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RosieG

What degree of damage can sound do you even if you cannot hear it? Sonic weapons? Deadly?

The American Embassy in Cuba was apparently one of the places where American diplomats were attacked by sounds. In their beds as well so it also occurred at home.  Most Americans are leaving. Why any of them would stay I cannot say. Is sound a good weapon to undermine/sabotage/cripple the targets?

Posted - October 1, 2017
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  • 22891
    i think you could lose your hearing with those
      October 1, 2017 4:45 PM MDT
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  • 3719
    The limit of sound intensity for the human ear seems to vary somewhat with your source of information, but anything within audible frequency range above a level of 80dB re 20µPa - to give the unit its full name usually just quoted as 80dB - will damage your ears depending on time of exposure to it; but it cannot possibly be concealed. You would hear it, and so would anyone else anywhere nearby! 

    I don't know the effect of sound above or below the audible frequency range, but the higher the sound's frequency the more it is attenuated by distance, and the more easily it is dispersed by objects in its path.

    The funny-looking number - 20microPascals which is 0deciBels on that scale - is the air pressure in the quietest whisper audible to the healthy human ear. It is an incredibly tiny pressure too, a mere 1 / 500 000 000 of sea-level Atmospheric Pressure.



    There was an item on the radio today about this suggestion of secret "sonic" weapons. The BBC  interviewed a Professor of Acoustics (sorry, I didn't note the name - I'm not good at that) who explained why this suggestion is not really tenable.

    Firstly, a sound source loud enough to do any damage at audible frequencies would be large and very difficult to conceal.

    Asked about infrasound (below human hearing range, so defined as <20Hz), he pointed out that if loud enough to harm you would feel it as vibrations in windows, panels, etc.

    Ultrasound (above human range so usually defined as >20kz) is theoretically possibly to focus into powerful beams, although it would not travel far and can be blocked very easily.

    He also made the point that if anyone had made any sort of effective acoustic weapon the US Military would be very well aware of it. (I'd have thought they'd have made their own by now!)

    There has been an acoustic weapon produced, mainly for helping to defend ships against pirates. It is simply a siren or amplifier and loudspeaker whose audible output is so loud it would be painful to approach closely and would prevent the attackers from talking to each other or hailing their victims. It would not kill anyone, nor make them ill, apart from deafness.

    So in trying to say why all those diplomats and civil servants were all ill with an assortment of different symptoms at around the same time, we'd have to look elsewhere for the reason. A concealed acoustic weapon is not really feasible and certainly extremely unlikely.


      October 6, 2017 4:45 PM MDT
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  • 113301
    Thank you once again for an extremely thoughtful, helpful and informative reply Durdle. I wasn't sure if you were aware of what some American diplomats experienced in Cuba at the American Embassy but also at home apparently in their beds.  Some were not affected at all but some seem to have permanent damage to their hearing and other symptoms that are very worrisome and mysterious. Now we cannot hear dog whistles right? So sound does exist beyond the range of our ability to hear it. The question is could it be damaging or maybe even lethal? These folks DID hear very loud noises at times. Cuba is supposedly looking into it but who knows if that is true? If one is physically assaulted without knowing the source that is a very scary thing indeed. I hope they get to the bottom of it or the top or the middle.  I don't know if  the mystery will ever be solved or if it is I don't know if we the people will ever be told about it. Another government secret? Maybe.
      October 7, 2017 3:05 AM MDT
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  • 3719
    I did note you were careful to use the word "apparently" in your original post.

    Oh yes, sound can be generated at frequencies far above human hearing range (20kHz at most in a fully healthy ear). Two examples:

       -   Bats hunt insects by echolocation at typically 80 - 120kHz, and their calls can reach extraordinarily high intensities (some at >100dBA), but as they are very small animals their power is very low so combined with ultrasound being dispersed rapidly by distance anyway, their range is very short.*

       -   Medical ultrasound works at from 1Mhz to 20MHz (Megahertz, or 1 millions cycles per second). The power is very low. 

    However...

    Backing what I wrote above, last night an American military intelligence expert interviewed on the BBC World Service explained that whilst it is theoretically possible to damage the human brain by high-frequency sound, it could only done at very high power, through transducers (slightly similar here to the loudspeaker in your portable 'phone) clamped to the head of a victim submerged in the bath! (The medical ultrasound scanner is pressed gently against the skin, with an intervening layer of a harmless gel to help the sound pass through the skin's surface.)

    Essentially, whoever suggested the strange illnesses were caused by sound, knows little or nothing about basic acoustics.



    *Footnote. If you are not sure why I italicised power and intensity, as a an analogue consider contrasting the light and heat emitted by an ordinary filament torch bulb (not an l.e.d.) and a 1-bar electric fire element.

    The bulb runs at perhaps 0.5W. The fire element at 1kW is 2000 times as powerful.

    The bulb's filament is white-hot but has emits only a modest amount of light and very little heat. The fire element is a lot cooler. It glows bright orange, but it emits more light energy and far more heat.

    Or the other way round,
    The low-power torch filament's temperature (heat intensity) is far higher, and its light a lot brighter (intensity of light), than those of the much more powerful heater's element.
      October 9, 2017 7:48 AM MDT
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  • 113301
    So if not sound then what? Could it be psychosomatic? Hysteria? Thank you once again for a very informative and helpful analysis. It really creeps me out. I HOPE the mystery will be solved and the why is detailed if not the how. It's a dangerous world out there and getting more so or we are simply becoming more aware of it. Either way I don't like the direction!  :(
      October 10, 2017 3:00 AM MDT
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  • 3719
    I don't know what it could be to make a large group of people all apparently fall ill at the same time unless they all showed at least some of the same symptoms and had been doing or visiting the same things. I doubt hysteria very much though. It's certainly odd.

    It's hard to say if the world is becoming more dangerous or not, but it's pretty clear the various threats keep changing
      October 10, 2017 7:09 PM MDT
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  • 113301
    Maybe it's just sameoldsameoldsameold and I just have more time to pay attention now because I'm retired than I did before when I was working. The main thing though that I notice more with the current political environment is that racists/bigots came out of the closet, up from the slime, out from under the rocks.  The KKK doesn't hide beneath  sheets. They take pride and march with ugly posters supporting their views and chant hideous slogans.  They used to be pariahs and reviled. Now they are part of the fabric of society and seem to relish the spotlight. There were always despots/dictators but I never in my wildest imagining thought the United States of America would elect one. Thank you for your reply Durdle. Every time I think the awful has reached its bottom in America I'm wrong. :( This post was edited by RosieG at October 11, 2017 2:43 AM MDT
      October 11, 2017 2:43 AM MDT
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  • 3719
    I didn't know the Ku Klux Klan even still exists, let alone that any of them would stand for political election. The popular image of them is their costume, which looks childishly silly but I assume was to hide their identities. Presumably past members wore those cloaks because they dared not admit being part of it, but are they now being open about it?

    On another web-site I have had an almost surreal conversation with a student who made it very clear he is a virulently anti-Semitic, Nazi sympathiser; so I wonder how much of that sort of ideology there is floating around a country that likes to say it is the Land of the Free.
      October 12, 2017 10:17 AM MDT
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