Speaker
Description
Compact spherical loudspeaker arrays enable the synthesis of controllable directivities using loudspeakers distributed over a rigid spherical surface. However, most existing designs rely on a shared rear enclosure, leading to acoustic coupling between loudspeakers. This coupling requires the use of multiple-input multiple-output crosstalk cancellation systems.In this paper, we propose an alternative approach based on the physical decoupling of loudspeakers through a parametric enclosure design using spherical fraction geometries. This design significantly reduces acoustic coupling, allowing the control problem to be simplified to a set of independent single-input single-output equalization filters.A prototype consisting of 18 loudspeakers arranged according to a Popov cubature rule is designed and manufactured. Acoustic crosstalk is experimentally characterized using laser Doppler vibrometry. Results show an average crosstalk reduction of approximately 20~dB compared to a reference spherical array with shared enclosure. Simulated directivity patterns, based on a spherical cap model combined with the measured acoustic coupling, demonstrate that this per-driver equalization is sufficient to synthesize directive beams.