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Music Media

Directed Sound 251

Posted by CmdrTaco from the stay-out-of-my-sweet-spot dept.
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!"
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Directed Sound More

Directed Sound

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  • Cone of Silence (Score:5, Funny)

    by Epistax ( 544591 ) <epistax@g[ ]l.com ['mai' in gap]> on Tuesday May 04, 2004 @08:04AM (#9049884) Journal
    One step closer to the cone of silence!

    Damn. I'm still grappling with the unmistakable cone of ignorance
    • Not cone of silence!

      Cone of marketing.
      Cone of limited time only specials!
      Cone of "welcome passerby, if you look directly to your left...."
      Cone of "your girlfriend can't hear this, so listen closely..."

      Just so this post isn't totally lame, here is a potential useful application.

      Directed sound technology might be useful in applications where you want to give someone audible feedback or instructions, where someone normally would have one of those tiny earpieces. Cyrano de Bergerac. (See the commedy
      • Another interesting idea: Quiet/Loud nightclubs and bars. I don't patronize these places much any more, partly because the loudness of these places, partly due to the music I'd rather hear isn't played, partly because of my hearing (or loss thereof), and mostly because *I have to* converse socially to make spending the time worthwhile, which you can't do when it's that loud.

        I had previously brainstormed about how a club experience would be better for me: the big one is if you could have a "cone of sil

  • The missus (Score:5, Funny)

    by Anonymous Coward on Tuesday May 04, 2004 @08:05AM (#9049887)

    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! :)

  • Sweeeeet (Score:2, Funny)

    by Anonymous Coward

    Now if they can project "burnt toast smell" I'll really be able to make people think they're nuts.

  • Ahhhh (Score:4, Funny)

    by jabbadabbadoo ( 599681 ) on Tuesday May 04, 2004 @08:06AM (#9049896)
    At last - high volume p0rn without waking up my girlfriend!!!

  • Cone of Silence? More like cone of annoyance. (Score:5, Interesting)

    by Maestro4k ( 707634 ) on Tuesday May 04, 2004 @08:07AM (#9049905) Journal
    Seriously, marketers will be in heaven, able to target ads at passerbys. Now you can look forward to being inundated with directed sound ads while walking the street. It'll be far more annoying because it'll be harder to ignore than ambient noise (ads running on outside speakers, people hawking their businesses on the sidewalk).

    And we think spam is bad...

    • A sea of calm (Score:4, Insightful)

      by the_twisted_pair ( 741815 ) on Tuesday May 04, 2004 @08:56AM (#9050201)
      It would be simple to defeat though. The effect relies on heterodyning a signal (mixing HF to produce an intermodulation effect) so broadcasting white noise above the range of hearing should drown the wanted signal nicely - just like interference on an AM radio. Say a small device located near the billboard - or two piezo drivers on the outside of headphones, heck you could build it into your cellphone hands-free kit.

      Done well, you wouldn't hear a thing; even partial cancellation should reduce the adspeak into something akin to a distant ocean sound.

      I think there would be privacy isues to overcome on the part of the Admen first however - remember the hoo-haa over subliminal advertising?
    • While I agree that this would suck, it could have benefits. Anything used for spamming receives a *LOT* of funding...this sort of technology could mature very, very quickly because of its revenue stream, leading to other, more practical uses. Remember, if it weren't for pr0n, we would prolly still be surfing on 28.8 modems, not broadband.

      --trb
    • I doubt they'll have people in towers beaming you from across the street... they would probably just have it so that if you were window shopping and you were in front of a particular dress or something, you would hear a little about that dress... that would be helpful in some situations...

      IMO, this technology has alot more potential for good than bad... think about sitting in a library or something and listening to something on a computer without headphones, or going to a museum/car/computer show and hearin

    • Seriously, marketers will be in heaven, able to target ads at passerbys.

      Targeting specific people in a crowd doesn't make any sense advertising-wise or cost-wise, especially if it costs more than broadcasting a message to the entire crowd.

      If marketers had any interest whatsoever in this type of advertising, there would be bullhorns in public places already constantly exhorting everyone to Drink Coke or Join The Army or whatever. As it stands, only political candidates and ice cream trucks are willing to
        • If marketers had any interest whatsoever in this type of advertising, there would be bullhorns in public places already constantly exhorting everyone to Drink Coke or Join The Army or whatever. As it stands, only political candidates and ice cream trucks are willing to do this.

        Depends on where you are, in Tokyo it's extremely common to see people paid to hand out tissues advertising a shop/resteraunt, or just stand out front and yell (well, yell's not the right word, but close enough) at passerby's to

  • Messin with people (Score:4, Funny)

    by binaryDigit ( 557647 ) on Tuesday May 04, 2004 @08:09AM (#9049914)
    Can you imagine how this could be used to really screw with peoples heads?

    On the edge psycho person: "Hey, did you hear that voice"
    Unknowing friend: "No, I didn't hear anything"
    On the edge psycho person: "Quit messing with me man, I can hear that voice a clear as day"
    Unknowing friend: "I told you, all I hear is some elevator music"
    On the edge psycho person: "AAARGH, get it out of my head, it's telling me to, to, to ..."
    Unknowing friend: "TO WHAT, TO WHAT!?!"
    On the edge psycho person: "GO TO AISLE 4 FOR A 2 FOR 1 ON LIGHT DAYS! AAAAAAAAAHHHHHHH"

    All kidding aside, there actually is a fair bit of harm one could use this tech for. Make the "sound" of high enough intensity, and it would make a very effective, and undetectable weapon.

    • Re:Messin with people (Score:4, Funny)

      by EpsCylonB ( 307640 ) <eps&epscylonb,com> on Tuesday May 04, 2004 @08:15AM (#9049951) Homepage
      All kidding aside, there actually is a fair bit of harm one could use this tech for. Make the "sound" of high enough intensity, and it would make a very effective, and undetectable weapon.

      so you could use it to kill harkonens...

    • Re:Messin with people (Score:5, Funny)

      by Bibulous ( 776791 ) on Tuesday May 04, 2004 @08:16AM (#9049961)
      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!"

    • Re:Messin with people (Score:3, Interesting)

      by E10Reads ( 732984 )
      Actually, this is already being implamented by the US Military in Iraq. It is used at checkpoints to speak to aproaching parties. And the Military has signed a new contract with American Technology for $1.1 million to deliver these LRAD's (long range acoustice divices) to the Marines. "LRAD is a breakthrough long-range hailing and warning, directed acoustic device that is designed to determine intent, change behavior, and support various rules of engagement. With LRAD, a sentry can issue a focused verbal

  • Hope it will work for "boom cars" (Score:4, Interesting)

    by old man of the c ( 515198 ) on Tuesday May 04, 2004 @08:09AM (#9049918)
    But I doubt the car owners would want it. Why have a loud sound system in a car if the whole world can't hear (and know about) it.
    • So diffrent passengers can listen to diffrent music.
    • I'm serious. Get on any commuter train or bus, and you'll no doubt be subjected to the tinny sound of some dumbass's (or several dumbasses') music spilling from their headphones -- audible even over the sound of the vehicle. Give them ultrasonic directed-sound headphones and they can destroy their hearing to their hearts' content without annoying me.

      (And don't get me started about the double-dumbasses who get on with their laptop or one of those portable DVD players and cranks something up on regular spe

  • The Lucas Sound Studio @ Disney (Score:4, Interesting)

    by adzoox ( 615327 ) * on Tuesday May 04, 2004 @08:09AM (#9049924) Journal
    Has anyone ever been into into the Lucas Sound Studio at MGM in Disney world? I believe it's co sponsored by AT&T.

    * There's something similar to this. You put on headphones.

    * You're in a booth about the size of a small 1/2 bathroom.

    *It goes completely dark, but you are told to close your eyes for an even better effect.

    You then proceed to "become a CEO" for a day of a Fortune 500 company - you get your hair cut and blowdried in the boardroom - you CAN FEEL the scissors and hear them close to your ears and atop your head. Then you can FEEL HEAT from the blowdryer - and it's nothing but sound rather an auditory/perceptual illusion.

    Imagine if this could be done with the directory sound.
    • This is actually accomplished through Binaural recording. It is achieved by created a human shaped and sounding head and putting microphones where the ears are. It works by accurately capturing the phase relationships in addition to the normal frequency and volume differences heard between your ears. Quite different technology as in order for it to work you would have to have exquisite aim with not just one beam of sound, but two, one for each ear.
    • What you're describing is slightly different from the original post, but also quite cool.

      This effect is called binaural audio. It's done by capturing the sound using very good microphones in the ear canals of something like a mannequin head. Playback is done with good headphones which line right up with where the sound was recorded, for a very realistic "3d sound" effect.

  • But Max, the Cone of Silence doesn't work! (Score:3, Funny)

    by Dachannien ( 617929 ) on Tuesday May 04, 2004 @08:14AM (#9049948)
    "One step closer to the cone of silence!"

    "Uh.... what was that, Chief?"

  • More Details... (Score:5, Informative)

    by MisterLawyer ( 770687 ) <mikelawyer AT gmail DOT com> on Tuesday May 04, 2004 @08:14AM (#9049950)
    This is more commonly called "HSS", or "HyperSonic Sound", rather than "UltraSonic Sound". The earliest citation to the term "Directed Sound [wordspy.com]" goes to American Technology Corp. [atcsd.com]:

    "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

    • The Audio Spotlight maker [audiospotlight.com] has been using "directed audio" since 1997, five years ahead of American Technology.
    • Normally, "supersonic" means moving faster than the speed of sound in the respective environment. And "hyper" normally is used as a stronger form of "super"[1]. E.g., supermarket <-> hypermarket, and so on.

      To me, hypersonic means moving much, much faster than the speed of sound. Which is not the intended meaning here -- they are talking about soundwaves, so how can the soundwaves move faster than sound?

      [1] - AFAIK, in Greek hyper means the same as super in Latin, namely above.

  • Prior art (Score:3, Funny)

    by Anonymous Coward on Tuesday May 04, 2004 @08:19AM (#9049978)
    Microsoft did it years ago already, with DirectSound! Or am I missing something ;-)

  • DUPEY DUPE DUPE (Score:5, Informative)

    by justforaday ( 560408 ) on Tuesday May 04, 2004 @08:21AM (#9049991)
    from here [slashdot.org] and here [slashdot.org].

    i'm sure this'll come around again in the next few months...

  • Already in use (Score:4, Interesting)

    by Big Nothing ( 229456 ) <tord.stromdal@gmail.com> on Tuesday May 04, 2004 @08:22AM (#9049993)
    This kind of technology (although not as refined as mentioned in the article) has been in use for quite some time. For example, in Oslo Lufthavn [www2.osl.no] (Oslo/Norway international airport) there are "quiet spots" where a speaker is used in combination with a parabole to create "sound spots" in the airport lounge area. The sound (sea waves, bird song, etc.) is basically only audible to the person standing directly under the speaker/parabole.

  • Frequency change=nonlinearity=high levels (Score:5, Interesting)

    by dpbsmith ( 263124 ) on Tuesday May 04, 2004 @08:29AM (#9050029) Homepage
    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.
    • I thought the basic principle of this was creating a beat frequency matching the original sound effect you want people to hear?

      Beat frequencies are usually demonstrated by tapping two tuning forks. The difference between their frequencies is audible as a third "beat" frequency.

      I could be wrong on this, but when I heard this effect during a science awards show at Epcot 5-6 years ago, that's how I assumed it was done =)
    • You've missed what happens completely. Two different ultra-sonic sounds combine at the focal point, join together linearly, and the beat frequency they create is sonic. Plain old normal sound. The signals themselves are ultra sonic (ie. S1 and S2), but the diff is sonic (S1-S2, or the beat subtracted from S1+S2)

  • Prior Art (Score:5, Informative)

    by Kevin Burtch ( 13372 ) on Tuesday May 04, 2004 @08:31AM (#9050043)

    Tab books published instructions [amazon.com] how to build a device that does exactly this decades ago... TAB!
    Yeah, I know the cover looks ridiculous... I bought it when I was a teen and still have it - neat projects inside and better written than the cover would indicate.

  • neither one (Score:4, Interesting)

    by ashot ( 599110 ) <ashot@noSpAm.molsoft.com> on Tuesday May 04, 2004 @08:36AM (#9050067) Homepage
    will dominate this market, because there is a new technique in acoustics that will eclipse the ultrasound method. Using something called time reversal, you can pinpoint the output of sound to a single location in 3 dimensional space, focusing around objects, people whatever; no beam, no drop off.

    This focusing can be done with more than just sound waves however, and the first applications are in medicine [sciencedaily.com], however, it does apply to sound as well.

    The basic idea is that if you create a sound from some source location, and record all of the noise at another location, then play this noise signal backwards from the recorded location the sound will reappear in the one spot from which it was originally played. An analogy is that if you take a pool ball, put it right in front of a pocket, and then bounce it outwards really hard, letting it bounce against the walls multiple times, but noting the exact location of the last bounce of the ball, then if you reshot the ball at the exact spot where you last saw it bounce, it would go back in the whole.

    • Re:neither one (Score:3, Insightful)

      by Viol8 ( 599362 )
      The sound could well appear back where it was originally played (though I have my doubts since its impossible to measure all effects of the sound everywhere) to a person standing there but other people standing nearby will still hear sound but it'll just be a jumble of noise. So thats hardly directed sound is it?
      • there may be a small amount of noise very near the space of focus, but similar things will happen with the ultrasound technique as well.
        Everywhere outside the space however, will have no signal (perhaps small amounts of noise) because the sum of the signals at this point will be random and will cancel (assuming a large number of signals).
      • though I have my doubts since its impossible to measure all effects of the sound everywhere

        No, it's not. The simple expedient of actually measuring the effects works perfectly.

        What we can't do is reverse engineer the sound, or generate such a sound from information about the environment. The cleverness of that technique is how it bypasses the need to do so, at the cost of being relatively limited.

        It would depend on a static environment, though; GP mentions going around "people" but if they move, kiss th

    • Re:neither one (Score:2, Informative)

      by gardyloo ( 512791 )
      For pure bamboozlement, the effect of an ultrasonic parametric array (the things that produce these "directed sound beams") can't be beaten -- I experienced a demonstration of one two years ago at the Physical Acoustics Summer School in California. It's pretty amazing to have the demonstrator up front with a little antenna looking thing, playing music through it... but you can't hear it! However, just one or two people in the audience have this awestruck look on their faces. Then, when he swings the thing a
    • I know a tiny bit about audio and that seems kinda far-fetched. Got any links?
      • you would be right to be skeptial. The idea is still in the research phase, however the results are extremely promising and powerful.. the best I can do for you is this:
        http://www.ncbi.nlm.nih.gov/entrez/query.fc gi?cmd= Search&db=PubMed&term=time%20reversal%20acoustics% 20AND%20hasabstract[text]%20AND%20English[Lang]

        The reason that I know about it at all is because I know several people who are directly involved... give it about a year though =]
  • Does it shoot a "laser" from a "Death Star". Which can be averted for "one million dollars"?
  • The company producing the equipment is American Technology Corporation at http://www.atcsd.com/tl_hss.html According to their own site one test showed a level of 110 db at 2 metres at 48KHz giving an apparent audio level (3 KHz) of 95 db. The level at 16 metres was 80 db at 48 KHz and still 90 db at 3KHz. Apparently they are already installing them in soft drink dispensing machines in Tokyo. (We soon won't know who is schizophrenic and who isn't). Cheers
  • I remember seeing a TV segment on similar technology in the early 80s. It was an Australian show called "Towards 2000".

    It worked by causing interference patterns between two ultrasonic beams. The low frequency beats translated into audiable frequencies, forming a 'beam of sound'. It seems awfully similar to this 'new' technology to me.

    I'll try and dig up a reference.

  • Cone of Silence (Score:3, Funny)

    by dalutong ( 260603 ) <djtansey AT gmail DOT com> on Tuesday May 04, 2004 @09:00AM (#9050223)
    *someone in the cone of silence*

    *sees peoples mouths moving. realizes they are talking to him.

    "I'm in the cone of silence, you insensitive clods!"
  • They also get a mention in this article [femail.co.uk] - which seems tailored towards a slightly different type of reader.

  • For all you South Park fans (Score:3, Funny)

    by smz420 ( 308094 ) on Tuesday May 04, 2004 @09:39AM (#9050552)
    Imagine combining this technology with "The Brown Noise"...now that would be the ultimate weapon!
  • Imagine it. You're innocently standing somewhere at night when you hear a disembodied voice that no one else around you can hear. Then all the cats and dogs start howling and bats start flying round in circles because they're all confused by the ultrasound. I wonder if Stephen King is an investor in this system??
  • Now I'll be able to aim one of these babies at the car next to me that's disrupting my heartbeat with it's pulsing audio garbage. I'll aim Maria Callas at 'em - at 120 decibels.
  • As a college lecturer, I've been able to use directed sound to selectively impart knowledge to certain students in my class and not to others... at least that's what my students tell me:
    "We didn't cover that is class!"
    "You never said we had a test today!"
    "Homework due?! You didn't tell us that."

  • These things can be dangerous (Score:3, Interesting)

    by Charles Dart ( 731692 ) <Charles_Dart@hotmail.com> on Tuesday May 04, 2004 @10:10AM (#9050888)
    My wife went to an tech award show last year at which this product won something. The presentor mentioned that the pentagon was also interested in the product. He said that it is possible to turn the volume up to lethal levels.
    • I'll bet the defense dept is interested! Imagine the possibilities. From a hidden location, aim one at a fundamentalist insert religion. Suddenly that person hears The Voice : "This is God / Allah / Vishnu / whomever, and I want you to destroy the Eiffel Tower / Church of the Holy Sepulchre / Wailing Wall / New York Stock Exchange / Kaaba Shrine". Or "I want you to build me an ark.".
  • Ultrasonics aren't necessary to delivery focused sound waves. There's a whispering gallery [msichicago.org] exhibit at chicago's Museum of Science and Industry demonstrates this. The technology is simply to have send and receiver of hte sound at the foci of an ellipsoid. The speaker and listener don't even have to be facing one another.
  • When this comes into common use, I will be developing my own invention. A battery powered, portable and directional EMP.

    One could argue that there is a need for it now - self defense from man *and* machine...

  • In Theory... (Score:5, Informative)

    by mistermund ( 605799 ) on Tuesday May 04, 2004 @11:25AM (#9051649)
    You could be standing right next to someone and they would hear nothing.

    That's the idea, but in reality it works a tad different. Wherever the beam hits sort of becomes the apparent source of the sound. So if you aim it at someone, they'll hear it quite clearly - more so than everyone else - but the sound will now appear to be coming from them. Quieter, but still apparent.

    I've got 2 of the HSS units right here, and though they're super-cool for messing with people, (See other posts) they've got some drawbacks.
    1) There's no bass, treble only.
    2) The units we have come with a rather noisy cooling fan.
    3) They clip quite easily - you have to watch your volume levels.
    4) They're not terribly reliable. I've seen them in a few labs I've worked in or with, and we all seem to have the same issues.

    Overall a cool product, especially for the gee-whiz factory, but certainly not ready for practical use just yet.
  • "kill him"

    muhahaha
  • While this thing really does exist, Holosonics [holosonics.co] seems to have problems getting the product out. They announced a new version at CES back in January, but it's still not on their web site.

    Once they get it working and get the price down, there are good applications. PC speakers for office environments. Audio at trade shows. Anywhere there are many audio sources that you don't want to interfere.

    It's not clear what the holdup is. It doesn't seem that complicated.

  • "No, they can't hear me! Only you can hear me! Now this is what I want you to do ...."

    Given that we already have states populated with people who want to outlaw teaching evolution and instead teach "creation science", as well as juries who are letting off people who kill their kids with rocks after God told them to do it, what could posiable go wrong with this technology?

  • In sixth grade.. went on a class field trip to Washington D.C. Touring one of those old-ass historical white pillar buildings, dont remember which one, but the tour guide stood a good distance from the group, and in a certain spot on the floor with his back turned, we could hear ever word he was whispering, but only when he was in that certain spot, and we were in our certain spot. amazing sheeat.
    • In the US Capitol [aoc.gov], "The half-dome shape of National Statuary Hall produces an acoustical effect whereby, in some spots, a speaker many yards away may be heard more clearly than one closer at hand. The modern-day echoes occur in different locations from those in the 19th century, when the floor and ceiling of the hall were different."
      • For those of you in New York, you can do this in Grand Central as well. Just behind the main hall over by the entrance to that Oyster diner (I forgot the name) there are a series of archways. If someone stands on one side and whispers into the corner of the archway, another person standing diagonally from them can hear them perfectly. It's eerie -- especially in a place as loud as Grand Central.
        ____________________________
  • Another form of the technology uses modulated microwave energy.

    It is based on the observation by microwave (radar and other) technicians would experience what "sounded" like popping or static inside their heads (ie, it wasn't coming in their ears) when they worked on live equipment. Apparently the microwave energy was causing neurons in the aural region of the brain to fire, which came across as "hearing" (though in the head only).

    This was later refined so that tones, then later voice, could be sent. I have

  • This technique has been around for some time, and is unsafe because it uses high ultrasonic power levels. To generate audio frequencies, you need to generate a beat frequency between two ultrasonic frequency, simply adding does not work, there has to be a non-linear element involved (as in RF mixing for example, in the front end of a radio receiver). The non-linear element is the air itself, but only if you push the level up way above 120dB. Now, many authorities believe that the safe pressure level is the
  • I'm deaf, you insensitive clod!
  • WHAT? WHAT DID YOU SAY????????

    (Dear Slashdot, yes, I *meant* to use all those caps, it is *supposed* to be like yelling!)

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