Sound field separation of multiple coherent sound sources with single measurement surface

2021 ◽  
pp. 107754632110201
Author(s):  
Jin Mao ◽  
Jinfu Du ◽  
Kai Liu ◽  
Jiang Liu ◽  
Yahui Cui
Keyword(s):  
Near Field ◽  
Sound Field ◽  
Single Measurement ◽  
Sound Sources ◽  
Equivalent Source ◽  
Coherent Sources ◽  
Measurement Surface ◽  
Acoustical Holography ◽  
Field Separation ◽  
Source Number

Sound field separation based on near-field acoustical holography has been developed worldwide, but with the increase in the number of sound sources, traditional measurement methods and calculation methods will generate more workload. To reduce the number of measuring points and save calculation time, the sound field separation of multiple coherent sources with a single measurement surface is proposed. On the basis of separating two coherent sources with this method, the separation formula of more sources based on an equivalent source method is given. Through numerical simulation, the effects of the number of holographic surface measuring points, measuring distance, array shape, and equivalent source number on the calculation accuracy of the sound field separation were compared at different frequencies. The correctness and effectiveness of the sound field separation method with a single surface are verified by actual experiments.

Simulation and experimental investigations for the patch near-field acoustical holography

2008 ◽  
Vol 222 (6) ◽  
pp. 945-953 ◽  
Author(s):  
C Yang ◽  
J Chen ◽  
J Q Li ◽  
W F Xue
Keyword(s):  
Fourier Transform ◽  
Sound Pressure ◽  
Near Field ◽  
Sound Field ◽  
Experimental Investigations ◽  
Regularization Methods ◽  
Aperture Size ◽  
Measurement Surface ◽  
Physical Necessity ◽  
Acoustical Holography

In order to reconstruct the sound field, the fast Fourier transform (FFT)-based near-field acoustical holography (NAH) demands that the measurement surface must extend to a region where the sound pressure decreases to a low level. This method is unfit for reconstructing the partial sound field in which the measurement aperture size is limited either by physical necessity or as a way of reducing the measurement cost. Statistically optimal NAH (SONAH) performs plane-to-plane calculations directly in the spatial domain, avoids all errors occurred in the FFT-based NAH and significantly increases the accuracy of the reconstruction of the partial sound field. In the present work, combined with the different regularization methods, SONAH is performed for reconstructing the partial sound field. The errors over the central and the peripheral sections of the reconstruction area are researched separately. Simulations and experiments show that SONAH is successful in reconstructing the partial sound field and the errors over the central sections are smaller than that over the peripheral sections. Experiments demonstrate that Tikhonov regularization in conjunction with Engl's criterion is suitable for the reconstruction of the practical sound field.

scholarly journals The principle of statistically optimal planar near-field acoustical holography and the sound field separation technique

2005 ◽  
Vol 54 (3) ◽  
pp. 1253 ◽  
Author(s):  
Li Wei-Bing ◽  
Chen Jian ◽  
Yu Fei ◽  
Bi Chuan-Xing ◽  
Chen Xin-Zhao
Keyword(s):  
Near Field ◽  
Sound Field ◽  
Separation Technique ◽  
Acoustical Holography ◽  
Field Separation

Development of Near-Field Acoustical Holograph and its Review

2014 ◽  
Vol 971-973 ◽  
pp. 1598-1601
Author(s):  
Xu Liu ◽  
Xiao Qin Liu ◽  
Chang Liu
Keyword(s):  
Near Field ◽  
Sound Field ◽  
Separation Technique ◽  
Acoustic Holography ◽  
Noise Sources ◽  
Engineering Applications ◽  
Powerful Technique ◽  
Experiment And Simulation ◽  
Acoustical Holography ◽  
Field Separation

Near-field acoustic holography (NAH) is a powerful technique for identifying noise sources and visualizing acoustic field.The theory and algorithm of NAH techniques are introduced , and it is proved by experiment and simulation. The researches on near field acoustical holography (NAH) are reviewed，including the sound field separation technique and Patch NAH technique arisen in recent years.The difficulties in NAH and research on current situations are discussed , Finally,some engineering applications are introduced by detailed examples.

STUDY OF SOUND SOURCE IDENTIFICATION BASED ON BEAMFORMING AND PATCH NEAR-FIELD ACOUSTIC HOLOGRAPHY

2009 ◽  
Vol 17 (03) ◽  
pp. 219-245 ◽  
Author(s):  
WENQIANG JIA ◽  
JIN CHEN ◽  
CHAO YANG ◽  
JIAQING LI
Keyword(s):  
Regularization Parameter ◽  
Near Field ◽  
Sound Field ◽  
Reconstruction Error ◽  
Tikhonov Regularization Method ◽  
Superposition Method ◽  
Sound Sources ◽  
Extrapolation Technique ◽  
Measurement Surface ◽  
Data Extrapolation

A study for applying data extrapolation technique based on wave superposition method (WSM) is proposed to overcome the disadvantages of near-field acoustical holography (NAH). Unlike conformal NAH, where the measurement surface surrounds the entire structure, in the patch holography the measurement surface needs only be approximately as large as the patch on the structure surface where the reconstruction is required. At first, a microphone array is used to acquire the sound pressure field radiated from a vibrator; then a beamforming method is adopted to locate sound sources; after that, a serial of equivalent sources are collocated around these sound sources; at last, a data extrapolation technique based on WSM is applied to extend the measurement aperture and reconstruct the sound field. Since the data extrapolation algorithm requires the inversion of Green's function matrix which may be ill-conditioned, Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. The effectiveness of this method is demonstrated by numerical simulation with two pulse ball model, and also experiment is carried out in a semi-anechoic chamber using two sound boxes. The results confirm that the exterior sound field can be accurately reconstructed with few iterative times and the reconstruction error is sufficiently suppressed by the proposed method.

Sound Source Identification and Acoustic Contribution Analysis Using Nearfield Acoustic Holography

2014 ◽  
Vol 945-949 ◽  
pp. 717-724 ◽  
Author(s):  
Jiang Hua Deng ◽  
Jun Hong Dong ◽  
Guang De Meng
Keyword(s):  
Source Identification ◽  
Noise Source ◽  
Near Field ◽  
Superposition Principle ◽  
Sound Field ◽  
Mirror Image ◽  
Sound Sources ◽  
Incoming Wave ◽  
Reflected Waves ◽  
Acoustic Contribution

The main goal of the present paper is to provide a method of source identification. Firstly, statistically optimal near-field acoustical holography (SONAH) techniques are applied to locate sound sources with the reflected sound field. In the presence of reflection plane parallel and perpendicular to the source plane, the incoming wave and reflected waves are separated based on the acoustic superposition principle and acoustic mirror image principle to satisfy the condition of the sound sources reconstruction using SONAH. Secondly, contribution of noise source to the special field point is analyzed and noise source ranking of interior panel groups are evaluated based the proposed three step acoustic contribution method. Finally, this method is verified experimentally.

Near Field Acoustic Holography for Cyclostationary Sound Field and its Partial Source Decomposition Procedure

2005 ◽  
Vol 127 (6) ◽  
pp. 542-546 ◽  
Author(s):  
Quan Wan ◽  
W. K. Jiang
Keyword(s):  
Principal Component Analysis ◽  
Sound Pressure ◽  
Near Field ◽  
Sound Field ◽  
Principal Component ◽  
Acoustic Holography ◽  
Sound Sources ◽  
Decomposition Procedure ◽  
Spectrum Density ◽  
Simulation Results

The cyclostationary near field acoustic holography (NAH) technique is proposed to overcome the limitations of the current NAH in analyzing cyclostationary sound field. The proposed technique adopts the cyclic spectrum density as the reconstructed physical quantity, instead of the spectrum of sound pressure. Moreover, introducing the principal component analysis into the technique, a partial source decomposition procedure is suggested to decompose the sound field radiated by multiple sound sources into some incoherent partial fields. More information about cyclostationary sound field can be shown clearly on the hologram of the proposed technique than NAH can, which is validated by the simulation results.

A comparison of near-field beamforming and acoustical holography for sound source visualization

2009 ◽  
Vol 223 (4) ◽  
pp. 819-834 ◽  
Author(s):  
Yong Thung Cho ◽  
M J Roan ◽  
J S Bolton
Keyword(s):  
Near Field ◽  
Random Noise ◽  
Sound Intensity ◽  
Field Measurements ◽  
Absolute Intensity ◽  
Visualization Technique ◽  
High Frequencies ◽  
Measurement Surface ◽  
Acoustical Holography ◽  
Source Geometry

Acoustical holography procedures make high-resolution visualization possible via estimation of the sound intensity on surfaces closer to the sources than the near-field measurement surface. Another source localization technique, beamforming, has been used to estimate the direction of arrival of sound from sources that typically lie in the far-field. However, little work has been done using beamforming as a visualization technique based on near-field measurements. As a result, the performance of beamforming and acoustical holography in terms of source resolution capabilities has not been directly compared when using near-field measurements. In this work, point source beamforming was used to visualize sources based on near-field measurements. Acoustic intensity estimated from beamformed pressure measurements was compared with the absolute intensity estimated using acoustical holography techniques. In addition to noise-free, anechoic simulations, cases of measurement pressure with random noise were generated and used to compare source resolution accuracy of acoustical holography and beamforming techniques in the presence of measurement noise. It was found that intensity estimated using acoustical holography provided the clearest image of sources when the measurement surface was conformal with the source geometry. However, sources can be resolved more accurately using near-field beamforming than acoustical holography at high frequencies when the sources are not located perfectly on a surface conformal with the measurement geometry.

Active Control of Low-Frequency Sound Radiation From Vibrating Panel Using Planar Sound Sources

2001 ◽  
Vol 124 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Kean Chen ◽  
Gary H. Koopmann
Keyword(s):  
Active Control ◽  
Near Field ◽  
Low Frequency ◽  
Sound Radiation ◽  
Sound Field ◽  
Sound Power ◽  
Frequency Range ◽  
Sound Sources ◽  
Frequency Sound ◽  
Secondary Sources

Active control of low frequency sound radiation using planar secondary sources is theoretically investigated in this paper. The primary sound field originates from a vibrating panel and the planar sources are modeled as simply supported rectangular panels in an infinite baffle. The sound power of the primary and secondary panels are calculated using a near field approach, and then a series of formulas are derived to obtain the optimum reduction in sound power based on minimization of the total radiate sound power. Finally, active reduction for a number of secondary panel arrangements is examined and it is concluded that when the modal distribution of the secondary panel does not coincide with that of the primary panel, one secondary panel is sufficient. Otherwise four secondary panels can guarantee considerable reduction in sound power over entire frequency range of interest.

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