THURSDAY AFTERNOON, 6 JUNE 2013 513ABC, 1:00 P.M. TO 5:20 P.M. Session 4pAAa Architectural Acoustics: Room Acoustics Computer Simulation II Diemer de Vries, Cochair RWTH Aachen Univ., Inst. fuer Technische Akustik, Aachen D-52056, Germany Lauri Savioja, Cochair Dept. of Media Technol., Aalto Univ., P.O. Box 15500, Aalto FI-00076, Finland Invited Papers 1:00 4pAAa1. The differences and though the equivalence in the detection methods of particle, ray, and beam tracing. Uwe M. Ste- phenson (HafenCity Univ. Hamburg, Hebebrandstr. 1, Hamburg 22297, Germany,
[email protected]) Within the numerical methods used in room acoustics, the geometrical and energetic methods of sound particle, ray and beam tracing are often confused. This rather tutorial paper does not treat the tracing algorithms but rather aims to explain the differences in the physi- cal models and the corresponding detection and evaluation methods. While ray tracing needs spherical detectors as receivers to count rays, the particle model is based on a weighting of the energies of the particles with their inner crossing distances to compute the local sound energy densities. For beam tracing, receiver points are sufficient. In its core, this paper shows the convergence of the evaluated intensities computed from immitted sound particle energies to those predicted by the well-known 1/R<+>2<+>-distance law for the free field—as applied with the mirror image source method and beam tracing as its efficient implementation. Finally, the geometrical methods are classified depending on their efficiency with higher orders of reflection and their extensibility by scattering and diffraction. 1:20 4pAAa2.