I can confirm the Long Range Acoustic Device LRAD has been in use for years. It is typically used for military purposes and to avoid maritime piracy and to control and give information to big crowds, riots and demonstrations.

You should see the LRAD as a kind of megaphone rather than a non-lethal weapon. It gives normal acoustic messages, however good engineering work have made it possible to narrow the sound beam. It is also a fact it can make an ear-splitting noise that nobody can stand. However, it is mainly used is to communicate and to give information in long distance in high ambient noise environment.

It is a great tool as one can communicate to the counterpart in several hundreds meter distance. Thereby it helps to avoid dangers situations and mistakes.

Also it can be used in case of disaster. The authorities can inform and warn the population very efficiently using the LRAD for long distance messaging.

Have a look at this LRAD video presentation to understand the product and what it can do [phodio.net]