Modeling and shaping specular and diffuse reflection sound fields in enclosures

• Published in: The Journal of the Acoustical Society of America 2010-10, Vol.128 (4_Supplement), p.2411-2411
• Main Authors: Michalis, Krista, Bliss, Donald, Franzoni, Linda
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3508605

Steady-state sound fields in enclosures, with specular and diffuse reflection boundaries, are modeled with an energy-intensity boundary element method using uncorrelated broadband directional sources. The specular reflection case is solved using an iterative relaxation method extended from a 3-D diffuse reflection solution. When chosen properly, only a few directivity harmonics are required. Starting with a diffuse calculation, higher harmonicsare estimated by post-processing, and the original diffuse influence matrix is refined accordingly and converges in a few relaxation steps. The method is higher-order accurate, computationally efficient, and similar to the diffuse case in that it includes strict enforcement of energy conservation. The simulations give accurate results compared to exact modal solutions. Sample calculations are presented to show that the mean-square pressure spatial variation can be tailored using a combination of diffuse and specular surfaces for the design of acoustic spaces.