Electronic Microphone Views

General Goods

Microphones produce a very small amount of current, which makes sense when you consider just how light the moving parts must be to accurately follow sound waves. To be useful for recording or other electronic processes, the signal must be amplified by a factor of over a thousand. Any electrical noise produced by the microphone will also be amplified, so even slight amounts are intolerable. Dynamic microphones are essentially noise free, but the electronic circuit built into condensor types is a potential source of trouble, and must be carefully designed and constructed of premium parts.

It is posible to exaggerate the directionality of cardioid type microphones, if you don't mind exaggerating some of the problems. The Hypercardioid pattern is very popular, as it gives a better overall rejection and flatter frequency response at the cost of a small back pickup lobe. This is often seen as a good compromise between the cardioid and bidirectional patterns. A shotgun mic carries these techniques to extremes by mounting the diaphragm in the middle of a pipe. The shotgun is extremely sensitive along the main axis, but posseses pronounced extra lobes which vary drastically with frequency. In fact, the frequency response of this mic is so bad it is usually electronically restricted to the voice range, where it is used to record dialogue for film and video.

There is an aura of mystery about microphones. To the general public, a recording engineer is something of a magician, privy to a secret arcana, and capable of supernatural feats. A few modern day engineers encourage this attitude, but it is mostly a holdover from the days when studio microphones were expensive and fragile, and most people never dealt with any electronics more complex than a table radio. There are no secrets to recording; the art is mostly a commonsense application of the principles already discussed in this paper. If there is an arcana, it is an accumulation of trivia achieved through experience with the following problems:

The sensitive transducer element of a microphone is called its element or capsule. A complete microphone also includes a housing, some means of bringing the signal from the element to other equipment, and often an electronic circuit to adapt the output of the capsule to the equipment being driven. A wireless microphone contains a radio transmitter.