Comment by mccoyspace | Hacker News Reader

Comment by mccoyspace | Hacker News Reader

This is such a fascinating (and disturbing) situation. And quite mysterious. High frequency ultrasound is used routinely in medicine and has never been shown to change brain tissue. Infrasound has some effect on tissue but its probably overstated. (the infamous 'brown note' [1]. Other sonic weapons rely on volume/amplitude. None of this seems to be the case here.

Another really interesting point is the description of the hyper localized nature of the sound -- present in one part of the room and not another. Its really hard to localize a sound signal, as anyone who has worked with parabolic speakers can attest. Yes, there can be focal points, but the sound definitely drifts out to the surrounding areas to a significant degree. One example of hyperlocalized sound perception is Lamont Young's 'Dream House' installation in NYC [2] Although not captured in video documentation, there are distinct and significant microtonal shifts that are easily perceptible as you move through the space caused by standing waves produced through the interaction of the tone generators and the architecture. But this happens within the context of a loud drone that fills the whole room. Not at all what is described by the diplomats and family members.

I hope they can get to the bottom of this and I hope that more information is made public.

[1] https://en.wikipedia.org/wiki/Brown_note [2] https://www.youtube.com/watch?v=WC6bhnu5Luc

https://en.wikipedia.org/wiki/Microwave_auditory_effect

This is the best bet I've seen since this story broke.

Exactly what I was thinking of too. The company that created MEDUSA (WaveBand Corp) was awarded a DoD grant in 2005 for a 3m^2 "Millimeter Wave Profiling Deployable Dosimeter".

https://www.sbir.gov/sbirsearch/detail/349546

Hey rootw0rm, all of your comments are autodead. Not sure what you did to deserve it, but this comment is additive here. Contact the admin to have rights restored.

Just go to the comment click "vouch" and it will go through.

Yeah, the descriptions they offer remind me of the few times I've “heard” meteorites plunging through the atmosphere: https://www.theguardian.com/education/2003/oct/23/research.h...

There is an actual recording of these sounds. Microwaves inducing sounds into a humans perception and at the same time inducing it in recording equipment does not seem plausible.

There is also an easy way to test whether the sound is actual sound conducted in air or the effect of microwave exposure: ear plugs.

There's an actual recording of signals inducted in wires - either from soundwaves moving a magnet in a field (sound picked up by a mic), or inducted by in the wires by electromagnetic radiation, surely?

I agree it might be unlikely that one signal might induce sound in a human that sounds like the sound a recorder might record - but I don't know. I just know that it's trivial for radiation to fool sound equipment (eg: cell phone signal too close to a speaker/mic/amplifier).

However, if this is a sophisticated weapon, there might be two signals: high power that target humans, lower power that target recording equipment?

If its a high frequency wave, then you would "hear" it with the skin and other tissue on your head rather than your actual ears. Earplugs wouldnt really help.

How it works: you can hear a high frequency wave if its modulated at audible frequency. If it's switched on and off at a relatively low frequency, you can sense the presence and absence of the high-frequency vibrations. Those waves are poorly absorbed from the air, but once they make it into the body they are transmitted much more easily by tissues besides bone. So your ears are not much better than the rest of your skin, which acts like a funnel for sound, diverting it to your cochlea.

Did you hear the recording? That's entirely the range of sounds that good hearing protection dampens.

If this is true there's a way we can block the effects...

> In 1962, Allan H. Frey discovered that the microwave auditory effect, i.e., the reception of the induced sounds by radio-frequency electromagnetic signals heard as clicks and buzzes, can be blocked by a patch of wire mesh (rather than foil) placed above the temporal lobe.

I'm ready http://static.tvtropes.org/pmwiki/pub/images/weirdalfoil_232...

White matter is the deep part of the brain. Microwaves wouldn't penetrate more than a couple cm.

Personally I think something much more benign is probably the answer. Maybe someone introduced drugs into their food/water? Sometimes a noise is just a noise.

I don't know, if this is some kind of sophisticated multiple-beam system using constructive interference (https://xkcd.com/1922/), it might have more penetrative ability than you'd assume.

ultrasound is completely capable of not only affecting brain tissue, but destroying it.

as with anything else: it's about the amount of energy you put into it.

Focused ultrasound would be completely capable, and share the quality of being perceptable in the targeted region, and absent elsewhere.

https://www.fusfoundation.org/diseases-and-conditions/neurol...

Yes, but at which frequencies, power and more important, acoustic coupling with the skull?

Check out "parametric speakers".

Amazon has an assembled kit for sale: http://amzn.to/2AxtPBS

Also, more info from soundlazer.com, here: http://www.soundlazer.com/what-is-a-parametric-speaker/

Also, reminds me of the MacGyver (original) episode "Soft Touch"- where a Columbian drug cartel tortures a federal agent in a garage using high-decibel noise.

But generating that much energy requires a huge piece of equipment. For example, the unit used for the ablative technique you linked to is quite large and works only at very short distances.

[image of device] https://www.israel21c.org/wp-content/uploads/2013/03/insight...

What about multiple devices where their respective waves converge at a specific point?

It'd be awfully difficult to precisely position and aim multiple transmitters discreetly.

That makes more sense to me, but still, the energy requirements would be huge. Given Cuba's electricity infrastructure (and probably even without that) I think you would be looking at 3 or more big pieces of equipment that require very large, very heavy, batteries. It seems like that would have been very conspicuous.

Ultrasonic waves are attenuated at a rate of 3-180 dB/m[1] (100-1000 kHz waves). So at 10 m a 150 kHz wave will have decreased in amplitude by over 300x. There's no amount of transmitters that can make up for the attenuation at high frequencies. It's not even possible for devices operating above a couple hundred kHz or farther than 10-20 m. A 500 kHz wave will decrease 200 dB over 5 meters, taking it from a shockwave (ie the pressure between pulses is vacuum) to undetectable. You'd need a transmitter strong enough to disintegrate organic material[2] but even the best detectors on earth won't hear it from across a road.

[1]: http://www.ktu.lt/ultra/journal/pdf_50_1/50-2004-Vol.1_09-A....

[2]: https://en.wikipedia.org/wiki/Sonication

Ultrasound does damage brain tissue.

It has been studied in China, where evidently it was considered ethical to do so. Search terms: China ultrasound study

What this does to the population's average mental ability and sanity is an interesting question. Autism is suspected.

Can something activate the perception of the sound in the brain, maybe a high intensity ultrasound or another frequency that with enough intensity would activate the hairs in the inner ear or the nerve signals. For something to cause brain damage through the skin and skull bone it would have to be pretty intense I would imagine...

I believe they have an audio recording of the sound, suggesting it's not purely a brain activation/attack.

https://youtu.be/HcI7yYK_6Z8

Yes, microwave energy can do pretty much exactly what you're saying, and perhaps other forms of radiation could directly activate nerves as well. It's also possible that if the brain damage includes auditory processing then it could be phantom sounds. It's too many options, too little evidence, but microwaves seem like a good culprit. It doesn't seem too far-fetched that such a system could induce something like a "recording" as well, or that recording could be coincidental.

If they had devices in the embassy which required maybe intersecting "beams" of microwaves to power up and transmit, and something went wrong...

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