Targeted Sound Beams

Mr_Kcleen writes: "Wired has a story on using sound beams targeted to only one person. They discuss various uses, from musical performances to possible weaponization." This is another one of those ideas that are right around the corner, really, honest.

Comments

Beat Frequency

[jafuser]

This is actually a very simple concept, called beat frequency. I guess nobody ever thought to try it on ultrasonic frequencies to recreate frequencies that are within our hearing range. You may remember beat frequency from your high school physics class, if your teacher ever demonstrated the "weird effect" you hear when you strike two very slightly different tuning forks, you'll hear both tuning forks, plus a beat frequency that is equal to the frequency difference of the two tuning forks. You also hear the effects of beat frequency if two people try to make the same tone with their voice (such as when singing duet), it almost sounds like there's a third voice in there.

I saw a demonstration of this technology a few years ago at Epcot center, during the Discover Magazine Awards for Technological Innovation. The demonstrator held this paddle-like device with an array of metallic discs on it, and as he turned it slowly across the crowd, you'd not hear a thing until it was pointed at you. Very cool :)

Interesting, but not for concerts

[hcdejong]

From the article: Pompei imagined that instead of loudspeakers blaring the same cacophony of instruments to all parts of the room, it would be more interesting to selectively spotlight the soloist to the left side of the audience, while featuring the percussion up front, and then switching them around.

But when I go to a concert, I want to hear all the instruments - without having to move around the room.

Also, I get the impression that current tests are being carried out in silent environments with few obstacles. In a concert, you'd have to crank up the volume of such a 'sound spotlight' in order to hear it over the 'general' sound system. And in a crowded hall, the sound from the beam would be reflected more. This would cause the sound generated by the spotlight to 'leak' out of the beam area, making it less effective.

And (also important in a concert) the audio engineer can't hear what he's doing with the spotlights, making it very hard to get right.

Conspiracy theory alert...

[cr0sh]

Want to learn something interesting? Look up "voice to skull" technology. I have managed to find direct evidence (via government websites) of both the United States and Austrailia researching this technology. Patents exist, and can be looked up. The technology is real, as has been known about for a few decades.

It looks like the tin-foil hat kooks may be right.

Two systems exist:

1. Audio over ultrasonic carrier - essentially uses the skull to filter the ultrasonic carrier wave - at that point it is simple bone conduction.
2. Audio over microwave carrier - this one is more "advanced" - it uses frequencies in the microwave region as the carrier wave for the sound. These waves then stimulate the vestibular region of the brain, which filter out the carrier and leave the sound information behind for the brain directly to figure out - causes strangeness to the recipient - a "voice in the head" type sensation. This form of V2S was first noticed by microwave and radar engineers who would "sense" or "hear" (in their heads) "clicks", "pops" and "whine" type noises as the worked around unsheilded microwave equipment.

Both of these technologies are real, as far as I can figure. Neither is "high quality" - but voice quality only (in fact, the microwave V2S system is actually pretty poor quality - rendering the voices in a "growling" type tone - which could be interpreted as "demons talking"). Both have potential "sinister" applications - neither have the quality of use for anything else.

I wish I was making this up - I haven't found anything that says "impossible" yet - but if someone could look into this with me, and let me know that I am wrong, I would love to see the information...