Pretty cool! I’ve seen similar implementation in the Elektor 2011 issue magazine.
The US navy uses the commercial brand of these speakers; LRAD (long range acoustic device) to ward off pirates at seas. LRAD is the company that makes them for defense purposes and they patented the name and acronym. But parametric speakers are used everywhere even museums and apparently for trolling Rick roll too! :)
Those things are so goddamn loud, I've seen them tested before a bunch. I used to see them for sale on ebay and amazon which was pretty funny. Not anymore. Still on aliexpress, as well as these sound laser directional speakers albeit the LRAD will run you at least 5 grand and you can probably make the directional speaker cheaper as in this DIY project
