The Many Uses of Sound
Each night for many years, I wake up in the wee hours to use the restroom. No big deal, it's perfectly normal and healthy behavior, done it all my life. However, within seconds of becoming conscious, I am blasted by a horn lasting three seconds. The pitch of the tone is always the same, a slightly flat variation of D major. Now mind you I don't wake up at the exact same time every night or morning as I am on no clock. It may be 2:35am or 3:42am, but this event occurs often at my waking; thereby indicating that my waking up is not coinciding with someone's scheduled activity such as the railroad or other entity. It is a huge disturbance to me and I'm sure others in the region may not be too fond of it either. In any case, I'm up then to fast forward into my day.
Can Sound Be Used As A Weapon?
Yes, in simple ordinary ways sound can be used as a weapon. It may be used to injure someone or cause some kind of harm. One can use a thumping stereo to annoy another or regularly sound a loud horn at them, maybe where they live or work. These minor occurrences of tyranny happen all the time across the country. Unfortunately, there are larger staged and engineered sounds and devices used for larger intentions of the crime. Read on.
Infrasound and Acoustic Sound
Among the most infamous developers of infrasonic weapons was a Russian-born French researcher named Vladimir Gavreau. According to popular media at the time, Gavreau began investigating reports of nausea in his lab that supposedly disappeared once a ventilator fan was disabled. He then launched a series of experiments on the effects of infrasound on human subjects, with results (as reported) ranging from subjects needing to be saved in the nick of time from an infrasonic "envelope of death" that damaged their internal organs to people having their organs "converted to jelly" by exposure to an infrasonic whistle. By the time 166 dB is reached, people noticed problems breathing. Gavreau had patented these, and they were the basis of secret government programs into infrasonic weapons. (Source: Popular Science) The only records of such are found in personal notes, journals, and regional media reports of the time. I would suspect that working for the government in secret, no official or public records of Gavreau's study or findings would be recorded.
Sound As A Tool
We all know of many every day uses of sound in our lives as tools. From the beeping alert of your microwave telling you it's done to various other sounds and uses such as burglar alarms or emergency vehicle sirens. Even my phone beeps to let me know when its internal battery is fully charged or running low. Warning and guiding sounds are everywhere too. They can help a blind person cross the street. Even a whistle can be used to call your dog. The possibilities of using sound as tools are endless.
Naval warships carry a device known as sonar used for detecting other vessels or objects underwater such as mines. Sonar transmits a sound whose resonant frequency sound waves travel through the water and bounce back when striking an object. By receiving and interpreting the strengths and characters of the return sound wave, Naval personnel can determine things such as the size of the object or even its precise location. This use of sound as a tool could also be construed as use as a weapon of both defensive and offensive capability. For example, knowing exactly location of an enemy submarine could enable the Naval vessel to launch an attack upon or in defense. Sonar and sound have both proven invaluable in military applications and many other useful and practical purposes.
Resonance and Sound Waves
All objects posses what is known as a natural frequency, or a frequency at which that object vibrates. If you tap a fork against a wineglass, the tinkling sound it produces is its natural frequency. Any sound reproducing that same natural frequency will cause the glass to vibrate. This common phenomenon is known as resonance and occurs because the sound displaces nearby air particles which crash into the glass like invisible waves. When the sound is amplified, these waves get more powerful. With enough amplification, the glass can vibrate so strongly that it shatters. All sounds travel on sound waves which are based on the frequency. Its frequency is defined as a specific measured pressure against a medium such as air. Knowing that sounds can be used to fracture solid materials, ask yourself; How fragile are you?
Take off your glasses or remove your contacts first. If you sit in front of a very good-quality sub-woofer and play a 19Hz sound or modulate it to 19Hz, Your eyes will twitch. As you turn up the volume, approaching 110 dB, you may even start seeing colored lights at the periphery of your vision or ghostly gray regions in the center. This is because 19Hz is the resonant frequency of the human eyeball. (Source: Popular Science) Prolonged exposure could cause blindness. I'll discuss the effects of sound on our ears and other organs in another article. For now, we have a testimony, our evidence and a crime.