From Wired:
http://wired.com/news/technology/0,1282 ... _tophead_1
"EDWARDS AIR FORCE BASE, California -- Air-raid sirens, Frank Sinatra songs and Muhammad Ali trash talk blared over the Southern California desert in a demonstration of new acoustic technology for crowd control and disaster communications.
In mid-90's morning heat at Edwards Air Force Base, HPV Technologies and American Technology demonstrated prototypes of non-lethal sonic devices for a group of military and law enforcement guests, including representatives of the U.K. Home Office.
Representatives of both companies say that within days, they will ship some units of their respective products to areas hit by Hurricane Katrina, so authorities can use the tools for crowd control, aid distribution and rescue operations."