A NEW NOISE MODEL FOR DESIGNING SUPERDIRECTIVE BEAMFORMERS FOR SPECIAL APPLICATIONS

The design of superdirective beamformers is based on the minimum variance distortionless response solution (MVDR) for a spherically or cylindrically isotropic noise field. In this contribution a new noise model is given. It excludes parts of the noise field near the pre-describ-ed look direction from the isotropic assumption. This leads to a new but suboptimal beamformer when mea-suring the directivity index, but it can provide a better robustness against steering errors. Furthermore, in some applications like recording orchestras the desired sources certainly are in front of the array and the audience as the disturbances are on the back side. Therefore, assuming an isotropic noise field is not the optimal choice. 1