TABLE OF CONTENTS by Glen Ballou
Every sound source has different characteristics; their waveform varies, their phase characteristics vary, their dynamic range and attack time varies and their frequency response varies, just to name a few. No one microphone will reproduce all of these characteristics equally well. In fact, each sound source will sound better or more natural with one type or brand of microphone than all others. For this reason we have and always will have many types and brands of microphones.
Microphones are electroacoustic devices that convert acoustical energy into electrical energy. All microphones have a diaphragm or moving surface that is excited by the acoustical wave. The corresponding output is an electrical signal that represents the acoustical input.
Microphones fall into two classes: pressure and velocity. In a pressure microphone the diaphragm has only one surface exposed to the sound source so the output corresponds to the instantaneous sound pressure of the impressed sound waves. A pressure microphone is a zero-order gradient microphone, and is associated with omni-directional characteristies.
The second class of microphone is the velocity microphone, also called a first-order gradient microphone, where the effect of the sound wave is the difference or gradient between the sound wave that hits the front and the rear of the diaphragm. The electrical output corresponds to the instantaneous particle velocity in the impressed sound wave. Ribbon microphones as well as...
