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Science

Sound-producing LCD Screens 36

Posted by Hemos from the dude-we-can-have-an-lcd-floyd-show dept.
haakon writes "The New scientist have a story about getting LCD screens to produce sound. I wonder if I can hack a X server to do that on my laptop? " Mmm...with this SGI flatscreen, and Rob's as well, I think we're to be having a concert - tickets go on sale Friday.
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Sound-producing LCD Screens More

Sound-producing LCD Screens

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  • My trusty old Zenith XT laptop (the one with the dual 720k floppies) makes a very distinct, very quiet whine. It gets even quieter when I turn the brightness control all the way down, but it's still perceptible. At the 1 minute mark (my LCD backlight timeout) it goes totally silent. I'd assumed that this was magnetic interference from the backlight inverter, but it sure could be the screen itself.
  • I wonder whether if a technology like this could be used to generate small regions of very concentrated sonic energy. If so, this might have industrial or chemical applications.

    Or military applications. Imagine a 130 dB sound centered on your skull.
  • Since if you put 10000 monkies in a room and they'll eventually write out the complete works of Shakespeare...

    if you put 10000 LCD's in a room will they eventually play the complete symphonies of Mozart?

    Just a though :)
  • I've heard of LCD panels mysteriously multiplying in the dark corners of IT offices. Maybe this is their natural mating call.
  • Well we all already know that LCD screens glow something like 50% brighter in bad computer movies, does this mean they will have a better "voice" or louder one, or something? Watch out Celine Dion......ha!
  • I'd be happy if they'd just settle on a standard connector, and lower quality LCD prices so I can stop buying CRTs.

    OpenLDI? Fine buy an SGI 1600SW and a lousy #9 Rev IV with a 3D chipset that gets in the neighborhood of 16 fps in Q3 test 1024x768.. oh wait will the drivers even work with OpenGL in windows 9x? good question, not worth 3k to find out if the 3D hardware reviewers are playing practical jokes.

    DVI? Great, lemme go out and buy a Sony 18" for 4K and run it on a leadtek GeForce for another $400, oh by the way, here's your eviction notice, and Visa called to say that the police will be arriving any minute to escort you to debtor's prison.

  • i wonder if there's any way of controlling the volume of the sound... seem's like a pretty cool way to provide sound capability to PDAs [MP3s on Palms etc.]

    Although for the expense of producing an LCD screen with a multitude of varying cell sizes to get the frequency range, it'd probably be cheaper to employ a couple of roadies full-time to cary a pair of B&W Nautilis 801's around behind you.
  • So, does this affect picture quality? I don't too many people who would be willing to use their thousand dollar LCD to emulate a $30 sound card if picture quality changes.
    On the other hand, if it does work, that's one less component to put in the laptop. Every little bit helps when it comes to weight and power consumption.
    But that's a whole new can of worms, how much power will these new LCD's require to do their sound thing? LCD's are already the largest consumer of power in a laptop, would any manufacturer be willing to increase the power consumption in order to get rid of the sound card?
    And while we're at it, what kind of volume can you get out of this? It didn't sound like much from the article.
  • It seems that manufacturers are willing to increase power consumption. Consider how hot your laptop runs today, versus 5 years ago. Remember those circa-P166 laptops that would almost burn you? Granted, most of that was from the processor and consumers seem to care about the MHz speed of their laptops. Laptop speakers, on the other hand, are pretty lousy all around (with the exception of laptops with sub-woofers).

    I would suspect that the inverter that is used to light the florescent backlight (since it is a high-voltage, high-frequency source) could also be used to create the voltages that are needed without additional hardware. The control logic wouldn't be much more than a normal sound card. Of course, having never heard my LCD panel click or create a tone, I don't have any experience with this, but I would suspect that the character of the sound is probably going to be much flatter than a speaker. I read the article as saying that there is a limited number of harmonics that each sized crystal can make, which would require a fairly large range of crystals to get something that doesn't sound like a PC speaker. :)

  • uhh, inside joke.
  • I was meeting about 3 weeks ago with a representative from Shock Technology Corp. [shock.com.tw], a speaker manufacturer in Taiwan, and the guy had brought along some prototype flat-panel speakers. These are fairly new and many people have seen them. What most people have not done, though, is hear them. They sound terriffic and are 1/4" thick with the plastic housing. The entire flat face of the speaker is used as a resonating board. I don't know about the "directional beaming" in this other method, but the accoustic properties of a resonating panel are omnidirectional. Unlike conventional cone speakers, there is no difference in volume or definition whether you are in front or behind the speaker.

    The most interesting part of the whole deal was that he said that the technology is directly applicable to LCD panels. Apparently there is little change in sound quality when you change materials or even thickness of the sounding board. As long as it's rigid and withstands a little vibration, it makes sound. Prototypes were already being produced by the company for internal testing. I saw a photo and the man said that the sound quality was just as good and just as loud as the flat speakers we were listening to. They were very loud, by the way -- loud enough you didnt feel comfortable turning the dial up past about 50%! I think that in the near future, all laptop sound will be produced this way instead of via those little quarter-size speakers.

    As for this article, the application of a clicking LCD is limited. Another thing I'd be interested is the source of the clicking. Something is oscillating in there (capacitors discharging probably) and the last time I built a sound machine out of discharging ceramic disc capacitors (3rd grade) the best it could do was buzz. The frequency range seems pretty limited in retrospect. Plus I blew up a lot of capacitors.

    ~GoRK
  • I've long since used florescent light bulbs in my music by putting a contact microphone on it and regulating the current to control the vibrations, as well as some other modifications and sound processing. I've never really noticed LCD hum before (on laptops I always thought the noise was completely an idling hard drive; shows you what I know!!!), but I think I could work with this.

    A small array of LCD screens, each with it's own regulators and controls, each one miced individually, and send through processors. Would make a hell of a live show, just due to the fact that the INSTRUMENT could be displaying images at the same time. Though the light bulb show looks pretty cool too because all you see is blinding light and hear waves of abstract sound. But I digress; I'm going to work with this (if and when I have time). Anybody want to colaborate/contribute design/construction??? ;-)

  • We already knew monitors emit sound! (Score:3)

    by watanabe ( 27967 ) on Thursday October 07, 1999 @03:42AM (#1631967)
    This is somewhat related --

    Markus Kuhn, a researcher at Cambridge University published a paper in 1997 on using monitors to emit radio frequencies which could be picked up by a short wave radio. His goal was to provide covert information dissemination techniques that worked solely in software. (His other goal was to provide information protection techniques that worked solely in software. I think the dissemination stuff is cooler. He's a good guy, though in my opinion.)

    The upshot of his research is that
    a) A computer monitor can be made to make certain visual patterns which will sound like something on a nearby radio
    b) You can get about 6 bytes per second like that, which is small, but enough to steal passwords, etc and transmit them at night when everyone's screensaver is running to a nearby hidden radio.
    c) He did this in Linux with XFree86.

    I find this totally cool. He also suggests that a graphics card could make a radio transmitter; this is also extremely cool. You can now publish over the airwaves. That would make a great icecast/shoutcast plugin...

    The paper is at http://www.cl.cam.ac.uk/~mgk25/ih98-t empest.pdf [cam.ac.uk].
    His homepage is at http://www.cl.cam.ac.uk/~mgk25 [cam.ac.uk].

  • Just a comment, but haven't there been multiple stories about "flat speakers" and in effect wouldn't this just fall into this category? I recall that the other stories had something to do with the bumps on the screens causing too much distortion if put into use. Oh well, just a thought.
  • There's already a transparent coating which you can put on LCD screens to make sound. British invention. Just got a What Hif-Fi innovation award. This sounds like trying to tune the bumps and rumbles of a car (US: automobile) instead of using a decent stereo. Might make for a cool performance instrument (anyone going to tell Jean-Michel Jarre?).
  • Don't let the FCC here about this or they will enter the software regulation business based on a potential interference argument...

    If it wasn't so scary, it'd be stupid

    TML
  • Acutally, yes, the hardware grabbing of computer information is also referred to as Van Eck phreaking, thanks to Neil Stephenson for popularizing the term. Markus refers to it as "Tempest," and in the case of using software to grab information, "Soft Tempest."
  • I've noticed sound-producing LCD screens before this. The best way to do it (on my current laptop) is to say 'xlock -mode forest'.

    I thought at first that the laptop's video system was interfering with its sound system.
  • Perhaps now NT sysadmin's can have a musical interlude while staring at the Blue Screen of Death. Perhaps "Blue Moon" or "Blue Suede Shoes". Or maybe something from Blue Oyster Cult or the Blues Brothers.
  • I know exactly what you're talking about. It hurts to walk into a room with a bunch of tv's on. Although it is cool to be able to tell whether or not there is a CRT on in a room before walking into it. oh, yeah!
  • I don't think emitting sounds (as in a speaker) is really the interesting part of this. After all, there's lots of pretty good, cheap speaker technology availble, so why invest in exotic LCD technology that does the same thing?

    The REALLY interesting thing is that the panel can be used as a sonic phased array, like the phased array radars which can be electronically pointed much faster than mechanically steered atennae. The most obvious application is noise cancelation. They mention cockpit noise cancellation, and there are obvious industrial analogs. There might be uses for a loudspeaker that could be "steered" so that it could only be heard in certain spots; perhaps there might be medical imaging applications.

    I wonder whether if a technology like this could be used to generate small regions of very concentrated sonic energy. If so, this might have industrial or chemical applications.
  • I think it depends on the species of monkey. I have 10,000 monkeys chained to 10,000 vterms (cheaper than typewriters these days). So far they've written Hamlet and Love's Labors Lost. But they keep attributing them to "Edward deVere" for some reason.

    btw, it's a good idea to find a monkey chow wholeseller before you go out and get 10,000 monkeys. Take it from me, you do not want to screw around with 10,000 hungry monkies. That Peter Tork's really vicious!
  • dialing into the web (text only, please) my old 486 made tons of screen noise when lots of text went scrolling by. i never thought of trying to purposely get it to make songs, though. these guys have a lot of time on their hands?
  • It's this really high pitched "Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeeeeee"
  • There was an interesting item on BBC Breakfast News earlier this week on two men (Canadians I believe) who were putting on a concert in London, using nothing more than a host of dot-matrix printers to make the sound.

    It sounded appalling - but it could have been worse, they could have used my old Amstrad DMP. This printer lacked a rubber roller, and the paper was pulled across the plastic base, over which the head traversed. It was necessary to leave the room (or the house) when printing anything over a few lines, due to the awful racket.

    It appears that this pair are on some sort of world tour. They were to move on to somewhere in the North-East of England, and then into Europe.


  • Or that old standard "Am I Blue?"...
  • If you put 4 monkeys in a room, they will write Windows 2000 in two hours...

    But seriously.. if you take an infinite number of monkeys and let them type for an infinite amount of time they will eventually retype this whole web site letter-for-letter, including the binary data in the images.

    They'll also write all the world's operating systems in pure binary, as well as design an infinite number of new computer chips and technologies.

    Question: how many bananas does it take to feed an infinite number of monkeys?




  • For some reason I really enjoy the sound of a dot matrix printer. I don't know why. I guess its a bit weird, but I could listen to that music.
  • And I bet most ppl can't hear it, right? I hear the same thing from some crts.
    Cheers,

    Rick Kirkland

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