Ultrasonic waves cannot be produced by loudspeakers. Loudspeakers can only produce sound waves within the human hearing range, which is typically between 20 Hz and 20 kHz. Ultrasonic waves, on the other hand, have frequencies higher than 20 kHz and are inaudible to the human ear.

Ultrasonic waves can be produced using specialized devices called ultrasonic transducers. These transducers convert electrical energy into mechanical vibrations at ultrasonic frequencies. The most common type of ultrasonic transducer is a piezoelectric transducer, which utilizes the piezoelectric effect of certain materials to generate ultrasonic waves.