Diffuse Field Sound Absorption of Microperforated Panels with Special Backings

2017 ◽  
Vol 1 (2) ◽  
pp. 464-470 ◽  
Author(s):  
Weiyun Liu ◽  
David W. Herrin ◽  
Emanuele Bianchini
Keyword(s):  
Sound Absorption ◽  
Microperforated Panels ◽  
Field Sound

Sound absorption of textile curtains – theoretical models and validations by experiments and simulations

2016 ◽  
Vol 88 (1) ◽  
pp. 36-48 ◽  
Author(s):  
Reto Pieren ◽  
Beat Schäffer ◽  
Stefan Schoenwald ◽  
Kurt Eggenschwiler
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Planning Process ◽  
Measurement Data ◽  
Theoretical Models ◽  
Sound Absorption Coefficient ◽  
Absorption Coefficients ◽  
Semi Empirical ◽  
Field Sound ◽  
Good Agreement

Textile curtains can be designed to be good sound absorbers. Their acoustical performance, as usually described by the sound absorption coefficient, not only depends on the textile itself but also on the drapery fullness and the backing condition, that is, the spacing between the fabric and a rigid backing wall, or the absence of a backing in the case of a freely hanging curtain. This article reviews existing models to predict the diffuse-field sound absorption coefficient, which to date can only predict the case of flat curtains. A set of existing models is extended to the case of curtains with drapery fullness using a semi-empirical approach. The models consider different backing conditions, including freely hanging curtains. The existing and new models are validated by comparing predicted sound absorption coefficients with data measured in a reverberation room. Hereby, curtains consisting of different fabrics and with different degrees of fullness are considered. Besides situations with rigid backing, also the measurement data of textiles hung freely in space are included in this study. Comparisons reveal a very good agreement between measured and predicted sound absorption coefficients. Compared to currently available commercial sound absorption prediction software that can only handle the situation of flat textiles with rigid backing, the results of the presented models not only show a better agreement with measured data, but also cover a broader range of situations. The presented models are thus well applicable in the design and development of new textiles as well as in the room acoustical planning process.

scholarly journals Diffuse-field sound absorption characteristics of a spherical-microperforated space absorber

2020 ◽  
Vol 41 (5) ◽  
pp. 784-787 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kusaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi
Keyword(s):  
Sound Absorption ◽  
Field Sound ◽  
Absorption Characteristics

Comparison of multiple-layer versus multiple-cavity microperforated panels for sound absorption at low frequency

2021 ◽  
Vol 69 (4) ◽  
pp. 341-350
Author(s):  
Pedro Cobo ◽  
Francisco Simón ◽  
Carlos Colina
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Single Layer ◽  
Helmholtz Resonator ◽  
Layer Versus ◽  
Low Frequencies ◽  
High Frequencies ◽  
Multiple Layer ◽  
Band Absorption ◽  
Microperforated Panels

Microperforated panels (MPPs) are recognized as suitable absorbers for noise control applications demanding special clean and health requirements.While it is relatively easy to design single-layer MPPs for sound absorption in one-to-two octave bands at medium-high frequencies, the performance for low frequencies (below 600 Hz) leads to a rather narrow-band absorption, similar to that of a Helmholtz resonator. However, multiple-layer MPPs can be designed as sound absorbers that yield low-frequency absorption in a wide frequency band. Recently, multiple-cavity perforated panels have been proposed to improve the performance of MPPs in the low-frequency range. In this article, the capability of multiple-layer and multiple-cavity MPPs to provide sound absorption at low frequencies is analyzed.

Laboratory and in situ sound absorption measurement under a synthetized diffuse acoustic field

2019 ◽  
Vol 26 (4) ◽  
pp. 223-242
Author(s):  
Olivier Robin ◽  
Alain Berry ◽  
Celse Kafui Amédin ◽  
Noureddine Atalla ◽  
Olivier Doutres ◽  
...  
Keyword(s):  
Acoustic Field ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Field ◽  
Geometrical Parameters ◽  
In Situ Conditions ◽  
Field Excitation ◽  
Acoustic Environments ◽  
Field Sound

This article reports numerical and experimental results concerning the estimation of the diffuse field sound absorption coefficient of several different materials under a synthetized diffuse acoustic field excitation in laboratory and in situ conditions. The proposed measurement method is based on a sound field reproduction approach and a synthetic array of acoustic monopoles facing the material to be tested. Numerical simulations are first conducted to optimize the geometrical parameters of the method and to compute theoretical sound absorption coefficients of the considered materials. Measurements on a set of six typical acoustic materials are then conducted following the standardized reverberant room method as well as the proposed approach in a hemi-anechoic room and in two realistic rooms. Albeit showing limitations in the low-frequency domain, the proposed method enables a significant reduction of the tested specimen dimensions compared with the reverberant room method and allows performing tests in non-ideal acoustic environments.

Proposal of numerical models to predict the diffuse field sound absorption of finite sized porous materials – BEM and FEM approaches

2021 ◽  
Vol 180 ◽  
pp. 108092
Author(s):  
M. Pereira ◽  
P.H. Mareze ◽  
L. Godinho ◽  
P. Amado-Mendes ◽  
J. Ramis
Keyword(s):  
Porous Materials ◽  
Sound Absorption ◽  
Numerical Models ◽  
Field Sound
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