Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice

Hughes, RJ ORCID: https://orcid.org/0000-0002-8916-1227, Angus, JAS, Cox, TJ ORCID: https://orcid.org/0000-0002-4075-7564, Umnova, O ORCID: https://orcid.org/0000-0002-5576-7407, Gehring, GA, Pogson, M and Whittaker, DM 2010, 'Volumetric diffusers : pseudorandom cylinder arrays on a periodic lattice' , The Journal of the Acoustical Society of America (JASA), 128 (5) , pp. 2847-2856.

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Abstract

Most conventional diffusers take the form of a surface based treatment, and as a result can only operate in hemispherical space. Placing a diffuser in the volume of a room might provide greater efficiency by allowing scattering into the whole space. A periodic cylinder array (or sonic crystal) produces periodicity lobes and uneven scattering. Introducing defects into an array, by removing or varying the size of some of the cylinders, can enhance their diffusing abilities. This paper applies number theoretic concepts to create cylinder arrays that have more even scattering. Predictions using a Boundary Element Method are compared to measurements to verify the model, and suitable metrics are adopted to evaluate performance. Arrangements with good aperiodic autocorrelation properties tend to produce the best results. At low frequency power is controlled by object size and at high frequency diffusion is dominated by lattice spacing and structural similarity. Consequently the operational bandwidth is rather small. By using sparse arrays and varying cylinder sizes, a wider bandwidth can be achieved.

Item Type:	Article
Themes:	Subjects / Themes > Q Science > QC Physics > QC221-246 Acoustics - Sound Subjects outside of the University Themes
Schools:	Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre
Journal or Publication Title:	The Journal of the Acoustical Society of America (JASA)
Publisher:	Acoustical Society of America
Refereed:	Yes
ISSN:	0001-4966
Related URLs:	http://scitation.aip.org/JASA
Depositing User:	TJ Cox
Date Deposited:	13 Apr 2011 14:54
Last Modified:	15 Feb 2022 15:52
URI:	https://usir.salford.ac.uk/id/eprint/14622

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