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Using Sound as a Weapon: How Sound Frequency and Pressure Can Cause Pain or Worse



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As mainstream media and liberals push for more stringent gun control measures including restricting gun magazine sizes and ammunition purchases, I’ve often wondered how we could make this behavior a “non-problem.” Then I got an idea, and I’ve been researching it ever since.

What if we could develop a defensive weapon that wouldn’t require firearms, ammunition, or permits? What if we used a completely different technology—one that isn’t controlled by the government? What if we used sound?

What is Sound?

Sound is all around us and much of it is comforting to humans—the pleasing sound of nice dinner music, a breeze wafting gently through the trees, gurgling water flowing in a brook, or the sounds of children playing—our world is alive with wonderful sound. For most, sound is a welcome reality. But when sound becomes noise, it increases stress and introduces emotional reactions in our lives and relationships. In fact, sound can distract, disorient, frighten, or injure.

Sound is a pressure wave. As such it occurs at a certain frequency. These cycles have amplitude (measured at the peaks) defining the power or intensity of the sound wave. Think of it like “loudness.”

We hear sounds by the frequency of their pressure waves around us. We call this pitch. A high pitch is a high frequency sound wave and a low pitch is a low frequency sound wave.

As shown in Table 1, we can’t hear some frequencies, although some animals can.

A chart comparing the hearing capabilities of humans, dogs, cats and elephants.

Table 1

Sounds between 20 Hz and 20,000 Hz are considered within our normal threshold of hearing. Sounds below 20 Hz are called infrasonic or infrasound. Low frequency infrasound at high dB can cause tremors inside our organs and it hurts! Sounds above 20 KHz—our upper range of hearing—are called ultrasonic. At 500 KHz and higher we label sounds megasonic. We can be affected by these sound frequencies, too. Sounds that occur outside our normal threshold of hearing are felt rather than heard. This presents interesting opportunities for controlling threats.

Table 2 shows some typical frequencies generated by sound sources:

A chart showing the frequency in hertz of various sound sources.

Table 2

As we age, our ability to hear high frequency sound decreases. This is why seniors can’t hear the buzzing of mosquitoes or even some drizzle. Animals can, and this is why many people keep dogs. They can hear and alert on danger long before we become aware.

The intensity or power of sound pressure is measured in decibels (dB). The decibel provides a relative measure of sound intensity. The higher the dB rating, the more volume sound has.

The intensity of a sound wave decreases with increasing distance from the source (inverse square law). The power (intensity) of sound is approximately equal to 1/d2 where d equals the distance from the sound source.  Double the distance, d and sound pressure (dB) drops to half its intensity. A 40 dB sound at 1 meter drops to 20 dB at 2 meters and just 10 dB at 4 meters. At 0 dB—the softest sound—your ears and brain search for something to hear.

Table 3 shows typical dB ratings for various sounds.

Table 52-3 dB Source 300

How loud is sound? The ear’s response to the loudness of sound occurs as a power of 10. It takes about 10 times the power to sound twice as loud. Loudness varies with age and the physiology of the person. Still, more intense sounds will appear loudest.

Sounds that Alert or Warn

Table 4 lists sounds that can stimulate action.

Table 52-4 Sounds that warn 300

Sounds that Calm or Soothe

As shown in Table 5 certain sounds can calm and relax a person (or an animal.)

table 5

There’s a story in the Bible (1 Sam. 16:23) about a young man named David who used sound to calm a belligerent, angry, and discontented King Saul. David would take out his lyre, a small harp, and play for the king. The sounds of this musical instrument soothed Saul’s emotions and he’d chill out.

You can buy sound devices that can produce calming sounds to help you relax and fall asleep.

Sound as a Deterrent

Make a sound that’s irritating to a person and you can deter that person from certain action. Teenagers don’t like sounds around 20,000 Hz and will try to distance themselves from this sound. A 20 kHz hum has been used to move loitering teens off streets or away from school playgrounds at night. Likewise, a high-amplitude sound can be used as a burglar deterrent.

Some frequencies aren’t heard. Sounds below 20 Hz or above 20 kHz can prove effective in warfare.

Generate high intensity sound below 20 Hz and people will feel the effect without hearing it. An ultra-high frequency blast at 19-20 kHz will disperse protesters and rioters—especially the younger ones.

Sound That Destroys Matter

By creating sound at the natural frequency of matter, we can cause various materials to vibrate. At enough energy, we could cause this material to break apart and disintegrate. There are devices that can do this today.

You need a strong sound pressure wave to make this happen, but the frequency of a sound generator equal to the natural vibration frequency of a material causes resonance and the amplitude of vibration of the material increases many-fold until the atoms in the material actually break apart.

In a ‘Walls of Jericho’ scenario, sonic warfare is used to destructively shatter objects and material. It takes a directed concussive effect to vibrate structures to rubble, and infrasonic energy to shatter bones and pulp organs from within. But it could be done. You would need a 240 dB source to get a person’s head to resonate destructively.

These sound waves would have to come from very loud objects, sound waves so powerful they could knock down walls and shake machines to pieces. Several college students showed that low frequencies between 30 and 60 Hz can actually extinguish a small fire using high intensity sound.

It’s possible to shatter glass with sound by producing a note that resonates sympathetically with the glass.

The natural frequency of earth is 7.83 Hz. Gold can vibrate at 1.7 MHz—silver at between 4.047 and 4.652 MHz. Even copper can vibrate at just over 28 MHz. The magnetic field around earth can reduce the resonant frequency of material.  For silver the resonant frequency in the Earth’s magnetic field would be a low audio 80 Hz (not 4+ MHz).

Sound That Injures or Kills

Between 0 dB and 90 dB, sound intensity is normal and typically won’t damage hearing.  But exceed 90 dB and hearing damage can occur if exposure is prolonged. Your body can tolerate 85 dB of sound intensity for eight hours without hearing damage, but at 100 dB, you can only take this for 15 minutes before it affects your health. And at 115 dB you are safe for only 30 seconds. This is why ear protection is recommended for all noisy environments. At 140 dB physical pain can be felt. Go above this and life becomes threatened.

An extremely high-power sound (160 dB) can disrupt or destroy your eardrums and cause severe pain or disorientation. This is usually sufficient to incapacitate a person. Less powerful sound waves can cause you to experience nausea or discomfort.

Loud sounds could also cause a seizure or heart attack. High-intensity (loud) ultrasonic sound (generally anything above 20 KHz) can cause physical damage. When Krakatoa erupted in 1883, it produced a sound that was recorded at 190 dB over 100 miles away. The shock wave ruptured the eardrums of sailors 40 miles away. Sound can be powerful. Theoretically sound could take down a drone.

As sound loudness increases, its effect on human beings and material becomes important. Sonolysis uses cavitation sound waves to break molecules apart and form small bubbles with an intense shock wave that can destroy materials. A milder form of cavitation called “lithotripsy” destroys kidney stones during medical procedures.

We’ve all watched the effects of shrill sounds in sci-fi movies, when an entire group of people were made helpless by a loud sound that permeated the area. They held their ears and fell to the ground unconscious. And movie-goers wondered if this really could happen.

Yes it can.

Several years back, a garage inventor created the ability to place sound energy at a specific location while canceling sound in other nearby areas. He could create the sound of rushing water within a narrow circle in a crowd. People in that circle could hear the water, but people a few feet away could not. This concept is used in shopping malls to lure shoppers.

Focused sound technology was successfully used at checkpoints in the Middle East to stop approaching vehicles far back from where guards were stationed. The device deterred suicide bombers or at least gave the checkpoint forewarning that a vehicle was not responding to orders to stop and be searched.

The garage inventor formed a company (LRAD) and designed sonic and ultrasonic weapons that can incapacitate, injure or kill. Their new long range acoustic device (LRAD) is now being used by law enforcement and the military as a directed beam weapon to control crowds and deter pirates or insurgents from attacking ships at sea.

It emits a 2.5 kHz warning tone at 146 dB one meter from the emitter with a maximum range of 300 meters (where the tone is degraded to 90 dB) causing nausea, discomfort, disorientation, reduced sensory motor functions, or severe pain. By transmitting at ultra-high frequency, an LRAD blast can cause eyeballs to vibrate generating unease and visual apparitions.

The LRAD can also produce a 90 dB warning tone that reaches out over three miles. If necessary, it can emit a 146 dB tone (beyond the human threshold of pain) with an upper limit of 190 dB.  People can die from a loud noise between 185 and 200 decibels. At 194 dB a sound wave can become a shock wave blasting the body, shattering the skeleton and tearing internal organs apart, killing the recipient. The LRAD 100X hand held device is effective out to 600 meters. The LRAD 2000X is effective out to 5,500 meters (3.4 miles).

The European Space Agency has a sonic weapon that can generate 154 dB sound energy using four giant acoustic orifices. This device can burst eardrums. Increase the loudness to 185 dB and it could cause an air embolism in the lungs or explode the heart.

Whales produce the loudest low frequency sounds on earth— at around 190 dB (17 to 30 Hz). Close up, the high-intensity calls by blue and fin whales can collapse lungs and cause death to other living creatures.

A car stereo made a world record by pumping out 182 dB of sound that could instantly cause hearing loss. It wasn’t energized for long. Acceptable exposure time was in seconds.

Sound waves can cause internal bleeding and stop a human heart with a frequency that resonates with the organ. Sonar has been used in the oceans to detect and kill hostile divers by destroying organs and bone. Exposure to high intensity (184 dB) ultrasound frequencies from 700 kHz to 3.6 MHz have been proven to cause lung and liver damage. Sound can be a killer.

In the next segment, I’ll explain how you can use sound for threat protection.

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