
Examining overlooked clues reveals how ultrasound could have caused harm in Cuba - NicoJuicy
https://spectrum.ieee.org/semiconductors/devices/how-we-reverse-engineered-the-cuban-sonic-weapon-attack
======
trdtaylor1
1\. They cannot claim they discovered constructive/destructive intereference

2\. They cannot claim they discovered interference that shifts frequency.

3\. They cannot claim to have "Reverse engineered the Cuban "Sonic Weapon"
attack"

They instead PROPOSE the U.S. Embassy in Cuba has brain-altering levels of
noise in the ultrasonic region somehow caused by two or more simple,low level
and possibly common ultrasonic emitters without malicious intent and THAT'S
why some people can hear it...

Xu's other recent works has been lacking meat and are better at fear-mongering
(Tesla ultrasonic 'hack', Smart grid 'hack').

Xu's ultrasonic Tesla 'hack' showed how dangerous the pedestrian avoidance
system was by wrapping one of her graduate students in Michelin Man-sized
ultrasonic dampening material. Tesla had to make an uncharacteristically
brusque comment stating they couldn't reproduce anything of risk to Tesla
drivers in the world.

She is the equivalent of the National Enquirer in the security research world
and steadily increased her ability to clickbait.

------
sjburt
Couldn't they obtain a 7khz tone by mixing any two tones seperated by 7khz and
applying a low-pass filter? I don't see how this proves anything.

And the 155dB number cited by the Canadian government would require
considerable (hundreds of watts) of power to produce at close range.

This whole case defies logic. The early reports were of mysterious symptoms
not associated with any obvious exposure. Once ultrasound/infrasound began
being mentioned, people began reporting hearing mysterious sounds.

The recording makes even less sense: If the sound levels were really
sufficient to cause physical trauma, surely they would overwhelm the phone's
microphone?

~~~
tossaway1
> Couldn't they obtain a 7khz tone by mixing any two tones seperated by 7khz
> and applying a low-pass filter?

I don't understand this comment. Are you implying that a low-pass filter would
shift the frequencies of part of the signal rather than (mostly) filtering
some of the frequencies away...?

~~~
kaoD
[https://en.m.wikipedia.org/wiki/Heterodyne#Mixer](https://en.m.wikipedia.org/wiki/Heterodyne#Mixer)

> In the most common application, two signals at frequencies f1 and f2 are
> mixed, creating two new signals, one at the sum f1 + f2 of the two
> frequencies, and the other at the difference f1 − f2.

Then the low pass filter is used to remove the original signals and the sum,
leaving only the difference.

------
dang
An earlier version of this work was discussed at
[https://news.ycombinator.com/item?id=16515552](https://news.ycombinator.com/item?id=16515552).

Since commenters here are objecting to the article title as misleading, we've
replaced it with the subtitle (with s/Havana/Cuba/ to fit in 80 chars).

~~~
trdtaylor1
Not you nor submitters fault. The ire of the intelligent community is towards
the people behind the obvious click-bait paper and article.

------
Negative1
The other attack they described ("DolphinAttack") is intriguing. I've yet to
read the paper (but plan to), but the idea of Voice control being ever more
present and likely extending to control of more parts of our lives (Banking,
Vehicle Controls, Home Security...) could make this a pretty effective attack
vector.

~~~
akira2501
> could make this a pretty effective attack vector.

Until we start putting high order low pass filters in everything.

------
foobarbecue
What a weird, rambling article. I read the whole thing and I'm really not sure
what point they were trying to make. Two ultrasonic signals can interfere to
produce lower wavelength sound? That's kind of obvious to anyone who has
studied signals...

~~~
alexandercrohde
I agree it was poorly written.

I believe the intent was to say:

A) We have recording from Cuba, therefore there's proof of ultrasonic noise.

B) This noise we have is in the audible spectrum, but we have reason to
suspect it's from the interaction of two ultrasonic frequencies that together
produce a very whiney audible frequency

C) Ultrasonic noise can be used for spying and voice-injection, so there's a
potential motive for the US to use such technology at an embassy.

------
slr555
Just a brief question from a non-engineer: Is this the same kind of phenomenon
that produces the illusion of a fifth voice in a barber shop quartet? Thanks!

------
jnaulty
A much better source... [https://www.scientificamerican.com/article/ldquo-
sonic-weapo...](https://www.scientificamerican.com/article/ldquo-sonic-weapon-
attacks-rdquo-on-u-s-embassy-don-rsquo-t-add-up-mdash-for-anyone/)

------
rurban
This is the last movement of Jean Sibelius Symphony No 1 in E minor:
[https://www.youtube.com/watch?v=dCIw_4oJ4Gg&t=27m20s](https://www.youtube.com/watch?v=dCIw_4oJ4Gg&t=27m20s)

At about 36m you can hear the rumbling IMD effects.

------
mycall
> Xu’s 2017 paper “DolphinAttack: Inaudible Voice Commands” describes how we
> used ultrasonic signals to inject inaudible voice commands into speech
> recognition systems such as Siri, Google Now, Samsung S Voice, Huawei
> HiVoice, Cortana, Alexa, and the navigation system of an Audi automobile.

So cool. I had this idea a long time ago but never approached it. Kudos to
them for some follow through.

------
mkempe
Until and unless they actually test their "reverse-engineered" device with
live subjects under similar conditions to what has been reported in Cuba, how
valid is that claim?

Edit: this is, of course, a rhetorical question. The "reverse-engineered
weapon" claim is clearly false.

~~~
smogcutter
They make this point themselves in the article: they can account for the
unusual recording from Cuba, but not for people's symptoms.

>> While the math leads us to believe that intermodulation distortion is a
likely culprit in the Cuban case, we haven’t ruled out other null hypotheses
that may account for the discomfort that diplomats felt. For example, maybe
the tones people heard didn’t cause their symptoms but were just another
symptom, a clue to the real cause.

~~~
mehrdadn
> While the math leads us to believe that intermodulation distortion is a
> likely culprit in the Cuban case, we haven’t ruled out other null hypotheses
> that may account for the discomfort that diplomats felt. For example, maybe
> the tones people heard didn’t cause their symptoms but were just another
> symptom, a clue to the real cause.

Unless what I read was just plain lies, I don't see how this is plausible.
Just reading The Guardian's article [1] I see no room for other plausible
explanations in every case... remember there were _at least 21 US victims_
(!!):

 _The blaring, grinding noise jolted the American diplomat from his bed in a
Havana hotel. He moved just a few feet, and there was silence. He climbed back
into bed. Inexplicably, the agonizing sound hit him again. It was as if he’d
walked through some invisible wall cutting straight through his room._

 _Soon came the hearing loss, and the speech problems, symptoms both similar
and altogether different from others among at least 21 US victims in an
astonishing international mystery still unfolding in Cuba. The top US diplomat
has called them “health attacks”._

 _New details learned by the Associated Press indicate at least some of the
incidents were confined to specific rooms or even parts of rooms with laser-
like specificity, baffling US officials who say the facts and the physics
don’t add up._

[1] [https://www.theguardian.com/world/2017/sep/14/mystery-of-
son...](https://www.theguardian.com/world/2017/sep/14/mystery-of-sonic-weapon-
attacks-at-us-embassy-in-cuba-deepens)

~~~
tgsovlerkhgsel
Sounds a lot like some sort of constructive interference. Or highly
directional microwaves of course.

~~~
mehrdadn
Microwaves carry sound now?

~~~
tgsovlerkhgsel
Modulated microwaves could. There are reports of random metal items suddenly
playing local high-powered radio stations, and modulated/pulsed microwaves can
cause
[https://en.wikipedia.org/wiki/Microwave_auditory_effect](https://en.wikipedia.org/wiki/Microwave_auditory_effect)

Note that the purpose of the microwaves doesn't have to be frying someone's
brain or creating sound; it can be some unrelated attempt to e.g. try to
intercept data think about possible attempts to use preexisting materials in a
way similar to
[https://en.wikipedia.org/wiki/The_Thing_(listening_device)](https://en.wikipedia.org/wiki/The_Thing_\(listening_device\))

