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High-Tech Microphone Picks Voices From a Crowd

Soulskill posted more than 3 years ago | from the watch-your-mouth dept.

Privacy 221

JerryQ writes with news of an impressive audio detection system from a company called Squarehead that was demonstrated during a professional basketball game. According to Wired, "325 microphones sit in a carbon-fiber disk above the stadium, and a wide-angle camera looks down on the scene from the center of this disk. All the operator has to do is pinpoint a spot on the court or field using the screen, and the Audioscope works out how far that spot is from each of the mics, corrects for delay and then synchronizes the audio from all 315 of them. The result is a microphone that can pick out the pop of a bubblegum bubble in the middle of a basketball game..."

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come on people... (4, Funny)

cencithomas (721581) | more than 3 years ago | (#33862032)

...is it 315 or 325? Sheesh.

Re:come on people... (5, Funny)

GungaDan (195739) | more than 3 years ago | (#33862066)

10 microphones were harmed during the posting of this story.

Re:come on people... (-1, Troll)

Shikaku (1129753) | more than 3 years ago | (#33862076)

True to /. form. Classy.

If you RTFA it's 325.

Re:come on people... (4, Funny)

cencithomas (721581) | more than 3 years ago | (#33862124)

...and it you *actually* read the fscking article you'd see they also said 315. Good work chief.

Re:come on people... (5, Funny)

the_banjomatic (1061614) | more than 3 years ago | (#33862276)

...and if you read the specs from the manufacturers website, they also list 285, 300 and 345 in various places

Re:come on people... (3, Informative)

kevinNCSU (1531307) | more than 3 years ago | (#33862278)

and if you actually read *all* of TFA the scientist says 300 as well. so now we have three numbers: 325, 315, 300. If they keep this up they'll get down to 1 and their product will be a lot cheaper ;)

Of course we can assume he rounded there for ease of explaining.

Re:come on people... (4, Insightful)

vlm (69642) | more than 3 years ago | (#33862456)

... so now we have three numbers: 325, 315, 300. ...
Of course we can assume he rounded there for ease of explaining.

If I were designing a "phased array radar" style microphone, in the front end I'd probably toss the mics that are the furthest away, and of the remaining mics, I'd toss the ones closest to clipping or otherwise distorting. There are also certain combinations of unfavorable geometry both inherently due to mic placement and also the acoustic design.

So its entirely possible they wired up 325 but before they do all the phased array calculations they toss out the 25 worst signals or something like that.

Re:come on people... (5, Funny)

KlaymenDK (713149) | more than 3 years ago | (#33862670)

You've all got it wrong. These are state-of-the-art modern quantum microphones. They work rather excellently -- as long as you don't try to count 'em. That's why the figures in the specs are all over the place -- if they'd just state *one* figure, the darn thing wouldn't be able to hear anything at all! How do you expect to sell something like that?

Re:come on people... (0)

Anonymous Coward | more than 3 years ago | (#33862716)

Or it could just be a mistake.

Re:come on people... (0)

Anonymous Coward | more than 3 years ago | (#33862862)

Interesting article.. I remember doing a similar thing with two microphones for a class project. We were given a couple sound files generated from two mics and had to clean up the signal. One group approached it by doing something similar to PRML but there were some problems with just two mics. Another group used some analysis methods to isolate sounds and they had some success. We pretty much just summed the signals and chopped out a portion that we somewhat arbitrarily selected as background noise. I wish I remembered some of the math involved because it was an interesting project.

I remember reading about telescope arrays and always wondered about using similar tech for sound.. There are some commercial apps that purport to clean up multiple DSLR images into a super high resolution image too.. Wonder if they use a similar tech...

Re:come on people... (0)

Anonymous Coward | more than 3 years ago | (#33863064)

Ah, the classic ignorant "Insightful". Did you even look at the design?

Re:come on people... (1)

shoehornjob (1632387) | more than 3 years ago | (#33863006)

DO I HEAR 400? 400 GOING ONCE 400 TWICE 400 SOLD TO THE MAN IN THE TRENCHCOAT. Damn got to stop watching those Mecum auction shows on HD Theater. Seriously though, what other reason do we need this besides spying on people?

Bah! (1)

damn_registrars (1103043) | more than 3 years ago | (#33862080)

...is it 315 or 325? Sheesh.

Fancy slashdot web2.0 math tells us there is no difference between those numbers.

Re:come on people... (-1, Troll)

Anonymous Coward | more than 3 years ago | (#33862264)

The writer just finished high school in Texas. In the new curriculum they have there, 315 is equal to 325 and you're a socialist if you disagree.

Re:come on people... (1)

siriuskase (679431) | more than 3 years ago | (#33862350)

"can pick out the pop of a bubblegum bubble in the middle of a basketball game"

whatever that means. I think it means the author is more interested in sounding clever than making sense. Don't you just hate that?

Do the players really chew while playing? And why would anyone want to hear it?

Re:come on people... (1)

ChinggisK (1133009) | more than 3 years ago | (#33862396)

Watch the video in TFA.

Re:come on people... (2, Insightful)

Black Cardinal (19996) | more than 3 years ago | (#33862444)

Did you actually read the article and watch the example video? This was an example shown in the video, where bubblegum being popped by someone sitting next to the coach (who was being focused upon by the system) was clearly audible above the crowd noise during a heated moment. It wasn't so much desirable as a concrete example of its effectiveness.

Re:come on people... (1)

Man Eating Duck (534479) | more than 3 years ago | (#33862514)

"can pick out the pop of a bubblegum bubble in the middle of a basketball game"
whatever that means.

If you'd STFVideo in the article you'd know what it means. You should, the video illustrates the filtering effect well. Assuming that it's not been "improved" in any way it's really quite impressive.

Re:come on people... (1)

Dthief (1700318) | more than 3 years ago | (#33862856)

Of course its been *improved*, that's the point...isolating sounds that are normally inaudible because of too many other sounds around them

Re:come on people... (1)

RoFLKOPTr (1294290) | more than 3 years ago | (#33863072)

Of course its been *improved*, that's the point...isolating sounds that are normally inaudible because of too many other sounds around them

He means "improved" in post-production. How do you not get that?

Re:come on people... (5, Funny)

Anonymous Coward | more than 3 years ago | (#33862608)

The quick breakdown of responses on Slashdot:

The last remaining nerds on Slashdot who actually like technology: "Sweet! That's an impressive display of audio recording techniques!"

The paranoia crowd: "ZOOOOOOOMG that means THEY(tm) can listen in on you! Then they're already stealing your identity to impersonate you! MY PRIVACY IS AT RISK OHNOEZ START REBELLION NOW PLZ KTHX"

The audiophiles: "Pfft. Everyone knows you need at least 560 microphones and analog pickups, else you'll clearly lose so much quality as to be unlistenable by any but the most primitive and underdeveloped of eardrums. Plebs."

cencithomas: "WHERE DID THE TEN MICROPHONES GO?!?"

Re:come on people... (0)

Anonymous Coward | more than 3 years ago | (#33862720)

I lolled. Entirely accurate breakdown, that there.

Data harvesting? (1)

chemicaldave (1776600) | more than 3 years ago | (#33862040)

I suppose this could be used to record an entire game and then go back and track what each player was saying during the game based on their positions on the court. I'd be interested to see if this could be used in a football stadium (domed or not) with all the extra noise and people.

Re:Data harvesting? (1)

damn_registrars (1103043) | more than 3 years ago | (#33862122)

I'd be interested to see if this could be used in a football stadium (domed or not) with all the extra noise and people.

Because of course professional basketball games are so dull, sparsely attended, and quiet that it makes a perfect test bed...

Re:Data harvesting? (1)

chemicaldave (1776600) | more than 3 years ago | (#33862170)

Compared to, say, the new Cowboys Stadium, yes.

Re:Data harvesting? (0)

Anonymous Coward | more than 3 years ago | (#33862434)

Or the University of Tennessee's Neyland Stadium?

Re:Data harvesting? (1)

danbert8 (1024253) | more than 3 years ago | (#33862632)

Except basketball arenas are generally MUCH smaller than football stadiums. Population per volume, I'd bet basketball arenas have a higher density and therefore should have more noise. But the real question is, can it filter out vuvuzelas at (insert preference of soccer/football here) games.

Re:Data harvesting? (2, Funny)

Dthief (1700318) | more than 3 years ago | (#33862882)

no, but it can focus entirely on one vuvuzela

Re:Data harvesting? (1)

MichaelKristopeit 34 (1917436) | more than 3 years ago | (#33862842)

I'd be interested to see if this could be used in a football stadium (domed or not) with all the extra noise and people.

Because of course professional basketball games are so dull, sparsely attended, and quiet that it makes a perfect test bed...

because pro basketball is played outdoors in the elements of whooshing wind and splattering rain...

Re:Data harvesting? (1)

wonkavader (605434) | more than 3 years ago | (#33862348)

"I'd be interested to see if this could be used in a football stadium (domed or not)"

You'd design the spacing of the microphone and the logic to match it based on the size and shape of the area. This array is not what you'd use. But you could certainly make an array or set of arrays which would work for a football field.

Re:Data harvesting? (1)

Man Eating Duck (534479) | more than 3 years ago | (#33862592)

I suppose this could be used to record an entire game and then go back and track what each player was saying during the game based on their positions on the court.

It can. FTFA:

Audio from all microphones is stored in separate channels, so you can even go back and listen in on any sounds later.

I don't know how they record and store 325 (or 315, 345 - whatever) channels of audio, but their equipment can process stored audio as well as the live feed.

Re:Data harvesting? (2, Informative)

arivanov (12034) | more than 3 years ago | (#33862664)

This is the classic phase array antenna approach from radar tech applied to sound. Cool application though.

In fact it is easier for sound because the amount of data per element is much smaller than in let's say a radar.

Would work on stored sound too (1)

hoggoth (414195) | more than 3 years ago | (#33862046)

It occurs to me that if you store all 325 audio streams with accurate time-codes and the relative positions of the microphones you would be able to do this at any time later on the stored sound as well. You could probably get away with much fewer than 325 microphones at some cost in quality.

Re:Would work on stored sound too (3, Informative)

Sarten-X (1102295) | more than 3 years ago | (#33862116)

In fact, that's exactly what TFA says.

Re:Would work on stored sound too (5, Funny)

hoggoth (414195) | more than 3 years ago | (#33862236)

Maybe I should've read it then.

But I, like most Slashdotters, am so quick that I can just glance at a poorly written summary and instantly understand all that needs to be known about the topic. It's really a wonderful time-saver being so damn smart I don't even need to know the facts.

Re:Would work on stored sound too (4, Funny)

dgatwood (11270) | more than 3 years ago | (#33862450)

Just like Congress!

And, to be back on topic, referees.

Re:Would work on stored sound too (1)

Dishevel (1105119) | more than 3 years ago | (#33862726)

Hoggoth is MUCH better than congress.

Hoggoth dose not cost me money.

Re:Would work on stored sound too (0, Offtopic)

falken0905 (624713) | more than 3 years ago | (#33862990)

Are you a member of the Tea Party? Do you watch Fox News?

Re:Would work on stored sound too (4, Informative)

Animats (122034) | more than 3 years ago | (#33862190)

It occurs to me that if you store all 325 audio streams with accurate time-codes and the relative positions of the microphones you would be able to do this at any time later on the stored sound as well. You could probably get away with much fewer than 325 microphones at some cost in quality.

Yes. And that's already part of the system.

Re:Would work on stored sound too (1)

Pinky's Brain (1158667) | more than 3 years ago | (#33862304)

I wonder if you could do this with mobile phones ... do these provide low level access to GPS signals? (For timing and differential location correction.) You might be able to crowd source a distributed recording for reconstruction.

Re:Would work on stored sound too (1)

vlm (69642) | more than 3 years ago | (#33862512)

I wonder if you could do this with mobile phones ... do these provide low level access to GPS signals? (For timing and differential location correction.) You might be able to crowd source a distributed recording for reconstruction.

Unless you're using 1980s era analog phones, the voice compression is going to destroy the phase relationships you need, and mask out the low level signals that you'd be adding up.

Also the mics are usually vaguely noise canceling, otherwise think of those dorks whom have cellphone conversations in the bathroom at work, the folks on the other side would hear all kinds of flushing and ... stuff. Or maybe they do hear it but just don't care? Always wondered about that.

Re:Would work on stored sound too (1)

Pinky's Brain (1158667) | more than 3 years ago | (#33862606)

I wouldn't suggest phoning it in ... it would be recorded together with the GPS data and send over IP with only lossless coding.

Re:Would work on stored sound too (1)

AndrewNeo (979708) | more than 3 years ago | (#33862578)

GPS likely isn't accurate enough to handle the delay calculations, the accuracy being anywhere around 5-15 meters.

Re:Would work on stored sound too (1)

Pinky's Brain (1158667) | more than 3 years ago | (#33862612)

Depending on how low level the access to the GPS data is you will be able to get much better differential accuracy (especially with some temporal averaging).

Re:Would work on stored sound too (1)

vlm (69642) | more than 3 years ago | (#33862850)

Depending on how low level the access to the GPS data is you will be able to get much better differential accuracy (especially with some temporal averaging).

So a wavelength of sound in air around 3 KHz is about five inches (rounded up). To get a couple decimal points of phase accuracy, you're going to need a similar couple decimal points relative to 5 inches. So at each data sample you need the coordinates accurate to a "carpenters level of accuracy". Not as harsh as a machinists level of accuracy but still pretty tough to achieve.

Also you need to sync your times. I'm thinking you'll need much better than 1/3000th of a second accuracy for your sample timestamps to maintain phase and amplitude correlation. Can store the data samples for later analysis, but you're going to need live running NTP or GPS clock to have accurate enough time.

Re:Would work on stored sound too (1)

balbus000 (1793324) | more than 3 years ago | (#33862626)

They already have. Unfortunately, Lucius Fox [wikipedia.org] destroyed it.

Re:Would work on stored sound too (1)

Pinky's Brain (1158667) | more than 3 years ago | (#33862706)

Heh, didn't even realise that ... of course the movie barely held my attention except for hilariously bad interrogation scene.

Re:Would work on stored sound too (3, Interesting)

internewt (640704) | more than 3 years ago | (#33862318)

This system might also be hackable, such that people can preserve their privacy and not be listened in on from hundreds of feet away.

You simply have a microphone near your mouth, sample it, and repeat the sound out of a speaker with slight echoes with randomised delays. There must be something that could interfere with the process they use to "zoom in" on a particular sound source. Maybe if you can measure the distance to the listening device, it would be possible to manipulate the frequency of sounds you are making so as to create a standing wave or something that would cause the microphones to be overloaded or to hear nothing..... shit, maybe the tech that drives noise cancelling headphones could be used here? Who you are speaking to gets an earpiece with unedited sound piped to them, and speakers on your lapels kick out anti-sound so eavesdroppers hear nothing.

So now in public, you just need to have strings of randomised flashing IR LEDs illuminating your face, so CCTV has a hard time capturing your image, and now something to mess with your voice so that The Man cannot listen in too! If you are thinking "paranoid fucker", I am thinking what the fuck business is it of people to listen in on me? And that's a rhetorical question: I don't need to be told to think of the children, etc..

Re:Would work on stored sound too (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#33862398)

Clearly a pedophile terrorist. Probably a Democrat too.

Re:Would work on stored sound too (1)

dgatwood (11270) | more than 3 years ago | (#33862484)

No, you just need to calculate the distance between you and someone on the opposite side of the stadium, then put a speaker over there with a phase inverter and a fixed digital delay to make the times match. Won't be perfect, but should be good enough since neither your voice nor the inverted copy will carry to the opposite side of the stadium.

Re:Would work on stored sound too (1)

vlm (69642) | more than 3 years ago | (#33862570)

Maybe if you can measure the distance to the listening device, it would be possible to manipulate the frequency of sounds you are making so as to create a standing wave or something that would cause the microphones to be overloaded or to hear nothing

Well, almost obviously, if you knew your location, and the exact location of each mic in the array, you could figure out the distance to each mic. Assuming constant speed of sound you know the time to each mic. So you make 200 or so clicks or pops each timed to saturate all the mics simultaneously. Then it doesn't matter where they're listening, you'll overload them. Works better if you have, say, thousands of click generators. Would probably make the venue sound like a field of crickets unless you happen to be at the focal point.

Re:Would work on stored sound too (1)

Man Eating Duck (534479) | more than 3 years ago | (#33862696)

...and now something to mess with your voice so that The Man cannot listen in too!

Hate to break it to you man, but they've probably done that to you for a long time already. Parabolic mikes are getting better, if not very inconspicuous :)

If you see someone carrying a 1m parabolic reflector aimed at you from a distance of 50m, better hope you didn't give them too much info already.

Re:Would work on stored sound too (1)

Dthief (1700318) | more than 3 years ago | (#33862940)

Well since you give up all rights by entering a stadium (TV peoples can use your image, for example, in all of their broadcasts) this is being used in an arena (pun intended) where there is no expectation of privacy.

I do agree its worrisome once this gets used in public places

FTFY (2, Insightful)

sheriff_p (138609) | more than 3 years ago | (#33862084)

Surely that would be better written as "terrifying" rather than "impressive"

Re:FTFY (4, Insightful)

amicusNYCL (1538833) | more than 3 years ago | (#33862288)

How come you get terrified by an array of microphones with an impressive spatial detection capability? The thing is technically impressive, whether or not it "terrifies" a certain person is about perspective, and that person's tendency towards becoming terrified by mundane objects.

Re:FTFY (3, Insightful)

wowbagger (69688) | more than 3 years ago | (#33862376)

"The thing is technically impressive, whether or not it "terrifies" a certain person is about perspective, and that person's tendency towards becoming terrified by mundane objects."

It is not the object that is terrifying, but rather what the existence of the object, plus the current trends in behavior by our Fearless(fearful) Leaders, plus a modicum of ability to put 2 and 2 together, yielding these devices being everywhere, able to monitor all conversations in the world.

Re:FTFY (2, Insightful)

amicusNYCL (1538833) | more than 3 years ago | (#33862970)

able to monitor all conversations in the world.

C'mon. The main reason this works so well in a basketball stadium is because everyone is sitting in their seats. When people are moving around it's going to take significantly more work to capture a single conversation, especially if you don't know their direction and speed. It's also only going to pick anything up past a certain volume level, and it's also limited by line of sight (or sound). If the person walks behind something, or turns their head away from the mic array, they lose the audio.

plus the current trends in behavior by our Fearless(fearful) Leaders

Seems to me that the population is way more fearful than the leadership. There's no reason to continue that.

Re:FTFY (0)

Anonymous Coward | more than 3 years ago | (#33862408)

How come you get terrified by an array of microphones with an impressive spatial detection capability? The thing is technically impressive, whether or not it "terrifies" a certain person is about perspective, and that person's tendency towards becoming terrified by mundane objects.

Perhaps because he likes his privacy?

Not me, though. I'm with you; I love Big Brother, and I am a loyal citizen who supports the Party.

Re:FTFY (0)

wagnerrp (1305589) | more than 3 years ago | (#33862800)

The thing is technically impressive

It's not really even technically impressive. The concepts are extremely simple. You know the position of your mics, you know the position of your target. From there, it's simple elementary school geometry to calculate the distance and time delays. Sum together your audio signals with the proper phasing, and your desired target gets boosted, while everything else averages into the background. The wider the mics are apart, the more dissimilar the background noise will be, and the lower the amplitude it will result in. It's just going to be an expensive system to simultaneously capture and store all several hundred audio feeds simultaneously.

Terrifying (1)

Oxford_Comma_Lover (1679530) | more than 3 years ago | (#33862818)

> How come you get terrified by an array of microphones with an impressive spatial detection capability? The thing is technically impressive, whether or not it "terrifies" a certain person is about perspective, and that person's tendency towards becoming terrified by mundane objects.

Well, why would anyone alive during the cold war get terrified about thousands of nukes that would effectively destroy the world? The thing is technically impressive; whether or not it "terrifies" a certain person is about perspective and that person's tendency toward becoming terrified by mundane objects.

--
Ah, the dreaded comma splice.

Re:Terrifying (1)

amicusNYCL (1538833) | more than 3 years ago | (#33862996)

Sorry, did you just compare an array of microphones in a basketball arena to the combined nuclear stockpiles of the world's two most powerful countries, capable of destroying the world?

Re:FTFY (1)

hoggoth (414195) | more than 3 years ago | (#33862290)

So now I will invent a little gadget that garbles your speech and a matching headphone that ungarbles it. Just sync your 'keys' before you head out and only the paired devices will be able to understand each other. I will sell the idea to Halliburton and they will implement it using ROT-13 encoding.

I'm not sure if it should look like the 'Cone Of Silence' from Get Smart, or like the speaking device used by Guild Navigators in Dune.

Re:FTFY (1)

dhall (1252) | more than 3 years ago | (#33862708)

How about a simpler solution.

A piece of paper and a pencil.

Heck, I'm sure there's an app for that...

Re:FTFY (1)

interkin3tic (1469267) | more than 3 years ago | (#33862538)

The two aren't mutually exclusive. Look at sharks: terrifying and impressive. And that's not all, frickin Lasers on frickin sharks: terrifying, impressive, and funny, all at the same time.

That said, I don't really see terrifying. I assume anything I can say out loud in public can be heard by someone. If I were often in the position of having to go to basketball games to discuss things so that the government bugs can't overhear me this might be terrifying to me, but I'm not so it's not. And it's not the tech itself, its what people might do with it that would make me uncomfortable anyway. Someone -could- put videocameras everywhere which would have high enough resolution to be able to lip-read what you're saying, but that hasn't seemed to happen most places yet.

Re:FTFY (1)

phantomfive (622387) | more than 3 years ago | (#33862694)

Not really, it's hard to imagine anyone thinking of a conversation in a stadium, or indeed any crowd, as private (and if you do, your stupidity is what's really terrifying).

The only time you have any reasonable expectation of privacy in conversation is if you're alone with someone, and the technology to listen in on that has been around for decades. If you think of this particular innovation as terrifying, it's probably because you're a social outcast and are afraid of having your face show up on TV at a ballgame. If that's what you're afraid of, don't worry, it's mainly going to be used to listen in on mega-fans who are paint their faces and have giant signs, not the boring loners in the 7th row. Or it will be used to hear what a coach says to his players, instead of just guessing based on vague lip-reading techniques like they do now.

They made movie about this in the 70s (4, Interesting)

MyFirstNameIsPaul (1552283) | more than 3 years ago | (#33862138)

The Conversation [imdb.com]

Finally! (1)

cjfs (1253208) | more than 3 years ago | (#33862150)

Now they can enforce the no cell phone usage while driving! Even those pesky key presses won't be able to hide!

Nothing to hide (2, Interesting)

Anonymous Coward | more than 3 years ago | (#33862178)

Wow... why limit it to just stadiums? You could have arrays of these things lining every street and every mall! Just imagine how many terrorists you could catch by processing all the millions/billions of conversations going on in public places. All that data would be handy for collecting evidence against criminals too, you just go back through your chatlogs (all indexed per-person with voice/facial recognition) and dig up every conversation they've ever had outside.

Re:Nothing to hide (1)

vlm (69642) | more than 3 years ago | (#33862654)

Wow... why limit it to just stadiums?

Gunshot detection works pretty well. Been unclassified for about 20 years. Been installed in Wash DC for a couple years. The problem is even big brother can't handle merely the volume of gunshots, making these systems thoroughly useless. If there's a cop whom is too close, in other words under fire, it doesn't tell them anything they don't know. If there is a cop close enough to make an arrest, they are already close enough to hear and need to be looking outside for the shooter not in car at a display. And if the cops are too far away to do anything, then it accomplishes nothing.

A conversation monitor would probably be less effective. And less effective than "not much" is very little indeed.

Re:Nothing to hide (0)

Anonymous Coward | more than 3 years ago | (#33863030)

Err, that's already in place in England and other places. And even better, it's *cameras* so they have audio and video.

Re: (3, Funny)

scruffy-tech (1821510) | more than 3 years ago | (#33862214)

I read the article. It went from 325 to 315 to 300. They may have gotten it down to a single mic had they kept writing.

You read the article? (1)

Kittenman (971447) | more than 3 years ago | (#33862274)

What are you doing on this website? This is no place for the likes of you.

Re:You read the article? (1)

scruffy-tech (1821510) | more than 3 years ago | (#33862294)

I'm new. I won't let it happen again, promise.

Sounds like beamforming (4, Informative)

DoofusOfDeath (636671) | more than 3 years ago | (#33862262)

This sounds like beamforming [wikipedia.org] . Submarines do this. Works great.

Re:Sounds like beamforming (2, Interesting)

Obfuscant (592200) | more than 3 years ago | (#33862302)

This sounds like beamforming. Submarines do this. Works great.

So THAT'S what that large, grey cylindrical object hanging over the heads of the crowd at the last professional basketball game I went to was. I always wondered...

I wonder if they heard me saying "I wonder what that large grey cylindrical object hanging over our heads is", or maybe "I hope those ropes don't break."

Re:Sounds like beamforming (0)

Anonymous Coward | more than 3 years ago | (#33862574)

Not just submarines, either. They use similar devices at NASA for aeroacoustic data. If I'm to believe the photo in the article is of their actual array, it appears to not be optimized. As I understand it, the array pattern benefits from a little entropy. You want unique angles and distances, so the ones I've seen have used logarithmic spirals as their bases rather than simple radial patterns.

Re:Sounds like beamforming (1)

john83 (923470) | more than 3 years ago | (#33862888)

Beamforming is only possible where you have as many microphones as sources. This is more probably some sort of blind source separation [wikipedia.org] algorithm - calculating the pseudo-inverse of a mixing matrix based on assumptions about speech.

Re:Sounds like beamforming (1)

DoofusOfDeath (636671) | more than 3 years ago | (#33863024)

Beamforming is only possible where you have as many microphones as sources.

As many mikes as actual sources, or as many mikes as there are sources of interest?

I think when you have very many sources of non-interest, approaches like this rely on the uninteresting sources partially cancelling each other out into background noise.

The future of Big Brother (1)

jnaujok (804613) | more than 3 years ago | (#33862306)

Just make a disc fifty feet wide, using optimal golomb ruler [wikipedia.org] placed microphones in a full hemispherical phased array [wikipedia.org] of around 10,000 microphones, hang it from a tethered helium balloon, and now you can pick out any conversation in an entire city-sized area.

Nope, nothing to be afraid of here...

Re:The future of Big Brother (1)

Michael Kristopeit 6 (1913320) | more than 3 years ago | (#33862386)

you know what is very very very difficult to shoot out of the sky? a tethered helium ballon.

nope, nothing insinuated here...

Re:The future of Big Brother (1)

Pinky's Brain (1158667) | more than 3 years ago | (#33862400)

I suspect Brownian noise starts becoming a bit bothersome at those distances.

Re:The future of Big Brother (1)

dgatwood (11270) | more than 3 years ago | (#33862534)

Not to mention that the signal levels at the required altitude would be way below the white noise floor for pretty much everything from the microphones to the amplifier stages.

Say, wasn't there a South Park... no, never mind....

Nothing to see here (1, Funny)

Anonymous Coward | more than 3 years ago | (#33862344)

The 70's called... they want their beamforming back

Eavesdropping must-see... (1)

toby (759) | more than 3 years ago | (#33862414)

The classic Coppola movie, The Conversation [imdb.com] .

Technique already in use in radar systems (5, Interesting)

bytestorm (1296659) | more than 3 years ago | (#33862420)

This is a cool application of a well used technique. http://en.wikipedia.org/wiki/Phased_array [wikipedia.org]

Prior Art (4, Informative)

Anonymous Coward | more than 3 years ago | (#33862454)

My father, would tell me stories when I was growing up about helping design a surveillance tool for ease-dropping on restaurant conversions that used the same principle. They had a map of the table layouts and you would place a pointer over the table you wanted to listen to. Mics hidden around the edge of the restaurant would capture the sound. This was back during the early 60's so they used a mechanical delay mechanism. Said it worked as well as if you had planted the mic at the table, plus you didn't have to worry about where they sat. Like many things, this is more powerful and versatile but hardly anything new.

Re:Prior Art (1)

bobgap (613856) | more than 3 years ago | (#33862734)

Isn't it hard to find restaurant conversions? You'd be more successful at a revival meeting, perhaps?

The real question... (1)

fahrbot-bot (874524) | more than 3 years ago | (#33862468)

The result is a microphone that can pick out the pop of a bubblegum bubble in the middle of a basketball game...

...is if that person brought enough gum for everyone.

Emperor Ming the Merciless... (1)

EdgeOfEpsilon (756307) | more than 3 years ago | (#33862518)

...will be most pleased that this is now possible.

Re:Emperor Ming the Merciless... (1)

bigrockpeltr (1752472) | more than 3 years ago | (#33862712)

until he uses the device and hears:
out of the sky, his rockets ignite..

Hope google finds some way to ... (1)

140Mandak262Jamuna (970587) | more than 3 years ago | (#33862542)

... add this recorded decoded demultiplexed sounds to the street view. Would be cool. Or Evil.

Coming soon... (3, Insightful)

frank_adrian314159 (469671) | more than 3 years ago | (#33862566)

... to a political rally near you. You probably don't need particularly accurate microphone placement and, in fact, if you had precise position and velocity coordinates of each of the mikes at any given time, they could even be moving.

Re:Coming soon... (1)

choongiri (840652) | more than 3 years ago | (#33862954)

On the other hand, I do wonder how difficult it would be to create this using a distributed network of cell phones, to literally crowd-source listening in on - say - what politicians are saying to each other apparently out of ear-shot of the crowd. I'd think the challenge would be sufficiently precise location awareness.

Given sufficient sensitivity (1)

srussia (884021) | more than 3 years ago | (#33862602)

a 4-mic tetrahedral array [wikipedia.org] can do the same thing.

Turbo super cool (4, Insightful)

Swarley (1795754) | more than 3 years ago | (#33862604)

Just in case anybody is confused, that is cool as shit. That's all.

Spying on 30 million people isn't part of my job.. (1)

gurps_npc (621217) | more than 3 years ago | (#33862644)

..description. But it sounds like it is in their business plan.

Hard of hearing? (1)

RealGrouchy (943109) | more than 3 years ago | (#33862806)

I hope this can be applied to people like me, who have difficulty picking out the voice of the person you're talking to when there's lots of background noise.

Maybe that's why I don't much like big crowds or loud parties. Best party I was at had lots of deaf people and others who knew sign language (including myself), so even if you were on opposite ends of the room, you could still carry on a conversation, despite the booming loud music.

- RG>

Cell strategy (1)

macraig (621737) | more than 3 years ago | (#33862832)

So I guess your local terrorist cells won't be having their strategy meetings under the cover of all that stadium noise any more. Of course it also means that Randy Dandy might wanna think twice before sitting in the stands with his best bud and confessing that he's been cheating on his wife.

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