Outside the convention hall, New York City police plan to control protesters using a device that directs sound for up to 1,500 feet in a spotlight-like beam. Meanwhile, a display of former Republican presidents inside the hall will feature campaign speeches that are funneled to listeners through highly focused audio beams. Both technologies feature unprecedented manipulation of sound, but for very different purposes. And while both technologies have unique, gee-whiz" factors, some remain uneasy with the idea of using sound to control crowds. When in weapon mode, LRAD blasts a tightly controlled stream of caustic sound that can be turned up to high enough levels to trigger nausea or possibly fainting. LRAD ... has been used by the U.S. military in Iraq and at sea as a non-lethal force. In these settings, operators can use the device not only to convey orders, but also as a weapon. In tests, police have shown how they can convey orders in a normal voice to someone as far as four blocks away. The sound beam is even equipped with a viewfinder so the operator can precisely target the audio by finding a person in cross hairs. Rather than using pure volume to throw sound far, the LRAD reaches distant ears by focusing the audio beam. Wherever the beam makes contact with air, the air molecules interact in a way that isolates the original audible sound. So if you're standing in front of the ultrasonic sound wave, you can hear the sound. If you're a few inches away, you hear nothing. Already, some Coca-Cola machines in Japan are equipped with the technology so passers-by hear the enticing sound of soda being poured into a glass of ice.