The US is investigating whether diplomats in Cuba were subjected to a sonic weapon that caused hearing problems:

  • The Guardian, 11 Aug 2017

    One or more Canadians affected after suspected use of sound weapon against US personnel in Havana led to expulsion of Cuban diplomats from Washington


    In the autumn of 2016 a series of US diplomats began suffering unexplained losses of hearing, according to officials with knowledge of the investigation into the case. Several of the diplomats were recent arrivals at the embassy, which reopened in 2015 as part of President Barack Obama’s re-establishment of diplomatic relations with Cuba.

    Some of the US diplomats’ symptoms were so severe they were forced to cancel their tours early and return to the United States, officials said. After months of investigation US officials concluded that the diplomats had been attacked with an advanced sonic weapon that operated outside the range of audible sound and had been deployed either inside or outside their residences.

On the scientific side, is it plausible the existence of these "sonic bombs" that go undetected by the victim? This article in a (more or less) scientific site suggests two mechanisms:

The IFLScience! web-site conjectured about the technology:

The curious thing about these incidents in Havana, though, is that the suspected sonic devices haven’t been accompanied by audible noises. They appear to be operating at a frequency beyond that of human hearing, and yet they’ve reportedly caused hearing loss and headaches in the targets.

There are two ways in which this could be achieved. The first would be to use microwaves. Imperceptible to people lacking detection technology, it has been shown that small beams directed at people’s heads rapidly heat tissue within the brain, generating a small shockwave. [...]

Infrasound – sound that is at a lower frequency than the range that’s picked up by human hearing – can also cause hearing loss in some cases. According to the US National Institutes of Health, being exposed to concentrated infrasound can cause “fatigue, apathy, and depression, pressure in the ears, loss of concentration, drowsiness, and vibration of internal organs.”

At this stage, it’s deeply unclear which is more plausible – but the point is that “silent” acoustic weapons do exist, and they certainly could have been deployed in Havana.

The iflscience article references a document by the US NIH. But this document itself, on page 9, states that

One argument against the feasibility of the use of infrasound in nonlethal weapons is that infrasound's wavelengths (17 m and above) are so long that they spread out too rapidly to be focused".

Is the existence of such "sonic bombs" plausible?

  • 2
    Note: Microwaves can be "focused" like lasers: Maser – Oddthinking Aug 12 '17 at 10:01
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    There have been a number of cases of injury apparently caused by super-low frequencies -- I'm guessing below 10Hz. Generally these are just upset stomachs and the like, with no major permanent injury, but it's hard to say what prolonged exposure would cause. Problems with high frequencies would be less likely, as they are so rapidly absorbed by any intervening materials. (And I'm wondering why, if this sort of thing has happened before, US embassies don't have sonic detectors.) – Daniel R Hicks Aug 12 '17 at 23:10
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    Somehow relevant to the question: cartasdesdecuba.com/… This article summarises the general opinion in Cuba about the topic. – yms Aug 14 '17 at 20:40
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    A few days ago I was reading that there are documented cases of hearing-injuries in babies as result of ultrasound tests during pregnancy, a journalist was arguing that someone may have "weaponized" this technology... but I still find it unrealistic. – yms Aug 14 '17 at 20:48
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    There is a new hypothesis now that the injuries might have been self-inflicted, by accident. See here (in Spanish): radio-miami.org/2017/08/14/rayo-la-muerte. Then here: technorobot.eu/en/pdf/LRAD-RX.pdf. Specially were it says "The LRAD-RX advantage: High Direccionality, reduces the risk of exposing nearby personnel to excessive audio levels" – yms Aug 15 '17 at 3:57

In 2008, WIRED magazine came out with this article: "Sonic Blaster + Laser = New Weapon"

Imagine being hit by a nonlethal blast that seems to explode in front of you – a deafening and blinding combination of light and sound. As the battle for "sonic blasters" heats up, a number of companies are looking at innovative ways to combine light and sound into new, nonlethal devices. One company, Wattre Corp., is working to couple its acoustic technology with a nonlethal laser. In a recent interview with DANGER ROOM, Curt Graber, president of Wattre Corp. explained this newfangled device, which puts together the company's collimated beam of sound with another firm's laser (which creates a sort of mid-air plasma ball). "It’s a laser that basically ignites the air in front of the person," Graber says. "It creates fireworks right in front of you."Hs60_promo_big

The combined effect is what Graber calls a "psycho-acoustical event."

Wattre's technology, called Hyperspike, is a Guinness Book of World Records winner for "loudest speaker." As for the laser portion, produced by a company called Stellar Photonics, DANGER ROOM's David Hambling actually has a good writeup of the technology at New Scientist. "The device uses a technology known as dynamic pulse detonation (DPD). A short but intense laser pulse creates a ball of plasma, and a second laser pulse generates a supersonic shockwave within the plasma to generate a bright flash and a loud bang," he writes. The Plasma Acoustic Shield System will eventually combine a dynamic pulse detonation laser with a high power speaker for hailing or warning, and a dazzler light source."

While the combined sound/laser weapon is certainly a novelty, Wattre Corp. has its eye on the growing long-range hailer market. It competed for a recent Navy contract that was ultimately awarded to American Technology Corp., which produces the Long Range Acoustic Device (Wattre protested the contract award; Graber says the Hyperspike technology has better beam forming capabilities in the human voice range, among other advantages).

While Wattre lost its protest, they've sold units to foreign navies, among other customers; Wattre has also made sales to France for riot control. "Now it’s just a mater of people trying to figure out the best possible usage," he says.

According to Wikipedia, the range of frequencies that people hear is from 20 - 20,000 cycles / second. But according to Electronics.StackExchange contributor Chris Stratton:

Can computer speaker emit ultrasound?

Generally, yes (confirmed by both theory and experiment) though probably not as effectively as they can lower frequencies.

Provided that ordinary computer speakers may emit inaudible sound...


It is most certainly plausible that the engineering work of Wattre Corp or other researchers could produce directed sound waves that are both inaudible and high-energy, in parallel with the ongoing work developing sonic weapons that are deafening and blinding.

  • Please read the claim. A key feature of the sonic weapon in the claim is that it is undetected by the victim. The sonic weapon in your answer is detected by the victim when it produces "a deafening and blinding combination of light and sound" – De Novo Oct 9 '18 at 16:50
  • @DeNovo, the more interesting applications are deafening and blinding... but the long-range hailer would most certainly be usable as a directional source of acoustic energy above the audible range. – elliot svensson Oct 9 '18 at 16:52
  • You obviously want to contribute to skeptics.SE, and you've made some good contributions, but please stop writing answers like this. If you can't find good evidence about a specific claim, it's better to not answer than to speculate. FYI, I'm not your downvoter here. I'm waiting to see if you can give some evidence about the claim before I vote. – De Novo Oct 9 '18 at 16:54
  • @DeNovo, the OP wanted to know if a claim was plausible, and the Wired article absolutely confirms that the claim is plausible. – elliot svensson Oct 9 '18 at 16:59
  • I've downvoted this answer. As far as evidence, it contains a wikipedia reference re: the range of human hearing, a link to an electronic.SE answer (with no supporting references) about computer speakers being able to produce ultrasound, and a reference with a long irrelevant quote about a sonic weapon that doesn't fit the claim. I'll convert my downvote to an upvote if you can follow these guidelines. The key things you're missing is references that support the answer. – De Novo Oct 9 '18 at 19:22

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