Modeling the extended reaction of porous absorbers in time-domain wave-based room acoustic simulations

Abstract

The absorption properties of room surfaces have a major influence on the acoustics of rooms. In wave-based room acoustic simulations it is common practice to model room surfaces using a local-reaction approximation, instead of modeling the full extended-reaction behavior. However, previous research has indicated that the local-reaction assumption is not appropriate for surfaces that have elastic properties or fluid layers, such as soft porous materials, porous materials backed by an air cavity and airtight membranes. In this talk we present a method for incorporating the extended-reaction behavior of porous absorbers into a time-domain discontinuous Galerkin (dG) based room acoustic simulation scheme. The dG method is attractive for room acoustic simulations due to its flexibility and cost-efficiency. The porous material is modeled using an equivalent fluid model (EFM). The EFM formulation is validated analytically and experimentally, and it is shown that using the EFM leads to significant and perceptually noticeable improvements in simulation accuracy, when modeling single reflections and full room simulations with various types of porous absorbers.