A5048667279- Acoustic Wave Phenomena Research
- Aerodynamics and Acoustics in Jet Flows
- Speech and Audio Processing
- Vehicle Noise and Vibration Control
- Music Technology and Sound Studies
- Ultrasonics and Acoustic Wave Propagation
- Underwater Acoustics Research
- Structural Health Monitoring Techniques
- Advanced Measurement and Detection Methods
- Optical measurement and interference techniques
- Microwave Imaging and Scattering Analysis
- Hearing Loss and Rehabilitation
- Geophysical Methods and Applications
- Noise Effects and Management
- Seismic Waves and Analysis
- Advanced Adaptive Filtering Techniques
- Experimental Learning in Engineering
- Advanced MEMS and NEMS Technologies
- Advanced Measurement and Metrology Techniques
- Image and Signal Denoising Methods
- Acoustic Wave Resonator Technologies
- Bluetooth and Wireless Communication Technologies
- Antenna Design and Analysis
- Hydraulic and Pneumatic Systems
- Diverse Interdisciplinary Research Innovations
Le Mans Université
2015-2024
Laboratoire d'Acoustique de l'Université du Mans
1996-2024
Centre National de la Recherche Scientifique
2015-2024
Institut des Molécules et Matériaux du Mans
1998-2024
Université Nantes Angers Le Mans
2019-2024
Conservatoire National des Arts et Métiers
2004-2013
The acoustic wave most commonly transmitted and detected in the high-porosity absorbent materials used noise control is generally air-borne slow compressional wave. In a new experiment, air saturating sample replaced by helium transmission studied at ultrasonic frequencies (70–600 kHz). experiment quite easily performed using standard ultrasonics vacuum equipment. main purpose of this work to propose method determine simultaneously both viscous thermal characteristic lengths with same...
Abstract Digital image correlation, deflectometry and digital holography are some of the full-field optical measurement techniques that have matured in recent years. Their use vibroacoustic applications is gaining attention there a need for cataloging their performance order to provide, broad community users potential future users, quantitative qualitative evaluations these three approaches. This paper presents an experimental comparison methods context vibration measurements, along with...
Piezoelectric micro-electro-mechanical-system (MEMS) speakers are emerging as promising implementations of loudspeakers at the microscale, they able to meet ever-increasing requirements for modern audio devices become smaller, lighter, and integrable into digital systems. In this work, we propose a finite element model (FEM)–assisted lumped-parameters equivalent circuit fast accurate modeling these types devices. The electro-mechanical parameters derived from pre-stressed FEM eigenfrequency...
In this article, a boundary element method is used to recover free field conditions from noisy bounded space situations. The proposed approach based on the Helmholtz integral formulation. requires knowledge of double layer pressure fields two parallel closed surfaces surrounding source. First, outgoing and ingoing are separated using integral. Then, incident scattered by tested source subtracted which would have been radiated in space. To simplify process, rigid body approximation for used....
This paper investigates the efficiency of a field separation method for identification sound sources in small and non-anechoic spaces. When performing measurements such environments, acquired data contain information from direct radiated by source interest reflections walls. To get rid unwanted contributions assess interest, is used. Acoustic (pressure or velocity) are then measured on hemispheric array whose base laying surface interest. Then, using spherical harmonic expansions, outgoing...
One of the main fields application personal sound zones (PSZs) is car industry. PSZ systems are usually designed assuming that acoustic environment not changing. However, due to variability in cabin's conditions, it necessary design a system capable adapting these variations. This paper introduces use filtered-x least-mean-squares algorithm adapt cabin when seat positions change. The article focuses on four aspects. First, effect initial coefficients investigated help with convergence...
Due to excessive reverberation or the presence of secondary noise sources, characterization sound sources in enclosed space is rather difficult perform. In this paper a process layer used recover pressure field that studied source would have radiated free space. This technique requires knowledge both acoustic and velocity fields on closed surface surrounding source. The calculation makes use boundary element method performed two steps. First, outgoing extracted from measured data using...
Acoustical (viscous static permeability, tortuosity, and viscous characteristic length) mechanical (skeleton viscoelasticity tensor) parameters which characterize the behavior of porous media are provided from measurements along three perpendicular axes. The performed on cubic samples open-cell foams. longitudinal direction is chosen to be parallel growth foam. results show that tested here exhibit a quasi-axisymmetrical geometry. It appears precise description this type reticulated...
This paper evaluates the potential of field separation method (FSM) for performing subwoofer measurements in a small test room with poor absorbing properties, as is commonly available. The FSM requires knowledge both acoustic pressure and velocity fields on closed surface surrounding tested source. Pressures velocities, measured using p-p probe half-sphere mesh, are collected under various conditions: variable reverberation time (6.4–0.6 s) four measurement radii. data expanded spherical...
A method for measuring the diffuse field sound absorption coefficient of a material using synthesis is proposed. planar loudspeaker array first used to generate acoustic plane waves with variable incidence angle on surface under test. Using two-microphone probe positioned closely sample’s surface, angle-dependent coefficients are then estimated. Finally, computed following Paris formula. Numerical simulations evaluate respective effects maximum value and number individual angles that...
The measurement of the pressure field radiated by a sound source has many applications in fields noise control and loudspeaker system design. In this paper, radiation mode method is used to measure complex acoustic whose surface impedance arbitrary does not correspond Neumann boundary condition for calculation modes. most effective modes are as test functions calculate expansion around under test, an that matches measured at limited number points close source. This then greater distance...
In this article, the fundamental principles of forward projecting time domain acoustic pressure fields are summarized. Four different numerical approaches presented and compared both with simulated measured signals. The differ in their definition domain: Frequency/time space/wave vector domains. source is a planar baffled piston excited Gaussian pulsed velocity. radiated by two real sources has been measured: first made up loudspeakers (a white noise can be third loudspeaker). second one...
This paper describes a beamforming method for one-eighth, quarter, and half-spaces, bounded by rigid planes. The proposed approach is based on the spherical fraction harmonic decomposition, similar to that of harmonics decomposition whole sphere. definition these functions given in detail. It also proved they form sub-basis harmonics, with fraction-dependent normalization gain, which makes it easy adapt from existing implementation. Taking advantage boundary condition, shown number used...
Time reversal is a widely used technique in wave physics, for both imaging purposes and experimental focusing. In this paper, complete double-layer time process proposed situ acoustic characterization of non-stationary sources, with perturbative noise sources reverberation. The method involves the use hemispherical array composed pressure-pressure probes. set underlying optimizations to sonic detailed, regard space reconstruction accuracy, resolution sensitivity reverberation, noise. tested...
The ACOUCOU platform is a web-based, interactive, acoustics training that includes set of free educational materials in various technical fields acoustics. Educational are designed to serve as modern self-development tool for students and engineers, well comprehensive solution professional education the work environment. On other hand, provided can be useful tool, supporting teachers, company researchers, academic lecturers process teaching part strategic plan expanding strengthening...
This paper presents a rethinking of the Pressure Matching Method (PM) used in generation Personal Sound Zones when responses some filters are already known. They then imposed calculation, resulting Forced method. new formulation is implemented to control two zones—a reproduction zone and dark zone—in two-seat configuration aimed toward Transportation industry. Due variations transportation acoustic environments, computational time added metrics typically literature (such as contrast, effort,...
Standardized methods for measuring sound absorption such as the impedance tube and reverberation chamber are limited to normal or diffuse incidence, respectively. Two research axes have been generally followed in literature develop alternative techniques, first one focusing on measurement part, that is from two-microphone technique use of microphone arrays pressure-velocity sensors. The second axis focuses excitation part with instance field synthesis techniques. Since acoustic coefficient...
Tortuosity, i.e., the high-frequency limit of squared propagation index, has been evaluated with narrow-band piezoelectric transducers on reticulated plastic foams. The basic procedure was recently reported by J. F. Allard, B. Castagnède, M. Henry and W. Lauriks [Rev. Sci. Instrum. 65, 754 (1994)]. Further experimental work related to anisotropic nature these materials done probing index versus angle. A simple numerical routine implemented in order recover along principal directions. These...