FDTD simulation ISO 3382 ISO 3382-1 ISO 3382-3 Mathematics & science PUFEM Research & information: general absorption acoustic heritage acoustic measurements acoustic parameters acoustic subspaces acoustical parameters acoustics acoustics simulation airflow resistivity archaeo-acoustics auralization building acoustics calculation models coherent image source method concert hall acoustics diffusers location diffusive surfaces directional decay rates discretization error dodecahedron eigenbeam processing explicit method finite element method