Sound is a vibration that travels through air as a wave. These waves are created when an object moves back and forth, compressing and decompressing air molecules. The frequency of these vibrations ...

Twin ultrasound transducers create highly focused audio Curved sound waves aren't audible ... announced their Hypersound ...

Crucially, the sound waves — specifically, ultrasound waves — used to create the audible enclaves can't be heard along the path they travel and can even be bent to avoid obstacles. Only when ...