Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Pete Erskine]

I understand what you are saying.  The post that I replied to indicated that a pressure wave would have been rippling through space following the big bang, it would not.  Debris would be flung outward and that debris would be vibrating but no pressure wave would be present in outer space.
A shock wave will travel through space via plasma but an acoustic pressure wave will not.

Now, would optical movement/vibration of an object be able to be read by the system being described in the video, yes.

Lee

You are right - this method could have recovered the material vibrations which would have made sound had there been air.

[Ike Zimbel]

You are right - this method could have recovered the material vibrations which would have made sound had there been air.

Wow...I almost regret making the "Big Bang" comment. To try and bring this back on topic, the ramifications of this technology are huge. Besides the obvious forensic and surveillance applications I wonder about things like: could someone make a bootleg recording of a concert from a video of, say, the side of a speaker cabinet...or an exit door of the arena? I would suspect that the quality of the sound would be dependent on the resonant qualities of whatever object was in the video but it's hard to say.

[Lee Buckalew]

Wow...I almost regret making the "Big Bang" comment. To try and bring this back on topic, the ramifications of this technology are huge. Besides the obvious forensic and surveillance applications I wonder about things like: could someone make a bootleg recording of a concert from a video of, say, the side of a speaker cabinet...or an exit door of the arena? I would suspect that the quality of the sound would be dependent on the resonant qualities of whatever object was in the video but it's hard to say.

Absolutely, huge ramifications as this technology matures.  I can imagine this combined with femto-photography and its ability to look around corners through seeing photon differences in reflected light that we can not begin to perceive (1 trillion frames per second). 
Some truly astounding technologies are being developed.

Lee

[Lyle Williams]

Cool stuff, but an impossibly niche technique.

[Tim McCulloch]

Cool stuff, but an impossibly niche technique.

Think of it from a forensics standpoint - being able to extract audio from a "silent" video.

[kristianjohnsen]

Much less expensive and potentially more intrusive than laser interferometry (aiming a laser at a window or other tympanic surface to extract audio from the other side by measuring the vibrations).

This means that "silent" video recordings or high-res surveillance cameras can provide some kind of audio.  Unplugging the mic is no longer good enough.

For a while I have been asking myself "when will a spy drone be produced that can listen as well as capture video".  Perhaps this will be the tech that makes it possible?

[kristianjohnsen]

Wow

Check out this video on YouTube:

http://youtu.be/FKXOucXB4a8

Very cool find, thanks for sharing!

I wonder how loud the playback sources were.  Do you know?

[kristianjohnsen]

A :  a particular auditory impression :  tone.
B :  the sensation perceived by the sense of hearing.
C :  mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (as air) and is the objective cause of hearing.

Interesting topic, for sure.

Let's say we put a loudspeaker in a vacuum and it is doing what it usually does when producing sound (although technically, there is no sound). 

Now, let's put a microphone physically up against the speaker cabinet and record the signal coming from the mic. 

Then, let's play back the recording from a speaker in a room With air in it. 

If we can hear a representation of the original signal that went to the loudspeaker in the vacuum, surely, there must have been sound there, even if it never travelled through air?

[ProSoundWeb Community]