Sound intensity is a directional quantity that measures the rate of energy flowing through a specified unit area. Typically, sound intensity is measured using a pair of phase-matched microphones at a fixed distance apart. A two-microphone sound intensity probe measures only the component of the total sound intensity traveling parallel to the axis of the probe.
Sound intensity is objective and can be measured by auditory equipment independent of an observer’s ability to hear. This makes sound power an excellent tool for noise source identification. Simple scans for manually viewing intensity levels and complex scans for developing a sound map of the test area are both common techniques used with sound intensity.
Not only is sound intensity a good tool for noise source identification, it also is a good tool for sound power measurements. The advantage of using intensity measurements for sound power is derived from the nature of the intensity, which is a flow of energy. Because of this, sound intensity allows sound power measurements in non-acoustically isolated environments, such as a factory floor. An area is mapped around the test object, and measurements taken on both sides of the test object, will cancel out any flow of steady state energy that is outside of the mapped area.
Sound Intensity is a popular option on SignalCalc Dynamic Analyzers.