Hybrid method for numerical simulation of room acoustics with auralization: part 1 - theoretical and numerical aspects

Abstract

A new hybrid simulation method for room acoustics is presented. It is grounded on two well known numerical simulation techniques for room acoustics. The hybrid method takes geometric acoustics for granted and uses an improved version of the classical ray-tracing technique for computing the specular reflections and a slightly modified energy transition method for simulating the diffuse reflections. The impulse responses (IRs) are then computed by superposition of the specular and diffuse ones. The reverberant part of the IRs gains a much more realistic aspect than the one obtained from either ones method alone. Both the ray-tracing technique and the energy transition method are reviewed and some improved features are discussed. The sound source and the receiver modeling are presented, including a new method for simulating the head related transfer functions (HRTFs), and based on the wavelet technique, which provides a shorter time computation of the binaural impulse responses for auralization purposes. In a companion paper, entitled Hybrid method for numerical simulation of room acoustics: Part 2 - Validation of the computational code RAIOS 3, a validation of the method in an international inter-comparison with other softwares and measurements data is presented, showing the efficiency and the accuracy of the proposed hybrid method over non-hybrid ones

Overview of geometrical room acoustic modeling techniques

“…An early hybrid technique that combined the image-source method and basic radiosity principles in rectangular rooms was presented in 1983 by Baines. 164 A similar hybrid that combines ray-tracing of the early reflections with a surface-based energy transmission algorithm has been presented also by Tenenbaum et al 165,166 In that model, special emphasis is put on how to achieve as uniform as possible distribution of rays over a sphere.…”

Comparative study of two geometrical acoustic simulation models

“…The software BRASS (Brazilian Room Acoustic Simulation Software) is based on previous experience with simulation tools [13] and was recently developed at UFRJ. It implements a traditional ray-tracing algorithm [14] with a clustering approach for treating the early reflections.…”

A ray tracing engine integrated with Blender and with uncertainty estimation: Description and initial results

“…8,9 Furthermore, some of the commercial software packages use hybrid methods, such as in Odeon 10 or RAIOS. 11,12 A comprehensive review of GA algorithms is given by Savioja and Svensson. 13 A list of commercial, free, and free for academic GA algorithms is shown on Table 1.…”