Golly I hope so.
In any case the approach is new, but we have had targeted audio for some time. Another method used in the past was done by two hyper sonic waves that when combined would reconstitute into a lower frequency. I forget all the details but it it nearly placed the sound in your head.
Keywords on that is "voice to skull" - though what I recall, the way it was done was by layering the audio over an ultrasonic carrier wave that could be focused on the targeted listener, and the carrier would be stripped away by the listener's skull, leaving the audio behind which would be heard via bone-conduction.
I'm not saying what you describe isn't a method either - it sounds plausible, and I haven't kept up with all of the developments in the technology.
None, though, was as interesting ("scary"?) as the microwave transmission method direct to the brain/neurons...
I think you would have a hard time making this illegal in the US, as I am sure somebody will tie it to freedom of speech. If a bull horn is legal, then this for sure would also be legal.
It wold also be a legal quagmire depending on how the law would be worded. "Use of directional sound is prohibited."? Simply aiming my mouth at you is doing the same. There are also more than one way to achieve directional sound. I think it was at Fry's -- in their checkout line, they have highly directional speakers that aim down and talk to you, move a few feet either way and you no longer can hear a thing.
Those laws are for sure not without theoretical constitutional issues, but in practice work well enough to keep the lid on.
Simply put, targeted protesting...
If your claim is that you could stand outside a restaurant blowing a bullhorn at patrons and passers-by for long enough to get caught doing it and that there would be no repercussions, I think you're mad.
Knowing that, I predict JCDecaux will have devices covering every inch of downtown that will beam high pitched ringing at anyone that passes by. The only way to stop it would be to press a button on their device that says "Stop the ringing". According to European law, this is good enough to count as "consent".
- Gaslight someone by making them hear voices
- Threaten someone then arrest them when they attack since to bystanders it appears to be unprovoked
- Similar to the previous one, provoke/trick protestors into "unprovoked" violence
- Trick someone into walking into oncoming traffic
- Harass someone without anyone else noticing
Or you want to do directed marketing. (For all the bustle about consent, that part is trivial to ignore.)
I would pay higher for a laptop with directed sound, so that at open offices (or public place) I can watch one off videos (typically for reference) without getting into hassle of wearing headphones.
Does anybody know if any of the files for these are public? I think it would be fun to experiment with this idea at home.
I would be very interested in the sound direction solely. My use case is to project sound to me, in a bed, without my wife, sleeping next to me, hearing a thing. I like to sleep with music and she doesn't. A directed alarm would be nice too.
Is this technology already available some where?
Directivity is about -50 dB off axis potentially. You can further enhance it some with active noise cancellation.