Published information
All manufacturers publish the audio levels for their products and such figures should be carefully examined and compared as part of the buying decision. When comparing the levels of noise, it is important to verify that the numbers on the like-for-like basis. The main considerations are the following:
- - Noise level sound power level or sound pressure level?
- If the sound pressure levels specified, at what distance from the source?
- Is quoted levels weighted average?
Sound power is the speed of sound energy output of the source and its units of watts. Sound power is an inherent feature of the source, while the acoustic pressure is also dependent on the environment (distance, reflection, absorption, transmission). Sound pressure is measured directly by the pressure sensitive microphone sensor; sound power is found from the measurement of the intensity of sound-the sound intensity, volume and flow direction of the acoustic energy per unit area in a particular place. Weighted data are adjusted so that the individual frequency levels correspond to the sensitivity of the human ear.
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Air-Conditioning