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An old KickStarter-backed project that does the same thing is currently available at http://www.soundlazer.com/ . The physics behind it are explained at http://www.soundlazer.com/what-is-a-parametric-speaker/ .

I have one of the soundlazers. Hardly use it because it's particularly punishing on the ears even at low volumes.

Was fun bringing into the office and reflecting sounds off the roof into other cubicals...