Simulation of sound diffusion paterns of fractal-based surface profiles

Abstract

Acoustcal design is one of the most challenging aspects of architecture. A complex system of competng influences (e.g., space geometry, size, proportion, material propertes, surface detail, etc.) contribute to shaping the quality of the auditory experience. In partcular, architectural surfaces affect the way that sound reflections propagate through space. By diffusing the reflected sound energy, surface designs can promote a more homogeneous auditory atmosphere by mitgatng sharp and focused reflections. One of the challenges with designing an effective diffuser is the need to respond to a wide band of sound wavelengths, which requires the surface profile to precisely encode a range of detail sizes, depths and angles. Most of the available sound diffusers are designed to respond to a narrow band of frequencies. In this context, fractal-based surface designs can provide a unique opportunity for mitgatng such limitations. A key principle of fractal geometry is its multlevel hierarchical order, which enables the same patern to occur at different scales. This characteristc makes it a potential candidate for diffusing a wider band of sound wavelengths. However, predictng the reflection paterns of complicated fractal-based surface designs can be challenging using available acoustcal software. These tools are often costly, complicated and are not designed for predictng early sound propagation paths. This research argues that writng customized algorithms provides a valuable, free and efficient alternative for addressing targeted acoustcal design problems. The paper presents a methodology for designing and testng a customized algorithm for predictng sound diffusion paterns of fractal-based surfaces. Both quanttative and qualitative approaches were used to develop the code and evaluate the results.