Speaker
Description
When predicting the sound transmission loss (STL) of a panel for an indoor situation, it is often assumed that the sound fields at both sides of the panel are diffuse. In this way, the STL does not depend on the detailed room geometries but rather represents the average panel performance across an ensemble of source and receiver rooms. Thanks to the reciprocity relation between direct field radiation and diffuse reverberant loading, the STL of a panel of arbitrary complexity can be computed by modeling it in full detail and coupling it to acoustic halfspace models at both sides. So far, a flat baffled geometry has been considered, such that the halfspace radiation stiffness can be obtained via the Rayleigh integral. However, computing the diffuse STL for panels mounted in a niche has remained an open problem. In this work, this problem is addressed by computing the radiation stiffness using a coupled finite element (FEM) – boundary element (BEM) approach. The air volume inside the niche is modeled using FEM, while the coupling to the acoustic halfspace is treated using BEM. This approach is validated on panels mounted in the standardized transmission opening for glazing of the KU Leuven Laboratory of Acoustics.