Design and Control of Mixed-Order Spherical Loudspeaker Arrays

Abstract

Compact spherical loudspeaker arrays are used to produce sound sculptures in electroacoustic music by modal beam- forming that orchestrates the wall reflections in the given space.Performance practice predominantly uses beams in the horizontal plane as they most effectively produce audi- tory objects via lateral reflections on unobstructed, close- enough walls and baffles. Revisiting mixed-order schemes, this contribution reveals ways to boost the horizontal di- rectivity of the dodecahedral loudspeaker from second to third order, of the icosahedral loudspeaker from third to fourth, and for similar directivity, new special mixed-order layouts are presented with significantly reduced number of transducers. Moreover, a two-band approach is tested with a lower band in which the modal beamforming is fea- sible with short crosstalk cancellation filters, and with a high-frequency band using AllRAD as amplitude panning approach to minimize spatial aliases and side lobes.

Further Material

• [1] Stefan Riedel, Franz Zotter, Robert Hoeldrich. “Design and Control of Mixed-Order Spherical Loudspeaker Arrays.” 2019 ICMC (International Computer Music Conference) New York City (Best Paper Award).
• [2] Stefan Riedel. Master-thesis: “Compact Spherical Loudspeaker Arrays: New Ideas on Filter and Layout Design”

---

Technology Stack: Ambisonics, Matlab, CAD, 3D printing

Work Affiliation: Institute of Electronic Music and Acoustics, University of Music and Performing Arts Graz. In collaboration with Ass.Prof. Dr. Franz Zotter and Prof. Dr. Robert Hoeldrich.