An extended formulation of the SODIX method with application to aeroengine broadband noise

Abstract

An improved version of the inverse source location method SODIX is presented. SODIX models broadband nosie sources with a st of directive point sources by minimizing the difference between a measured and a simulated cross-spectral matrix of microphone signals. One big advantage of the method in comparison to other source location methods is, that it calculates a directive source strength from each point source towards each microphone. The new version of SODIX includes an implicit consideration of the constraint of positive source strengths in the iteration process. This improvement made the optimization process more stable and in addition independent of the initially assume source distribution. The method is also extended for applications with multidimensional source and microphone arrangements. Further, it is shown that the main diagonal of gthe cross-spectral matrix can be removed from the calculations without any mathematical violations and that the absolute strengths of the dominating sources are preserved. The improvements of the method are shown with exemplary results using measured data from a static aeroengine freefield test.