Non-cuboid iterative room optimizer

Abstract

In past years, various iterative optimization programs emerged to separately determine optimal room ratios, sources and listening positions in perfectly reflective cuboid rooms, using the image source model. This approach fails to account for scattering, phase change at the boundary and cannot be extended to non-cuboid rooms. The present work presents a solution, using the boundary element method (BEM) to compute the frequency response at low frequencies, considering the effects of the complex admittances of the boundaries and all acoustical elements inside the room. With BEM as its engine, a genetic algorithm was developed to optimize source and receiver positions simultaneously with the room geometry, within architectural restraints. Given real-world limitations, optimizing source and listener positioning and room geometry is not always an option. Therefore, a damper module was added, which addresses low frequency acoustic treatment. By using different transfer matrix models, the acoustical behavior of different low-frequency pressure absorbers can be modeled and inserted into the BEM simulation, to evaluate the change in the room's acoustic field and frequency response at the receiving positions of interest. 3-D waterfalls are used to illustrate the modal decay following optimization. Examples will be presented.