Long range acoustic device - Tech FAQ (2023)

it isLRADor the Long Range Acoustic Device developed by American Technology Corporation, can emit a maximum of 151 dB of sound within 30 degrees of where the device is pointed. This device can be used to deter combatants or as a crowd control device, blasting painful sounds into the ears.

The LRAD weighs around 210 kilograms and can emit sound within a 15 to 30 degree beam. The LRAD has a range of 300 to 500 meters and, at maximum volume, can emit sounds 50 times the human pain threshold, allowing it to cause permanent damage.

Sound propagation principles used by LRAD

Sound waves propagate in all directions as they travel through a medium and lose strength in proportion to the distance from the source. However, high-frequency sound waves travel less than low-frequency sound waves. Also, sound waves with longer wavelengths travel much farther than those with short wavelengths. Sound waves can also cancel each other or merge into a larger amplitude sound wave, depending on whether or not they are out of phase.

LRAD applies all of the above sound properties to make the device work.

The technology behind the LRADLong range acoustic device - Tech FAQ (1)

Instead of the usual diaphragm that normal speakers use to create sound, the long-range acoustic device uses a set of piezoelectric transducers that can convert electrical energy into sound. These piezoelectric transducers are permanently polarized, so any deformation of the shape of these transducers creates an electrical impulse and vice versa. By using a power source to deliver this electrical pulse, piezoelectric transducers can rapidly change shape, creating sound waves in the process. The drivers are also arranged in phase with each other so that the resulting sounds they emit can be combined to make the projected sounds louder.

The tone that the LRAD produces can be steered so that the propagation is lower than normal. This results in a 20 dB drop in volume 15 degrees out of beam. This directional sound propagation stems from the fact that the LRAD uses external and internal transducers to generate sound waves that are not completely in phase with each other. This allows other sound waves to cancel those at the other end of the beam. The resulting sound wavefront is also flatter than normal, preventing sound from propagating as it travels. Also, as the sound waves generated by the LRAD interact with air, they create additional frequencies within the wave, which enhances the tone.

Pros and cons of LRAD

The main advantage inMilitary-miaccusationIt's making the rounds that LRAD is a less-than-lethal solution that has the potential to prevent antagonists from continuing their unwanted activities without endangering the friendly team.

The main disadvantages of the LRAD system are:

  • The loud noises emitted by the LRAD can cause permanent hearing damage to those within range.
  • The LRAD sound wave can be completely suppressed with conventional earplugs. The better the earplugs block sound waves, the less effective the LRAD will be.
  • The noise emitted by the LRAD can be reflected back to the source using a flat solid object.
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    (Video) Long Range Acoustic Devices

    I have something to say:

    29 comentarios
    1. Junkyardnuss

      April 13, 2016 at 4:52 p.m.

      They still do this to me!!!


    2. Junkyardnuss

      April 12, 2016 at 7:37 p.m.

      Poor quality vibrations and smells stopped for half an hour, so far so good. I'm 99.9999% sure it will come back. just go!
      stop-eeeeeeeeeeeeeeeeer! Goodbye forever ! My fucking neighbor can move in too, after all it was her original idea all along, not mine...I'll stay here...go! I'll be so glad to see you go with your wickedness!


    3. Junkyardnuss

      April 12, 2016 at 7:35 p.m.

      We have to live under a government that has a gentle left arm and at the same time bullies people with its right arm. Liberal? my ass!


    4. Junkyardnuss

      April 12, 2016 at 7:17 p.m.

      James, you can think of funny jokes until it happens to you... you're going to freak out!


    5. Junkyardnuss

      April 12, 2016 at 7:02 p.m.

      I am also happy to know that I am not alone, because I have always been sure of that. I hope more of us will step up until the day comes when the authorities have to start acknowledging this and say goodbye to this place!


    6. Junkyardnuss

      April 12, 2016 at 6:59 p.m.

      Darren, you may be considered persona non grata, so you're being harassed. I don't mean to make fun of you because the same thing you describe is happening to me. It's also possible that I'm smelling things that aren't there, like my brain is located right where my smell is... and I'm frying... I don't know... vibrations in the earth. 🇧🇷 Right now, I'm assuming someone is digging under my house and running some kind of power generation there to make extra money selling it to the local utility because I noticed my neighbor's meter is slightly different than mine. It seems they don't pay anything for electricity because they have a big generator under my house during power outages that blow up the local transformer so often. My neighbor is using my property without my knowledge let alone my consent which I would never get! I am currently implementing countermeasures to temporarily halt its operations. But they came back anyway.


    7. Junkyardnuss

      June 14, 2015 at 11:48 p.m.

      They're obviously trying to run you out of town... for some reason, you can only dream for yourself. At least you still have the basic right to defend yourself if you still like your own block. So be it... Fuck her!


      (Video) WHAT IS "LRAD"

    8. Junkyardnuss

      June 14, 2015 at 11:45 p.m.

      james., LRAD is not audible.. rattles in your bones.


      • roberto

        April 11, 2016 at 8:34 p.m.

        LRAD is certainly audible. It can be used to transmit many different types of sounds.


        • Junkyardnuss

          April 12, 2016 at 6:41 p.m.

          Yes, audible is one of them, but there's a lot more to LRADs than you might think. I don't know if you are trying to trick other readers into believing that LRADs are strictly audible, which they are not. LRADs are used on terrorists held captive in Cuba to harass them. Infrasound can go through walls and through your bloody bones and skulls!
          My neighbor, with the help of the local police in Antioch, California, definitely uses this on me. It is torture and agony!


      • roberto

        April 11, 2016 at 8:34 p.m.

        A guy is painfully loud and squeaky.


    9. Junkyardnuss

      June 14, 2015 at 11:44 p.m.

      I agree with you because similar things happen to me too. Is it your neighbor's work? this is called bullying. Call a harassment lawyer, but will the lawyer listen with understanding?


      • Junkyardnuss

        April 12, 2016 at 7:08 pm

        It's funny that the fluttering stopped so suddenly after I posted this one above. But hey, I know it's coming back anyway. I'll be very greatful!


    10. microphone winner

      July 23, 2014 at 1:24 PM

      Instead of reflecting back at the source, find a softer target. The reflected sound will not be as loud. Reflect on something vulnerable and less protected.

      Give each one a lightweight acoustic shield (based on a foam core), about 24 square inches. Give it a good coat of polish and paint it with beautiful thoughts on dangerous acoustic weapons. Orient the panels in the direction you want to convey your views on the use of these dangerous devices by vulnerable people.


    11. tongue

      May 10, 2013 at 12:04 PM m.

      (Video) LRAD - Long Range Acoustic Hailing Devices

      The abuse of LRAD transmissions leaves the United States vulnerable to a new generation of attacks on our privacy: fail-safe.


    12. Devan Beiswenger

      January 16, 2011 at 5:26 pm

      Is it possible for civilians to purchase any type of LRAD and if so how much would it cost?


      • memenódio

        January 17, 2011 at 3:24 pm

        You can checkLRAD Corporation "Where to Buy" Pageand ask her. However, it's probably expensive even if they sold it to a civilian. There is an LRAD for sale on eBay, as long as it's not fake, since the seller has no reputation votes and the price is around $15,000.

        But what would you use it for?


        • April storms

          May 11, 2012 at 9:18 p.m.

          For the same thing that the police use it for. Create a fucking hassle back


        • james hampton

          August 2, 2013 at 4:37 pm

          Well, to give you an idea, you can annoy people by pointing out congested roads and explosive concert music, country westerns, xxx audiobooks, horrible 80s music, self-help tapes, in a monotone voice, the history of the most boring and simpler than you can imagine, imaginable taped ads for pills and ointments to help with a broken "tent pole", annoying insurance ads, britney spears, justin beiber and much more inappropriate/annoying material for several hours i think it's fucking hilarious.


    13. Steve Ortega

      January 15, 2011 at 4:52 am

      Would the police be legally required to prevent others from using ultrasound on others, psychologically examining them, and even diagnosing them as sitaphernia? What if charges were filed against that person or other people if they were apprehended? There are no laws regulating ultrasonic and acoustic devices. And the victim?


      • Junkyardnuss

        June 14, 2015 at 11:46 p.m.

        not ultrasonic, on the other end called infrasound, low frequency sounds mixed with other unknown wavelengths that go through walls and things down to the bone. You may not hear much about it if you don't.


        • roberto

          April 12, 2016 at 7:03 p.m.

          The LRAD was not designed for infrasound. I know you're going to argue with me, but it's rated at 1kHz to 5kHz, well within the range of normal human hearing. It is not designed for sub-kilohertz. (Infrasound is 20 Hz and below.)

          "Contrary to some reports," states the LRAD Corporation website, "LRAD does not produce the ultra-low frequency tones necessary to cause nausea and disorientation." where the human ear is most sensitive.


          (Video) Best LRAD System!... For Your Money
          • Junkyardnuss

            April 12, 2016 at 7:10 p.m.

            The pure bullshit is gone now!


            • roberto

              April 12, 2016 at 7:21 p.m.

              Absolutely not. Feel free to ignore me, but under no circumstances will I leave. Your refusal to believe the facts is your problem. I checked the specs and they are not designed to emit infrasound. You can easily check it yourself. But your categorical refusal to deal with this shows me that you'd rather complain about coconuts than understand what you're talking about. To generate infrasound with high enough decibels, a completely different setup is needed. Usually with a rotating subwoofer.

              Not on one side. The brown note doesn't actually exist.

          • Junkyardnuss

            April 12, 2016 at 7:18 p.m.

            Robert, if you're sure this isn't LRAD, you still don't have the correct name or pertinent term with lawyers or law enforcement where applicable...maybe secret agent...pig


            • roberto

              April 12, 2016 at 7:35 p.m.

              What do you mean "I can't think of a name or term"? Want to come up with a name or term for your fictional infrared sound gun? Of course not, because it's not out there. Like I said, they use audible sound at very high decibels.

              The main + of Lrad is that they are highly directional and if you are out of the beam you will not be affected.

    14. aj ballard

      October 11, 2010 at 1:18 PM

      The LRAD was developed in 2002 by General Dynamics, Bath Iron Works Advanced Technology Division, for the US Navy in response to the attack on the USS Cole.

      The correct term for this technology is the Acoustic Hailing Device and there are other manufacturers such as Ultra-USSI who make the Hyperspike Acoustic Hailing Device and IML Corp who make the Sound Commander.


      • Junkyardnuss

        April 12, 2016 at 6:44 p.m.

        I don't think the LRAD is very new, as it has probably evolved over time with the latest advances in sonic engineering and such. This is probably the reason why so many people have gone insane and been committed to psychiatric institutions through no fault of their own. They were probably considered persona non grata anyway. So why not break your head?


      • Junkyardnuss

        April 12, 2016 at 6:45 p.m.

        The cruelest irony is that these Americans who are being harassed by other Americans have nowhere to go if they want to escape America... Come on, think about it...


        (Video) Long Range Acoustic Device (LRAD) G20 Pittsburgh


    Do noise Cancelling headphones work against LRAD? ›

    Noise-cancelling headphones are good at cancelling low-frequency sound, but the deterrent tone of an LRAD is high frequency.)

    What are the side effects from long-range acoustic devices? ›

    Short-term exposure to loud noise like the LRAD's deterrent tone may cause a sensation of stuffed or ringing ears, known as tinnitus, which can cease minutes after the exposure or last for days. Other sound injury symptoms include headaches, nausea, sweating, vertigo, and loss of balance.

    What is the policy for long range acoustic device? ›

    A Long Range Acoustical Device may only be deployed with the approval of the Watch Commander or Incident Commander. In a rapidly evolving event where there is the likelihood of serious injury or property damage, trained personnel are permitted to deploy the LRAD for use as a communication tool with supervisor approval.

    How do long-range acoustic devices work? ›

    An LRAD is a loudspeaker-like device that emits a focused beam of sound. What makes these systems unique is that rather than transmitting sound like a loudspeaker in many directions (similar to the way a lightbulb emits light), LRAD systems transmit sound in a narrow beam (much like a flashlight).

    Can people hear my background with noise cancellation? ›

    A noise cancelling microphone is designed to help eliminate noise from your environment. This means the person you're speaking with shouldn't hear much of what's going on around you. That said, this feature is designed for the benefit of those you're speaking to, and not for you.

    Can you still hear with noise cancelling? ›

    Noise-cancelling technology cannot completely isolate sound due to the air trapped between your audio device and eardrum. However, the air is important for you to be able to hear music. Suppose you were able to remove the trapped air, the net effect is silence, no matter what volume your music is on.

    Can sound waves damage your body? ›

    Loud noise can damage cells and membranes in the cochlea. Listening to loud noise for a long time can overwork hair cells in the ear, which can cause these cells to die. The hearing loss progresses as long as the exposure continues. Harmful effects might continue even after noise exposure has stopped.

    Can acoustics affect hearing? ›

    The acoustics of a room or other indoor space plays a crucial role in how easily and comfortably you can hear. Acoustics have a particularly big impact on people with hearing loss, and can make it either possible or impossible to hear what is said.

    What are the effects of LRAD? ›

    Police usually use models that are not quite as powerful as the military-grade version; however, generating levels ranging from 137 dB to 154 dB, they are capable of causing pain, disorientation, nausea, migraines, and permanent damage. The NYPD's LRAD use was to be challenged in US federal court in 2020.

    What frequency is LRAD? ›

    The LRAD's siren is one of its main deterrents. It is specially designed to be weighted to transmit sound loaded in the frequency range where human hearing is most sensitive, roughly 2,000–4,000 Hertz.

    What is the basic requirement of good acoustic? ›

    an appropriate reverberation time. uniform sound distribution. an appropriate sound level. an appropriately low background noise.

    What does an LRAD sound like? ›

    The principle behind using an LRAD as crowd control, rather than for long-distance communication, is similar to the idea behind a whistle or a siren: they all emit tones in the most sensitive range of frequencies for most humans. At a distance, an LRAD deterrent tone may sound like any other alarm.

    Can you block an LRAD? ›

    Low quality ear plugs will dampen the effects some, but if the LRAD is close enough and pointed at you.... You better cover your ears. Or get industrial hearing protection, which will block it completely.

    What is the main role of acoustic devices? ›

    Acoustic Hailing Devices are designed to deny access into/out of an area to individuals, move individuals through an area, and suppress individuals. This technology has the potential to support multiple missions including: Force protection.

    Does sound power level change with distance? ›

    According to the inverse square law, it can be shown that for each doubling of distance from a point source, the sound pressure level decreases by approximately 6 dB. Examples of points sources could include valves, small pumps and motors.

    Does noise cancelling block talking? ›

    Unfortunately, they're not great at blocking sounds that are high-pitched and fluctuating. A classic example of this is people talking. While noise cancelling headphones definitely reduce noise, you shouldn't expect absolute silence from them.

    What frequency does noise cancelling work? ›

    Noise from conversation ranges from about 200Hz to 4 kHz—but noise-canceling systems don't work above 1kHz or so.

    How do I block out background noise? ›

    How to get rid of unwanted background noise when recording
    1. Get close to the mic. ...
    2. Find a sturdy mic stand. ...
    3. Use pop filters to block out plosives. ...
    4. Opt for dynamic mics in noisy environments. ...
    5. Use clean electrical sources. ...
    6. Record in the quietest room in your house. ...
    7. Check your plugs. ...
    8. Watch your gain levels.
    Jul 29, 2022

    How do I know if my noise cancelling is working? ›

    There are a few ways to check if Noise Canceling is On:
    1. Place both earbuds in the charging case, leave them for a few seconds, and then remove them from the charging case. ...
    2. While wearing the headphones, tap the touch sensor until you hear Noise canceling.
    Feb 2, 2022

    Why wont my noise cancellation work? ›

    Sometimes Active Noise Cancellation can be affected if debris or earwax builds up in the area shown below. If this happens, you might experience: A loss of bass sound. An increase in background sounds, such as street or airplane noise.

    What headset does not pick up background noise? ›

    What are the best noise-canceling headphones for most people? ZDNET deems the Sony WH-1000XM5 the best overall noise-canceling headphones based on price, compatibility, battery life, isolation technology, noise reduction, and more. However, the Sony WH-1000XM4 are a close runner up.

    What is the most harmful sound frequency? ›

    The most dangerous frequency is at the median alpha-rhythm frequencies of the brain, 7 hz. This is also the resonant frequency of the body's organs.

    Which frequency is harmful to humans? ›

    For frequencies from 100 kHz to 300 GHz, tissue heating can occur and must be limited.

    What frequency is painful to humans? ›

    In addition to decibel levels, harmful sound frequencies can also be damaging to human hearing. Low frequencies (under 20 Hz) and high frequencies (above 20,000 Hz) that humans cannot perceive can also affect the ear and have adverse effects on our health.

    What are the 3 things that can cause hearing damage? ›

    Causes of hearing loss include:
    • Damage to the inner ear. ...
    • Gradual buildup of earwax. ...
    • Ear infection and abnormal bone growths or tumors. ...
    • Ruptured eardrum (tympanic membrane perforation).
    Apr 16, 2021

    What sounds can damage your hearing? ›

    A whisper is about 30 dB, normal conversation is about 60 dB, and a motorcycle engine running is about 95 dB. Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears.

    What affects acoustic signal? ›

    The circumstances that surround acoustic signals can also alter their meaning. These include the time of year, time of day, spatial location, weather conditions, and physiological state of the organism (such as reproductive state).

    Do noise Cancelling headphones block everything? ›

    Noise isolating/cancelling headphones significantly reduce the sounds you hear. But they can't completely turn off your surroundings. As mentioned, noise isolating headphones create a physical barrier to muffle the sounds around you.

    Are there noise Cancelling headphones that block all noise? ›

    There aren't any headphones that block all sounds. Even the best headphones can only reduce noise, not eliminate it. Active noise-canceling headphones electronically minimize background sound, while noise-isolating headphones use silicone or foam to seal around your ears.

    What dB level is LRAD? ›

    The LRAD is device that can put out a highly directional “beam” of incredibly loud sound, up to 160 decibels (dB).

    What damage can an LRAD do? ›

    As a rough reference, standing directly behind a jet engine as it takes off is between 130-140dB, and a nearby gunshot rates at approximately 150db. Anything over 140dB will cause pain for most people, but even sounds over 120dB can cause permanent hearing damage from even short periods of exposure.

    How far can you hear LRAD? ›

    Typically, this range is 50 meters or less. In addition to its "voice" feature, which acts as a loudspeaker, the LRAD has an "alert" feature, which emits loud chirping or beeping sounds, which can be used at the top of the decibel range of the device. These sounds have been reported to cause pain and hearing damage.

    How do you block an acoustic wave? ›

    Adding dense material to treatment helps stop sound waves from exiting a source wall, ceiling or floor. Materials include mass-loaded vinyl, drywall, soundproof sheetrock, plywood, fibreboard, concrete or rubber. Different widths and densities in soundproofing material reduces sound within a variable frequency range.


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