Quantized Pyramidal Beam Tracing - a New Algorithm for Room Acoustics and Noise Immission Prognosis

Some ideas of a new room acoustical algorithm are outlined combining the advantages of three algorithms in one: the mirror image source method, the sound particle simulation method and the radiosity method. Transient carriers of energy are pyramidal beams ("pyrs") each representing a mirror image source which are split at each reflection or diffraction thereby giving their energy to new pyrs. Above a certain reflection order, the pyrs are quantized with respect to source position and solid angle. Their number is limited to an optimum. This Quantized Pyramidal Beam Tracing (QPBT) converges to an efficient time dependent radiosity method, being able to take reflections and diffractions of higher order into account but avoids the usually expected exponential increase in computation time. Applications concern not only room acoustics but also the field of noise immission prognosis in a free field. Some fundamental properties of the algorithm are discussed.