7. Pressure gradient microphone

7.1 Bidirectional microphones

In the pressure microphone, the active force is the pressure acting on the outside of the diaphragm. Due to the scalar nature of this pressure, the microphone's response is independent of the wave's angle of incidence, as long as the wavelength is longer than the diaphragm's dimensions.

In the pressure-gradient microphone, the active force is the force due to the difference in pressures p ₁ and p ₂ acting on the front and rear faces of the diaphragm, respectively.

This force SΔp = S │p ₁ – p ₂ │ depends, this time, on the step...