Specifically it's called an LRAD. It doesn't incapacitate anyone farther than maybe nausea and permanent hearing damage. I believe the first use against protestors was 2009 in Philadelphia. http://en.m.wikipedia.org/wiki/Long_Range_Acoustic_Device Hearing protection is probably effective.Carl Gruenler, a former vice president of military and government operations for American Technology Corporation said that being within 100 metres (330 ft) of the LRAD is extremely painful, and that it was designed for use in short bursts at 300 metres (980 ft), to give targeted people a headache. He said that "you definitely don't want to be" within 100 m; and, that the device will cause permanent auditory damage.
When you are permanently taking away something like a sensory ability, that is especially criminal. There is absolutely no reason that these devices should ever be used... anywhere. Other non-permanently damaging methods of riot and crowd control are just as effective. Utilizing LRAD is the result of someone's (really, multiple persons') hard-on(s) for harming other people. It's about fucking time that we started having a national dialog about the out-of-control militarization of the U.S. police force. That it took such a series of unfortunate events to get peoples' wheels turning is pathetic.It doesn't incapacitate anyone farther than maybe nausea and permanent hearing damage.