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M@X

Forum & Site Admin Group

Co-founder, Admin & Webmaster

Joined: January 29 2004
Location: Canada
Status: Offline
Points: 4028

Topic: Directed Sound
Posted: May 04 2004 at 10:15

Technology Review has an interesting article on directed sound. Ultrasonic 'sound' is sent out from a 'speaker' and the distortion encountered on hitting the air produces hearable sound, but only in certain spots. You could be standing right next to someone and they would hear nothing. One step closer to the cone of silence!"

http://www.technologyreview.com/articles/schwartz20504.asp?p =1

Prog On !

Stormcrow

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Joined: February 05 2004
Location: United States
Status: Offline
Points: 400

Posted: May 04 2004 at 15:23

Arrrgh.

I'm not sure I like the "sound" of this. "THEY" already have sub-sonic sound cannons that can shred your ear drums, drop you to your knees and make you void your digestive system from both ends.

Now there's going to be mobile, focusable higher frequency "sonic ray guns" able to pick any one person out of a crowd and liquify their brain.

Peter

Special Collaborator

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Joined: January 31 2004
Location: Canada
Status: Offline
Points: 9669

Posted: May 05 2004 at 20:32

Stormcrow wrote:

Arrrgh.

I'm not sure I like the "sound" of this. "THEY" already have sub-sonic sound cannons that can shred your ear drums, drop you to your knees and make you void your digestive system from both ends.

Now there's going to be mobile, focusable higher frequency "sonic ray guns" able to pick any one person out of a crowd and liquify their brain.

Cool Cool! I want one for my classroom!

Great way to ensure good behaviour, but -- due to a dearth of grey matter -- it wouldn't work on some of the boneheads I've taught in the past....

"And, has thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!'
He chortled in his joy.

Fitzcarraldo View Drop Down

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Joined: April 30 2004
Location: United Kingdom
Status: Offline
Points: 1835

Posted: June 18 2004 at 07:25

As someone who has not followed HI-FI technology for at least 20 years, this new loudspeaker technology sounds interesting.

Broadening the discussion, what other loadspeaker technologies exist these days? I'm of course interested in fidelity, but compactness is also of high interest.

goose

Forum Senior Member

Joined: June 20 2004
Location: United Kingdom
Status: Offline
Points: 4097

Posted: July 02 2004 at 09:36

"Here's what you do:

1. Find a big, round garbage can. Get rid of the lid, you don't need it.

2. Cut a hole about 9 inches across in the bottom of the garbage can. Make it as round as possible, and make sure its significantly narrower than the total diameter of the bottom of the can (improvise a bit here).

3. Take extra wide wax paper and put it tight across the top of the garbage can. It may require more than one sheet of wax paper to get it all the way across- put them faciing the same direction and attach them using a single strip of the lightest tape you can find. Make it as tight as possible over the top of the can so when you flick it with a finger, it vibrates instead of sagging.

4. Get subwoofer. Take the wires and strip em down so you have a couple bare leads.

5. Attach one wire to the negative terminal of a nine volt battery (the negative wire). Let the other one hang free, but with enough slack so you can contact the positive terminal.

6. Put the can on its side and place the subwoofer's front flush against the wax paper.

7. Point hole in bottom of can at Mormon, Jehovah's Witness, or Scientologist.

8. Contact the positive wire to the positive terminal of the nine volt for a brief second. The subwoofer should go "WOOMPH". Watch as, a few seconds later, the target is knocked on their ass.

Notes: A bigger can and more powerful sub mean a bigger blast of air.

Is that a valid loudspeaker technology? I'm sure it would be useful to use on intruders on your property, and they'd have no evidence with which to sue you!

Fitzcarraldo View Drop Down

Special Collaborator

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Joined: April 30 2004
Location: United Kingdom
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Points: 1835

Posted: July 17 2004 at 05:50

And now, speakers made of cardboard. There's an article dated 14 July 2004 here: http://www.msnbc.msn.com/id/5404920/ about some new portable flat-pack speakers made of cardboard. Here's an excerpt from the article:

"But the people at Sonic Impact Technologies have. Using something called NXT flat panel technology the SI people have designed low-cost cardboard speakers that actually sound pretty good.

The SoundpaX speakers come in a very flat package; unfolded, the speakers are tall and pyramid-shaped, 13.5 inches high and 12 inches deep. They weigh next to nothing. Don’t forget, it’s just cardboard.

On the inside of the front surface is the device that makes cardboard into speakers; the Soundpad. It’s a small, white plastic device which vibrates and makes anything attached to it vibrate. The British company NXT explains the material, its shape and the vibrating motor used in their Soundpad are governed by some very complex rules of physics!

If you don’t like the way it looks or you’re allergic to cardboard, SI sells Soundpads separately for $24.95 a pair. You can stick them on anything (posters, thin tables, bookcases, door panels and ceiling tiles) and see how well they do as speakers. Don’t forget you’ll still have to do something with the wires from your new speakers to the amplifier."

Wonders will never cease.