High-Tech Microphone Picks Voices From a Crowd 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..."
FTFY (Score:3, Insightful)
Surely that would be better written as "terrifying" rather than "impressive"
Re:FTFY (Score:5, Insightful)
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 (Score:4, Insightful)
"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:come on people... (Score:3, Insightful)
Re:come on people... (Score:5, Insightful)
... 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.
Coming soon... (Score:4, Insightful)
... 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.
Turbo super cool (Score:4, Insightful)
Just in case anybody is confused, that is cool as shit. That's all.
Re:FTFY (Score:3, Insightful)
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.
First phrase to be picked up by this mike will be. (Score:3, Insightful)
Re:Terrifying (Score:3, Insightful)
Yes, to point out that a thing's technical impressiveness need not preclude its creation of terror.
That's fine, but you're comparing a device whose purpose is to capture audio with a device whose purpose is to cause as much destruction as possible.
Recording every voice in the crowd has significant implications for society. Some people will find those implications terrifying--especially people who distrust society because they have been intellectually threatening to often-foolish authority figures for much of their lives. Such people happen to hang out on slashdot.
This is just a microphone array. If a government is going to conduct surveillance on its people without a warrant, it doesn't really matter what device they use to do that. That capability already exists. If a government is doing that, the answer is to get the government to stop doing that, not limit your technical progress.
Do you think the people who build this are the first to think of or build it? Are these people giving the nefarious government a tool that they don't already have? Local governments in the US have been using audio triangulation to pinpoint the source of gunfire in a city for a long time, this is very similar. Instead of identifying the unknown location, you're targeting the known location.
http://en.wikipedia.org/wiki/Gunshot_Location_Detection_System [wikipedia.org]
That was inspired by seismology, which has been going on for even longer.
Re:Sounds like beamforming (Score:3, Insightful)
Can't speak to radar, but for passive sonars - you're dead wrong. Some USN passives are broadboand, others narrow, but none are single freq.
Re:FTFY (Score:3, Insightful)
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.
Pffftt! I had teachers with ears that could do this when I was in primary school in the 80s! Every time I talked trash about them I'd end up in detention! ;-)
Re:come on people... (Score:2, Insightful)
...and if you read the specs from the manufacturers website, they also list 285, 300 and 345 in various places
Actually the older model had 300 mics. Currently Squarehead makes small 225 mic array, a medium 285 mic array and a large 345 mic array. The largest array has a diameter of 2.12m (about 7 feet) and the smallest 1.05m (about 3.5 feet). Audio zoom is available both realtime and in replay as all channels can be stored.
And yes, it does run on Linux (and Mac OS X)
J
Software Engineer @ Squarehead Technology