WASHINGTON — It sounds arrange of like a mass of crickets. But not quite. A high-pitched whine, but from what? It seems to undulate, even writhe. Listen closely: Some hear multiple, graphic tones colliding in a nails-on-the-chalkboard effect.
The Associated Press has obtained a recording of what some U.S. Embassy workers listened in Havana, partial of the series of unnerving incidents after deemed to be counsel attacks. The recording, expelled Thursday by the AP, is the first disseminated publicly of the many taken in Cuba of sounds that led investigators primarily to think a sonic weapon.
- Listen to the sound in the video above
The recordings from Havana have been sent for research to the U.S. Navy, which has modernized capabilities for examining acoustic signals, and to the comprehension services, the AP has learned. But the recordings have not significantly modernized U.S. trust about what is harming diplomats. Officials contend the supervision still doesn’t know what is obliged for injuries to its personnel, but the U.S. has faulted Cuba for unwell to strengthen American diplomats on its soil.
The Navy and the State Department did not respond to requests for criticism on the recording. Cuba has denied impasse or trust of the attacks. However, White House Chief of Staff John Kelly isn’t convinced.
“We trust that the Cuban supervision could stop the attacks on the diplomats,”.
Not all Americans harmed in Cuba listened sounds. Of those who did, it’s not transparent they listened precisely the same thing.
Yet the AP has reviewed several recordings from Havana taken under opposite circumstances, and all have variations of the same high-pitched sound. Individuals who have listened the sound in Havana endorse the recordings are generally unchanging with what they heard.
“That’s the sound,” one of them said.
The recording being expelled by the AP has been digitally extended to boost volume and revoke credentials noise, but has not been differently altered.
The sound seemed to perceptible in pulses of varying lengths — 7 seconds, 12 seconds, two seconds — with some sustained durations of several mins or more. Then there would be overpower for a second, or 13 seconds, or 4 seconds, before the sound abruptly started again.
Whether there’s a approach attribute between the sound and theis unclear. The U.S. says that in general, the attacks caused hearing, cognitive, visual, balance, nap and other problems.
A closer hearing of one recording reveals it’s not just a singular sound. Roughly 20 or some-more opposite frequencies, or pitches, are embedded in it, the AP detected using a spectrum analyzer, which measures a signal’s magnitude and amplitude.
To the ear, the mixed frequencies can sound a bit like inharmonious keys on a piano being struck all at once. Plotted on a graph, the Havana sound forms a series of “peaks” that burst up from a baseline, like spikes or fingers on a hand.
“What it is revelation us is the sound is located between about 7,000 kHz and 8,000 kHz. There are about 20 peaks, and they seem to be equally spaced. All these peaks conform to a opposite frequency,” pronounced Kausik Sarkar, an acoustics consultant and engineering highbrow at The George Washington University who reviewed the recording with the AP.
Those frequencies competence be only partial of the picture. Conventional recording inclination and collection to magnitude sound may not collect up very high or low frequencies, such as those above or next what the human ear can hear. Investigators have explored either infrasound or ultrasound competence be at play in the Havana attacks.
The recordings have been played for workers at the U.S. Embassy to learn them what to listen for, pronounced several people with trust of the conditions in Havana. Some embassy employees have also been given recording inclination to spin on if they hear the sounds. The people weren’t certified to plead the conditions publicly and demanded anonymity.
Cuban officials wouldn’t contend either the U.S. has shared the recordings with Cuba’s government.
Another big doubt remains: Even if you know you’re under attack, what do you do? Still doubtful by what’s causing this, the United States has been at a detriment to offer advice.
The embassy’s confidence officials have told staff if they trust they’re being attacked, they should get up and pierce to a opposite location, since the attack is doubtful to be means to follow them, the commenting people said. The AP reported last month that some people gifted attacks or listened sounds that were narrowly cramped to a room or tools of a room.
At slightest 22 Americans are “medically confirmed” to be affected, the State Department says, adding that the series could grow. The attacks started last year and are deliberate “ongoing,” with an occurrence reported as recently as late August.
Cuba has shielded its “exhaustive and priority” response, emphasizing its zeal to support the U.S. investigation. Cuban officials did not respond to requests for criticism for this story but have complained in the past that Washington refuses to share information they contend they need to entirely investigate, such as medical records, technical information and timely presentation of attacks.
The recordings also seem to order out one probability for a high-tech weapon: electromagnetic pulses.
The extended array of symptoms reported, including those not simply explained by sound waves, had led to questions of a probable x-ray or radio call device frying physique hankie from afar. Research conducted by the U.S. military decades ago showed that short, heated “pulses” of microwaves could impact hankie in the conduct in a way that was interpreted by the ear as sound, definition that a x-ray device could potentially “beam” sounds directly into people’s heads.
If that were the case, the sounds wouldn’t show up on a recording.