Sound intensity probe
Bruel and Kjaer

The measurement of sound intensity provides information on the magnitude and the direction of the sound energy in the sound field. The measurement technique is used for a variety of applications such as the determination of sound power, sound absorption and sound transmission. Sound intensity is calculated from the quotient of the sound pressure and the particle velocity; sound pressure can easily be measured directly but the particle velocity is usually determined by a finite difference approximation. This requires two phase-matched microphones in a face-to-face configuration.

Brüel & Kjær provides a number of sound intensity probes that conform to Class 1 in the Sound Intensity Instrumentation Standard, IEC 61043, which describes the characteristics of microphone pairs, intensity probes and calibration techniques for intensity measurements.