Voices in Your Head

ceejayoz writes "MSNBC/Newsweek is running a story about a 'Hypersonic Sound System' that can 'can take an audio signal from virtually any source and convert it to an ultrasonic frequency that can be directed like a beam of light toward a target up to 100 yards away.' Sounds like something that advertisers will love - Minority Report just got a little closer." These guys (and the Audio Spotlight guys) have been hyping this technology for years with nothing much to show from it. But now, Newsweek promises, it's going to change the world as we hear it.

Comments

What if it gets turned up to 11??

[billmaly]

My only concern here is what happens when someone cranks up the amp on this and points it at someone's head at close range? Does it become a sonic bullet, destroying hearing (or worse), or is it limited in it's power by default?

Have I got a product for you..

[James_G]

If advertisers like this, then I've got an even better device. Rather than broadcasting to a single individual up to 100 yards away, it will broadcast to EVERY SINGLE PERSON within a 500 yard radius! It's a device I like to call a "speaker" and you're going to see a lot of these around over the coming years.

This amazing device can be yours for a minimal price. Just sent me $2000 and I'll ship a couple of devices capable of producing hundreds of watts of sound. None of this crappy 1 person 100 yards away stuff.. Man, where do they get their ideas?

Just Super

[Inexile2002]

Now I can have information about increasing my penis 3 to 6 inches beamed directly into my head as I walk down the street. The very idea of pedestrian spam, spamming houses, cars, offices... give the advertisers military grade psychological warfare equipment and this will make email spam seem like well... something pretty damn trivial (drew a complete analogy blank there).

The day I get blasted with an add for Coke beamed directly into my head while walking down the street is the day I quit my job and start organizing consumer boycotts full time.

This is how it works in layman's terms

[wackybrit]

For some reason I feel this is a double post, but no-one here seems to have noticed, so I must be nuts.

Here's how it works in laymans terms. I am no science wizard, but this sounds good to me..

There are things called beat frequencies that occur when you have two frequencies present. For example, if you play 20Hz into one ear, and 25Hz into the other, your brain can be 'tricked' into thinking it is hearing 5Hz (the difference between the two frequencies).

This is all well and good, but 20Hz soundwaves don't travel too good. Ultrasonic frequencies do though. Remember those TV remote controls in the 70s and 80s that used ultrasonics? You could control your neighbor's TV. (See the start of Poltergeist 1 if you forget)

But how does sending 50Khz sound waves through the air help you hear anything? Ay, well there's the rub. The concept of beat frequencies is used once again.

If you send a 50Khz sound wave from one source and pinpoint it at a certain spot, and then send a 51Khz sound wave from another source to the same spot, anyone at the place where those two beams join up will hear a 1Khz sound, thanks to beat frequencies.

That's how you can pinpoint sounds to a single place. It just took a genius to get the connection between beat frequencies and ultrasonics to work this one out. I think it's cool.

Should help schizophrenics...

[cliveholloway]

My wife's a psychotherapist - she used to suggest to her schizophrenic clients that they carry a cell phone (or at least know where the nearest payphone was). When they felt they needed to argue with the voices in their heads, she suggested they just pretend they are making a call to help ease the embaressment of the situation.

Now i guess they just need to push the arguments towards, "No, I don't want to buy a fucking Coke" and no-one will suspect a thing...

cLive ;-)

Newsweek Objectivity

[PRickard]

"But now, Newsweek promises, it's going to change the world as we hear it."

OK, Newsweek has now slipped into the same category as the TV channels that show infomercials 20 hours a day. A couple of weeks ago Newsweek touted Microsoft Palladium as the revolutionary future, now they're saying this sound wave thing will be. How much would it cost me to have Newsweek run a long article about my futuristic world-changing vaporware product that happens to be 8 to 15 years away from actual production? It's worse than biased media, it's buy-your-own-news.

Close, but no cigar

[wowbagger]

You got a few things right, but a few things wrong.

First, beat frequencies are quite real - there is no "tricking" your brain into hearing something that isn't there - the signal is there.

Specifically, whenever you feed 2 signals f1 and f2 into a system with any non-linearities, you will get four frequencies out - the original f1 and f2, and two new frequencies (f2-f1) and (f1+f2). So, if I feed 51kHz and 50 kHz into a system, you will get 1 kHz, 50 kHz, 51 kHz, and 101 kHz. This is the same principle that all modern radio receivers work on - it is called heterodyning, and a modern radio is a superheterodyne receiver.

Now, in terms of propagation, low frequency sound does better than high frequencies - hence why thunder goes "CRACK" when it is close and "rummmblee" when it is far away - all the high frequencies have been attenuated by the air. Also, this is one of the reasons why all you hear of the assholes with the ThunderThump 3000 car stereos is the low frequencies - what little high frequencies they produce are attenuated by the car's body and the distance.

However, to get any directionality from a sound transducer, it must be large with respect to the sound frequency. The problem is that the bulk of the frequencies humans hear have very long wavelengths - it is possible to make a directional beam of 20 Hz sound, but you would need a speaker system the size of a football field. Somewhat impractical if you want them all over the place, pumping out your "BUY ME NOW" message.

However, by translating the frequencies up to 50 kHz, you reduce the wavelengths down to the point where the speaker needn't be much larger than a paperback to get the directional gain you want. So, you upconvert the signals to ultrasonic frequencies, and you use the fact that just hitting a surface acts as a nonlinear mixing element.

However, I have always wondered how much of the signal is going into the (f2-f1) component, and how much of the power is in the other three frequencies you cannot hear? What kind of damage will this energy do over the long run?

Not to mention that, with the steady erosion of the respect of the right of people to be left alone, how will this be abused? Will we see "reality TV" shows freaking people out? (say, by beaming "LOOK OUT! HE'S GOT A GUN" to one person in a crowd). Let alone the targeted advertisments ("Hey lard butt! Yeah, YOU. Get your fat ass into Fred's Gym, across the street. NOW!")

Personally, if this sort of thing gets deployed in public places, I want to start carrying one of the boxes you used to downmix bat echolocation down to audible, locate the speakers, and use my Leatherman on them... Or my Browning...

artist's rendition

[jjeffries]

Here is an rare drawing of the initial design...

Re:Minority Report

[John Hasler]

Physics majors, any answers?

A simple metal helmet should protect you. In fact, tinfoil might be sufficient.