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Experimental investigation on the enhancement of plenum window noise reduction using solid scatterers

Li, Xiao Long; Lam, Wai Kit; Tang, S. K.


Xiao Long Li

Wai Kit Lam


The sound transmission across plenum windows installed with rigid non-resonant cylindrical scatterer arrays was investigated in detail using scale-down model measurements carried out inside a fully anechoic chamber. The arrays have manifested to some extent the acoustical behaviors of virtual sonic crystals. The maximum cross section blockage ratio was 0.6. The effects of plenum window gap, array configuration, and scatterer diameter on the sound transmission characteristics were also examined. Results indicate that the window cavity longitudinal modes and the gap modes control the sound transmission characteristics at low frequencies. The upper bound of this frequency range increases with decreasing gap width. Within this frequency range, the scatterers have negligible effect on the sound transmission. At higher frequencies, the array configurations with scatterer(s) attached to the window walls result in stronger sound reduction. There are relatively higher sound transmission loss improvements around the frequencies where a full bandgap is observed. There are wide bandgaps in various lattice directions, and the present results suggest that they play a role in the broadband improvement of sound reduction.


Li, X. L., Lam, W. K., & Tang, S. K. (2023). Experimental investigation on the enhancement of plenum window noise reduction using solid scatterers. The Journal of the Acoustical Society of America, 153(2), 1361-1374.

Journal Article Type Article
Acceptance Date Feb 6, 2023
Online Publication Date Feb 23, 2023
Publication Date Feb 23, 2023
Deposit Date Jul 19, 2023
Publicly Available Date Jul 25, 2023
Journal Journal of the Acoustical Society of America
Print ISSN 0001-4966
Electronic ISSN 1520-8524
Publisher Acoustical Society of America
Peer Reviewed Peer Reviewed
Volume 153
Issue 2
Pages 1361-1374
Public URL


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