chapter  5
29 Pages

First-Order Directional Microphones

The great majority of directional microphones in professional use today are members of

the first-order cardioid family. The term first-order refers to the polar response equation

and its inclusion of a cosine term to the first power, or order. These microphones derive

their directional patterns from combinations of the pressure and gradient microphones

discussed in the previous two chapters. By comparison, a second-order microphone

will exhibit a pattern dependent on the square of the cosine term. Stated differently,

a first-order microphone has response proportional to the pressure gradient, whereas a

second-order design has response that is proportional to the gradient of the gradient.