A Comparison of Two Different Sound Intensity Methods to Measure the Sound Power Level

Measurement of sound intensity involves determining the sound pressure and the particle velocity at the same position simultaneously. The p-p method for measuring intensity uses two pressure microphones that determine the particle velocity component in the direction of the axis of the probe by a finite-difference approximation to the pressure gradient in Euler's equation of motion, and the sound pressure is simply the average of the two pressure signals. The p-u method uses a sound intensity probe that combines an acoustic particle velocity transducer with a pressure microphone (p-u probe). These two sound intensity methods could be used to measure the sound power level of sources.