Investigation of the anisotropy of hemi-dodecahedron noise source radiation

Abstract

If loudspeakers with the radiation characteristics of point sources located in a reflecting plane are needed, a possible option is to use polyhedra cut in half. In contrast to the octahedron, the dodecahedron can be cut for this purpose only in such a way that reflection at the plane does not complement it to again form a regular dodecahedron. But by modifying the symmetry, the isotropy of the radiated sound field is degraded. The investigations described relate to the anisotropy of the radiated intensity in the far field in comparison with the octahedron and the original regular dodecahedron, both by expansion in terms of spherical functions and by boundary element calculations.