Measuring Diffusion in a 2D Digital Waveguide Mesh

Simon Shelley; Damian Murphy
DAFx-2005 - Madrid
The digital waveguide mesh is a method by which the propagation of sound waves in an acoustic system can be simulated. An important consideration in modelling such systems is the accurate modelling of reflection characteristics at boundaries and surfaces. A significant property of an acoustic boundary is its diffusivity. In fact partially diffuse sound reflections are observed at most real acoustic surfaces and so this is an important consideration when implementing a digital waveguide mesh model. This paper presents a method for modelling diffusion that offers a high degree of control. The model is implemented with varying amounts of diffusivity, and a method for measuring its diffusive properties is outlined. Results for the model are presented and a method to calculate the diffusion coefficient is described.