Research on a novel audio beam loudspeaker based digital signal processor

A novel audio beam loudspeaker based on digital signal processor (DSP) was fabricated by utilizing the nonlinear propagation effects of ultrasonic in the air to generate audible sound with high directivity and controllable space distribution. In terms of the notable Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, the modulation equation of how to process the audio signal is deduced. Moreover, the ultrasonic transducer array is explored to generate audible sound with high directivity. It is proven that increasing the quantity of transducers in the ultrasonic transducer array to generate audible sound with high directivity and suppress the amplitude of sidelobes is feasible when it is impossible to make the distance between transducers less than or equal to a half of the wavelength of ultrasonic.