Quite different, state-of-the-art and very useful acoustical measurements:
Whereas common noise assessments are based on the sound pressure level, which is a scalar quantity that has only the magnitude and is measured with a single microphone, the sound intensity level is a vector quantity that has both the magnitude and direction, and is measured with a sophisticated probe of two carefully spaced and opposite-directed microphones.
The advantages of sound intensity measurements over sound pressure measurements include the abilities to:
The great merit of measurements of the sound intensity is that these measurements allow to isolate acoustically different sources of noise that work (have to work) together, close to one another, as on the photograph below.
For example, if you have a pumping station where a number of pumps work simultaneously (cannot be switched off separately), you may determine the individual sound power level of each of the pumps by measurements of the sound intensity over each of the pumps in the presence of noise from the remaining pumps operating in background.
If you need to:
the measurements of sound intensity are the best approaches.
We carry out sound intensity measurements with Brüel & Kjær (B&K) Modular Precision Real-Time Sound Analyzers type
2270, with Sound Intensity Probe type: 3595
with a Pair of Microphones type: 4197 (state-of-the-art hand-held sound intensity system).