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Re:DC police used sonic cannon to direct crowd flow during W... by Sephr on Tuesday December 26, 2017 @09:45PM (#16012478)
High power directed ultrasound can potentially cause brain damage from induced mechanical strain in brain tissue. I feel like parametric ultrasonic speakers should be more stringently regulated before every single police department starts using them as if they were regular loudspeakers.

I support requiring something akin to an amateur radio license to operate high powered parametric ultrasonic speakers.

Re:DC police used sonic cannon to direct crowd flow during W... by djsumdog on Tuesday December 26, 2017 @10:19PM (#16012586)
I support them not being allowed ever. But just like the totally ineffective body scanners at airports, too much money has been sunk in for officers not to use them.

No one actually cares about the sunk cost fallacy.

Re:DC police used sonic cannon to direct crowd flow during W... by whateveracct on Tuesday December 26, 2017 @10:40PM (#16012669)
Sunk cost fallacy isn't even what's driving that sort of thing. It isn't even that they spent the money and want to keep justifying it. There are parties with a vested financial interested in the continued use of such things.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Tuesday December 26, 2017 @11:51PM (#16012912)
Yeah, those scanners where you hold your hands up were a big boondoggle.
Re:DC police used sonic cannon to direct crowd flow during W... by secret_island on Tuesday December 26, 2017 @10:28PM (#16012624)
Quite right. Israel's El Al simply profiles everyone that flies and by doing so they obviate the need to use stupid, expensive equipment that does nothing other than bottleneck airports and cause frustration. The Israelis are the best in the world at what they do regarding air security. The West has considered using the same techniques and they likely should. I'm not opposed to profiling if the person fits the profile. Better profiling than dead innocents. People do not have the right to not be offended. I get the heavy hand for some reason every time I fly and I'm literally the grey man, but I understand and go along with it. I'm also squeeky clean from a legal standpoint.
Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Tuesday December 26, 2017 @10:49PM (#16012696)
El Al security is not a good model at all.

I'm still yet to figure out what they achieved by seizing my backpack (that had all of my personal documentation) and damaging my brand new MBP 2016 and Pixel tablet (by very clearly dropping them a dozen times) had to do with security. Especially when they lied about putting it on the plane and I arrived at Ben Gurion with literally nothing other than a passport in one pocket and a dead phone in the other.

El Al's actions say the opposite about what you say about Israelis: El Al clearly believes that they are better at what they do than the IDF or Ben Gurion airport security, so they take it upon themselves (as private citizens) to pick up the slack. For what it's worth, the woman who interviewed me at Ben Gurion didn't have a lot of nice things to say about El Al either.

Re:DC police used sonic cannon to direct crowd flow during W... by KKKKkkkk1 on Tuesday December 26, 2017 @11:50PM (#16012909)
Why has El Al security seized your backpack? I can see why they'd want to search a backpack, but can't for the life of me understand why they'd seize it. I know airlines can sometimes check-in your carry-on items when they run out of cabin space. Is this what happened to you?
Re:DC police used sonic cannon to direct crowd flow during W... by virtualwhys on Wednesday December 27, 2017 @12:33AM (#16013084)
Seized my 23" LG travel monitor for 3 weeks, claiming it was a potential bomb.

Fortunately I was in Israel for 4 months, so a minor inconvenience in the scheme of things, but still, seemed a bit over the top...until I stepped out of the airport and saw teenagers wielding machine guns (serving in military), the Israelis aren't messing around ;-)

If you're Israeli I'd imagine the security measures aren't nearly as stringent.

Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Wednesday December 27, 2017 @10:30AM (#16015276)
Because they just wanted to screw with me. They specifically didn't let me take on a paper file which had my invitation letter, citizenship copy and various other things that would have made my life easier at Ben Gurion.

They promised they'd put it on the plane and they didn't. I got it two or three days later as El Al doesn't fly during Shabbat.

Re:DC police used sonic cannon to direct crowd flow during W... by PhasmaFelis on Wednesday December 27, 2017 @01:13AM (#16013220)
People with a little power and no supervision are likely to abuse it for their own ego. I doubt it's anything more than that.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Tuesday December 26, 2017 @10:38PM (#16012663)
Being singled out for invasive searching and questioning whenever you fly for no reason other than your ethnicity goes a little beyond "not being offended."
Re:DC police used sonic cannon to direct crowd flow during W... by Retric on Tuesday December 26, 2017 @10:47PM (#16012686)
It's not simply (ed: only) based on ethnicity.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Tuesday December 26, 2017 @11:49PM (#16012904)
When people talk about banning "profiling" that's what they mean.
Re:DC police used sonic cannon to direct crowd flow during W... by Retric on Wednesday December 27, 2017 @12:53AM (#16013160)
A credit score could be made more accurate if you included race and ethnicity, but current models are more accurate than one built simply on race and ethnicity. (This may simply be measuring the recial bias of society, but more data is almost always useful.)

Sure, it may offend people to include race, it's not required. EX: People without children are a higher risk than those with children. On it's own not a big deal, and you can't trust any one thing, but screening even 1 in 3 people is still vastly cheaper than everyone.

In the end we can be just as effective without including race if we simply spend more money to profile more people. Making more people suffer for little gain vs. standing up for your principles is less clear cut than people want to admit. Still, both options are viable.

Re:DC police used sonic cannon to direct crowd flow during W... by decebalus1 on Tuesday December 26, 2017 @11:23PM (#16012805)
It's definitely not. My dad had one of those 'extensive questioning' sessions the first time (and only the first time) he flew to Israel because (we think) he is former non-US military. He's also whiter than snow, basically the definition of Caucasian.
Re:DC police used sonic cannon to direct crowd flow during W... by everdev on Wednesday December 27, 2017 @12:11AM (#16012993)
You're right that there are many ways to profile, but race and religion have been historically pervasive profiling techniques.

It does seem more fair to simply put everyone through the same process. If you're annoyed at why you (an innocent) have to be subjected to such stringent and time consuming security, that's how innocents who fit "the profile" might feel as well.

Re:DC police used sonic cannon to direct crowd flow during W... by sooheon on Wednesday December 27, 2017 @12:55AM (#16013168)
If those doing the profiling are interested in being successful, and race and religion prove to be ineffective indicators of threat, then such profiling should stop (or bombs will keep getting through at an inordinate rate). Otherwise, race and religion are simply observations about passengers which have value in directing attention.
Re:DC police used sonic cannon to direct crowd flow during W... by everdev on Wednesday December 27, 2017 @04:14PM (#16018091)
Correlation != Causation

If we examine the background of anyone who has ever committed terrorism, every major race and religion would be covered. And so much of crime comes from social context, so at what point could you ever say: it's safe to assume that anyone with X ethnic background is not a threat. You can take any race and put them in a hostile, violent context and see them either continue the violence or die.

Or, if you say the majority of terrorists are men, so let's stop profiling women, I'm sure you would find more women committing terrorism. Then are women the greater threat or is it simply that we've made it harder for men to be terrorists?

I don't see a way to profile without affecting the statistics.

Re:DC police used sonic cannon to direct crowd flow during W... by sooheon on Wednesday December 27, 2017 @07:34PM (#16019360)
I agree with the gist of everything you've written here. And I think you're slightly missing the point.

> "so much of crime comes from social context"

Agreed. This is why I advocate taking that context into account. Not profiling would mean treating every single individual the exact same way, removing all social context from consideration.

> at what point could you ever say: it's safe to assume that anyone with X ethnic background is not a threat

This is not the point of profiling. The point is to build probability distributions, and hone them.

> I don't see a way to profile without affecting the statistics.

This is literally the point! You want to profile on such an exacting superset of factors (behavior, history, autonomous responses, forensics...) that you cause the incidence rate of terrorism to go down, across the board.

A brittle policy like "only screen middle eastern men" will of course get gamed, but that is terrible profiling. It builds a one-dimensional "profile"--you want a profile that is harder to fool, and based on actual behavioral cues.

Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @06:38AM (#16014186)
> If those doing the profiling are interested in being successful, and race and religion prove to be ineffective indicators of threat, then such profiling should stop

I mean maybe if the profiling is being done by robots, but in reality I have my doubts.

Re:DC police used sonic cannon to direct crowd flow during W... by sooheon on Wednesday December 27, 2017 @07:38PM (#16019375)
I think humans can do this as well, they just need the right incentive structure (i.e. tied to actual results). CYA security theatre is not it.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Thursday December 28, 2017 @09:39AM (#16022198)
I think the bias is too deeply ingrained to disappear without strong, sustained institutional pressure to avoid it.
Re:DC police used sonic cannon to direct crowd flow during W... by alexeldeib on Tuesday December 26, 2017 @10:36PM (#16012652)
I agree broadly that the Israeli model seems the one to follow. My understanding differs, however, in that it's not strictly profiling in the sense that carries heavy negative connotations in the US. I haven't traveled to Israel so can't comment, but I understand that in "profiling" the focus is on more objective metrics than an American might think when they hear the word -- e.g., physiological responses (sweating, increased heartrate, nervousness), consistency under questioning, etc.

If that's not the case, would you mind providing some details about your own experience, since you mentioned being pulled aside repeatedly?

Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Tuesday December 26, 2017 @11:10PM (#16012762)
None of those are the metrics they use. Despite being an Australian citizen with a very clean record, as well as having a very Western name, I was red flagged before I even arrived because of my country of birth.

With El Al, you're interrogated before you board the plane. When you go to check in, there is a "pre check-in" where you show staff your passport and they check your name off against a paper list. That paper list would already indicate whether or not you're going to be interrogated and at what level.

My coworker flying with me was also red flagged, and he was explicitly told it was because of my country of birth and that he was flying with me.

He had much less of a rough time than me, though, where I was being interrogated over where I got the 100 shekels they found in my wallet (apparently exchanging a nominal amount of Aussie dollars for shekels at Sydney airport "just in case" astounded El Al security, and it was much more likely that there was something much more sinister going on).

Re:DC police used sonic cannon to direct crowd flow during W... by alexeldeib on Tuesday December 26, 2017 @11:44PM (#16012888)
Thanks for the detail, and for your own experience.

The interrogation interests me. It sounds you don't feel it was useful? I had heard about this kind of interrogation over mundane stories, and understood it as a way of "testing" individuals' stories (especially under duress). But that would depend on it being repeated/prodded thoroughly, which it seems isn't the case.

Re:DC police used sonic cannon to direct crowd flow during W... by Pyxl101 on Wednesday December 27, 2017 @02:06AM (#16013361)
It sounds like this interrogation strategy could be designed to make the interviewee think that the interlocutor is onto something, even if they aren't.

If you're a regular guy, you're likely to react by becoming bored and tired. If you're doing sinister stuff, there is a chance that you might start to stress out from the interaction. I believe similar techniques are used when screening people for government security clearances using a polygraph. They seem to push people hard and accuse them of lying. I can only assume it's with the intent of causing legitimately guilty people to "crack".

I am not trying to justify the practice, just speculating about the purported rationale. Not a very fun experience as an innocent person.

Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Wednesday December 27, 2017 @10:21AM (#16015203)
You're trying to justify it in the sense that they're some sort of smart people with a plan. They're just civilians, they're not spies. No malice or cunning elements to it - just idiocy.

The takeaway I got is that they just don't want people to visit Israel and made it as difficult as possible for me (which involved taking away my personal documentation, such as my invitation letter and copies of my citizenship, to give me a tough time when I got to Ben Gurion).

Re:DC police used sonic cannon to direct crowd flow during W... by azernik on Wednesday December 27, 2017 @01:29AM (#16013262)
"Repeated/prodded thoroughly" matches all of the descriptions of the long-form interrogations by Israeli airline and airport security. If they got to the 100 shekels in his wallet, then that means they probably asked him about a lot of other things first, and searched his wallet, and probably tried to put together a timeline of exactly when he went where to try to find cracks in the story.
Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Wednesday December 27, 2017 @10:19AM (#16015187)
Not really. It was a standard run-of-the-mill search. The shekels are the only thing they were genuinely interested in. They couldn't comprehend why I had gotten it.

It was bizarre.

Re:DC police used sonic cannon to direct crowd flow during W... by azernik on Wednesday December 27, 2017 @03:50PM (#16017911)
Weeeeeeeeeeeird.

But then, I'm Jewish Israeli, so I don't have a lot of first-person experience with the full interrogation experience, just second-hand accounts from both sides of the table.

Re:DC police used sonic cannon to direct crowd flow during W... by alexeldeib on Wednesday December 27, 2017 @01:36PM (#16016836)
This is the theory that I'd heard behind the strategy. Having not experienced it myself, I'm curious how it plays out in practice. It seems they have a high true positive rate and low false negative (i.e., properly suspecting people who should be suspected), but perhaps also a somewhat high false positive rate? This still would be favorable in my eyes to the security in America.
Re:DC police used sonic cannon to direct crowd flow during W... by stevenjohns on Wednesday December 27, 2017 @10:27AM (#16015247)
The "interrogation" felt more like they didn't want me to visit Israel again. Genuinely, that was the only take away I had.

They tried to intimidate me with their faux "all seeing eye" - asking about whether or not I trained judo (in reference to the jiu-jitsu Gi I had in my luggage) but aside from that, the questions about the shekels in my wallet and also taking issue with the rubber waistband on my pants, they didn't really ask about anything else. The shekels thing and the issue they took with it was just absurd.

It was really just civilian employees on a power trip trying to mess with me... because they can.

Re:DC police used sonic cannon to direct crowd flow during W... by username223 on Wednesday December 27, 2017 @12:10AM (#16012985)
> physiological responses (sweating, increased heartrate, nervousness), consistency under questioning, etc.

Is this what Canadian border guards are supposed to be doing? I hate dealing with them, and therefore minimize my border crossings. I just want to pour money into the Canadian economy as a tourist from time to time, and actual Canadian cops (RCMP) are much less aggressive than their US counterparts, but the border crossing is almost always unnecessarily miserable.

Re:DC police used sonic cannon to direct crowd flow during W... by brador on Wednesday December 27, 2017 @12:08AM (#16012978)
Who decides the profiles?
Re:DC police used sonic cannon to direct crowd flow during W... by sschueller on Wednesday December 27, 2017 @02:23AM (#16013398)
With the incident in Cuba I would think we would be a bit more reluctant to use such devices on civilians.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @10:24AM (#16015224)
Why?
Re:DC police used sonic cannon to direct crowd flow during W... by e40 on Wednesday December 27, 2017 @11:49AM (#16015907)
Because the hypothesis is that people in Cuba have brain damage due to devices like these.
Re:DC police used sonic cannon to direct crowd flow during W... by rectang on Tuesday December 26, 2017 @11:21PM (#16012795)
> brain damage

Surely that's a feature, not a bug, when the police have to deal with civil rights protesters. Recall the dogs, batons, and water cannons of the south.

Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Tuesday December 26, 2017 @11:52PM (#16012918)
They used water cannons on people in Standing Rock in some seriously cold temperatures just last year.
Re:DC police used sonic cannon to direct crowd flow during W... by jonlucc on Wednesday December 27, 2017 @02:10AM (#16013370)
And dogs on protestors in Ferguson in the hours after the police shooting of Michael Brown.
Re:DC police used sonic cannon to direct crowd flow during W... by peak_body_yo on Wednesday December 27, 2017 @04:39AM (#16013821)
Isn't mental instability positively correlated with antisocial, disruptive behavior? I'd imagine that they want well behaved protesters.
Re:DC police used sonic cannon to direct crowd flow during W... by godzillabrennus on Tuesday December 26, 2017 @09:51PM (#16012502)
It’ll take some high dollar lawsuits getting paid out before any regulation around these will happen.
Re:DC police used sonic cannon to direct crowd flow during W... by wallace_f on Wednesday December 27, 2017 @12:12AM (#16012995)
Ah, one of the remaining only ways "doing the right thing" ever gets done in the States these days.

Why can countries like South Korea, Taiwan or Japan provide public services like roads, internet infrastructure, police and healthcare at an incredibly small fraction of the cost that is lightyeaes ahead in quality and competency (for the 99%)?

Re:DC police used sonic cannon to direct crowd flow during W... by TeMPOraL on Wednesday December 27, 2017 @02:36AM (#16013434)
Path dependence? US went a bit too far in the "individual liberty" direction, and it now can't get out of the mess. In principle, things could be fixed, but good luck getting enough lawyer mass on this.
Re:DC police used sonic cannon to direct crowd flow during W... by TheCoelacanth on Wednesday December 27, 2017 @09:42AM (#16014980)
Surely allowing police to use excessive force to control protestors is the exact opposite of "individual liberty".
Re:DC police used sonic cannon to direct crowd flow during W... by imjustsaying on Wednesday December 27, 2017 @10:35AM (#16015303)
>individual liberty causes high prices and low quality. this could be fixed with more lawyers

please elaborate

Re:DC police used sonic cannon to direct crowd flow during W... by TeMPOraL on Friday December 29, 2017 @04:59PM (#16032297)
Free market causes low quality.

What I meant in my comment was something else though - that strong individual liberty/independence causes difficulties in coordinating people on large-scale infrastructural projects. I.e. by the time you get through all the lawsuits and payouts, your new rail line takes 10x time to build and costs 20x the money a less liberal country would need to spend.

Re:DC police used sonic cannon to direct crowd flow during W... by daveFNbuck on Wednesday December 27, 2017 @02:49AM (#16013476)
These countries all have at least 10x the population density of the US. I'm not sure about healthcare, but the rest of your list gets cheaper as population density increases.
Re:DC police used sonic cannon to direct crowd flow during W... by AlexandrB on Wednesday December 27, 2017 @10:18AM (#16015179)
And the US has 10x the population density of Canada. Yet we manage it somehow (except for internet). I love how the US is simultaneously the most powerful economy in the world and completely hapless at putting any of that to use for the good of its citizens.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @10:27AM (#16015250)
To be fair, the vast majority of Canadians live near Canada's southern border.
Re:DC police used sonic cannon to direct crowd flow during W... by AlexandrB on Wednesday December 27, 2017 @06:04PM (#16018866)
My main point is not that providing quality public services is easy but that excuses like "we don't have enough population density" are a red herring. The real hurdles are entirely political.

Some back of the envelope calculations:

Length of US/Canada border: 8,890km [1] Population of Canada: 36,708,083 [2]

Assuming ALL of Canada's population lives within 100km of this border a rough estimate of this area might be 889,000km^2 giving a population density of 41 people per square kilometre. This conservative estimate is in the same ballpark as the US population density of 33 people per square kilometre [3] with the caveat that this population is spread across a long, thin 9000 km ribbon increasing the cost of roads and any other infrastructure versus the US's more favourable shape. And let's not forget that Canada's GDP per capita is $46,437 while America's is $57,467 [4]. This is a factor of 1.24 in favour of the United States.

Given all this, why is the US incapable of providing the kind of single-payer healthcare that Canada does to its population?

[1] https://www.statcan.gc.ca/pub/11-402-x/2012000/chap/geo/geo-...

[2] http://www.statcan.gc.ca/tables-tableaux/sum-som/l01/cst01/f...

[3] https://en.wikipedia.org/wiki/List_of_countries_and_dependen...

[4] https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(PPP)...

Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @08:15PM (#16019541)
It isn't but I thought we were talking about infrastructure (there are clearly political factors at work there too of course).
Re:DC police used sonic cannon to direct crowd flow during W... by jacob9706 on Wednesday December 27, 2017 @02:27PM (#16017246)
To be fair, it's cold up north...
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @02:35PM (#16017321)
For sure. It's not a mystery why people would rather live in Toronto than Yellowknife. But it does mean that low population density is in some sense mostly on paper.
Re:DC police used sonic cannon to direct crowd flow during W... by louithethrid on Wednesday December 27, 2017 @05:43AM (#16014019)
Fine, we are talking about the trhee main urban centers of the US here - not the whole country. Now that this strawman is out of the way- are we allowed to continue?
Re:DC police used sonic cannon to direct crowd flow during W... by daveFNbuck on Wednesday December 27, 2017 @11:45AM (#16015859)
I don't think that's a strawman. Roads and internet have to reach everyone in the country, not just major urban areas. The money for these projects comes from people in major urban areas too.

You make a good point about policing. Density wouldn't explain why policing in Tokyo is better and cheaper than in New York.

Re:DC police used sonic cannon to direct crowd flow during W... by tatersolid on Wednesday December 27, 2017 @07:12AM (#16014295)
No. You don’t get to wire up NYC at the expense of all taxpayers.
Re:DC police used sonic cannon to direct crowd flow during W... by twobyfour on Wednesday December 27, 2017 @08:36AM (#16014643)
NYC pays far more in both state and federal taxes than it receives in services. NY State pays far more in federal taxes than it receives in services. Rural parts of the US receive far more in services than they pay in taxes.

The rest of the country isn't paying for a thing in NYC - it's the other way around. Just leave us more of our own tax money and we could do all sorts of things that aren't currently considered possible.

Re:DC police used sonic cannon to direct crowd flow during W... by randallsquared on Wednesday December 27, 2017 @09:30AM (#16014915)
> Just leave us more of our own tax money and we could do all sorts of things that aren't currently considered possible.

At (roughly) what number of people does that argument stop working? 5M? 500K? 50K? 5?

Re:DC police used sonic cannon to direct crowd flow during W... by twobyfour on Wednesday December 27, 2017 @09:39AM (#16014969)
I'm not clear on what it is you're asking.
Re:DC police used sonic cannon to direct crowd flow during W... by emodendroket on Wednesday December 27, 2017 @10:26AM (#16015236)
In the case of healthcare it's because the US is alone in the degree to which its system is privatized.
Re:DC police used sonic cannon to direct crowd flow during W... by vinay427 on Wednesday December 27, 2017 @11:12AM (#16015562)
I agree that this is a major factor for the US, but as a point of clarification, empirically (based on other countries) there seems to be a degree of privatization that increases efficiency.
Re:DC police used sonic cannon to direct crowd flow during W... by jsz0 on Wednesday December 27, 2017 @11:33AM (#16015743)
The US government is like old legacy software. It's not as good as modern software but it's too difficult and expensive to replace.
Re:DC police used sonic cannon to direct crowd flow during W... by PrimHelios on Wednesday December 27, 2017 @12:20AM (#16013028)
Even that won't cause any real regulation. If anything the legal battles will just drag on for years before they're eventually settled out of court for almost nothing.
Re:DC police used sonic cannon to direct crowd flow during W... by etrautmann on Tuesday December 26, 2017 @09:51PM (#16012503)
This requires direct mechanical coupling to the head. The air to skin interface is an impedance mismatch which causes very little of the energy to be transmitted to the brain. This is likely not a real concern.
Re:DC police used sonic cannon to direct crowd flow during W... by Sephr on Tuesday December 26, 2017 @09:53PM (#16012508)
The air pockets in your head will resonate quite effectively. The impedance mismatch in the air pockets can result in powerful vibrations. Your head isn't filled with 100% liquids and solids.
Re:DC police used sonic cannon to direct crowd flow during W... by epmaybe on Wednesday December 27, 2017 @10:06AM (#16015092)
I am interested in investigating this further. Could you link me to any scientific articles that have explained how all this works?
Re:DC police used sonic cannon to direct crowd flow during W... by fencepost on Wednesday December 27, 2017 @12:24PM (#16016267)
It sounds like you have a lot more technical knowledge about these than most people. Can you expand on this?

I see people in this thread doing what Muckrock likely desired and getting all worked up because the police used an LRAD, but I also see that it was used as an announcement system not as a loosely-targeted weapon. Does its use for announcements carry dangers that aren't clear to those of us without technical knowledge of it?

Re:DC police used sonic cannon to direct crowd flow during W... by kevin_thibedeau on Wednesday December 27, 2017 @09:48AM (#16015007)
LRADs don't generate ultrasound. The worst they can do is create the brown note.
Re:DC police used sonic cannon to direct crowd flow during W... by dwyerm on Wednesday December 27, 2017 @12:14PM (#16016161)
I'm pretty sure that they do. They're parametric speakers, like the 'Soundlazer[1]', that use a very loud ultrasonic carrier and make audible sound from the interference between the beams of ultrasonics.

Even when an parametric speaker is playing 'silence', it is probably blasting 120dB of ultrasound. Soundlazer's faq on Kickstarted mentioned this explicitly: "...you will be hit with 120.5Db of sound pressure that you can't hear! It starts hurting your ears after 10 minutes."

http://www.soundlazer.com/

Re:DC police used sonic cannon to direct crowd flow during W... by kevin_thibedeau on Wednesday December 27, 2017 @07:07PM (#16019236)
They max out at 2.5kHz. All they can do is loud speech and infrasound.