Examining acoustic emission of engineered ultrasound loudspeakers

Measurement results of the sound emitted from an ultrasound custom-made system with high spatial directivity are presented. The proposed system is using modulated ultrasound waves which demodulate in nonlinear medium resulting in audible sound. The system is aimed at enhancing the users´ personal audio space, therefore the measurements are performed using the Head and Torso Simulator which provides the realistic reproduction of the human auditory system. Based on the measurements of the sound emitted from the two parametric arrays of ultrasonic transducers the directivity of the proposed system and the interaural crosstalk characteristics are determined. The application of the system concerns creating a personal audio space for users of mobile platforms, such as notebooks, and applying 3D audio algorithms without the need of using headphones.