How It Works
What is a Parabolic Microphone?
When a microphone, an electronic element that converts sound pressure into an electrical signal, is mounted inside a parabolic collector, it is referred to as a parabolic microphone. As mentioned above, the unique shape of the parabolic collector is used to collect incoming sound (pressure) waves and focus them onto a single point where the microphone converts the collected sound energy into an electrical signal. Because the sound energy from a large area is focused onto a single point, the sound is, in effect, amplified. The electrical signal generated by the microphone is then amplified electronically as well.
This is the same technology that is used to capture the sounds of the game during professional football games every weekend. In fact, the Sound Shark is manufactured by Klover Products, the leading manufacturer of parabolic microphones used for professional sports.
The Sound Shark, however, is unique in that it is small enough to be mounted directly on a video camera, a light stand, a tripod, or a Magic Arm. This flexibility allows the Sound Shark to be located out of the camera’s field of view, regardless of where the video camera may be.
How does a parabolic collector work?
The unique shape of the parabolic collector allows anything coming into the dish that is parallel to the center line of the dish to be focused onto a single point. This shape is based on a mathematical formula called a parabola. That is where parabolic collectors get their name.
This focusing effect works with light, electromagnet energy or sound energy. Satellite dishes use this same concept to gather electromagnetic signals from space. According to Wikipedia, German physicist Heinrich Hertz constructed the world’s first parabolic reflector antenna in 1888, but the principle of parabolic reflectors has been known since classical antiquity, when the mathematician Diocles described them in his book On Burning Mirrors and proved that they focus a parallel beam to a point. Acoustic Mirrors used the same effect to detect enemy aircraft prior to the invention of radar.
Is this the same concept I have seen at parks and museums?
Exactly. A whisper can be heard from a great distance if you stand at the focus point of a large parabolic dish. Museums and science centers commonly refer to these as Whisper Dishes.
Is The Shape Of The Dish That Important?
Yes. The parabolic shape is critical to the performance of the parabolic collector. The dish must be manufactured to the exact specifications. The Sound Shark’s dish is manufactured to tolerances of only a few thousandths of an inch. While you can collect sounds with an inexpensive dish, that sound will be distorted or “garbled,” and the amplification will be reduced significantly.
