There is a large history of sonic weapons, starting from the Havana syndrome, though various weapon patents such as Voice-to-Skull (V2K) and with the pinnacle maybe being Long-range Acoustic Devices (LRAD)s due to marking the moment when sonic weaponry became blandly mainstream and less covert by joining the standard police riot arsenal.

As it stands, there should be some fundamental principles that all these devices subscribe to, as well as some cultural and political environmental factors that could explain their usage and application. Similarly, in terms of technology, there shold also be a scale in terms of sophistication that these weapons are able to perform at; clearly and LRAD is a crowd-disperser because it can emit a large amount of noise, V2K does a bit more in terms of maybe being able to suggest or maybe there are lesser variants of the former that run in the wild unnaccounted for and designed by third parties.

The following page will focus on a lower variation of a sonic weapon that more than likely is part of the Havana syndrome, seems to have been misdiagnosed as Tinnitus but does not perform all that spectacularly compared to V2K and is more of a makeshift harassment device that just leverages a few principles of physics and human hearing. Similarly, the page will set some context as to the possible origin, observed characteristics and will offer a way that has been found to be foolproof for defeating the weapon with the most elementary and readily available components.

• operator, the person or people using the weapon,
• subject, the individual that the weapon is being used on

The noise is perceived as a barely-audible pulse, somewhere in the upper-audible range, very similar to a very short hiss, akin perhaps to a short burst of TV static. The noise pulses can vary slightly in terms of amplitude and duration but they seem to hoover around more or less the same high-pitched frequency audible to humans. Similarly, multiple pulses can be delviered in succession instead of one longer pulse.

For audio professionals, there might be "industrial" equipment out there, such as a wide-spectrum microphone frequency analyzer that would be able to listen on all frequencies at the same time in order to hopefully read a spike within the upper part of the audible hearing range for humans. However, it does go without saying that such equipment is expensive, and even if a pulse is observed, there is still the lingering problem of burden of proof to prove beyond a reason of a doubt that the pulses are intentional and also have the intent stated in this document. Generally speaking, unless the subject is an acoustic professional, we generally would not recommend going down this route due to the former, as well as the fact that this weapon is easily dispelled otherwise without having to resort to purchasing expensive equipment. Bear in mind that as stated before, the weapon is more than likely used as part of a police and/or espionage operation such that there is more "in the air" than just this "clicker"-device and it is a good policy for the subject to conserve their resources.

More than likely the noise is not measurable with a Software-Defined Radio (SDR) because it clearly must be at least barely audible by a human being, such that investing in such an equipment does not make sense for the study of this weapon in particular. Of course, it is always nice to know what sort of EMI/EMF pollution exists around oneself, especially around living quarters where the purpose should be the pinnacle of relaxation but given that an SDR greatly exceeds the audible range, it's usage would not make much sense for the detection and study of this device.

Detecting the noise is a matter of taking some time to learn the weapon usage patterns in relation to everyday activities because compared to medical conditions such as Tinnitus, the weapon is not random in terms of contextualization and works on the most basic of Pavolovian punishment and reward principles by trying to dissuade or encourage the victim to prefer some actions over others. For instance, noticing that the weapon is used more intensely for a given activity, rather than a different activity, first makes it clear that the noise is not random and secondly would suggest that the operator of the weapon is trying to either dissuage or encourage the activity in question, depending on the reaction of the subject to the weapon. In many ways, this weapon is no different than, say, a cattleprod, a shock collar, or any other coercitive device meant to influence behavior.

Perhaps it might vary on a cultural level in terms of how a subject would deal with such a weapon, maybe some people would consider that the manipulation is "cool" and they are being drawn into some "secret agent" stuff, or maybe other people might outright consider it obnoxious and would rather not hear it at all. Obviously, the more a subject is capable to ignore the harassment, the more the operator must go out of their way to even further increase the intensity of the weapon as well as its contexualization relative to everyday activities.

It is realizable that such as device would require a feedback system, in particular, in terms of observability where the use of the weapon has to be coupled with some espionage like microphones or cameras in order to gauge the reaction of the subject and then have the operator adjust the usage pattern to match depending on whatever the set goal might be. With that said, we recommend caution because the data spill from the espionage itself, including irrepudiable or "kompromat"-like data collection, perhaps even as an implicit result of needing observability of the subject, might be the largest threat and the largest generator of long-term damages making the weapon seem more like an infaturation after the largest amount of damage has already been dealt.

Given prolonged use, which seems to be one of the usage pattern, it is possible that the weapon might induce some form of nausea, clearly, even from the obnoxious properties alone of being exposed to excess noise, even if inducing nausea is not an explicit goal. Similarly, the weapon is also used to keep a subject awake, during the night, for example, by delivering the annoying pulses when they try to fall aslepp, thereby waking them up, maybe even several times till they are unable to fall asleep again. The former also does not seem like an explict goal but could be easy to accomplish given the weapon and some observability. Of course, taking the former to the extreme, the obnoxiousness can lead to an increased aggressivity, decrease in willingness to participate or cooperate as well as any other feature that would carry over from any other exposure to something annoying.

The following is a list of properties based on past reportings with some comments:

• underground tunnels seem to hamper the intensity of the noise in terms of amplitude (noise level), although not completely
  • the emitter placement is then possibly airborne or on satellites,
• being in motion always suppresses the noise entirely, and also makes it seem like the operator must continuously recalibrate the weapon to account for the motion, with the noise sometimes falling spatially either in-front or behind in terms of spatial hearing perception,
  • planes and plane travel do greatly decrease the noise but does not suppress it entirely,
• the weapon does not seeem to work with certain architectural or geometric distributions such that there are perceivable gaps; ie: standing under a certain desk that is placed in a certain position of the room, etc, might diminish the noise levels, up to completely suppressing the noise,
• running electronics seems to "influence" the noise in certain ways such that if the power is cut off completely, the noise is suddenly very difficult to perceive
  • this might be attributed to bias, corroborated with the fact that the weapon seemingly needs (re)calibrations to be made in case the environment or gemoetric disposition changes, such that surrounding electronics might, in this case, just be some property of the environment that would change when the power is shut off
  • the weapon does recover after a while even with all the power and othe electronics shut off
• small possibilty that cats might hear the pulse too
  • as this chapter would imply, the noise might actually not represent an exact pin-point targetting of an individual but rather be scoped to a large area but for other people in the vicinity the short burst might not be that easily perceived if it is not contexualized or attributed to some activity

Perhaps the most infamous sighting of this weapon, assuming it is the same one by judging on the symptoms of witnesses, is the renowned "Havana syndrome", with the earliest being sometime in 2017 in Cuba where U.S. personnel at the U.S. embassy in Cuba started to experience noises that were similar to "Tinnitus" yet they were described as the noises produced by "grasshoppers" (the latest reporting incident being as close as 2021). Nevertheless, the "Havana syndrome" seems to be a more ample bundle of symptoms that are not specifically tied to the high-pitched "Tinnitus" noise, but rather seem to also pan around "nausea", "tiredness", "memory loss" and others, with some of the staff describing the event as "noise pressure", akin to opening a window while driving, instead of the actual characteristic "grasshopper" noise.

It might be that the weapon is somewhat more complex or that various "upgrades" exist, some of the functionality being able to just emit acute noises, and maybe some other part being able to emit "vibrations" closer to what an LRAD is capable of doing. Also, depending on the purpose, whether it is general harassment to make a person go away, or maybe conditioning, it seems clear that various intensities or styles might be possible.

In terms of intents and purposes the accounted-for "Havana syndrome" incidents almost always pertain to diplomatic or espionage personnel, with the actual victims appearing to be staff with a certain degree of threat. It is not excluded that regular "civilians" would be targeted the same way, maybe, if they are important enough or would have some value to offer with the value always being relative to the region of the world where they would be harassed. Admittedly, there is little collection of data when it comes to citizens reporting these symptoms so the "political aspect" of the Havana syndrome might just be reporting bias, given that the people working in a diplomatic context would definitely be mentioned and would know to whom to report such incidents whereas a regular civilian might just be dismissed by a regular doctor for "symptoms of Tinnitus".

As it turns out, reporting of the "Havana syndrome" are exclusively attributed to diplomatic personnel of first-world countries. Democratic and open forms of governance generate private wealth as opposed to a top-down hierarchical forms of governance (or oligarchies) where wealth is stored at the top, which, in context, might explain why occurrences of this sonic weapon would be under-reported in developing countries where civilians might not end up a target. Another important factor that would hint that the weapon is of "Eastern"-origin, perhaps ex-Soviet satellite countries or other developing regions that have had a well-established track record for carrying out espionage and mass-surveillance, is that this sonic weapon couples great with notions like "political psychiatry" or, more generally, would work great in regions that criminalize and outlaw various psycho-pathologies or deviations from a base normal with the complicity of medical staff. Many times, due to their developing nature, any aberration from the base-normal (whether it works to the advantage or disadvantage of the subject) in these geographical areas, becomes a privilege for abuse, either by medical staff, or by the government for purposes ranging between political infighting of groups and up to becoming a showcase or flaunting piece for outbound propaganda or even passed as hand-me-down intentional information spill by the police to organized crime for the sake of generalize repression or suppression of the people. Lastly, another hallmark of Eastern-nations would be the low technological development of such areas that helps with occluding the usage or existence of such weapons that might either lack the imagination or any "real-life examples" to corroborate their experience with; the same would not apply to first-world nations where the use and abuse of technology has been thoroughly documented publicly. Just become only one nation admits publicly to mass-surveillance does not mean that they are the point-singularity of the planet, but rather that other countries might still persist in doing so unapologetically.

Eerily the weapon usage seems unbelievably widespread by lots of reports on "Tinnitus" that could not really be explained in terms of any medical evolution of human beings. For instance, it seems that there is a boon of papers after the 1960s studying Tinnitus with an ever-increasing amount of cases that does not seems to be too justified in terms of organicity. Some of the statistics are more than likely biased in terms of medical observability and reporting over time that might make the statistics increase just due to people being more forward with reporting their medical condition by seeing a doctor. However, medical checkups were well in effect even before the 1960s such that the surge seems awkward without any other explanation. Nevertheless there is also a steady increase in the age groups, in particular younger age groups that report "Tinnitus" more than before, that also does not seem to be justified too well given that "Tinnitus" is attributed to people above the age of 60 and up.

Ironically, regardless of the science and tracing back maybe via symptomatic manifestations, certain sleeping-aids devices seem to have mysteriously appeared on the market, along with lots of reports from people claiming that they need "sleeping aids", autonomous sensory meridian response ("ASMR") or other parasympathetic technologies just to manage to relax or fall asleep. Medical staff attribute the symptoms usually to generalized stress, habitual patterns, bad nutrition or even Schizophrenia. Whilst stress might indeed be a mood changer, it would be very rare that stress alone would trigger outright hallucinations, especially without any history, in large populations with members that are otherwise very socially or civically functional.

For example, there is a sharp emergence of "sleeping headphones" that are designed to be worn while falling asleep that have some built-in memory and will resort to playing back various "ASMR" tunes, like waterfalls, rain or melancholic music that helps the body slide into sleep. The reviews on such devices, just taken by the sheer quantity alone is baffling making it seem that "Tinnitus" should rather be studied epidemiologically than some quaint medical condition surging since the 1960s, with hundreds upon hundreds of users sharing their experience with the "sleeping headphones" as well as their story on how they work for them. From time to time, within those reviews, you can find stories that do not resemble "Tinnitus" but would rather indicate the usage of the weapon described above, in particular due to the person writing the review claiming that there are contextual differences when the noises that occur vary with the individual's activity rather a constant hissing noise that defines the "Tinnitus" condition.

Lastly, the use of psychotropic drugs, even if prescribed by a doctor should really be limited to emergencies or personal emergencies because their usage in context is silly. First, the drugs will sedate the victim instead of doing anything to the operator and it would be a more sane solution to find the operator and hold them responsible. Second, and here's the cookie cutter, psychotropic drugs have the side-effect of rendering the subject even more suggestible such that the task of the operator is made even easier if the subject is under the effect of drugs.

The best way that we have found to suppress this device is to slipstream some noise into the regular material that is being listened to by the subject. The method was derived intuitively off the "age-old" claim of people that report these annoyances and that also claim that listening to noises of "waterfalls" seems to blur out the noise. More than likely due to the speed of water falling at high speed, a waterfall emits noise in the upper-audible spectrum of the human hearing range such that a recording of a waterfall works perfectly for blurring out the noise of the weapon or rather diluting the intent of the noise pulse at a given moment within a pool of similar noises.

In other words, coming back, and after having observed that different activities trigger different noise patterns trying to dissuade or encourage a subject to prefer one action of the other, in case a constant stream of "waterfall" noises are played back, then the pulses emitted by the weapon in different contexts cannot be distinguished in intent anymore. Just pure pedantry, but playing back the waterfall noise has the same effect as joining the contexts together such that it become unclear what action the subject is hinted to when the noise is always the same regardless of the device being used or not.

There are two properties of sounds that seem to be relevant for defeating this weapon and those are the sound intensity (or sound pressure) measured and the actual frequency range being used. Observably, the intensity varies a little depending on the operator using the weapon but the frequency seems pretty fixed to a small range that never seems to slide between some hard-limits.

There seems to be a very nice article "Evaluating water sounds to improve the soundscape of urban areas affected by traffic noise" by Jin You et al. in 2010 ¹⁾ that seems very close to the methodology that will be applied here to defeat the sonic weapon and that seeks to blur out urban noises produced by high-traffic noise pollution like in China by leveraging the noise patterns of natural oscillators like waterfalls or fountains.

The authors explain the "blurring" that we mentioned by using the term masking and make the same argument that the ample noise (in terms of point-density of noise pulses) produced by oscillators such as waterfalls or fountains have the statistical effect of shadowing any noise that is falls within the noise generated by the oscillator such that the noise is then not perceivable by the human subject. We are just going to use the same figure (balled Figure 3 in the article) that the authors offer but it will be cut up an overimposed such that it will offer a quick, dirty and yet effective overview of the actual "masking" that the authors intend to perform.

The blue band (frequency range around the mark) corresponds to the noise produced by falling water and the black band also around the mark represents the noise produced by road traffic. The time and dBA can be used to convert to frequency and the results would indicate that the two noise generators could be made to overlap in terms of intensity and frequency such that playing one on top of the other achieves the masking effect. The authors proceed to explain the methodology through which they started to vary the intensity of the "falling water" noise to the effect of gradually blurring out the road traffic.

Note that the purpose of the article by Jin You et al. is to mask out noise pollution for road traffic and it is important to observe that the road traffic noise takes place unintentionally such that its distress is marked in terms of overall discomfort produced by its abundance but that in terms of defeating this sonic weapon, where the purpose is to trigger noises at opportune moments to change behavior, the blurring or masking of the noises is even more important given that the usage pattern of the weapon is intentional.

Human hearing is said to range from about to about with some peculiarities, for example, the best heard frequency being centered on average at about . However, there are other points that seem interesting in context, given that they represent "peaks" that the ear is capable of distinguishing better than the neighboring sloping frequencies.

There seem to be "inflexion" points at , and that can be marked on the same chart that we are going to label "impressionable" points because these points represent statistical anomalies where a frequency delivered precisely on that point is easier to perceive by a human subject than the rest of the other surrounding points.

The base case is at , which is thoroughly documented, where any sound or noise at is heard much better than any other noise across the whole human audiogram and hence why it is the best heard frequency. However, the other points cannot be excluded because a noise delivered at those frequencies is easier to distinguish from the rest. In layman terms, if a human is listening to a TV show that produces a varied spectra of ups-and-downs in terms of frequency to noise, then if a noise pulse is delivered at , or the noise has a chance to be heard much better over the sound produced by the TV show even at matching noise intensities. In other words, delivering a pulse at should be perceived by a human being much better than a noise pulse at , which might seem strange and counter-intuitive given the assumption of a linear hearing distribution, but it follows immediately from the plot.

To check this theory, an online tone generator can be used that will generate tones at various frequencies, with different intensities (volume) and various sound patterns. It was found that the noise matching the weapon the closest was a , sawtooth pulse played back at a higher volume. Interestingly, we managed to get ahold of an individual that confirmed that this configuration matches the noise that they are perceiving the closest.

With all that in mind, it is clear that the tomfoolery takes place somewhere beyond the mark and perhaps the next-up peak is used at in order to make it a distinguishable noise to the subject of the weapon from the typical baseline hearing mark common to all individuals.

In order to use the same counter-measures as Jin You et al. on masking urban noise, a tone generator could be used that would play back a noise across a frequency range within some headphones, a tone that would be over and up that would then overlay with the regular usage patterns of the headphones. However before devising such a fine-grain blur, we can take a look at noise colors that represent standardized patterns of frequency-to-noise distributions that are conveniently labeled for their typical usage in audio filters.

In essence, we are going to create a band-pass filter, very similar to HAM radio band-pass filters, but a filter that would apply to the human audible range instead. That being said, given that it is known that the weapon noise is located somewhere at , it is desirable to pass all frequencies lower than while blurring or masking all frequencies above, say , with the final resulting aspect of the filter being a slope that starts from the middle of the audible spectre and then slopes up all the way towards the high-end of the audible spectre.

Then, looking at the noise colors, it seems that we'd need a generator that can generate blue noise, or, being more specific, purple noise because those patterns seem to blur our the desired frequencies. In order to see this better, the color noises can be overlaid on top of the human ear frequency response that was shown earlier in order to observe what part of the audible spectre the noise generators would blur out.

With that being said, some blue or purple noise or both of them combined has the highest chance of succeeding to mask this sonic weapon while at the same time having the effect of letting other frequencies pass through. This means that you could watch a movie or even listen to some music with some blue or purple noise overlaid on top in order to not be distracted by the weapon noise.

Most DJing software solutions should work and there are just oh-so-many-variants to playback two or more sounds at the same time. A good and minimalist one is Mixere that can overlay multiple audio tracks and then play them back at the same time synchronized and overlaid. It was chosen to play back both a blue and a purple noise track at the same time for a better coverage of the possible frequencies that could be generated by the weapon.

Note that the frequency-to-intensity plots showing the noise color patterns should rather be interpreted in terms of "shape" rather than frequency-accurate representations and that playing back either blue, purple or a combination thereof should be coupled with the adjustment of the volume in order to find the sweet spot where the setting will work best for blurring out the noise generated by the weapon. The only drawback is mostly habitual, in the sense that it is an extra chore to play back the compound sounds but the method works pretty well to remove most of the suggestions that the weapon operator is trying to confer to the subject.

Otherwise, you can experiment with a digital frequency generator in order to produce some noise that would match the weapon noises even closer simply by varying the frequency and observing what works best at masking the noise whilst also being ideal at passing through the rest of the frequencies. Overall the method is not that great given that the operator is able to change the sound intensity such that the weapon might generate a peak that would be heard over the baseline background noise that is meant to mask the weapon but there are various tweaks possible such as randomly changing the volume of the background noise in order to counter such issues. It is also possible to change the wave shape, which might be more effective at defeating localized sound spikes, but most of the work is done once the frequency of the weapon is determined and from then on out, it's just a matter of optimizations.

We review some of the available hardware that seems to be specific for the purpose of eliminating sleep distractions that also carry value in terms of reducing the weapon noise. Just some examples are shown, mostly because they were reviewd in-shop and we have some hands-on experience with them, but given Chinese manufacturing it is perfectly viable to be able to find something at a fraction of the price that would work just as well or even better.

Just as theorized, the high-frequency noise emitted by the weapon passes right through the ANC on regular headphones, with ironically, the best "ANC mode" for masking the weapon noise being the "transparency" setting where real world noise is mixed with the sound being listened to by the user. This seems due to what ANC accomplishes in terms of "isolation" with ANC being supposed to provide some sense of "focus" to the user by narrowing their audible attention span to the actual sounds being listened to inside the headphones. With the ANC turned to blocking out external noises, this unfortunately generates an attention echo-chamber where the focus of the user is even better at picking out the weapon noise and obsessing over it rather than blocking out or masking the noise in the first place.

Again, this interpretation is lightly advanced and ANC will generally speaking manage to block out the weapon noise but only to some degree, after which, depending on what is being listened to, if the sound has any gaps, the weapon will still be effective at deterring attention or being suggestive relative to the content being watched or listened to.

Otherwise, regular headphones have the only drawback of being too large to be slept on when the subject turns on their side but headphones, in general, combined with a sound mixer are the standard way to blur out the weapon noise. Given that this weapon has also been sensed outside the home, it also makes sense that the headphones should be wireless and portable in order to be worn when needed in all situations. Additionally, at the time of writing, music players like MP3 players are unbelievably cheap due to Chinese manufacturing quantities such that the user has a very large choice to pick something minimal that would be able to play back noise colors in order to mask the weapon noise.

The combination between a regular headphone set and a cheap music/MP3 player are perhaps the baseline tools to mask the weapon noise.

Perhaps one of the most representative earbuds are the Anker Earbuds A20 that are created following a kickstarter crowdfunding and are specifically designed with defeating anything from sleep apnea to helping any sort of sleep disorder by integrating various elements such as a medical-design that makes the buds minimal enough to fit seamlessly inside the ear, Automatic / Electronic noise cancelling (to be done in the next followup release of the ear buds) and with built-in sensors that detect when the wearer falls asleep, at which point the earbuds commute to playing back a noise preset that can be created by the user as a combination of various sounds like waterfalls, fountains, noise colors, etc.

The Android application features a noise mixer where the user can pick and mix various sounds that the earbuds will play back when the earbuds switch to "sleep mode". As can be observed, the things that we talked about are already there, with "violet noise" and "pink noise" being some of the choices, along with the more Zen-inclined choices like waterfalls, forests and so on that are meant to mask background noise.

The buds more than likely have an internal memory and the sounds presented in the Android application mixer are more than likely seamless short clips that are then repeatedly played back by the ear buds.

The reviews for this device are overwhelming, and for the purposes of this document, in terms of quantity with a tremendous amount of people commenting on them and documenting their usage with way too many reviews mentioning issues along the lines of "Tinnitus" to be purely an organic manifestation.

Anker Earbuds A20 are not the only ones with other companies following shortly by releasing their own variants of earbuds designed as sleeping aids and with that said, the criticism we have is to be interpreted purely in terms of class of technology with the problems revolving around earbuds being an issue of architecture constraints that make the earbuds a good but expensive solution to get right. Here are some of the problems and design challenges that would make effective sleep ear buds difficult to create or would bump up the price just due to constraints:

• the buds have to be designed to fit seamlessly inside the ear while keeping in mind that the user should be able to sleep on their side without the ear bud sticking out of their ear and pressing against the pillow, which makes these sleep earbuds very small with a range of consequences across the board that limit the capabilities of the earbuds just due to that,
  • battery lifetime is short due to the small size and no room to fit a larger capacity battery; battery lifespan is also short and prolonged usage will very speedily reduce the battery lifespan with the battery also being in most cases, not only the Anker Earbuds A20, unserviceable by the user and cannot be replaced,
  • the main difference between sleep earbuds and regular earbuds is really just the size such that depending on the situation, the ear size of the person, the pillows and others, it is possible to just use regular earbuds and just play back the masking noise, provided that the earbuds are not annoying to sleep on,
• ear wax can easily block the small speakers of the earbuds to the point that there is literally no noise coming out of the earbuds making them seem broken,
• the automatic switching specific to the Anker Earbuds A20, that switches from listening to "sleep mode" based on a sensor that detects when the user falls asleep is superfluous and not necessary, as well as being a little bit of an anti-design given that the user typically has problems falling asleep in the first place but after that the noise being mostly irrelevant; with that said, just a manual approach would have been enough and most users report switching off this feature that takes up design space unnecessarily while not providing anything too practical,
• the Android application specific to the Anker Earbuds A20 allows users to generate sound mixes based on presets but we were unable to determine whether the user can upload their own soundclips (apparently, it is not possible) and while there are a lot of presets available, right about any user that has the know-how to use these ear buds also has the know-how to google or find their own sounds on YouTube and then play them back with software like Mixere or any other sound application; Youtube alone has an impressive amount of seamless "1 hour" or even "10 hour" looped tracks available for various sounds, snippets of music clips and others that can just be downloaded, converted to a sound clip and then used with the ear buds making the Android application for the Anker Earbuds A20 cute but ultimately not really necessary,
• active noise cancelling (ANC) only marginally manages to block the weapon noise that we are documenting such that having earbuds with or without ANC is mostly the same; interestingly, we have found that the weapon noise is actually dispersed more easily when the ANC-mode is "transparency" that ironically is a mix between outside noise and the audio being listened to

All-in-all we've found that sleep earbuds in general, even regardless of the brand, are a beautiful display of technology but the constraints make such earbuds a whim just for the purpose of defeating this weapon noise, "Tinnitus" or sleep apnea with very cheap variants being available that make such an expensive device unnecessary. Don't get us wrong, the Anker Earbuds A20 are so pretty and comfortable that we would want to wear them ALL the time, not only for the purpose of sleeping or dispersing the weapon noise, but for this document they represent perhaps the best item on the market that regrettably is overpriced for the purpose.

Sleep headbands are the best solution that we have found to be the most effective in defeating this weapon while at the same time being compatible with sleeping such that a subject will be able to seamlessly transition between performing daily tasks and taking naps. Additionally, sleep headbands are way larger than sleep buds and hence have way more wiggle room in terms of technological design, allowing for larger speakers, better and larger batteries and able to integrate even more technologies such as ANC at a bargain price.

There are just so many brands and sub-brands of these devices that are all Chinese knockoffs off each other that are great at masking out the weapon noise while being available at prices as low as ten bucks. Ironically, as cheap as they are these headbands have a huge playtime that reaches up to half a day playtime due to the battery being located at the front with the observation that the user will never end up sleeping with their face flat down. Most of these headbands, just like the earbuds, have Bluetooth connectivity with very standard chips that are compatible with any device that can play back sound ranging from mobile phones to desktop computers.

Furthermore, these headbands are remarkably comfortable, maybe less-so aesthetically pleasing than headphones that they can even be a replacement for regular heaphones. Due to their design that hides two speakers inside the headband, with a controller and battery hidden at the front, the headband is also impermeable to some degree making them useful for regular usage, sleeping, working out or sports events as well as being a "better alternative" to listening to music inside a helmet given that ear buds might have the tendency to fall out due to vibration.

We were unable to ascertain the existence of "high end" music headbands in order to cross-check the feature-set with the feature-set of the "ten bucks headbands" in order to determine how the price would scale with the effectiveness at masking out weapon noise. In fact, the only headbands available on Amazon are still low-cost and no-brand headbands and the low-cost headbands work so well that it is difficult to speculate what could be done better aside from the standard "optimizations" like adding a larger battery.

To be fair, these are perhaps the best variant of headphones that can defeat the sonic weapon being discussed in this document and it can do so for about ten bucks; ten bucks for which the whole psychological suggestive mumbo-jumbo just falls apart. We are so impressed with these, compared to the alternatives and given the low cost, that we have no words and never thought that defeating the noise weapon would be so easy.

One of the efforts in Eastern Europe starting from a few years back to the time of writing is the "thermal isolation" of Soviet-style rebar residential buildings. The process involves applying a coating of Styrofoam plates all around the building block in order to increase the thermal isolation of the building. One of the interesting side-effects of the effort is that Styrofoam is also great at reflecting sound frequencies with the "impressionable points" of the human audible spectra falling very conveniently in the most absorbed frequency ranges of Styrofoam.

A paper by Magda E. Tawfik et al. in the Journal of Applied Polymer Science titled "Hard wood-composites made of rice straw and recycled polystyrene foam wastes" offers a plot of the most absorbed noise frequencies by the various types of Styrofoam.

The figure is labeled with "Sound absorption coefficients of recycled expanded polystyrene foam waste (PS), hard wood composite (HWC) and hard wood-composite with maleated polystyrene (HWCg)." and it can be observed that frequencies above seem to be absorbed very well by "polystyrene foam waste" (PS) as well as hard-wood composite (HWC) marked as the blue, respectively orange plots on the chart.

In fact, the Styrofoam acts like a band-pass filter for the most relevant part of the human audible range dampening both low and high frequencies that are not easily heard by the human ear, thereby providing some very nice isolating for very annoying sounds in both extremes of the audible frequency range. It is one bet that the Styrofoam will hence provide some dampening of the weapon itself, in case the source of the weapon is on the outside of the building, which somehow seems to be the case to some level given the difference in dampening relative to the outside.

Of course, this is not to say that the effort to increase the thermal isolation of buildings factored in the audio properties of the Styrofoam but it is worth mentioning because it is very incidental that Styrofoam provides great sonic isolation at a very cheap price.

Even though not directly related to the weapon analyses in this article, there is a technology related in terms of being a sonic weapon, that has amassed some interest over time with the usual discussions oscillating between "it's a myth and you're crazy" and some actual patents and other documentation being brought to light.

The technology is loosely named "voice to skull" or V2K for short and in simple terms it is a "telephatic technology" that allows an operator to seemingly "inject thoughts" in a subject's mind but without other people in the surrounding area being able to hear the voice of the operator.

This technology is actually available over the counter and is related with the hissing sonic weapon in terms of the properties of human hearing. One of the public circuits is made by Kazunori Miura from Japan and it was published in Elektor magazine back in March 2011. The following image shows the circuit realized and available to be purchased over the counter on Amazon.

And we took the liberty to save the pages from the Elektor March 2011 magazine for archival and documentation purposes that pertain only to the circuit itself short of having to upload the entire magazine such that the documentation that describes the circuit and functionality can be consulted locally.

The functioning principle is also simple, a high-frequency oscillation is used as carrier "noise" for the very purpose that the hissing sonic weapon also picks high-frequencies, namely that the higher-frequencies travel at higher speeds and also have the property of being more directionally focused than lower frequencies that tend to bleed into every surrounding object (ie: low-hum vibrations). The carrier "noise" is then used to modulate a simple voice recording such that the high-frequency noise will just be the carrier but the voice will still play back normally when delivered. The combined effect of a high-frequency carrier and a regular recording will manage to project the voice recording over long distances and with the additional property that the device can be oriented to a subject in a crowd and only that subject will hear the voice.

Looking at the circuit, the device is pretty easy to create, the bottom left part of the circuit being just a voltage regulator based on a typical 7812 chip that we have used many times at Wizardry and Steamworks for various projects and the upper part of the circuit seems to rely on two ICs and represent the implementation of the device. The only cost sink would be to obtain the small ultrasonic speaker array, so one would have to purchase small speakers in bulk. However, Amazon has one such device available that unfortunately only ships to the U.S. and goes for USD140.

What is interesting to us and the reason we mention this V2K device on this page rather than on its own page is that when we analyzed the original sonic weapon resembling Tinnitus, we actually speculated without knowing for sure about those "impressionable" points that are characteristic to human hearing, by stating that those frequencies, namely , (which is the best frequency to center any audio device on that is meant for human hearing) and are more than likely the transmission frequency that one would like to chose for a concealed sonic weapon because those frequencies are heard better by the human ear than the surrounding frequencies (lower than to some point and higher than to some point) such that they would stand out in terms of perception to a subject. We even stated that the frequency seems very attractive because it is fairly high compared to the baseline such that it also has the property of achieving a better penetration in terms of projecting the sound through various mediums.

What we noticed while browsing around to find this ultrasonic V2K device is that the specifications mention that the device is made to work on which matches our hypothesis that those frequencies would be the frequencies to use for (concealed) sonic weapons.

Before this turns into the terrorism section looping around from counter-terrorism or starts looking like the Anarchist's cookbook, one idea would have been to purchase this device and then mount it on a PTZ caddy that we designed for the Catchaser 2000 ROV (or just use an older PTZ camera for the extra benefit of seeing the direction precisely) and then start sending secret messages to people in a crowd.