The Microphone Book, 2nd Edition

CHAPTER 3

THE PRESSURE MICROPHONE

INTRODUCTION

An ideal pressure microphone responds only to sound pressure, with no regard for the directional bearing of the sound source; as such, the microphone receives sound through a single active opening. In reality, a pressure microphone exhibits some directionality along its main axis at short wavelengths, due principally to diffraction effects. As we saw in Figure 2–12, only as the received wavelength approaches the circumference of the microphone diaphragm does the microphone begin to depart significantly from omnidirectional response. For many studio-quality pressure microphones, this becomes significant above about 8 kHz.

The earliest microphones were of the pressure type, and the capacitor pressure ...