Open-source platforms for fast room acoustic simulations in complex structures

TL;DR

This paper introduces open-source, optimized numerical tools in Matlab and Blender for fast, large-scale room acoustic simulations using a hybrid ray-tracing/image-source method, validated on complex structures like the ancient theater of Orange.

Contribution

It develops a scalable, open-source simulation framework with a Divide and Conquer approach, enabling efficient acoustic analysis of complex geometries with detailed impulse responses.

Findings

Simulation times are less sensitive to mesh density.

Validated accuracy against theoretical test cases.

Successfully applied to complex geometry of the ancient theater of Orange.

Abstract

This article presents new numerical simulation tools, respectively developed in Matlab and Blender softwares. Available in open-source under the GPL 3.0 license, it uses a ray-tracing/image-sources hybrid method to calculate the room acoustics for large meshes. Performances are optimized to solve problems of significant size (typically more than 100,000 surface elements and about a million of rays). For this purpose, a Divide and Conquer approach with a recursive binary tree structure has been implemented to reduce the quadratic complexity of the ray/element interactions to near-linear. Thus, execution times are less sensitive to the mesh density, which allows simulations of complex geometry. After ray propagation, a hybrid method leads to image-sources, which can be visually analyzed to localize sound map. Finally, impulse responses are constructed from the image-sources and FIR filters are proposed natively over 8 octave bands, taking into account material absorption properties and propagation medium. This algorithm is validated by comparisons with theoretical test cases. Furthermore, an example on a quite complex case, namely the ancient theater of Orange is presented.