A variety of nonlethal acoustical weapons have been proposed and evaluated. Some of these are little more than fancy loud-speakers, while others involve more subtle or sophisticated processes and truely deserve the designation of acoustic weapon.
Acoustic weapons, also known as sonic or ultrasonic weapons, are devices that distract, harass, injure, or even kill a target using sound.
Simple high-intensity sound causes the inner ear to generate nerve impulses that register as sound. Since the inner ear also regulates spatial orientation, saturation of the inner ear by high-intensity sound may cause spatial disorientation. For example, loud music was used by American forces to drive Manual Norriega from the Vatican Embassy in Panama in 1990.
High-intensity low-frequency sound may cause other organs to resonate, causing a number of physiological results, possibly including death.
This video shows some of the acoustic weapons that are being developed