Laser microphones?

Laser microphones have been around for a while, just not in a practical package like those Sennheiser mics. One nice thing about them is that there's no mass to be moved by air as the head's motion itself is being detected. What I wonder is if the sound is like that of a pickup on a guitar, lacking in the complex, developed tones you get from a mic.
 
Dang, I told my old boss about this idea a few years ago. He lives in SF and recently started on a new project. I wonder if he is a part of this????
 
By avoiding bleed and comb filtering I'm wondering if that also eliminates shell tone. Seems like it would take the room out of the picture. Maybe something like this could be used to make some kind of sample trigger system that isn't as prone to mechanical failure as some of the other systems out there. I'm curious to hear what these things sound like.
 
bouldersoundguy said:
Spies have been using them to pick up sound through windows. You bounce the beam off the glass and measure the deflection as the glass vibrates.
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Really? You would think wind etc makes the glass vibrate relatively much more than the microscopical amount of vibrations caused by a human voice?
 
No, they use the window. It is subject to interference. You can defeat the device by putting something noisy close the the window. But it does work in many cases.
 
bouldersoundguy said:
Spies have been using them to pick up sound through windows. You bounce the beam off the glass and measure the deflection as the glass vibrates.
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Yeah, it is all in the analog realm. My idea is strictly digital.

DainBramage said:
Really? You would think wind etc makes the glass vibrate relatively much more than the microscopical amount of vibrations caused by a human voice?
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That gets filtered out. Movement from the wind and building is probably less than 10hz. A useful voice range for that application is probably 500hz - 1Khz.
 
Another thing they can do is pick up the RF noise put out by your monitor and reconstitute what's on the screen. That probably changed when CRTs went out, but I'm sure there are other tricks.
 
bouldersoundguy said:
...but I'm sure there are other tricks.
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There are!! The NSA has been working with the Chinese manufacturers to embed encrypted code within the firmware of LCD/LED screens to port data back to the computer. If the computer is connected to the internet, the NSA can harvest that data. But, you didn't hear that from me. :D
 
Chili said:
There are!! The NSA has been working with the Chinese manufacturers to embed encrypted code within the firmware of LCD/LED screens to port data back to the computer. If the computer is connected to the internet, the NSA can harvest that data. But, you didn't hear that from me. :D
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As if they needed access to your monitor to get that data.
 
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