How Sound Frequency Can Cause Pain

How Sound Frequency Can Cause Pain


What will happen if we use sound as a defense weapon? This article explains the ways in which sound can be an excellent self-defense tool.

Sound as a Defense Weapon: Using Sound Frequency to Survive

 

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

Hearing Range

Hearing Range | Sound As A Defense Weapon: How Sound Frequency Can Cause Pain

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

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 as megasonic.

Frequencies of Sound Sources

Frequencies of Sound Sources | Sound As A Defense Weapon: How Sound Frequency Can Cause Pain

Table 2 shows some typical frequencies generated by sound sources:

Decibels (dB) is the measurement of the power or intensity of sound. The decibel provides a relative measure of sound intensity. The higher the dB rating, the more the 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.

Decibel Ratings of Sounds

Decibel Ratings of Sounds | Sound As A Defense Weapon: How Sound Frequency Can Cause Pain

Table 3 shows typical dB ratings for various sounds.

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

Sounds That Alert or Warn | Sound As A Defense Weapon: How Sound Frequency Can Cause Pain

Table 4 lists sound that can stimulate action.

Sounds That Calm or Soothe

Sounds That Calm or Soothe | Sound As A Defense Weapon: How Sound Frequency Can Cause Pain

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

You can buy sound devices that can produce calming sound 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 a 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 can 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.

Sonic Warfare

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 is possible. You will 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 the 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 the 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; however, prolonged exposure to sound exceeding 90 dB can cause hearing damage.

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.

We’ve all watched the effects of shrill sounds in sci-fi movies when an entire group of people is made helpless by a loud sound permeating the area. They hold their ears and fall to the ground, completely unconscious. And moviegoers wondered if this really can happen.

Yes, it can.

Focused Sound Technology

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.

The 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 and gave the checkpoint forewarning that a vehicle was not responding to orders to stop.

The garage inventor formed a company (LRAD) and designed sonic and ultrasonic weapons that can incapacitate, injure, or kill. Law enforcement and the military now use their new long-range acoustic device (LRAD) 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). This can cause nausea, discomfort, disorientation, reduced sensory-motor functions, or severe pain. By transmitting at an ultra-high frequency, an LRAD blast can cause eyeballs to vibrate generating unease and visual apparitions.

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 can cause an air embolism in the lungs or explode the heart.

The Effects of Sound Waves

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 the 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. The energy didn’t last 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. Experts have used sonar in 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 has caused lung and liver damage. Sound can be a killer.

 

Try this cool hearing test by Bright Side and find out if you are superhuman or worse than average:

As the 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 can 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 use a completely different technology – one that the government doesn’t control? What if we use sound for protection? Will you agree?

What are your thoughts about using sound as a defense weapon? Let us know in the comments section below!

Up Next: 5 Surprising Self Defense Tips To Crush Attackers

 

Editor’s Note: This post was originally published on August 29, 2016, and has been updated for quality and relevancy.

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Hi,

I have been in Seattle for a few years, but since I didn’t grow up here, I don’t know many of the fishing opportunities, especially in the winter or spring. I was wondering if and how salmon can be caught by casting from the shore in Puget Sound during the winter and spring. I had also heard about sea-run cutthroat fishing from the beach. What type of lures would you cast for them, and when and where can they be caught?



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Milford Wanderer sails the fiord.

What to Expect From Your Milford Sound Cruise


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Whether you’ve arrived into Milford Sound under your own steam via the Milford Track, or ridden the exciting 950m (3100ft) final descent from the Homer Tunnel to sea level by bus, we’re sure you’ll agree it is a magical place. The scale of the granite mountain faces, the flooded glacial valleys, and the mostly untouched forests, are simply breathtaking. Rudyard Kipling described this place as the eighth wonder of the world; it’s easy to see why.

Mitre Peak and its reflection in the still water of the Fiord.
A still day on Milford Sound gives a perfect reflection of Mitre Peak and the surrounding peaks.

So where does the name Milford Sound come from?

Milford Sound has had a bunch of name changes since it was discovered in 1812 by Sealer Captain John Grono, who named it Milford Haven after his home town in Wales. As us Kiwis have become more conscious of conservation, and protecting our Maori culture and influence, Milford Sound became Milford Sound/Piopiotahi in 1998. But wait! There’s more! Milford Sound is actually incorrectly named… A sound is a river valley which has been flooded by the ocean, and just like so much of our dramatic South Island, Milford was formed by glaciers, and so it’s a fiord. This is a popular trivia question, so take note for your New Zealand adventure!

Milford Sound has several permanent waterfalls, including Stirling Falls – more than three times the height of Niagara Falls. And Lady Bowen Falls; a short distance from the wharf area. Seeing as the granite landscape doesn’t absorb a drop of the annual 6,412mm (252in) rainfall, it made sense for Bowen Falls to be used to power the small town of Milford Sound.  It is during the regular periods of rain in Milford when the waterfalls really come alive. Hundreds of new falls cascade down the steep faces of the mountains, and if you catch Milford on a rainy day, why not name your own?

Group of kayaks approach Lady Bowen Falls
A group of Kayakers approach Lady Bowen Falls.

Overnight Cruise on Milford Sound

If you choose to take an overnight cruise on Milford Sound, you’ll be choosing luxury, tranquillity, and stunning natural beauty. You’ll board the ‘Milford Wanderer’ mid afternoon and cruise the 15km (9.3miles) out to the Tasman Sea, passing by Lady Bowen Falls, and getting close enough to Stirling Falls to feel the fresh spray from the Wanderer’s deck. As the afternoon fades into the coloured light of evening the captain will drop anchor in a sheltered cove, where you can go exploring with specialist nature guides, either by kayak or in the vessel’s small craft, until it’s time to climb back on board for your carvery buffet dinner and some stargazing with a glass of New Zealand wine.

Milford Wanderer sails the fiord.
The Milford Wanderer cruises, under sail, on the fiord.

The next morning we suggest emerging from your private cabin in time to watch the sunrise, it should help to clear your head if you really enjoyed the Kiwi wine! Then tuck in to a hearty buffet breakfast. Your captain will once again point the Milford Wanderer in the direction of the Tasman Sea, take this opportunity to do some wildlife spotting: Dolphins of three different species, New Zealand Fur Seals, and Fiordland Crested Penguins can all be seen at the right time of year in the Sound, alongside New Zealand’s vast array of native and introduced bird life. Occasionally, and most recently in 2016, a pod of Sperm Whales made the 15km (9.3miles) trip into Milford from the coast, marine biologists attributed this to the uncharacteristically low levels of rainfall for that time of year, which in turn allowed Phytoplankton to thrive, the whales’ main food source. If you get to see whales on your cruise you’ll be among a very lucky few – don’t forget your camera!

A seal swims amongst kayakers
A New Zealand Fur Seal playing amongst the kayaks.

Finally the Milford Wanderer will return to dock at the wharf, and we’re sure you’ll disembark rejuvenated, full of good food and great memories, to continue your New Zealand adventure.

Highlights of the Overnight Cruise:

  • Full length Milford Sound Cruise.
  • Optional access to a section of the Milford Track (guided).
  • Three course buffet dinner, fully licensed bar, cooked or continental breakfast.
  • Overnight on the Fiord in Harrison Cove.
  • Specialist Nature Guides for duration of the trip.

 Check out our Tui trip, Essence of the South Island, for an itinerary that includes the overnight option.

Day Cruise on Milford Sound

Several of our itineraries involve cruises on Milford Sound, it’s definitely one of the best ways to get out there and do it, to get up close with nature. The day cruise is included in our Weka itinerary, as well as our Kiwi, and Manuka trips.

Several companies operate daytime cruises from Milford Sound wharf, and we always aim to pick the most personal experience for our guests. We like the guys who only allow their vessel to be booked to half capacity, leaving you with plenty of room to chill out, roam around the decks, or visit the open wheel house and have a yarn with the Captain.

The two-hour Milford experience starts with a slow cruise up the left side of the fiord. Your captain will point out hanging forest, permanent waterfalls, and name some of the tallest peaks. The specialist nature guides on board can also help answer your questions about the geology and wildlife.

Once your vessel arrives at the Tasman Sea, the captain will turn her around and head slowly back up the opposite side of the glacial valley. On the return journey they like to point the bow towards Stirling Falls, and give you a chance, if you want, to be drenched by the spray of one of Milford’s highest permanent waterfalls. If there’s rain and wind, keep an eye out for Milford’s waterfalls to nowhere – try and grab a photo of the cascade before the wind blows it away.

A day trip boat points its bow into Stirling Falls.
A day trip boat points its bow into Stirling Falls.

We know that Milford Sound is right up there on many people’s bucket lists, and can be the greatest reason our guests choose to come to New Zealand in the first place. We have put together a list below of our trips that include either the overnight cruise, or the day trip. If you’d rather have a workout whilst you explore Milford, check out our Rimu itinerary for a kayaking option, or read our page on kayaking Milford Sound here.

kayakers taking a break on Milford Sound
Two kayakers enjoy a moment of quiet on Milford Sound.

Whichever you choose, know that the majesty of this place is reserved by its remoteness, and that by making the journey to Milford Sound itself, you are experiencing somewhere special, somewhere truly New Zealand in all its rawness, and somewhere that will stay with you long after you leave.

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