based subcarrier modulation in underwater acoustic multipath channel is an important issue. Therefore, we proposed a novel Expectation Maximization-Block-Quasi Hybrid Likelihood Ratio Test (EM-Block-QHLRT) method which effectively improved the identification rate while using the blind channel impulse response (CIR)

The TL (transmission loss) is an important index to evaluate muffler performance. The design of muffler should not only consider acoustic performance, but also its volume, manufacturing cost and its influence on comprehensive performance of diesel engine. If the prominent structural parameters of muffler can be found, the TL can be maximized without sacrificing the overall performance of diesel engine

We present the double-leaf acoustic black hole beam embedded mass oscillator, and discuss the different elastic waves modulation effects. Vibration transmission spectrum indicates that strong wave trapping region corresponds to the anti-symmetrical vibration attenuation (Fano-like resonance) and the weak wave trapping region corresponds to the symmetrical vibration attenuation (Bragg scattering). The

In this paper, an intelligent evaluation of the interior sound quality (SQ) of electric vehicles (EVs) was designed using intelligent algorithms and artificial neural networks. First, interior noises from different EV brands and models were collected using noise tests that are based on relevant standards. Second, a subjective evaluation was applied to appraise the SQ using a laboratory-scale jury test

This paper has developed a 5-DOF driver and seat suspension system model for active vibration control. A novel fast system parameter identification method from vibration measurement data has been proposed for the seat-occupant system based on the multi-objective Genetic Algorithm optimization (GA). This system parameter identification method can identify the seat system parameters of a 5-DOF lumped

Acoustic lenses composed of metamaterials are used as highly anisotropic subwavelength media and have broad applications in a wide range of industrial areas. As reported in recent research, an acoustic lens composed of a cross-shaped structure can achieve high-intensity 3D focusing in an underwater system. However, the operating characteristics of this lens at different frequencies have not been studied

This paper describes a Digital Acoustic Projector (DAP), which is a hybrid sound system combining both a digital loudspeaker and a parametric array to convert directly an n-bits digital electrical signal into sound. It consists of a set of ultrasonic transducers emitting a sinusoidal signal modulated by a sampled and quantized low-frequency signal. Self demodulation effect is used to demodulate the

Large spaces, circular in plan, can be preferred by architects to design large auditoria, even though they can cause acoustical singularities such as focusing and whispering gallery. In large auditoria for multipurpose functions are becoming a common request to use the space for different activities such as conferences, concerts of classical and amplified music, shows, etc. and the necessity to find

This paper investigates the use of acoustic signals in diagnosing stator inter-turn faults in Line Start Permanent Magnet Synchronous Motors (LSPMSMs). Singular spectrum analysis (SSA) is proposed to analyze the acoustic signal for fault detection. The proposed methodology involves collection of experimental acoustic data using a smartphone from an interior mount LSPMSM under different loading levels

Acoustic feedback is a frequently encountered problem in assistive listening devices (ALDs). Feedback paths in ALDs are typically sparse in nature and sparsity aware adaptive feedback cancellers can improve perceived audio quality under such scenarios. In an endeavour to improve the feedback canceller performance, a decorrelated polynomial zero attraction (DPZA) normalized least mean square (NLMS)

This study aimed to understand the correlation between standard impact sound sources and real impact sources in lightweight floor structures. Six real impact sources (adult walking, child running, child jumping on the floor, and three objects falling) were used to be compared with standard impact sources (i.e. tapping machine and impact ball). Measurements were conducted on a lightweight timber joist

1-3 piezoelectric composite material is widely applied in medical ultrasound transducers. The acoustic impedance mismatching still exists between composite materials and human tissue, this mismatching limits the performance of the 1-3 composite transducer. In this work, Parylene coating technique is employed to enhance the performance of a 1-3 piezoelectric composite transducer whose center frequency

Based on the study of sound propagation characteristics and acoustic radiation in periodic tube arrays, we found that the wave front differed from the no-tube arrays at the same frequency. The phenomenon indicated that there was different sound velocity in tube arrays. This research considered tube arrays as an effective medium for sound and studied the effective sound velocity at different frequencies

Smartphones have evolved into powerful devices with computing capabilities that rival the power of personal computers. Any smartphone can now be turned into a sound-measuring device because of its built-in microphone. Many sound measuring apps exist on the market for various mobile platforms. In our earlier research, we showed that a smart device with an adequate app can achieve compliance with most

This paper examines the feasibility of using an audio-visual methodology for sound source localization of acoustic sources hidden from direct view. A four channel microphone array is used in conjunction with LiDAR and 2D/3D mapping to merge estimated angles of arrival with room parameters for sound source localization. The time difference of arrival (TDOA) approach is used to estimate the angle(s)

The aerodynamic noise of an alternator, which is difficult to predict due to the complex internal flow, has become an issue for vehicles in recent years. To study the acoustic characteristics of the vehicle claw pole alternator, a numerical simulation method is proposed in this paper to predict its aerodynamic noise. First, a Scale Adaptive Simulation (SAS) in the numerical calculation is used to calculate

In masking-based deep neural network (DNN) speech enhancement, the time–frequency masking value cannot be estimated accurately because the potential structure information of speech is ignored. In this paper, a speech enhancement method is proposed by combining adaptive sparse non-negative matrix factorization (NMF) feature extraction and soft mask to optimize DNN, using the advantages of the sparse

This paper presents an overview on advancement made in designing of a digital infinite impulse response (IIR) filter. The design problem of an IIR filter was found to be challenging due to presence of poles in its transfer function. This makes the phase response of an IIR transfer function nonlinear and its magnitude response is also drifted due to quantization of coefficient values of denominator

When a vehicle is under the idle condition, the direct engine noise and structure-radiated noise caused by engine vibration are perceived by passengers more easily than the vehicle is in moving due to the absence of road and wind noises. These abnormal noises have become the most annoying sound of passenger vehicles. However, there are very few researches on the mechanism of how such noises were generated

Audio wearable devices, or hearables, are becoming an increasingly popular consumer product. Some of these hearables contain an in-ear microphone to capture audio signals inside the user’s occluded earcanal. Mainly, the microphone is used to pick up speech in noisy environments, but it can also capture other signals, such as nonverbal events that could be used to interact with the device or a computer

Bio-inspired camouflage covert underwater acoustic communication has been studied widely recently. In order to improve the camouflage ability and communication rate, a bio-inspired covert underwater acoustic communication method based on combined encoding of diverse time–frequency characteristics of sperm whale clicks is proposed. The characteristics of time–frequency contour shapes and frequency-band

This paper concerns the measurement and prediction of rainfall noise with a particular focus on measurements made using the method described in the ISO rainfall noise standard. Rainfall noise is generated by rain impacting on a surface which excites the surface producing noise. Here, several different models for the force produced by a water droplet impacting on a flat inclined surface are presented

This study investigated the effects of classroom acoustics on speech intelligibility in secondary school and university classrooms. Speech intelligibility tests were conducted in 9 secondary school classrooms and 18 university classrooms and the acoustical measurements were performed in these classrooms. Subjective speech intelligibility tests were obtained from phonetically balanced (PB) word lists

In this paper, we proposed multi resonant scatterers which is comprised of two coaxial resonant shells. Four conceivable scatterers which are combinations of two different types of resonant shells such as shell with slit and perforations are examined. We calculated the insertion loss of sonic crystal made with said scatterers via simulation first. It is shown that, with said scatterers, the resonance

The sound quality of vehicle interior noise is under a deep influence of the exhaust noise determined by exhaust system, playing a significant role in the customer perception of passenger car. Therefore, in this paper, the relationship between the structure parameter of exhaust system and the sound quality of vehicle interior noise was indicated and a structure-SQE model was proposed. As the basis

This work evaluates the effect of the excitation signal used when measuring the absorption coefficient on an impedance tube. This paper aims to offer some guidance on the selection of the excitation signal to perform sound absorption measurements using the impedance tube. Four possible excitation signals defined in ISO 10534-2 Standard were studied: two of them, random noise and two of them sine sweep

Nanotechnology has been widely used for developing sound absorption materials in air, but studies for underwater applications remain limited. In this study, carboxyl functionalized multi-walled carbon nanotubes (MWCNT-COOH) were added into polydimethylsiloxane (PDMS) with dispersant to enhance the underwater acoustic properties. A water-filled impedance tube was built to determine the underwater sound

The acoustic radiation efficiency of a cylindrical shell is an important parameter in estimating the sound radiation emitted by a structure. However, many of the relevant previous studies have approached acoustic radiation problem by employing numerical methods, requiring large computational resources. In this study, an analytical method is developed to calculate the acoustic radiation efficiency of

Seasonal statistics on underwater ambient noise in the deep area of the South China Sea (SCS) were analyzed on the basis of the experimental observation data. The depth dependence, correlation with environmental parameters, empirical expression and probability density function (PDF) of noise levels (NL) in summer were compared with those in winter. Average of NLs at receiver depths shallower than 800 m

Vowel formants provide information as to how a vowel is uttered. Formant frequencies are relevant in applications involving human speech processing. However, such implementations are mainly performed with non-Spanish speakers. Thus, the Spanish vowels characterization should be further explored. In this study, a method for formants extraction based on the discrete wavelet transform is presented. The

This work deals with an experimental investigation of the acoustic absorption of two kinds of materials, i.e. chips, and sawdust of red, and beechwood. For this purpose, several particle sizes classes, and thicknesses were tested in the impedance tube in the frequency range [50–1400] Hz. The results show that the classes of (0.31 mm−0.63 mm), (0.63 mm−1.25 mm), and (1.25 mm−2.5 mm) give a better absorption

Speech feature fusion is the most commonly used phenomenon for improving the accuracy in Speech Emotion Recognition (SER). But in this, there is a disadvantage of increasing the complexity in SER system in terms of processing time. Besides this, some of the features could be redundant and do not contribute for SER and lead to incorrect emotion prediction and reduction in SER accuracy. To overcome this

Airfoils generate intensive laminar boundary layer instability noise at low-to-moderate Reynolds numbers. Experimental studies are conducted to investigate the noise radiation characteristics of a NACA 0012 airfoil operated at various angles of attack and Reynolds numbers. It is found that the instability noise changes from a broadband hump to intensive tonal noise with increasing angle of attack,

In multi-resonant Tonpilz longitudinal vibrating piezoelectric transducers with a clamped bolt of which both ends are screwed directly into their head mass and tail mass, the influence of a radial gap between clamped bolt and transducer’s component elements on the transducer’s wide-band characteristic was illustrated through detailed qualitative and simulation analysis. In order to verify the validity

The sperm whale (Physeter macrocephalus) is one of the largest and most widely distributed marine mammals. The Mediterranean population, classified as Endangered in the IUCN Red List, is affected by a number of anthropogenic threats, including noise increase. The individuals of this species tend to spend long periods “rafting” and socializing at the surface inbetween deep dives and this make them highly

A laboratory experiment has been carried out in this paper to study the effects of masking sound and signal-to-noise ratio (SNR) on occupants’ objective performance and perceived sound environmental quality in Chinese open-plan offices. The serial recall task performance and subject perceptions of 30 participants were tested under 14 different acoustic conditions, including “Quiet” (the condition without

Underwater acoustic (UWA) communication encounters significant difficulties posed by the simultaneous presence of multipath and time variations. It has been recognized that, under the assumption that channel keeps static within the processing windows, time reversal (TR) processing approach is capable of mitigating multipath via the spatial–temporal focusing. However, for a rapidly time-varying UWA

Nowadays, the virtual prototyping method is widely used for industrial applications and can lead to a powerful tool for musical instruments making and conservation. Nevertheless, physics-based models of musical instruments are barely developed for this purpose and the confrontation between model predictions and experiments have been the focus of very few researches. The objective of this paper is to

The basic objective of environmental protection against noise is the care for acoustic climate, among others via maintaining the allowable noise levels. In many countries, ISO 1996 standards constitute the reference for the measurement and assessment of acoustic environment, thus it is necessary to verify the guidelines contained therein in different measurement circumstances. The presented study covered

In this paper, we propose a novel calibration method for the batch measurement of hydrophone sensitivity in a tank. This calibration method is based on the source spatial averaging method of constructing a ‘diffused sound field’ in a small-volume tank. Source spatial averaging is implemented as follows: the transducer radiates steady-state signals whilst moving irregularly and slowly at a certain space

Occupational noise exposure is a documented risk among fish harvesters worldwide. So far, researchers’ main concern has been the detection of onboard noise levels causing noise-induced hearing loss. However, this fails to consider the relationship between hazardous noise levels and noise-induced fatigue. Differently from previous studies and regulatory standards, this research activity focuses on the

Experimentally validated models of a heavyweight reception plate using finite element methods (FEM) have been used to assess reception plate measurements of structure-borne sound power injected by single- and multiple-contact, broadband sources. Measurements and FEM indicated high velocity levels near corners and edges of the plate; hence the reception plate power was underestimated by up to ≈9 dB

Single-stage forming is widely used in automobile industry due to less cycle times, cost-effectiveness and ease of implementation. The continuously adaptable blank holder force (BHF) systems help produce defect-free components during the deep drawing process. However, this manufacturing process induces a significant amount of variability both at geometry and functional performance of the component

It is known that the underwater acoustic channels (UAC) exhibit non-uniform cluster-sparse characteristics, meaning that the channel impulse response (CIR) typically consists of a large number of near-zero taps and with only a few none-zero ones assemble in clusters in a structured manner, moreover, the cluster structure is non-uniformly distributed on the time domain. In this paper, an improved proportionate

Existing deep learning-based speech denoising approaches require clean speech signals to be available for training. This paper presents a deep learning-based approach to improve speech denoising in real-world audio environments by not requiring the availability of clean speech signals as reference in training mode. A fully convolutional neural network is trained by using two noisy realizations of the

Indoor acoustic comfort under existing outdoor noise generally depends on the sound insulation characteristics of the building façade. The importance of the acoustic classification of dwelling façade among the classification of other building elements was presented in a COST Action report and by developing the ISO/AWI TS 19488 project. Two approaches are used to describe the façades classification

In this paper; we propose two new substitution schemes for digital audio watermarking based on the Fourier transform. The integration of the watermark will be performed by combining the parity of the successive coefficients values; each variant will represent a different combination. In our experiments several variants of the Fourier transform are used (Discrete Fourier Transform, a Fractional Fourier

A variant of the traditional modal scintillation index is proposed for the discrimination of the active submerged/bottom target in a shallow water waveguide. Referred to the scintillation index applied in the passive surface/submerged target discrimination, the mathematical definitions of the modulated scintillation index (MSIm) and the total scintillation index (TSI) are introduced for active targets

This research develops an underwater acoustic metamaterial, which can serve to absorb broadband low-frequency underwater sound under high hydrostatic pressure ranging from 200 to 2000 Hz. Every unit cell includes 12 harmonic oscillators as multi-scatterers in the proposed acoustic metamaterial, which induces lots of local resonance modes for absorbing sound energy in the investigated frequency range

Condition monitoring of gear trains by classic techniques based on vibrations and/or extensometry measurements requires the preparation of the sensor contact surfaces and the cables installation. In the case of planetary gear trains, this task is more difficult due to their compactness and the complexity of the relative movements among their different elements. As an alternative, the authors studied