low_delta: (faerie)
It's a new way of projecting sound that allows the same kind of private listening headphones offer, without any of the cords or hardware.

Woody Norris is the inventor of hypersonic sound, a novel technology which uses vibrations that occur outside the range of human hearing:
"It's generally defined that the range of hearing extends from - on the low end, down to twenty cycles per second - all the way up to twenty thousand cycles, or vibrations, per second. When you go above that, it's still mechanical vibration of air molecules bumping into each other. And the air is actually capable of vibrating many millions of times a second, believe it or not."

While air can vibrate at high speeds, our ears can't detect these very high frequency sounds. Hypersonic speakers -- or emitters -- capitalize on this. They produce different streams of high frequency sound starting at one hundred thousand cycles. That's well above the range of human hearing.

"You emit your hundred thousand, and hundred one thousand cycle signals into the air, and by some magic which happens in the air itself, the difference between those two tones is made right in the air. In fact, it's made all along an infinite number of points in that ultrasonic column. In this case, the difference is a thousand cycles, which people can hear."

By creating two streams of high frequency vibrations, an audible sound can be produced and it can be pinpointed and transmitted up to a hundred fifty feet away.

"For instance, if you're a lifeguard or a policeman trying to have riot control to get the instigator of a riot, you can point it at a lead person and communicate with that person. We've got people in Florida and in New York using it to scare away birds."

Voices of Innovation is presented by the American Association of Engineering Societies.

Date: 2003-07-23 04:00 pm (UTC)From: [identity profile] ravenfeather.livejournal.com
Hmmm.. I wonder how that would work for someone like me who hears outside of the "normal range" of sound. I hear silent alarms, electronic pest chasers and dog whistles.. those kinds of things. I can't even walk into a jewlery store because the buzzing of the cases is so loud to me. It gives me a headache.

Date: 2003-07-23 08:49 pm (UTC)From: [identity profile] low-delta.livejournal.com
I'd think it would still be WAY above your range. Even that of the average dog.

Date: 2003-07-24 02:10 am (UTC)From: [identity profile] nephychu.livejournal.com

Specifically you'd need about a 435% increase in upper frequency range sensitivity (as an average person) to be able to perceive the "hypersonic" sounds generated by the instrument.  Greater if you wanted to perceive it clearly at normal volume.

Dogs would need to be about 218% their norm, cats 156%.

Some animals that would definitely hear the hypersonic transmissions at their normal hearing range:

Some species of moths: an evolutionary response to perceive bat "sonar"
Dolphins: sonar navigation (echolocation), communication
Coastal-area-dwelling Beluga Whales: sonar navigation (echolocation)
Porpoises: ditto
Bats: echolocation (some species are so sensitive that they can actually deafen themselves if they do not close off their ear canals before emitting hypersonic tones)

Date: 2003-07-24 02:56 am (UTC)From: [identity profile] ravenfeather.livejournal.com
I would hope so. I get really irritated at those store alarms.. I don't think I am that unusual, and I wonder how many others can't handle going into stores that are supposed to be silent to "normal range" people.

Date: 2003-07-24 10:39 am (UTC)From: [identity profile] low-delta.livejournal.com
I can hear a higher range than most people, but nothing like what you describe. I haven't heard store security systems in many years. I don't think they use that kind around here anymore. But they never bothered me, they were just barely audible.

Date: 2003-07-24 03:47 pm (UTC)From: [identity profile] ravenfeather.livejournal.com
Maybe I should move. They make me feel like my teeth itch and my head is going to explode.

Date: 2003-07-24 01:02 am (UTC)From: [identity profile] nephychu.livejournal.com

I'd like to hear how that would actually sound on the receiving end.  I'd also like to get me one of those pinpointer communicator things; just imagine the fun you could have with people by targetting them from a high (ie. unseen) vantage point in a heavily congested public place.

“This is the government.  We are experimenting with new mind control technology and will be controlling your thoughts from satellite for the next five minutes.  Please do not be alarmed, do not hide indoors where the signal may be interrupted.  This is very important.”

Seriously, give me one of those and a high quality digital videocamera...  And I'm good to go. :D

Date: 2003-07-24 10:37 am (UTC)From: [identity profile] low-delta.livejournal.com
Ha!

That would be most pleasurable!

Date: 2003-07-24 03:36 pm (UTC)From: [identity profile] emschin.livejournal.com
This "non-scientific person could just barely follow that, but it still was interesting. I've tucked it away in my head and when that subject comes up again (oh, yes, it probably will) I'll have a starting point to listen.

Date: 2003-07-24 09:53 pm (UTC)From: [identity profile] low-delta.livejournal.com
I didn't follow it either.

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