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sarongsong
2005-Apr-24, 07:18 PM
April 24 (http://www.nctimes.com/articles/2005/04/24/special_reports/science_technology/19_23_444_23_05.txt)
"...uses ultrasonic energy to focus sound to precisely where the user wants it, even if that point is in midair..."When it's shining on the wall, the wall becomes the speaker and when it's on your face, the sound seems like it's inside your head"...On Friday, [Elwood] Norris...was presented with the annual Lemelson-MIT Prize...The $500,000 award is the largest single cash prize for invention in the United States, making it a science geek's dream..."

Sammy
2005-Apr-25, 04:30 AM
In the SF novel "The Space Merchants" (c 1954), ad agencies run the world, and hapless consumers are bombarded with aural and visual ads even when they walk down city streets.

Is the future here?

Evan
2005-Apr-25, 06:52 AM
I saw the Discovery Channel interview. He had his hypersonic loudspeaker with him. It is a flat plate with some sort of regular pattern on the front surface. He claimed that it projects sound within only a two degree beamwidth. He proved it by aiming it at his mic and then away.

I haven't the slightest idea how it works and would really like to know. Does anyone know the patent number?

Van Rijn
2005-Apr-26, 08:06 PM
Don't know about the patent, but from:

http://www.acoustics.org/press/133rd/2pea.html



When two sound sources are positioned relatively closely together and are of a sufficiently high intensity, two new tones appear: a tone lower than either of the two original ones and a tone which is higher than the original two.

There are now four tones where before there were only two. It can be demonstrated mathematically that the two new tones correspond to the sum and the difference of the two original ones, which we refer to as combination tones.

For example, if you were to emit 200,000 Hz and 201,000 Hz into the air, with sufficient energy to produce a sum and difference tone, you would produce the sum - 401,000 Hz - and the difference - 1,000 Hz, which is in the range of human hearing.

The HSS concept originates from this theory of combination tones, a phenomenon known in music for the past 200 years as "Tartini tones." It was long believed that Tartini Tones were a form of beats because their frequency equals the calculated beat frequency. However, it was Hermann von Helmholtz (1821-1894) who completely re-ordered the thinking on these tones. By reporting that he could also hear summation tones (whose frequency was the sum rather than the difference of the two fundamental tones) Helmholtz demonstrated that the phenomenon had to result from a non-linearity. Could a method be found today to utilize this non-linearity of air molecules in a manner similar to the non-linearity of an electronic mixer circuit?

Ultrasonic frequencies can be directed very tightly. At the point of intersection between two "beams" using different ultrasonic frequencies, if you do it right, you can hear audible sound.

The concept isn't new, and these aren't the only folks working on it. I've been hearing about it for years (no pun intended). Making it practical is a big trick, apparently fancy signal processing - fancy chips and fancy software - is a key requirement. And it doesn't handle bass very well.

Here's a background article:

http://www.woodynorris.com/Articles/TechnologyReview.htm

publiusr
2005-Apr-27, 07:26 PM
This would make for a good spookhouse. At certain freqencies--when you have a standing wave--it can create hallucinations. Add such a standing wave to this and--yikes. You could make a stature appear to talk to one person--while two people to either side don't hear a thing. Maddening whispers (to follow Al Quaeda types around)--cursing Mohammed.

An individual at a lectern would hear voices, while a magnetron beam aimed at the head would cause a seizure--making an assasination target seem to go mad and have a stroke.

Ewww.

sarongsong
2005-May-21, 12:51 AM
In a recent interview, Norris explained if he accepts the $500K outright, the taxman will reduce it by half. So he's set up a foundation to 'give it away' to worthy endeavors---got one?
Also check out his $50,000 AirScooter II (http://www.airscooter.com/pages/airscooter_main.htm):
"... Like the flying pods in Star Wars, the AirScooter scoots about with intended operation below 50 feet or so..."
http://www.airscooter.com/assets/body_pic_2.jpg