LRAD (Long-Range Acoustical Device)
A long-range acoustic device (LRAD) is a specialized loudspeaker that produces sound at high power for communicating at a distance. It has been used as a method of crowd control, which has caused permanent hearing damage, having an extremely high decibel capacity up to 160 dB measured at one meter from the device.
LRADs have the potential to be used as non-lethal weapons. The human ear can typically stand a sound pressure level of 120 dB before feeling pain. LRADs are capable of 135 dB or more of acoustic energy. Any sound pressure level over 90 dB requires hearing protection. As volume increases so does the chance of hearing loss. The effective non-lethal range of an AHD depends on the total acoustic output of the unit. Typically, this range is 160 feet or less.