Low frequency sound absorption by compliant Helmholtz resonators

2019 ◽  
Vol 145 (3) ◽  
pp. 1725-1725
Author(s):  
Shichao Cui ◽  
Ryan L. Harne
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Frequency Sound ◽  
Helmholtz Resonators

scholarly journals A new route to exposed thermal mass: Sound-absorbing poured concrete

2017 ◽  
Vol 38 (4) ◽  
pp. 408-420
Author(s):  
S Lombardo ◽  
JJ Orr ◽  
DA Coley ◽  
MJ Wood
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Embodied Energy ◽  
Thermal Mass ◽  
Grid System ◽  
Acoustic Environment ◽  
Frequency Sound ◽  
Helmholtz Resonators ◽  
Operational Energy ◽  
Dependent Absorption

This paper investigates the novel possibility of utilising the structural concrete floor slab as a means of providing additional mid- to low-frequency sound absorption through the addition of cavities on the ceiling side, formed using flexible formwork, acting as Helmholtz resonators. Mid- to low-frequency sound absorption in rooms is typically achieved through the use of perforated plasterboard or a suspended tile-in-grid system. Such an approach can separate the room from the thermal mass of the ceiling above, leading to higher peak temperatures or increased cooling load. Suspended ceilings can also increase the embodied energy of the building and limit the potential for stack effect ventilation by reducing room height. In this work, frequency-dependent absorption coefficients of perforated concrete samples were measured using an impedance tube test. The results were found to agree with a theoretical analysis, suggesting that it would be relatively easy to predict the performance of perforations of other depths and diameters including those targeted at absorbing higher frequencies. Practical application: The measurements indicate that such a slab could be used as a practical replacement for perforated plasterboard or a tile-in-grid system. This would allow the slab to be tuned to the building’s acoustic performance and structural requirements. The approach has the potential to: (1) reduce the embodied and operational energy of buildings; (2) improve thermal comfort and (3) create a better acoustic environment in situations where surface robustness or longevity is important, for example public stairwells, pathways under roads and metro stations.

Low frequency sound absorption of adjustable membrane-type acoustic metamaterials

2022 ◽  
Vol 188 ◽  
pp. 108586
Author(s):  
Tuo Xing ◽  
Xiaoling Gai ◽  
Junjuan Zhao ◽  
Xianhui Li ◽  
Zenong Cai ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Frequency Sound ◽  
Membrane Type

A double porosity material for low frequency sound absorption

2020 ◽  
Vol 239 ◽  
pp. 111978 ◽  
Author(s):  
Honggang Zhao ◽  
Yang Wang ◽  
Dianlong Yu ◽  
Haibin Yang ◽  
Jie Zhong ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Double Porosity ◽  
Frequency Sound
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