The Pressure Microphone
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.