Quite different, state-of-the-art and very useful acoustical measurements:
Measurements of Sound Intensity
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:
- determine the sound power level of a mechanical system (compressor, lawn-mower,
air-conditioner, pump, fan) in-situ, in your laboratory or factory, without the necessity
of placing this system inside the anechoic or reverberant chambers (expensive) or in
the acoustically free-field (in many cases unattainable);
- search for, pinpoint, rank and quantify individually all significant sub-sources of
noise within a mechanical system (e.g. an air-conditioning unit), such as compressors,
cooling fans, worn-out bearings, covering panels, motors, gear boxes and supporting structure -
this permits effective, optimally targeted (informed) noise reduction modifications; and
- scan walls, windows, doors, floors and ceilings to determine, which of these elements
or their part(s) are acoustically inadequate and need to be replaced or reinforced.
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:
- determine sound power level of your products for technical specifications, sale contracts
or legal requirements;
- carry-out a modern noise reduction program for your products or
equipment that you use;
- decrease transmission of noise between two rooms;
- reduce the impact of aircraft or road traffic noise affecting your office,
residence and/or school;
- control noise escaping from your factory building, sound studio, discothèque and/or club;
the measurements of sound intensity are the best