Its quite interesting. The directional ultrasonic array broadcasts a carrier frequency, not unlike am radio. You can read about the function of this sort of dev

Its quite interesting. The directional ultrasonic array broadcasts a carrier frequency, not unlike am radio. You can read about the function of this sort of device at hackaday. https://hackaday.com/2019/02/14/creating-coherent-sound-beams-easily/ https://hackaday.com/2019/02/14/creating-coherent-sound-beam...