# Thread: How this thing works?

1. Today, I saw the Super Bowl. When the TV camera was taping few players and we actually could listen what are they talking. I know there was a thing that could collect the sound even it was far away from the TV camera. But I don't know what was that thing and how that worked. Does anyone can help me? I think there are some physics principle can apply on this thing.

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3. They have little microphones attached to certain players - Jerome Bettis in the Super Bowl.

4. If, however, someone can explain how a telescopic microphone works, I for one would be grateful.

5. Silas, It works just like a telescope works, only instead of light it collects and concentrates sound waves. You have to use a dish and it's to collect more sound like a giant ear that the mic amplifies. They make some pretty sweet ones that can penetrate some pretty impressive layers (brick walls) to spy on the other side.

7. Yes, Ophiolite, I understood that, what I don't understand is how they shield all the intervening sound. All the sound between here and what I'm spying on. You get me?

8. Originally Posted by Silas
Yes, Ophiolite, I understood that, what I don't understand is how they shield all the intervening sound. All the sound between here and what I'm spying on. You get me?

They use a parabolic reflector which focus the sound waves on the mike. Parabolic reflectors only reflect to the focus the waves coming in a narrow array of directions (paralel to the axis). A directional mike on the focus will only pick focused sounds, i.e. sounds reflected by the parabolic reflector, i.e. sounds coming from the right direction. All other sounds will be damped.

If you think about it, it's litherally a "sound telescope", just it works with radio-like wavelengths (human voice has got a wavelenght about 15-25 cms) and longitudinal waves rather than transverse ones.

9. It is related somewhat to the effect seen in the Whispering Gallery, in the Dome of St. Paul's in London. Standing in the gallery one can clearly here people speaking on the other side of dome, above all the incidental and other noise.

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