Sound intensity probe

The sound intensity (in watts per square meter) is given by

${\displaystyle I=pv}$

where

${\displaystyle p}$ is sound pressure in pascals

${\displaystyle v}$ is particle velocity in meters per second

A p-p type of sound intensity probe measures the sound intensity using two phase-matched microphones. These microphones are usually positioned face-to-face and are used to determine a pressure gradient. From this pressure gradient it is possible to calculate the particle velocity. The sound pressure is determined from the average from both microphones output.

A p-u type of sound intensity probe measured both the sound pressure and the particle velocity directly. Sound pressure is measured using a microphone and particle velocity using a particle velocity probe