Don’t throw out those old speakers yet …

DARPA’s at it again:

SchrodingerZ writes:

“The Defense Advanced Research Projects Agency (DARPA) is known for making odd scientific advances ranging from hypersonic unnamed rockets to bionic prosthetic limbs to insect-sized reconnaissance drones.

But recently DARPA has made a interesting advancement in the field of fire suppression. Using two speakers arranged on either side of an open liquid fuel flame, an acoustic field was emitted and engulfed the fire.

‘The sound increases air velocity, which then thins the area of the flame where combustion occurs, known as the flame boundary.’ This make the flame weak and much easier to douse. Another wonderful thing about this: it’s not even that loud!

DARPA began its testing in 2008, stating that despite extensive research in this area, there have been no new methods for extinguishing and/or manipulating fire in almost 50 years. The agency plans to expand on this experiment and try to make it successful on a practical scale.”

Chuckles breaks the 4th wall in reverse by buying in:

Yes, sounds familiar from years ago. I used to be very interested in the opposite, which is ‘flame loudspeakers’, where you stick a couple of electrodes (bits of copper wire or similar) into a flame or fire, park about 3-400 volts DC across them to ionise everything, and then superimpose the amp output on top of the DC. Works a treat.

And then, there’s always this:

So James will also buy in and asks if we could perhaps all get together to try building one of these?

4 comments for “Don’t throw out those old speakers yet …

  1. July 26, 2012 at 09:24

    I’m sure Mythbusters blew out candles with speakers.

  2. ivan
    July 26, 2012 at 09:45

    A lot of research needs to be done on vibration and frequency effects from ultrasonics through to audio frequencies.

    DARPA has to be congratulated for the fact that they at least look at odd, non mainstream, ideas – something the ‘establishment’ will not.

  3. Chuckles
    July 26, 2012 at 10:29

    We were very interested in them in the 70s for disco and live PA work when Wireless World or one of the other UK electronics mags had an article about flame loudspeakers.

    Light, fire, sound modulated, what’s not to like?

    Unfortunately, while the audio quality is excellent with a decent setup, the power output is low, so it’s not going to fill the stadium with sound.

    The fire dept. were less than thrilled as well….

    It was apparently a 1968 Popular Electronics article. (You can find ANYTHING on the internet –

  4. July 26, 2012 at 14:07

    Sounds ^_^ a bit like noise cancellation tech, or maybe how they get sand to make patterns with sound, where some places there is no sand and others there is sand.. only with air?

    Could you use a neon tube as a speaker do you think? Isn’t it ions make them glow. Tho I guess you might need tougher glass for opera? ^_^

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