
Audio Engineers Built a Shield to Deflect Police Sound Cannons - elsewhen
https://www.vice.com/en_us/article/dyzpna/audio-engineers-built-a-shield-to-deflect-police-sound-cannons
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pjc50
Amazing how in a supposedly litigious society like America it's possible to
deploy a device which causes intentional, indiscriminate, _permanent_ injury
across a crowd and not get sued into oblivion. Bit like how tobacco, asbestos
and Kinder eggs all incurred product liability because they weren't intending
to be damaging to health, but gun manufacturers aren't liable because their
products are supposed to be dangerous.

~~~
rectang
I wonder if inflicting permanent disability without leaving any obvious
physical traces on people that the police see as their adversaries is in fact
part of what makes these devices attractive.

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DenisM
Are you saying that the police prefer dealing out permanent damage over non-
permanent damage?

~~~
voxic11
No he is saying the police have no reason to prefer one to the other if the
effects are hidden.

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ISL
It seems like a corner-cube would do a serviceable job in this context and
might be lighter, as long as the reflector is substantially larger than the
wavelength of the sound.

[https://en.wikipedia.org/wiki/Corner_reflector](https://en.wikipedia.org/wiki/Corner_reflector)

Wikipedia claims that the LRADs operate at ~2.5 kHz, which corresponds to ~13
cm wavelength. If a corner-cube is about the size of a protest sign, it might
be sufficient? As a rule of thumb, if it is about as big as the LRAD device
itself, it'll probably have some efficacy. The more-directional the LRAD is,
the more effective the corner-cube will be.

In Seattle, at least during "normal" protests, there are restrictions on the
materials used in constructing protest signs (no wood bigger than 1", etc.) in
order to limit the extent to which they can be used as weapons. One ought to
be able to pretty-readily test whether or not foam-core-board corner-cubes (or
any design) are effective reflectors with relatively low-intensity sound
sources.

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shitpostbot
Protesters should make a parabolic reflector with the focus about 50ft out.
Pretty sure cops would stop using these things instantly

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ISL
Parabolic reflectors require alignment and they bring incident energy to a
focus no matter what.

Focusing the energy of an instrument that is designed to approach dangerous
sound-intensity levels is certain to make the situation _more_ dangerous. Non-
violent action is predicated on the idea that hurting anyone, including an
aggressor, is counterproductive. A corner-cube reflector won't hurt an LRAD
operator any more than the LRAD operator is hurting others. A parabolic
reflector could.

If the golden rule isn't sufficient motivation to avoid a focal instrument,
perhaps friendly-fire will be: A parabolic reflector will always bring
parallel waves/rays to a focus at the focus. If the reflector is more than a
focal-length inside a crowd, it is going to destroy the ears of a protestor.

Like glass bottles that start fires in the Australian Outback by concentrating
sunlight, anything that concentrates sound energy in an environment with an
LRAD is a recipe for unintended consequence.

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oh_sigh
Is having a parabolic reflector a violent action? The only way it could hurt
someone is by reflecting the pain they were trying to put on you.

If I had armor that ricocheted bullets back at the shooter, I wouldn't
consider myself culpable if someone who tried to shoot me shot themselves.

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dragonwriter
> Is having a parabolic reflector a violent action? The only way it could hurt
> someone is by reflecting the pain they were trying to put on you.

Yes, violent retaliation is still violence.

Violence only in retaliation and/or self-defense may be a valid approach to
protest in some circumstances, but it's not non-violent protest.

~~~
mdorazio
You have a strange definition of 'retaliation'. If you throw a ball at a brick
wall and it bounces back and hits you, the wall didn't retaliate or act in
self-defense. The entire impetus and result is 100% on you. The same applies
here.

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dragonwriter
The first use of “retaliation” should be “retaliation and/or self-defense”,
like the other. I was staying a broader principle which applies to but extends
beyond the immediate case.

I will agree that the proposed device might (if targeted appropriately) be
more defensive than retaliatory, though the fact that it only causes harm to
the focussed-on target if someone attacks it doesn't make it purely defensive
or non-retaliatory, in fact, if not carefully targeted it makes it quite
indiscriminate retaliation.

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1024core
> LRADs have been a part of anti-protest tactics since the mid 2000’s, when
> they were adopted by police after being used as a crowd control tool by U.S.
> military forces in Iraq and Afghanistan.

Those who stand by idly while America does this to other people should
remember that what we're inflicting on them will be inflicted on us tomorrow.

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DenisM
>Those who stand by idly while America does this to other people should
remember that what we're inflicting on them will be inflicted on us tomorrow.

The US military used B2 bombers in Iraq. Do you expect these to be deployed in
Seattle any time soon?

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minikites
>The US military used B2 bombers in Iraq. Do you expect these to be deployed
in Seattle any time soon?

[https://en.wikipedia.org/wiki/MOVE#1985_bombing](https://en.wikipedia.org/wiki/MOVE#1985_bombing)

>From a Pennsylvania State Police helicopter, Philadelphia Police Department
Lt. Frank Powell proceeded to drop two one-pound bombs (which the police
referred to as "entry devices") made of FBI-supplied Tovex, a dynamite
substitute, targeting a fortified, bunker-like cubicle on the roof of the
house. The resulting explosions ignited a fire from fuel for a gasoline-
powered generator stored in the rooftop bunker. The fire spread and eventually
destroyed approximately sixty-five nearby houses.

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DenisM
Wow this spectacularly bad judgement on the part of LEO (FBI), right up there
with the Waco siege (ATF). Thanks for bringing this up, I did not see it
before.

Still, this looks like an improvised explosive device was used by the police,
and it's not an off-shot of the US military programs.

So my point still stands - just because something is deployed by the US
military abroad does not mean it will be deployed at home. To suggest
otherwise is to spread needless gloom and panic.

~~~
solstice
> Just because something is deployed by the US military abroad does not mean
> it will be deployed at home.

Maybe not necessarily in 100% of the cases but once something is manufactured
it is likely that the manufacturer will look to expand its customer base.
Hence (imo) the militarization of police across the US and indeed the world.

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rozab
>Rife and Liberti designed their shield to reflect audible sound waves that
are condensed and carried via ultrasonic frequencies

>According to a detailed teardown of the LRAD 300X posted by another audio
technician, the LRADs produced by Genasys, the company that pioneered the
devices, do not use an ultrasonic beam to project sound.

It's an art piece. Someone figured out a way to get news coverage with minimal
effort (and it really was very little effort). Check out their site:

[https://www.daveandgabe.care/](https://www.daveandgabe.care/)

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imglorp
Add some copper mesh or foil to the design, and you can block ADS as well!
(microwave pain ray)

[https://en.wikipedia.org/wiki/Active_Denial_System](https://en.wikipedia.org/wiki/Active_Denial_System)

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non-entity
Dammit now I'm curious and have to research microwave pain rays

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bitwize
Reflecting dangerous soundwaves back to the police may be prosecuted as
assault on a police officer, a serious crime (automatic felony in NYC, for
instance).

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ashtonkem
That really bugs me. If it’s a crime to reflect back onto the cops, why wasn’t
it a crime for them to use it without justification?

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CompanionCuuube
"Why is it a crime if I detain criminals but not a crime if the police do?"

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booleandilemma
Isn't citizen's arrest a thing? I think you _could_ detain criminals if you
wanted to.

[https://en.wikipedia.org/wiki/Citizen%27s_arrest](https://en.wikipedia.org/wiki/Citizen%27s_arrest)

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jascii
While citizen's arrest is a thing, it does not automatically give you the
right to detain someone. A use of force (as would be required to detain a
subject) is often only legal to stop a direct felony from taking place.

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kindatrue
"The shield is also 50 lbs, so it’s not exactly easy to transport through a
crowd."

That's putting it mildly.

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jsilence
Seen hippie girls carry this weight in a backpack thru Asia.

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ashtonkem
There is a big difference between 50lbs in a backpack and holding 50lbs out in
front of you.

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mrigor
Do earplugs not work for these?

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sp332
Nope, your skull picks up the ultrasonic vibrations and delivers them to your
eardrums. Kinda like bone-conduction headphones.

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CountHackulus
The article claims that the LRADs in use do not use ultrasonics. However this
is a good point for other directed-sound weapons that might be in use.

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sp332
I was getting this confused with a different tech then.
[https://www.youtube.com/watch?v=HF9G9M0cR0E&t=170](https://www.youtube.com/watch?v=HF9G9M0cR0E&t=170)

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vzidex
As someone who values their hearing - I religiously wear earplugs at concerts
and muffs at the gun range - these absolutely terrify me. Good to see
solutions, even if they're just initial prototypes that may/may not work,
being developed.

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booleandilemma
Can I get a couple of these for my apartment?

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drummer
In a similar way they will be able to use the beamforming capabilities of 5G
for crowdcontrol once the stations are deployed everywhere.

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gruez
okay i'll bite. What's the power output for a "5G" station, and how much of
that energy can be directed to a small area with beamforming? Finally, how
does that figure compare to sunlight, which is around 1000W/m^2?

