Sound diffusers based on sonic crystals

An appropriate copyright notice must be included along with the full citation for the published paper and a Web link to ASA's official online version of the abstract. There are no format restrictions; files prepared and/or formatted by ASA, AIP, or its vendors (e.g., the PDF, PostScript, or HTML article files published in the online journals and proceedings) may be used for this purpose. If a fee is charged for any use of the posted article, ASA permission must be obtained.A sound diffuser is proposed based on sonic crystals, structures formed by a periodic distribution of cylindrical scatterers in a host medium, which is usually air. The diffuser is a so-called biperiodic structure, as formed by two arrays of sonic crystals with slightly different periodicities. Large diffusivity at low frequencies is achieved when the typical scale of the blocks is much larger than the periodicity of the crystals, determined by its lattice constant. An interpretation of the low frequency behavior of the diffuser is given in the homogenization limit in terms of multiple reflections and interference between the fields scattered by the different blocks. It is also shown that sonic crystal based diffusers enhance time spreading in comparison with other conventional diffusers.We acknowledge fruitful discussions with George Massenburg and Brett Leonard at McGill University, and Martin Pilchner of Pilchner-Schoustal International in Toronto. This work was financially supported by the Spanish Ministerio de Economia y Competitividad through Project FIS2011-29731-C02-02 and by Generalitat Valenciana through GV/2011/055.Redondo, J.; Picó Vila, R.; Sánchez Morcillo, VJ.; Woszczyk, W. (2013). Sound diffusers based on sonic crystals. Journal of the Acoustical Society of America. 134(6):4412-4417. https://doi.org/10.1121/1.482882644124417134