Here's a clue.
Back when I was working at Space and Naval Warfare Systems Command in San Diego, I went to LRAD's offices and we got a pretty good demo when they first went public with their system which they proposed as a form of area denial non-lethal weapon. The sound is projected from the dish and while it is not as focused as a laser beam, it is channelled and remarkably loud at enormous ranges. We were looking at using them later for venue security at the Greek Olympics and set up a couple in our offices in Old Town. It's a pretty cool system and I don't see why it wouldn't work above the audible frequencies we can hear and still create considerable damage to the ear and nervous system.
|Long Range Acoustic Device (LRAD) For Police Crowd Control|