Wave-Based Room Acoustics Modelling: Recent Progress and Future Outlooks

Room acoustics simulations have conventionally relied on the high-frequency simplifications of geometrical and statistical acoustics. In such models, sound is assumed to propagate along rays and wave diffraction effects largely neglected. Furthermore, late parts of room impulse responses are assumed to be diffuse and decaying in a predictable manner – precluding, e.g., the onset of double-slope decays, or flutter echoes. In contrast, wave-based simulations of room acoustics have the potential to capture all relevant acoustical features of a room, across the entire audible spectrum and in non-diffuse settings. The use of full-bandwidth wave-based methods is increasingly becoming possible thanks to modern parallel computing hardware, despite the fact that computational costs scale strongly with frequency – which had relegated their uses to low frequency analyses for some time.

This talk will give an overview of FDTD (finite difference time domain) methods in the context of full bandwidth auralisations for architectural acoustics purposes. Recent developments will be presented, including the modelling of arbitrary geometries, variable and frequency-dependent wall conditions, viscothermal effects in air, techniques to mitigate numerical dispersion, and parallel implementations across multiple GPUs. Sound examples, resulting from full-wave and hybrid auralisations of existing spaces, will be presented.