Startling and disturbing information relative to how sound can be used as a tool of control and manipulation can be found in the pages of a formerly classified U.S. Defense Intelligence Agency document dated March 1976. Its title: Biological Effects of Electromagnetic Radiation (Radiowaves and Microwaves) Eurasian Communist Countries (you can find it at this link). Written by Ronald L. Adams and Dr. R. A. Williams, of the U.S. Army (and specifically of the Medical Intelligence and Information Agency), it notes in part:

“The Eurasian Communist countries are actively involved in evaluation of the biological significance of radio-waves and microwaves. Most of the research being conducted involves animals or in vitro evaluations, but active programs of a retrospective nature designed to elucidate the effects on humans are also being conducted.”

Of deep concern to the United States military and the intelligence community, was the incredible revelation that the Soviets had developed technology that allowed them to beam “messages” into the minds of targeted individuals. Rather notably, the DIA and the Army concluded that such messages might direct a person to commit nothing less than suicide. Even if the person was not depressed, said Adams and Williams, the technology could be utilized to plunge them into sudden states of “…irritability, agitation, tension, drowsiness, sleeplessness, depression, anxiety, forgetfulness, and lack of concentration.”

The authors added: “Sounds and possibly even words which appear to be originating intra-cranially can be induced by signal modulation at very low average-power densities.” They concluded: “The Soviets will continue to investigate the nature of internal sound perception. Their research will include studies on perceptual distortion and other psycho-physiological effects. The results of these investigations could have military applications if the Soviets develop methods for disrupting or disturbing human behavior.”

When, in the mid-1980s, plans were formulated by the iron-fist regime of then-Prime Minister Margaret Thatcher to base nuclear “Cruise” missiles at strategic military bases in the British Isles, it provoked massive demonstrations on the part of the general public – and particularly at a military establishment called Royal Air Force Greenham Common, a now-closed down installation in Berkshire, England.

As a result of the planned placement of missiles at Greenham Common, a large group of women peace-protesters set up camp outside the base. It wasn’t long, however, before many of the women began to experience a series of disturbing symptoms, including deep depression, overwhelming anxiety attacks, intense migraine-like headaches, alarming losses of short-term memory, and much more of a distinctly mind-destabilizing nature. As a direct result of this alarming and highly suspicious development, theories began to quickly develop and circulate to the effect that the women were being specifically targeted with electromagnetic weaponry, as part of an intensive effort to bring their demonstrations – which had generated a large amount of support – to an abrupt and permanent end.

Then, there’s the matter of New Mexico’s notorious “Taos Hum.” Live Science notes of the hum that it “seems to have first been reported in the early 1990s. Joe Mullins, a professor emeritus of engineering at the University of New Mexico, conducted research into the Taos Hum. Based on a survey of residents, about 2 percent of the general population was believed to be ‘hearers,’ those who claimed to detect the hum.” Those who were able to pick up the hum said it irritated them, provoked stress, and caused panic-attacks and insomnia.

In more recent years, such hums have been heard all around the world. In 2015, the U.K.’s Independent newspaper reported: “In Britain, the most famous example was the ‘Bristol hum’ that made the news in the late 1970s. One newspaper asked readers in the city: ‘Have you heard the Hum?’ and at least 800 people said they had.” Alarmingly, it was revealed that when the humming was at its absolute height, people were affected by intense migraines and even bloody noses. When the humming stopped, so did the side-effects. As for the specific sound, it was likened to a car engine which was “idling,” some distance away from the people affected.

In a 2016 article titled “A Maddening Sound,” writer Colin Dickey detailed a number of such examples, including this one: “Sue Taylor first started hearing it at night in 2009. A retired psychiatric nurse, Taylor lives in Roslin, Scotland, a small village seven miles outside of Edinburgh. ‘A thick, low hum,’ is how she described it, something ‘permeating the entire house,’ keeping her awake.”

Taylor’s initial thought was that perhaps the annoying – almost destabilizing – noise was coming from a factory close by. Maybe a generator. As a result, Taylor decided to do a bit of detective work, checking out the surrounding area, and even hanging out outside the homes of her friends and neighbors, in an effort to try and resolve the mystery. Unfortunately, and although the hum was clearly a real phenomenon, she failed to crack the mystery. Things proceeded to get worse: the hum plagued her during the night – to the extent that she even had hear ears examined by a doctor – who could find no problems at all. She began to suffer from a cross between vertigo and dizziness – to the point that she felt sick. Even the house itself felt as if it was shaking slightly.

In 2011, Andrew Liszewski wrote an article for Gizmodo with an eye-catching title: “Future Riot Shields Will Suffocate Protestors with Low Frequency Speakers.” Sci-fi, this was not. It was all too disturbingly real. Liszewski said: “It’s not the first crowd control tool to use sound waves, but Raytheon’s patent for a new type of riot shield that produces low frequency sound waves to disrupt the respiratory tract and hinder breathing, sounds a little scary.” Many might agree.