Caracterização acústica de salas: um método híbrido combinando os métodos do traçado de raios e fontes virtuais

Abstract

For the simulation of Room Impulse Responses (RIRs) are specially well succeeded methods built within the geometrical acoustics principles. For wave lengths which are small in relation to the room dimensions, such methods facilitate the obtainment of RIR estimates, since the sound waves are modelled as rays, eliminating the need for a wave equation-based solution. Given the relevance of such methods, this paper presents an implementation of the hybrid method proposed by Michael Vorländer in 1989, which combines the Ray tracing and the Image sources methods. This improved method combines the speed of the Ray tracing with the precision of the Image sources. Initially is proposed a version of this hybrid method, which is implemented in MATLAB using its parallel processing capacities. Other benefits of the development of the method in MATLAB are expected, such as the ease of disclosure through packages of scripts and its application in signal processing and acoustics undergraduate and graduate classes. Then the method’sperformance was analyzed through the comparison of simulated and analytically obtained RIRs using acoustical parameters and MSE. Were also analyzed the impacts of the implementation of non-uniform sound source and diffuse reflections. The results were not absolutely conclusive, but they show promising paths for further research. New studies using more concentrated non-uniformities on the sound source and more variations of the diffuse reflections applying the diffusion coefficient of surfaces are next steps to be taken.