Prediction of sound fields radiated by finite-size sources in room environments by using equivalent source models: three-dimensional simulation and validation

The use of equivalent source models (ESM) has recently been extended, with appropriate modifications, from its original application in acoustical holography to room acoustics simulations. This approach can serve as an alternative that is less computationally intense than the boundary element method and which is more flexible than traditional ray-tracing models in terms of dealing with non-compact sources and lower frequencies where the ray approximation is no longer accurate. Such room acoustics ESMs are based on the assumption that the room component of the total sound field can be represented by a number of equivalent sources of certain types, and that the total sound field can be predicted, with given free-space source information, by estimating the strengths of these equivalent sources based on a least-square match of the impedance boundary conditions on both the source and the room surfaces. However, to-date, the room acoustics ESMs have only been formulated and validated for two-dimensional cases. In the current work, the ESM formulation has been extended to three dimensions by replacing the two-dimensional equivalent sources with their three-dimensional counterparts, and its applications in a realistic three-dimensional room environment has been validated by successfully comparing the ESM and boundary element predictions.