A rapid computational method to investigate the directivities of quasi-omnidirectional sources of sound

Abstract

While dodecahedron loudspeakers are widely used in acoustical measurements as quasi-omnidirectional sources of sound, other multiple-driver configurations may also be used for this purpose. Previous experimental work has shown that loudspeakers with higher-order Platonic solid geometries tend to produce higher omnidirectional cutoff frequencies than their lower-order counterparts. However, as their radiated fields transition from omnidirectional to multidirectional at higher frequencies, their directivities may or may not be closer to the omnidirectional ideal. Additional testing has been required to better understand the effects, but it has been cumbersome because of the difficulty of constructing and measuring many modified loudspeakers. This poster presents a practical method to estimate the directional characteristics of multiple-driver sources based on spherical enclosure geometries and the use of common mathematical software such as MATLAB. It enables one to easily and rapidly predict the directivity patterns of these sources and the effects of altered driver diameters, positions, numbers, vibrational patterns, and enclosure volumes. The method is shown to produce several interesting results that are validated by the boundary element method and experimental measurements.