Ultrasonic vibrations can be perceived as audible sounds when a piezoelectric transducer is pressed against certain areas of the human body. In the range of frequencies investigated (20 to 108 kcy/sec), the threshold of perception seemed to lie near the threshold of feeling (about 10(-4) watt/cm(2)), and the perceived audible sound appeared to be between 8 and 9 kcy/sec, as judged by six test subjects. The threshold of perception and the perceived frequency appear to be dependent upon the hearing characteristics of the individual.
No takes yet. Share an insight, caveat, or question.
Haeff et al. (1963) studied this question.