LRAD - defend your ears from their new tool.

reply to post by Talltexxxan


Nope. A mattress will not stop the microwave device. I just saw an update about that device on the evening news one to two weeks ago. The reporter was complaining that, although the military has had this thing ready to go for quite some time, they still have not used it in Iraq or Afghanistan because the commanders didn't trust it to be effective and refused to use it. They did a demonstration where the reporter held a mattress between himself and the device, which was a few yards away. He could not stand it for more than a few seconds.

reply to post by gidwa

What about those lead vests that they put over you when having x-rays done at the dentists? If somebody were to make a jacket and pants out of those I imagine it would work. Although if you needed to run at any point you'd be hosed because that would be quite heavy lol.


Edit: Burst out laughing to myself when I pictured Kramer from Seinfeld in a scenario like this. Struggling to run from a riot squad weighed down by lead stuffed clothing.

Originally posted by bobs_uruncle

Originally posted by Jameela
would having an Mp3 player headphones in and listening to your Mp3 player be a protection against this?

Or is the only protection going to be expandable foam ear plugs?

No, that wouldn't work and dependent on the frequency of the LRAD, even expanding foam plugs wouldn't work. If the sound pressure transfers through the skin and bones in the head, you've got a serious problem. You know the old saying, "fight fire with fire?" That stands as truth in this case, except you fight an audio wave with an equal but inverted audio wave. I don't know if this is feasible however as it is sound pressure, your inverted source would have to be far enough away from your ears that it didn't damage your hearing.

But here's a thought... If you made a helmet that had at least one layer of vacuum with a baffled breathing system and the space between the inner part and outer part of the helmet was suspended by elements that were either magnetic (not touching) or were resonant at a much higher frequency than the LRAD signal, the vacuum would stop the sound. If it isn't patented, anyone can do it now, I just made this method using a vacuum and magnetic suspensors public knowledge ;-)

Cheers - Dave

Ohh very nice thank you! that was very informative!

reply to post by Jameela


Here's another trick for everyone when it comes to insulating against load sounds/noise. I built a recording studio, the wall roof and floor were easy, I used 6" studs, put in 4" sound insulation and a 1/2" of polystyrene on each side, inside the walls and the roof (I also put in grounded foil and screen but that was for EMF protection). Then I put down two layers of 3/4" rubberized underpad (with screen again for EMF) plus 100 ounce carpet. The inside of the walls were 2.5 lb "egg carton" shaped formed sound insulation foam (about 4" thick - from a company in Detroit, it was 72 cents a square foot, great price). But I had to have a window and here is where the trick comes in, the window was 2 feet high and 4 feet wide. Normally you would get a ton of sound through something that size especially when there is up to 2400 watts RMS pushing 125db+ on the other side of the wall. What I did was I set up 5 glass panes, that were spaced differently every pane, so, 1.5" between the first pair, 1" between the second pair, 3/4" between the third pair and 3/8" between the 4th pair. This very effectively attenuated the sound levels down to next to nothing.

You could use the same kind of technology, not as extreme however in a very large "headphone-like" format with sound insulation on the outside and then a series of movable baffles or dampers on the inside. That way you'd have sound insulation when you need it and would be able to hear when the sound insulation isn't in use.

Cheers - Dave

The reason this stuff isn't used in Iraq and Afghanistan is that, unlike here in the US, the locals will shoot back with live ammo. Here, it's used on unarmed crowds who will not for one reason or another defend themselves. Why anyone would voluntarily put up with this kind of abuse is beyond me. The purpose of demonstrations is to get leaders/rulers to listen and to support your side and change their policies. Surely people must have figured out by now that Obama's about as interested in changing policy as is, say, Mitt Romney. Nonviolent civil disobedience and this "the whole world is watching" stuff hasn't done a damned thing to change anything, not now and not for the last nine years or so. Maybe people could put two and two together for once and figure out more effective ways of changing things.

Reflect it back at them, get large wooden boards and aim it back. See how they like it.

reply to post by THE_PROFESSIONAL

Would that really work though? I mean if they're all standing there holding up large wooden boards, that just leaves them vulnerable to an assault.

reply to post by Xaphan


Boards also provide physical protection from one side like batons etc..Boards are defensive in nature.

It would be also advisable to look at the patents of such devices:

Patents Related to LRAD

This is in order to study the technology and to learn ways to defend against it.

Just smash the damn thing.

Resist.

(also - Mirrors or other reflective surfaces might send the frequency back out. Although I don't think ear muffs or ear plugs will help much as effectively the device is using YOUR body as the acoustic resonator.

Frequency is the pitch of a sound, and is determined by the space between sound waves. Short distances between waves give a higher pitch and longer waves give a lower pitch. Pitch or frequency is measured in Hertz (Hz). Named for Heinrich Hertz (1857-1894) the measurement simply means cycles per second. In this case a cycle is one wave. Since the speed of the waves is fixed at (speed of sound) the number of waves occurring in a second determine the sound's frequency.
Amplitude is the volume of a sound wave. The larger the compression and decompression of the air from the normal atmospheric pressure the louder the sound is. Amplitude is measured in decibels (dB). Unlike the Hertz the decibel has no fixed unit, but rather is a measurement of relationships between sounds. However, there is a convention as to sound pressure level . The threshold of hearing is measured at .0002 microbar. This measurement is one of atmospheric pressure, it means that the faintest sound perceivable to young human ears is 1/20000th the pressure of the average atmospheric pressure measured at sea level. The "threshold of hearing" is listed as 0db on a conventional sound level chart. Another common reference is the " threshold of pain" which is listed as 140db on a conventional sound level chart.

owyheesound.com...

Now let's have a looksee at LRAD product itself:

www.lradx.com...

LRAD provides the acoustic performance, flexibility and reliability needed for operation at distances from 10 to 3,000 meters. LRAD’s beam width, frequency range and maximum continuous output ensures 100% intelligible communication over distance and loud background noise. Each LRAD model presents the loudest and most intelligible product in its size and weight category. LRAD’s performance record coupled with military construction and survivability standards has made each model the communication tool of choice for police departments and military units around the world. Additionally LRADs provide a portable capability in a rugged lightweight waterproof casing, as well as the option to operate the device remotely across an IP-accessible network. LRAD can provide communication solutions to meet any operational requirement.

also:

science.howstuffworks.com...

The LRAD uses the phase of the sound waves, the size of the device and the properties of air to create more directional sound:
The outer transducers are not completely in phase with the inner transducers. The sound waves interact with one another, canceling out some of the outermost waves and making the sound less audible outside of the "beam."
The device's diameter is larger than most of the wavelengths it produces. This allows the device to create a wave front that's more flat than rounded, keeping the sound from dispersing.
Air interferes with sound waves as they pass through it. As the LRAD's sound waves interact with the air, they create additional frequencies within the wave. Such waves are referred to as parametrically generated, and many speakers try to prevent them. The LRAD uses them to create a greater range of pitches and to add volume

Basic specs for the LRAD 2000x:
Range: 8,900 meters (speech)
Beam width: +/-15° @ 1.0 kHz/-3dB
Maximum output: 162dB SPL at 1 meter

www.currentcorp.com...


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Higher frequencies are easier to reflect and diffuse, although I still say smashing it would be more effective

Originally posted by mr-lizard
Higher frequencies are easier to reflect and diffuse, although I still say smashing it would be more effective

More fun, too!