Here’s a cool Ultrasonic Hearing System which lets humans to hear ultrasonic sounds. Well, it’s a patent but maybe it will go into production so we can hear what insects and animals are listening to.
A direct drive hearing system for providing an ultrasonic signal to a portion of the human ear. The direct drive hearing system includes an ultrasonic direct device. The device includes a housing with at least one coil coupled to the housing. Inside the housing is a magnet, which vibrates at an ultrasonic resonant frequency in direct response to an externally generated electric signal through the at least one coil.