The Research About The Bem-Sea Based Hbrid Model For The Sound Field Radiated By The Sound Source In A Large Room

For the sound radiation within a large room, the acoustical wavelength in the range of frequencies of interest is far smaller than the wall size even if it is larger than the source size. Therefore, the sound is the low-frequency sound for the source surface, but the high-frequency sound for room walls. Modeling this interior sound field precisely is accordingly unpractical due to tremendous degrees of freedom (DOFs). One hybrid approach is studied for modeling the interior sound field radiated from the sound source within a large room by combining the boundary element method (BEM) and the statistical energy analysis (SEA). In this approach, it is assumed that the modal overlap factor of the interior sound field is high, and the nature frequencies and the modal shapes obey the statistics of Gaussian orthogonal ensemble (GOE). The explicit expression of the cross-spectrum matrix of the reverberant sound pressure within the room is then deduced from the acoustical FEM equation of the interior sound field, considering the effect of room walls by SEA. The interior sound field radiated from the sound source within a large room can be predicted by combining this expression of the reverberant sound pressure with the BEM model of the direct sound field. Modeling precisely the effect of room walls is needless for this approach, and only the structural source surface needs to be discretized. Therefore, the number of DOFs of this hybrid approach is far smaller than the one of those fully precise FEM/BEM models.