back to article MIT's thin plastic speakers fall flat. And that's by design

Engineers at MIT have created paper-thin speakers using a plastic film and a piezoelectric layer embossed with tiny domes. These sheet speakers could potentially be applied to any surface for sound output or input: think surround sound or noise cancellation in aircraft. The technology also has potential for ultrasound imaging …

  1. Scott Broukell
    Coat

    So, when they present their findings in a paper to those gathered at the annual conference of the society for audiological innovation . . . they won't actually need a speaker.

  2. Michael Hoffmann Silver badge

    PET indeed

    Having moved with pets and having them travel in air carriers in loud aircraft or sitting on even louder tarmacs, I've long wished for some technology that can add noise-cancelling to the already compact, nay, crammed pet carriers/cages. These could be ideal as they wouldn't take up space on the inside.

    Provided they can produce the required frequency range of whatever sounds need to be cancelled.

    1. Blank Reg

      Re: PET indeed

      they only go down to 100hz, so it can't cancel out a lot of the low end noise that you hear on a plane

      1. Col_Panek

        Re: PET indeed

        They've been tested to 100 Hz, not telling you how well they work there.

  3. Tom 7

    Presumably a part of a hemisphere

    could be used to focus the sound.

    Not that I'd want to wander around with what might look like an exploded bra while boogieing down the street.

  4. KittenHuffer Silver badge

    How long .....

    ..... before they make a transparent version that they then apply to your TV to give decent speakers without the need for a soundbar?

    1. Paul Kinsler

      Re: How long ..... to give decent speakers

      Ridiculous. They'll instead use the technology to make even worse speakers for your TV, but ones that save them a tiny amount of money per device.

      1. Eclectic Man Silver badge

        Re: How long ..... to give decent speakers

        Sony already has a vibrating screen TV:

        "the BRAVIA OLED can do things no other TV can do. Thanks to the vibrating units behind the panel, sound can move from side to side within the picture and be isolated to certain parts of the screen. Dialogue and sound effects emanate directly from onscreen objects, providing an audio experience that’s as immersive as the video. And they vibrate the screen so delicately that the movement isn’t even visible to the human eye."

        https://www.wired.com/brandlab/2017/05/sights-sound-inside-acoustic-surface-powering-sonys-first-oled-tv/

  5. jmch Silver badge

    Interesting tech!

    Re noise-cancelling - in cars and aeroplanes the sounds tend to be lower frequencies. 100Hz to 100kHz range means they're not covering the 20-100Hz bracket where a lot of mechanical background noise lies. Also, human hearing tops out around 16kHz (higher for kids, lower for adults), that's why audio headphones / speakers have audio ranges of typically 20Hz-20kHz. (at really low frequencies, vibrations are no longer 'sounds' heard in the ear but rather vibrations felt in the whole body ).

    Another interesting application might also be short distance radio-wave-free low-power communications in the inaudible range.

    Although I do foresee a dystopian future where every surface that isn't an ad-screen is a speaker surface spouting inane muzak.

    1. Paul Herber Silver badge

      Re: Interesting tech!

      'Although I do foresee a dystopian future where every surface that isn't an ad-screen is a speaker surface spouting inane muzak.'

      Although I do foresee a dystopian future where every surface that isn't an ad-screen is a microphone listening to everything everywhere.

      FTFY

    2. Tom 7

      Re: Interesting tech!

      The lowest string on bass guitar is 41 Hz. Most so called hifis dont get down there and as for sound bars no chance. Size is extremely important when it comes to lower notes - simply to stop the sound going round the back and cancelling itself out!

    3. Danny 2

      Re: Interesting tech!

      Re noise-cancelling - very pro for cars

      I was driving north on a totally empty stretch of the M1, probably doing 100, when I heard a lorry about to crash into me. Except there was no lorry in front or in my mirrors. It was an RAF fighter jet buzzing me for laughs, except I was terrified and could easily have crashed. Ghost lorries in the sky. After that I drove that road with cigarette filters in my ears.

      My dad's advice when he taught me to drive was life saving. "Everyone is always trying to kill you on the road. Don't pay them any attention, just concentrate on your own driving - because I pay for your insurance."

      All cadet pilots are inadvertently dangerous, RAF cadet pilots are deliberately dangerous.

    4. Spherical Cow Silver badge

      Re: Interesting tech!

      I'm not sure that noise cancelling in an aeroplane would necessarily be a good thing: I'd rather not be able to hear the conversation in the next row.

  6. Denarius

    updated cliche

    as well as the eyes in the picture following you around the room, its listening too

  7. drand
    Joke

    Needs work

    Promising but it won't sound any good until there's an audiophile version. I'm thinking incorporate some gold leaf for a warmer, more rounded signal and fill those domes with argon for a really expansive soundstage.

  8. Jonathan Richards 1
    Unhappy

    What a pity...

    > At a distance of 30cm (12 inches), it's claimed, these thin-film speakers can generate high-quality sound equivalent to the volume of a typical conversation

    What a pity that they chose not to demonstrate that in the linked video, then. Only when I read the video title did I understand that I ought to have been able to hear a Queen track (God bless you, Ma'am) but I can still only barely pick it out of the noise. Reminds me of the quality of LW radio from a 6-transitor receiver, I'm afraid.

  9. Howard Sway Silver badge

    It can be mounted on the surface of any object and used for sound recording

    Great. So inevitably somebody's going to market "smart wallpaper", which will talk to you and listen to everything you do or say.

  10. ClockworkOwl
    Go

    Bass response...

    Given how the perceived sound changes as the sheet is manipulated, I suspect the frequency response issues are mechanical in nature.

    Maybe if a large sheet was tensioned in a frame you could get some good low frequency response.

    I'm thinking of a solid state version of the legendary Quad electrostatic speakers...

    1. Martin Gregorie

      Re: Bass response...

      It would seem as though Quad beat them to it by some 66 years. The Quad electrostatic speakers were released in 1956, some 66 years ago - and they are a proper full audio range hi-fi speaker.

      1. Tom 7

        Re: Bass response...

        They didnt go down very low though - below 100hz or so its mainly harmonics and not the actual note. The 63s are a bit better down to 60hz. I've got a pair of each and the originals on the valve amps sound superb but its a bit of a con. But then you need a large room to allow the wave to even get going.

        Outside tests on seriously expensive ribbon mike and full freq analysis of output not just normal db graph.

    2. NXM Silver badge

      Re: Bass response...

      They also used to make electrostatic headphones. But I didn't want several hundred volts that near my head.

      1. Eclectic Man Silver badge
        Happy

        Re: Bass response...

        NXM: "I didn't want several hundred volts that near my head."

        Whyever not? It is the amps that kill you. On an edition of BBC's 'Tomorrow's World', one of the presenters (William Woolard, I think) demonstrated static electricity by taking off a nylon jumper (it was the '70s) and claiming that he was charged up to about 4000 Volts. He then lit a gas flame by 'earthing himself' to a Bunsen burner by touching it with his fingertip.

        Buy your incredibly expensive (near small car price) electrostatic headphones here:

        https://mynewmicrophone.com/top-best-electrostatic-headphones/

        1. Tom 7

          Re: Bass response...

          You can make your own for a lot lot less if you fancy a Ken Dodd hairstyle!

    3. John Brown (no body) Silver badge

      Re: Bass response...

      "I'm thinking of a solid state version of the legendary Quad electrostatic speakers..."

      That was my first thought when I read the headline. Same old, same old, but with different tech. I wonder if the inventors have even heard of electrostatic speakers?

      I'm sure there will be uses for this new kit, and maybe it will improve, and though the tech is new, the idea isn't.

      I'm still waiting for "wallpaper" screens. Walk into a shop, choose from various width rolls and the shop assistant then cuts off the length you want. Stick it on the wall. Job done :-) You could even past it up in portrait mode if you only even watch mobile phone videos :-)

  11. a pressbutton

    It sounds an awful lot like NXT.

    Having a quick google indicates that the NXT technology has (possibly is) in use in noise cancelling fighter aircraft cockpits (wind noise)

    It has been used in hifi products but does not seem to work well below 100hz, so you need a sub

    It seems to compete well with electrostatics in good implementations

    Currently it seems to be used in https://symphonova.com/technology/

    1. Anonymous Coward
      Thumb Up

      I was trying to remember the NXT name. Thanks.

    2. Julz

      Just what I was about to say. So what here is new other than it's done in the USA?

    3. Notenoughnamespace

      I was lucky enough to visit NXT for El Reg, a decade ago...

      https://www.theregister.com/2012/07/05/nxt_loudspeaker/

  12. brainwrong

    wot no bass?

    "The sheet-speakers supposedly require only 100 milliwatts of power per square meter of speaker area"

    Er, how much power it consumes depends on how loud you want it, surely.

    What size device are they testing? Was testing done at 100mW input power?

    12 inches is quite close to make measurements, I thought 1 metre was standard.

    They claim it goes down to 100Hz, they don't quote a figure for how loud, but extrapolating the 6dB/octave between 1KHz and 10KHz down to 100Hz suggests it outputs 46dB, so you'll need quite a lot of it to get any bass.

  13. NXM Silver badge

    Rock this house

    Good job it doesn't have much bass, otherwise you'd be able to demolish the house if you turned it up to 11.

  14. Death Boffin
    Coat

    Wallpaper

    Sounds tinny not woody. Gives new meaning to "the walls have ears".

  15. steelpillow Silver badge
    Thumb Down

    eet eez only waffer theen

    This is one of those perennial ideas. The killer is always the sheer physical distance travelled for bass output. Almost as bad is the low-frequency mechanical resonance of a large, semi-rigid flat sheet. Nor do the two combine well. The Quad HiFi electrostatically-driven speakers of the 1970s were the bees knees - but faded away badly in the bass. I had a pair of "poly-planar" expanded polystyrene speakers that had concentric grooves filled with gunk in order to dampen the resonances. They worked quite well and more importantly were beer-proof, but were engineered for cheapness and would have needed CAD analysis to achieve High Fidelity. Then there was the Qinetiq flat speaker, where they re-discovered that the resonances make the surface flap around and eat up all the travel that was supposed to be for the bass - and the flapping makes the mid-range sound like a Hammond organ. Then NXT, who put the bloody things in TVs, thus creating the market for sound bars. Now this.

    File in the same folder as broadband over power cables.

  16. gormful

    Can this thing be driven as a phased array? Sound is directional at 100kHz...

  17. Robin 12

    Reminds me of the old electrostatic speakers that were out decades ago and were supposed to be the future. We have been using piezo speakers for electronics and MIT just came up with a better way to make them. Without bass response, I won't be looking at these anytime soon.

    1. TaabuTheCat

      Still around

      They are very much still around: https://magnepan.com/ and once you give a listen to their 20 or 30 series you'll understand why. Even the 1.7s are really good if you add a sub.

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