Wave-based sound propagation in large open scenes using an equivalent source formulation

Abstract

We present a novel approach for wave-based sound propagation suitable for large, open spaces spanning hundreds of meters, with a small memory footprint. The scene is decomposed into disjoint rigid objects. The free-field acoustic behavior of each object is captured by a compact per-object transfer function relating the amplitudes of a set of incoming equivalent sources to outgoing equivalent sources. Pairwise acoustic interactions between objects are computed analytically to yield compact inter-object transfer functions. The global sound field accounting for all orders of interaction is computed using these transfer functions. The runtime system uses fast summation over the outgoing equivalent source amplitudes for all objects to auralize the sound field for a moving listener in real time. We demonstrate realistic acoustic effects such as diffraction, low-passed sound behind obstructions, focusing, scattering, high-order reflections, and echoes on a variety of scenes.

Wave-based sound propagation for VR applications

“…In this section, we introduce a novel, frequency-domain technique based on equivalent sources to model wave-based sound propagation in large environments for interactive applications [19]. This technique can handle static sources and dynamic listeners at runtime.…”

“…Wave-based techniques can accurately perform sound propagation at low frequencies, but their computational complexity increases significantly for high frequencies. Current interactive wave-based techniques [13,26,19] have a high precomputation overhead and can only model source directivity during the offline computation stage. As a result, the source directivity gets baked (precomputed and stored) into the final solution, and it is not possible to modify the directivity pattern at runtime for interactive applications e.g.…”

“…We have demonstrated that this directivity and spatial sound framework works for both offline and interactive wavebased sound propagation techniques by incorporating it into the state-of-the-art offline boundary element method [17] and the interactive equivalent source technique [19]. The runtime system has been integrated with Valve's Source TM game engine.…”

Wave-ray coupling for interactive sound propagation in large complex scenes

“…They then encode perceptually salient information to perform interactive sound rendering. Mehra et al [2013] proposed an interactive sound propagation technique for large outdoor scenes based on equivalent sources. Other techniques use geometric methods to precompute high-order reflections or reverberation [Tsingos 2009;Antani et al 2012] and compactly store the results for interactive sound propagation at runtime.…”

“…As a result, these techniques are limited to interactive sound propagation at low frequencies (e.g. 1-2KHz) [Raghuvanshi et al 2010;Mehra et al 2013], and may not scale to large environments.…”