I'm not talking about the LRAD*, this is far more interesting. Thingiverse user neurothing ( or should I say Brown University neuroscientist Seth S. Horowitz ) lists among his interests "creating neurosensory algorithms for weapons class sound". In addition to the implied military applications, it seems he can use a mysterious sound algorithm to modulate emotion, attention, and state of mind. He has started a company called neuropop to commercialize these effects :
Our proprietary Neurosensory Algorithm (NSA) technology can be used to modify virtually any sound or music to activate specific parts of the listener’s brain to encourage sleep, reduce stress, enhance attention, or create specific mood-states. We are currently developing health and wellness, entertainment, and gaming products.
Finally, I feel like I'm living in the future. I am, of course, reminded of BLIT. Neuropop claims uses such as meditation, altering state of mind, enhancing effectiveness of advertisements, and providing music for movies and video-games better tuned to manipulate the listener. You can even test out some of the simpler effects on their website. If you guessed that binaural beats have something to do with this, you're right, but they also use a diversity of other techniques, not all of which appear to be published, to achieve much more than binaural beats are capable of. Having not (yet) experienced their auditory stimuli, I can't verify that their technique works. However, having seen what a couple of colored flashing LEDs can do to my visual cortex, I'd wager their effects are real. The big question, then, is weather or not Professor Horowitz was joking about the "weapons class sound".
*Having witnessed the LRAD in deployment I should note that some young folk these days are immune to it, due to a decade or more of loud rock concerts. However, if your hearing happens to be intact this machine will quickly induce the accumulated damage of a decade of loud rock concerts (hyperbole), which is painful. I imagine ultimate military or riot control applications of Horowitz's sound algorithms might be piped through something such as the LRAD, but perhaps could induce confusion at a less damaging decibel level.