Wide-band sound reproduction using a 576-channel focusing parametric array loudspeaker

Generating high-contrast, wideband audio over a confined target area remains challenging for electrodynamic loudspeaker (EDL) arrays due to the large source size and extensive multi-channel signal processing requirements. In this study, we address this challenge with a multi-channel focusing parametric array loudspeaker (PAL) array. Unlike traditional multi-channel EDL/PAL arrays that apply time delays directly to wideband audio signals, we apply time delays to the ultrasonic signal to achieve beam focusing. This approach, utilizing a square-wave ultrasound signal, significantly reduces hardware resource demands while effectively controlling nonlinearly generated audio beams. We designed and fabricated a 576-channel PAL array capable of wideband sound reproduction at the focal point. Experimental results demonstrated the system’s effectiveness, achieving wideband (250 Hz to 4 kHz) sound at the focal point, with audio outside this region attenuated by more than 14 dB. Our work advances the potential for high-performance wideband sound reproduction systems using massive multi-channel PAL arrays.