Recording Handbook - Hol.gr

• II. Specifications.
• III. Pick Up Patterns
• IV. Typical Placement
• V. The Microphone Mystique
I. How They Work.
A microphone is an example of a transducer, a device that changes information from one form to another.
Sound information exists as patterns of air pressure; the microphone changes this information into patterns
of electric current. The recording engineer is interested in the accuracy of this transformation, a concept he
thinks of as fidelity.
A variety of mechanical techniques can be used in building microphones. The two most commonly
encountered in recording studios are the magneto-dynamic and the variable condenser designs.
THE DYNAMIC MICROPHONE.
In the magneto-dynamic, commonly called dynamic, microphone, sound waves cause movement of a thin
metallic diaphragm and an attached coil of wire. A magnet produces a magnetic field which surrounds the
coil, and motion of the coil within this field causes current to flow. The principles are the same as those
that produce electricity at the utility company, realized in a pocket-sized scale. It is important to remember
that current is produced by the motion of the diaphragm, and that the amount of current is determined by
the speed of that motion. This kind of microphone is known as velocity sensitive.
THE CONDENSER MICROPHONE.
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