TIME ITERATIVE BOUNDARY ELEMENT METHOD (TIBEM) - A NEW NUMERICAL-METHOD OF 4-DIMENSIONAL SYSTEM-ANALYSIS FOR THE CALCULATION OF THE SPATIAL IMPULSE-RESPONSE SUMMARY

The greatest weakness in the calculation of the spatial impulse response by ray-tracing, or by the method of images is the neglect of diffraction and interference effects. There exists a numerical boundary element method for the solution of the Helmholtz equation with boundary conditions which is based on ray theory. An intrinsic disadvantage of this method is that it necessitates the solution of very large system of equations and involves a correspondingly large computation time. This article presents a new method which takes into account the wave properties of sound and the required frequency dependent wave impedances. The recursive algorithm presented here means that no systems of equations need to be solved and the computation time is drastically reduced. Possible areas of application include sound field calculations in motor vehicle interiors, office interiors and concert halls.