Smoke and laser microphone
Conventional microphones are fairly simple devices – they basically work on the reverse principle of a speaker. Sounds, which are air movement, move a membrane on the microphone, which converts this motion into an electrical signal with a transducer of some sort. This is then transmitted to an amplier and finally a speaker, which reverses the whole thing, translating the electrical signal into movement of a membrane, which then causes air movement.
Almost every microphone uses this concept to capture sounds, and it has been the best method that we know to accomplish this… until now.
David Schwartz of the Institute of Technology and Schwartz Engineering and Design in Rochester has been researching an entirely new method of capturing sound using an inventive new method. Instead of using a membrane, he uses synthetic smoke and a laser beam. The laser beam passes through the particles in the synthetic smoke created by a generator, and modulation of the smoke particles caused by air pressure changes (ie sound) is detected by this laser. A photoelectric cell does the job of converting this into an electrical signal.
Now, this technology is still in it’s infancy, and it’s understandable difficult to get it all working properly. The great thing is that using this method, it should be possible to create a truly high fi microphone, as there are no mechanical issues to cause problems – such as flexibility and ageing of the membrane. It would also be possible to calibrate the sensor to substatially reduce the self-noise of the unit, something that you can’t really accomplish with a conventional mic.
David is even contemplating using the device to run a plugin to model other microphones, since his mic will have very little signature sound of it’s own, allowing it to act as a ‘neutral’ device.
As I said, he’s still in very early stages – as you can tell from the videos, the microphone is far from perfect, but the science behind it is perfectly valid. This could lead to some very exciting pieces of gear in the future. His United States Patent #7580533 was issued on 25 August 2009.
Here are a couple of videos of his prototypes:Related posts: