US forces in Iraq have a new non-lethal (but really annoying) weapon in their arsenal. According to American Technology Corporation's press release, the Long Range Acoustic Device (LRAD) is a "hailing and warning, directed acoustic device that is designed to determine intent, change behavior, and support various rules of engagement. With LRAD, a sentry can issue a focused verbal challenge with instructions in excess of 300 hundred yards, and follow up with a warning tone to cause behavior change." According to an Associated Press article, the LRAD tone is similar to that of a smoke detector but
twice as loud and directed in a tight beam at a volume of 150 decibels. (As bb reader Grant Hamilton points out, that's 10db louder than the sound of a jet at take off!) "Inside 100 yards, you definitely don't want to be there," says the American Technology VP quoted in the article.
This reminds me a bit of infrasound weaponry research, exploring the use of ultra-low frequencies to cause discomfort, pain, suffering, and, er, bowel movements. The AP report also makes a reference to another non-lethal weapon almost ready for field testing, an energy beam that repels enemies. This one has a great name: the Active Denial System.