scholarly journals Sound field separation with sound pressure and particle velocity measurements

2012 ◽  
Vol 132 (6) ◽  
pp. 3818-3825 ◽  
Author(s):  
Efren Fernandez-Grande ◽  
Finn Jacobsen ◽  
Quentin Leclère
Keyword(s):  
Particle Velocity ◽  
Sound Pressure ◽  
Sound Field ◽  
Velocity Measurements ◽  
Field Separation

Study of a sound field separation technique based on a single holographic surface and wave superposition method

2009 ◽  
Vol 223 (8) ◽  
pp. 1827-1836
Author(s):  
W Q Jia ◽  
J Chen ◽  
C Yang ◽  
Z Y Wang
Keyword(s):  
Sound Pressure ◽  
Regularization Parameter ◽  
Sound Field ◽  
Mirror Image ◽  
Separation Technique ◽  
Tikhonov Regularization Method ◽  
Superposition Method ◽  
Wave Superposition ◽  
Measurement Surface ◽  
Field Separation

In order to overcome the limitation of traditional near-field acoustical holography (NAH), that the sound field on one side of the holographic surface must be free, a sound field separation technique based on single holographic surface and wave superposition method (WSM) is proposed. According to the WSM, the field on and near the measurement surface may be approximated by the field produced by virtual source points placed on a surface inside the structure. The source strengths are evaluated by applying boundary conditions on the measurement surface. Here, the ‘pseudo’ sound pressure of the reconstruction surface is first obtained based on the principle of sound field mirror image and WSM, then the sound pressure of the target sound source acting on the holographic surface is separated by the sound pressures of the holographic surface and the reconstruction surface, and the sound field separation is realized. The technique requires the inversion of the Green's function matrix, which may be ill-conditioned. The Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. Through the numerical simulation and experiment, the results show the validity and efficiency of this technique.

scholarly journals Scan and Paint: Theory and Practice of a Sound Field Visualization Method

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Daniel Fernández Comesaña ◽  
Steven Steltenpool ◽  
Graciano Carrillo Pousa ◽  
Hans-Elias de Bree ◽  
Keith R. Holland
Keyword(s):  
Particle Velocity ◽  
Sound Pressure ◽  
Sound Field ◽  
Theory And Practice ◽  
Acoustic Intensity ◽  
Practical Applications ◽  
Transfer Path ◽  
Sensor Position ◽  
Time Requirements ◽  
Visualization Techniques

Sound visualization techniques have played a key role in the development of acoustics throughout history. The development of measurement apparatus and techniques for displaying sound and vibration phenomena has provided excellent tools for building understanding about specific problems. Traditional methods, such as step-by-step measurements or simultaneous multichannel systems, have a strong tradeoff between time requirements, flexibility, and cost. However, if the sound field can be assumed time stationary, scanning methods allow us to assess variations across space with a single transducer, as long as the position of the sensor is known. The proposed technique, Scan and Paint, is based on the acquisition of sound pressure and particle velocity by manually moving a P-U probe (pressure-particle velocity sensors) across a sound field whilst filming the event with a camera. The sensor position is extracted by applying automatic color tracking to each frame of the recorded video. It is then possible to visualize sound variations across the space in terms of sound pressure, particle velocity, or acoustic intensity. In this paper, not only the theoretical foundations of the method, but also its practical applications are explored such as scanning transfer path analysis, source radiation characterization, operational deflection shapes, virtual phased arrays, material characterization, and acoustic intensity vector field mapping.

scholarly journals Time-Domain Sound Field Reproduction with Pressure and Particle Velocity Jointly Controlled

2021 ◽  
Vol 11 (22) ◽  
pp. 10880
Author(s):  
Xuanqi Hu ◽  
Jiale Wang ◽  
Wen Zhang ◽  
Lijun Zhang
Keyword(s):  
Computational Complexity ◽  
Particle Velocity ◽  
Time Domain ◽  
Sound Pressure ◽  
Filter Design ◽  
Sound Field ◽  
Eigenvalue Decomposition ◽  
Spatial Sound ◽  
Complexity Problem ◽  
Reproduction Method

Particle velocity has been introduced to improve the performance of spatial sound field reproduction systems with an irregular loudspeaker array setup. However, existing systems have only been developed in the frequency domain. In this work, we propose a time-domain sound field reproduction method with both sound pressure and particle velocity components jointly controlled. To solve the computational complexity problem associated with the multi-channel setup and the long-length filter design, we adopt the general eigenvalue decomposition-based approach and the conjugate gradient method. The performance of the proposed method is evaluated through numerical simulations with both a regular loudspeaker array layout and an irregular loudspeaker array layout in a room environment.

Active control of the scattered radiation with a reflecting surface

2019 ◽  
Vol 67 (3) ◽  
pp. 190-196
Author(s):  
Ning Han
Keyword(s):  
Control System ◽  
Active Control ◽  
Scattered Radiation ◽  
Sound Pressure ◽  
Sound Field ◽  
Control Area ◽  
Mirror Image ◽  
Three Dimension ◽  
Control Effect ◽  
Reflecting Surface

Based on a prediction method of the scattered sound pressure, an active control system was proposed in previous work for the three-dimension scattered radiation, where all the relevant simulations and experiments were implemented in three-dimensional free sound field. However, for practical applications, such as the anti-eavesdropping system or the stealth system for submarines, the sound field conditions are usually complex, and the most common case is the one with reflecting surface. It is questionable whether the previous control system is still effective in non-free sound field, or what improvements should be operated to ensure the control effect. In this article, based on the mirror image principle, two methods of calculating the control source strengths are proposed for the scattered radiation control, and numerical simulations with one-channel and multi-channel system are implemented to detect the corresponding control effect. It is seen that the local active control for the scattered radiation is still effective, and the reduction of the sound pressure level as well as the control area is extended with the increasement of the error sensors and control sources.

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