The “Pressure Chamber” is a simple structure-born noise measuring device which can be fixed as attachment to common ½”-microphones of building acoustics measurement systems and is pressed against the vibrating component.
The alternating pressure pH measured with the microphone in the cavity is proportional to the vibration velocity of the component (rubber membrane). By connecting it to a volume V2 with an overflow opening with a resistor R the body sound velocity and the sound pressure in the cavity of the pressure chamber will be proportional in a wide frequency range. See the following schematic diagram:
In practice, the pressure chamber is used in the following areas: