Feasibility of a finite-difference time-domain model in large-scale acoustic simulations

Abstract

Wave-based techniques for room acoustics simulations are commonly applied to low frequency analysis and small-sized simplified environments. The constraints are generally the inherent computational cost and the challenging implementation of proper complex boundary conditions. Nevertheless, the application field of wave-based simulation methods has been extended in the latest research decades. With the aim of testing this potential, this work investigates the feasibility of a finite-difference time-domain (FDTD) code simulating large non-trivial geometries in wide frequency ranges. A representative sample of large coupled-volume opera houses allowed demonstration of the capability of the selected FDTD model to tackle such composite geometries up to 4 kHz. For such a demanding task, efficient calculation schemes and frequency-dependent boundary admittances are implemented in the simulation framework. The results of in situ acoustic measurements were used as benchmarks during the calibration process of three-dimensional virtual models. In parallel, acoustic simulations performed on the same halls through standard ray-tracing techniques enabled a systematic comparison between the two numerical approaches highlighting significant differences in terms of input data. The ability of the FDTD code to detect the typical acoustic scenarios occurring in coupled-volume halls is confirmed through multi-slope decay analysis and impulse responses' spectral content.

Reviving the Low-Frequency Response of a Rupestrian Church by Means of FDTD Simulation

“…FDTD acoustic modelling has been applied to solve acoustic problems for a long time [27] but given the computational load it has been mostly applied to low frequencies [28], while the availability of parallel computation distributed by several GPUs fostered a gradual extension to a much wider frequency range [21,22,[28][29][30]. FDTD starts from the assumption that a generic derivation operator can be replaced by one of its finite difference forms:…”

“…To this purpose, in this paper an application of the finite-difference-time-domain (FDTD) method is proposed, by implementing a simple scheme with frequency-independent boundary conditions limited to the lowest frequencies. Even though this method has been already applied to larger buildings and covering a much broader spectrum [21,22] using parallel computation on several graphical processing units, the present implementation aims at providing a useful low-frequency complement to conventional geometrical acoustic-based simulations, without requiring a high computational load.…”

Acoustic Ambience and Simulation of the Bullring of Ronda (Spain)

“…The applications of the wave-based methods are limited to low-medium frequencies and small rooms, while the GA methods, based on the validity and application of the laws of specular and diffuse reflection, offer better results in large rooms and at relatively high frequencies where wave phenomena are less significant. Currently, hybrid algorithms that provide accurate broadband results by taking advantage of the benefits and minimizing the drawbacks of each method are emerging [23,27].…”

Comparison of Simulated Head-Related Transfer Functions Accuracy for Different Model Complexities Using the Finite-Difference Time-Domain Method

“…One of these advantages is the compatibility of the method with parallel processing (due to its explicit nature) to improve its computational performance. Thus, FDTD simulations are relatively fast, considering that the whole 3D domain is discretised, which can be useful to generate large data sets, e.g., for training machine learning models (e.g., [6]) or for large-scale simulations for acoustic applications (e.g., [7][8][9][10]).…”