Wednesday, February 9, 2011

Speakers and Microphones..How they work

A speaker is made of a magnet, wire coil, and cone shaped diaphragm. An alternating current is generated by the microphone or an amplifier, which flows through the wire coil in the speaker. The current alternates at the same frequency as the sound waves and induces an alternating magnetic field that is in the wire coil. The polarity of the magnetic field alternates and is attracted and repelled by the magnet. The coil then vibrates and causes the diaphragm to vibrate and produce the sounds of the microphone or the amplifier.
Microphones detect sound information and translates it into electric current patterns. Magneto dynamic microphones have thin metal diaphragms and are attached to wire coil. The air vibrations are intercepted by the microphone and transmitted into metal surfaces, which is turned into electrical currents. The speed and motion frequency of the diaphragm are the factors that determine how current is transmitted. These microphones are known as "velocity sensitive."
Microphone sensitivity measures the amount of electrical output produced by a sound. Sensitivity levels have to be high to capture short and low sounds. Microphone overload is when loud sounds overdrive the mic. Diaphragms may be damaged if the coil and magnetic field lose contact. Microphone distortion is when the diaphragm is not aligned correctly and the sounds produced do not come out right.
Speakers and microphones are two different devices, but they use many of the same materials and both create sound.

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