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?

  • 4
    Note: Microwaves can be "focused" like lasers: Maser
    – Oddthinking
    Aug 12 '17 at 10:01
  • 3
    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.) Aug 12 '17 at 23:10
  • 2
    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
  • 3
    It's worth noting that microwaves are a kind of light, not a kind of sound. en.m.wikipedia.org/wiki/Microwave Aug 20 '17 at 16:00
  • 4
    At the risk of being called a pedant, a weapon that operated outside audible frequencies is either subsonic or supersonic, not sonic. Aug 6 '19 at 2:35

Possibly. There have been many advances in acoustics, especially in the application of ultrasound, that may explain that incident in Cuba.

The Incident

In 2017, US diplomatic staff began to suffer mysterious traumatic injuries that have now been dubbed “Havana syndrome” by the US and Canadian media. The diplomats stationed in Cuba initially referred to the phenomenon as “The Thing“ whereas University of Pennsylvania specialists who examined victims brought back from Cuba gave it the name "Immaculate Concussion".

So far, it has affected US and Canadian diplomatic staff in Cuba and US diplomatic staff in China. The symptoms are more serious than just hearing loss and have since been confirmed to constitute a form of brain damage. The physical symptoms are:

The official response (Cuban incidents) ---------------------------------------
  • White House chief of staff John Kelly:

We believe that the Cuban government could stop the attacks on our diplomats”.

  • President Donald Trump:

I do believe Cuba’s responsible. I do believe that […] it’s a very unusual attack, as you know. But I do believe Cuba is responsible.”

The official response (Chinese incidents) ----------------------------------------- - statement: > “[The State Department received medical confirmation that a U.S. government employee in China suffered a medical incident consistent with what other U.S. government personnel experienced in Havana, Cuba][8].” - State Department warning sent to staff via email: > anyone who experiences "[unusual acute auditory or sensory phenomena][9]" while in China should move away from the source of the noise. - [affected staff at the American Consulate in Guangzhou are evacuated][10]. The remaining staff and their families underwent testing by medics from the the State Department.
  • China’s Foreign Minister:

We don’t want to see that this individual case will be magnified, complicated or even politicized. We hope people will not associate it with other unnecessary matters.”

  • U.S. Secretary of State Mike Pompeo:

We notified China of what took place as best we know it and they have responded in a way that is exactly the right response.”

The Sound ([from Cuban incidents via AP][2]) --------- https://youtu.be/Nw5MLAu-kKs

The Associated Press has obtained a recording of what some U.S. Embassy workers heard in Havana in a series of unnerving incidents later deemed to be deliberate attacks. The recording, released Thursday by the AP, is the first disseminated publicly of the many taken in Cuba of mysterious sounds that led investigators initially to suspect a sonic weapon.

The recordings themselves are not believed to be dangerous to those who listen. Sound experts and physicians say they know of no sound that can cause physical damage when played for short durations at normal levels through standard equipment like a cellphone or computer.

The sound seemed to manifest in pulses of varying lengths — seven seconds, 12 seconds, two seconds — with some sustained periods of several minutes or more. Then there would be silence for a second, or 13 seconds, or four seconds, before the sound abruptly started again.

A closer examination of one recording reveals it’s not just a single sound. Roughly 20 or more different frequencies, or pitches, are embedded in it, the AP discovered using a spectrum analyzer, which measures a signal’s frequency and amplitude.

To the ear, the multiple frequencies can sound a bit like dissonant keys on a piano being struck all at once. Plotted on a graph, the Havana sound forms a series of “peaks” that jump up from a baseline, like spikes or fingers on a hand.

“There are about 20 peaks, and they seem to be equally spaced. All these peaks correspond to a different frequency,” said Kausik Sarkar, an acoustics expert and engineering professor at The George Washington University who reviewed the recording with the AP.

The multiple peaks could be accounted for if the alleged sonic device is a phased array speaker made of multiple ultrasound transducers. Phased array speakers are used to "steer" and "aim" sounds without actually changing the position of the speakers. Phased arrays work by exploiting acoustic interference timed in order to propel a wave in a particular direction.

Besides the discordant phase effect little else is known about the sound itself.

Clinical features of “Havana syndrome” ([July 2019][12]): --------------------------------------------------------- > - Mean whole brain white matter volume was significantly smaller in patients compared with controls, with no significant difference in the whole brain gray matter volume.
  • There were significantly greater ventral diencephalon and cerebellar gray matter volumes and significantly smaller frontal, occipital, and parietal lobe white matter volumes; significantly lower mean diffusivity in the inferior vermis of the cerebellum; and significantly lower mean functional connectivity in the auditory subnetwork and visuospatial subnetwork but not in the executive control subnetwork.

This profile is close to leukariosis, a kind of white matter disease caused by, ordinarily hypertensive, injury to small blood vessels that supply cortical white matter around the parietal lobes. Leukariosis is a precursor to the dementia known as “Binswanger’s disease” but the progression doesn't always happen.

We now know that the injury is real. The US and Canadian reaction has been to accuse Cuba of foul play, to expel Cuban diplomats and to repatriate non-essential staff as well as family members to the home country. This reaction is consistent with a real perceived threat. There is obviously something hurting these diplomats but there's no evidence that the cause was a "sonic bomb".

Sound can be used to cause harm to humans in a variety of ways.

Loud Noises

Injury to the inner ear. Loud sounds can rupture parts of the inner ear. This is a well known cause of hearing loss. According to the National Institute on Deafness and Other Communication Disorders, sounds [above 85 dBA are potentially injurious][13] but this figure is sensitive to the frequency of the sound. High decibel sounds dissipate too quickly to make for effective weapons. Their range is too short.

High-intensity focused ultrasound (HIFU) ablation

Ultrasound focused by a lens to a high pressure is capable of causing injury inside the body at the focal point. This technique is called [high intensity ultrasound therapy][14] and is used to treat small tumors non-invasively. In therapy, the mechanism used is usually hyperthermic (and therefore cannot be the cause of Havana syndrome) but can also be mechanical. Mechanically, [lesions can be opened inside an organ via acoustic cavitation of bodily fluids][15]. The high energy sound waves disturb bodily fluids causing bubbling. The increased pressure inside a sac or vessel will open a lesion.

High intensity ultrasound necessary for concussion could be achieved by using an array system of ultrasound transducers. This is consistent with descriptions of the injury as immaculate (focused) concussion by specialists.

Concussive force starts above 85 g-force with the average concussion being at 95 g-force.

Sonosensitisers and Sonodynamic therapy

In medicine, sonosensitisers are chemicals that, in solution, oxidize when treated with frequencies of sound. The chemical phenomenon is known as [acoustic cavitation][17] and its use biomedically is known as [sonodynamic therapy][18]. Sonosensitisers are often chemicals that release reactive ions that cause chain reactions that release chemicals toxic to cells. Many are also photosensitisers. An example is [Copper Cysteamine][19] which releases the [Cu+ supercation that reacts with water to produce reactive oxygen species][20] that cause necrotic cell death.

Doctors can deliver these cytotoxins to targeted tissues by conjugating the individual nanoparticles with antibodies. This is known as immunochemical passive targeting. Adapting these cytotoxic drugs for oral delivery is feasible, less harmful copolymerizing medicines have been, but is not practiced in cancer therapy because of the dangers. In addition, other sound-sensitive nanoparticles exist that rely on piezoelectric principles to cause cell death. This is the same technology used in leadless, batteryless pacemakers. Finally, there are also antibodies that bind to small vessel endothelial cells in the central nervous system. These are supposed to be used for drug delivery behind the blood–brain barrier.

A nation-state actor, if so inclined, could repurpose medical innovations in order to manufacture a sound-responsive poison that causes "mild traumatic brain injury" deleterious to white matter. This explanation is consistent with the claims of former NSA officer, Mike Beck, who claims have developed Parkinson's disease, along with a colleague while stationed in China. Beck thought a microwave weapon might be responsible. This explanation is undermined, however, because specialists who inspected the first returnees from Cuba reportedly found no evidence of a toxin.

  • 1
    You make several controversial claims that are not supported by your references. (1) "We now know the injury is real." - Well, we know there are (clinically unclear) significant differences in white matter. This doesn't mean there is an injury, and it certainly doesn't mean there is a weapon.
    – Oddthinking
    Aug 5 '19 at 6:32
  • (2) You cite the "National Institute on Deafness and Other Communication Disorders" vaguely. Please reference that claim.
    – Oddthinking
    Aug 5 '19 at 6:33
  • 2
    (3) "Adapting these cytotoxins for oral delivery is feasible" Please reference this claim.
    – Oddthinking
    Aug 5 '19 at 6:33
  • 2
    (4) "A nation-state bad actor could easily repurpose all this in order to manufacture a sound-responsive poison that causes brain injury." Says who? This is rather speculative. The question is "Do they exist?" not "Could someone come up with an idea for one?"
    – Oddthinking
    Aug 5 '19 at 6:34
  • 2
    This remains hugely speculative - at the level of science fiction. The reference shows that bringing an ultrasound probe right up to a petri dish of prepared cells can kill the cells. You have jumped from that to a hidden ultrasound device that can remotely target some cells in the brain. The question is "Does this exist?" You show no evidence that it exists and poor evidence that it could exist.
    – Oddthinking
    Aug 6 '19 at 3:55

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.

  • 1
    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. Oct 9 '18 at 16:52
  • 2
    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. 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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