Finite-difference time-domain simulation of low-frequency room acoustic problems

TLDR

As a direct time‑domain simulation suitable for large modeling regions, the finite‑difference time‑domain (FDTD) approach appears to be a good brute‑force method for solving room acoustic problems. The study demonstrates using FDTD to model low‑ and middle‑frequency room acoustics and to adapt a digital filter that accurately represents the source‑to‑observer transfer function. The authors employ FDTD simulations, addressing key challenges such as frequency‑dependent boundary conditions, non‑Cartesian grids, and numerical error, to model room acoustics and design an accurate digital filter. The approach is illustrated with an example, showing that the resulting digital filter can be used for auralization experiments.

Abstract

This paper illustrates the use of a numerical time-domain simulation based on the finite-difference time-domain (FDTD) approximation for studying low- and middle-frequency room acoustic problems. As a direct time-domain simulation, suitable for large modeling regions, the technique seems a good ‘‘brute force’’ approach for solving room acoustic problems. Some attention is paid in this paper to a few of the key problems involved in applying FDTD: frequency-dependent boundary conditions, non-Cartesian grids, and numerical error. Possible applications are illustrated with an example. An interesting approach lies in using the FDTD simulation to adapt a digital filter to represent the acoustical transfer function from source to observer, as accurately as possible. The approximate digital filter can be used for auralization experiments.