Anyone who has tuned a pipe organ has experienced a sound similar to this example, the “warbling” is caused by two notes of different pitches being played together. I have experienced mild headache and dizziness after prolonged exposure during the tuning process. Old CRT displays sometimes make a similar screech.I’m glad flatscreens have replaced them!
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I’m sorry … it just sounds too much like all those attacks of mass hysteria you used to hear about at workplaces or public schools or whatever… one kid/person gets nauseous and yells about funny smells, and the first thing you know every one is passing out and calling 911 to report non-existent gas leaks or chemical spills or something. Then, a thorough investigation reveals that there IS no gas OR chemicals etc. and the whole thing was just hysterics. Sounds a whole lot like this situation to me …
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I was scrolling down the comment thread to see if anyone would hit on this possibility. I know from some very limited experience during the bad old Cold War days that the Soviets were always engaged in technology attacks and broad based evesdropping against US personnel. We generally established electronic perimeter defenses that jammed their attacks and made it safe once you within the embassy compound.
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You read my patent !
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What the US needs to do is invent an app that listens out for the sound, and if it appears then to send out an alert. The manhunt can then begin. Further, if enough people are using the app, the position of the device should be easy to triangulate.
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The recorded sound is the interference pattern between multiple sound sources. They need to install sophisticated directional-detecting equipment and extremely high-frequency recording equipment. I suspect that the large signals have frequencies that are well-above the spectrum of human hearing, and what is currently recorded is just the interference pattern between multiple high-frequency signals.
Realize that high-end high-fidelity audio equipment reproduces sound way above the spectrum that humans can hear. The best of us can hear up around 20 kilo-Hertz, but high-end audio systems can produce 100 kilo-Hertz. This is because most percussion instruments and some non-percussion instruments in Orchestras produce interference patterns that are in the human-perceptible audio range, and it’s the interference patterns produced when the super high-frequency sound is reproduced that we hear.
We weld plastic with ultrasound. What do you think those high frequencies will do to neural tissue at high power? Look at the spectrum provided under the “Ultrasound” section here: http://www.learneasy.info/MDME/projects/A1A2_project/robot_sensors/robot_sensors.htm
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Yes, I can hear it. And it hurts. It’s like a needle being jammed into my ear. But as much as this hurts, the recording embedded in the article hurts much more.
ETA: I actually still have some residual ringing from the embedded audio. This must be hours later. Sheesh.
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The difference is that in this case, people have detectable ear and brain damage. Mass hysteria victims don’t have objectively detectable infections or damage to their bodies.
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You don’t necessarily want to hear the human-detectable sound except to alert the victim to escape. You want to detect the sounds that are at much higher frequencies than the human-detectable sound. Why? Because it will be much easier to triangulate on the super-high frequency sound. The human-detectable sound is an interference pattern.
Just curious: How can you tell?
I am late to this and haven’t read all the comments, but isn’t it likely the Russians who don’t want Cuba to have better relations with US? And they got their boy who did what they’d want.
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errr, and which cord is discord? I thought it was dat cord over there.
For one thing, I know math. Among other pursuits, I do signal processing. I’ve done a lot of research during my long life. You can take multiple sinusoidal frequencies and produce interference patterns easily, and you can show the interference patterns mathematically. As a simple example, if you play guitar, then go ahead and barely detune two adjacent strings and try to play the same note. If the two frequencies are off by 1 Hertz, you can hear the interference pattern, and it produces a 1 Hertz beat.
If the interference pattern is 10 kilo-Hertz (kHz), then the beat pattern you hear has that high obnoxious 10 kHz pitch. If I wanted to make a weapon that did damage and used sound, I would use ultrasonic frequencies, and I would use multiple piezo-electric transducers arranged into an array to do it. Now, if the piezo-electric transducers get a little warm and start drifting their frequencies a bit, they will produce an interference pattern, but those lower frequency interference patterns will only contain a small fraction of the power compared to the really dangerous weapon-frequencies.
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Not only the damage, but the number of folks as well … a healthy dose of cynicism is OK once in awhile, but in this case your cold water didn’t reach … too many medical issues in too many folks …
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Yeah. No way Cuba came up with this, at least not on their own. I mean, they’re driving cars from the 50’s there still for Pete’s sake.
Sounds like a high pitched dentist drill to me.
Maybe someone is drilling a tunnel underneath the embassy.
Got me. 
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That wasn’t actually an answer. I know you can create any waveform over a time window from a fourier series. I understand the basic concepts of what interference patterns are. What I was asking was how can you tell the sound in this recording was produced by multiple sound sources creating an interference pattern?
Thank you for this. Makes sense to me, BWDIK? A rational explanation regardless. The notion that what is recorded is a result of some other ultra high frequency sounds makes a really good avenue of research. As does the idea that really high frequency sounds can cause real damage to human tissue.
Maybe we can test this theory on an embassy in Washington?
Owie… Not good. My cat’s ears pricked up when I played it but my dog slept right through it, but she’s already a bit deaf. You should really put a warning on that audio before posting. Its been over 10 minutes since I played it for only 20 seconds or so, and the ringing in my ears is still happening.
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oh, right, they used stuff from the Conet Project, didn’t they…
I’ve listened to a bunch of those Conet recordings… really creepy stuff.
How can I tell? Occam’s razor for one thing, but that’s likely not very satisfying for you to read, so I apologize in advance. You aren’t going to do neural damage with 10 kHz unless the volume is hell-raising paint-blistering wall-heating ENORMOUS. However, if you have reasonable volume at ultrasonic frequencies, you can melt plastic and burn neural tissue without sound, except for the sound of the interference frequencies. Furthermore, the only way to realistically produce the needed volume at these ultrasonic frequencies is with multiple piezo-electric transducers. If they are arranged in a flat array (say, like the flat radar array on an Aegis missile cruiser), then you can modulate the voltage and phase to each transducer and direct a concentrated ultrasonic beam just like they direct radar energy and efficiently paint the sky with radar. Now, this array might be reasonably portable, so you could place it on the side of a building, or in a wall, or the side of a vehicle. Understand that as the transducers heat up, their frequencies can drift apart, and it is this drift that produces the interference frequencies. To keep the frequencies tight together, you’d need to carefully cool the transducers to nearly the same temperature.
If you have two coherent single-frequency sound sources, then with the simplest model, you have one interference frequency. If you have three sources, you have as many as three interference frequencies. As the source quantity increases, the quantity of interference frequencies grows dramatically, because each source can interfere with all the other sources as each source frequency drifts. Furthermore, in extreme cases the interference pattern can also interfere with the sources and produce harmonic beat patterns. Does this make sense to you? It gets more complicated if the transducers produce a spectrum that is not a single frequency.
Edited to make the text more accurate.
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