ABSTRACT
All modern microphones are used with electrical amplification and thus are designed primarily
to sample a sound field rather than take power from it. In order to understand howmicrophones
work from the physical and engineering points of view, we must understand the basics of sound
transmission in air. We base our discussion on sinusoidal wave generation, since sine waves can
be considered the building blocks of most audible sound phenomena. Sound transmission in
both plane and spherical waves will be discussed, both in free and enclosed spaces. Power
relationships and the concept of the decibel are developed. Finally, the effects of microphone
dimensions on the behavior of sound pickup are discussed.
