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Directed Sound
yawningyellowyak writes "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!"
standing right next to someone and they would hear nothing
That would be great if someone could rig my wife up with one of these... the silence would be bliss! :)
And we think spam is bad...
Sorry, it doesn't work on the noises you make.
"We are focused on achieving high volume applications featuring the unique benefits of HSS directed sound. --"To the Shareholders of American Technology Corp." Business Wire, March 25, 2002
I saw a TV programme about this a while ago.
One of the guys who was developing it enjoyed pointing it down towards people on the street and speaking to them. He said they got really creeped out and started looking around to see if anyone else heard it.
I think it'd be more fun to involve two people and two speakers. Have a sort of devil and angel think going on.
"Kill that guy over there!"
"No, don't do it"
"Go on, don't listen to that pussy!"
Oh yeah, like, that's exactly what I want. Lying in bed with my girlfriend watching p0rn and then not getting laid.
I think you might want to rethink that plan Sparky.
KFG
from here and here.
i'm sure this'll come around again in the next few months...
I'll turn into a supernova and burn up everything. Well I'll turn into a black little hole and you'll turn into string.
I don't know what the official definition of vapourware is, but I have seen this in use from rooftops at MIT (it's fun to see the reaction of people as they try and figure out if anyone else heard that voice), and am helping in the development of a line of products that use these speakers as a key component.
I think the reason you probably haven't seen it yet is that there aren't many finished products made yet, and part of that might have to do with the fact that lots of local bylaws seem concerned with this kind of thing (they liken it to talking on cell phones while driving).
It won't be long before this is everywhere. I think the tech is just slightly outpacing the market right now.
The world's only surviving livewriter.
Linear transformations cannot create new frequencies, only alter the relative intensity of frequencies that already exist. If ultrasonic sound is being heard, some nonlinearity somewhere is converting it to audible sound.
The thing that I have to wonder about is that this kind of nonlinearity implies fairly high (ultrasonic) sound intensities, and suggests that stuff inside your head is being driven beyond its elastic limit. The big thing that seems to me to be missing from the article is any statement of the ultrasonic sound power level, in decibels, that is being delivered to your head (and the ratio between the actual ultrasonic sound level and the apparent audible sound level).
How does this compare, for example, to the sound levels used for ultrasonic imaging in medicine?
I'm not suggesting that the process is necessarily dangerous, but it isn't obvious that it's intrinsically safe, either. It's one thing to be subjected to high-power ultrasound a few dozen times during your lifetime for the purpose of preserving your health. It's quite another to be subjected to it day in and day out, for your convenience in listening to music, or for some advertiser's convenience in interrupting your train of thought.
"How to Do Nothing," kids activities, back in print!