When we build a Home Entertainment, a Karaoke System or a hifi Stereo Set we always need microphone. A microphone is an equipment to convert sound energy into electrical energy. This energy can convert by using electrostatics, electromagnetism, piezo-electric effects or the change in resistance of carbon granules. But in this blog we only discuss about Dynamic and Condenser Microphone.

DYNAMIC MICROPHONES

Dynamic microphones have the advantages of being relatively inexpensive and hard-wearing, and they don’t need a power supply or batteries to make them operate. In live sound, nearly all the mics used are dynamics, and in the studio, instruments such as drums, electric guitars, and basses may also be recorded using dynamic mics.

A lightweight diaphragm, usually made of plastic film, is attached to a very small coil of wire suspended in the field of a permanent magnet. When a sound causes the diaphragm to vibrate, the whole assembly works as a miniature electricity generator, and a minute electric current is produced. Because the electrical output is so very small, it has to be amplified using a mic preamp before it is large enough to be useful.

In practical terms, the outcome is that dynamic microphones fail to reproduce very high frequencies accurately. In some applications, this isn’t too serious, but if you’re working with an instrument where a lot of tonal detail is contained in the upper harmonics, a dynamic mic is unlikely to bring out the best in that instrument.

In the studio where the mic is used very close to the sound source, this lack of efficiency is not a major problem, but if you’re trying to capture a quiet or very distant sound, then a dynamic mic isn’t likely to produce good results.

CONDENSER MICROPHONES

Basically, the heart of any condenser mic is a pair of conducting plates, one fixed and the other in the form of a moving diaphragm. When the spacing between the plates changes (as it does when the diaphragm vibrates) the capacitance varies, and if a fixed electrical charge is applied to the capacitor, an electrical signal is produced which faithfully represents the diaphragm vibration.

To keep the weight down, the diaphragm is often made from gold-coated plastic film. As a result, the diaphragm assembly is very light compared to that of a dynamic mic, so the system is much more efficient, and is capable of capturing harmonics right up to the range of human hearing and beyond. The size of the diaphragm also has an effect on the tonal quality of the mic — large-diameter models are chosen for vocal work because of their warm, flattering sound. Small-diaphragm models tend to be chosen where high accuracy is required.

And now we can choose a microphone when we build our home entertainment or karaoke system. We just only choose an dynamic or condenser microphone.