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Noise Level Measurement
Noise Level Measurement
Fan noise level is measured in accordance with CNS 8753 standard (which
is similar to DIN 45635) ISO 3744 in a semi-anechoic room where the
background sound level is no more than 15dBA (The background noise level
in Shyuan Ya's semi-anechoic room is below 10 dBA ). Fastened vertically at
all four corners using strings, a microphone is then placed one meter away
from the center of the fan from the air intake side. The decibel readings taken
from the sound level meter are plotted as Sound Power Level against the
octave frequency bands.
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Calculations of Sound pressure level (SPL) and sound power level (PWL) have been shown as below.
Where:
SPL: sound pressure level
SWL: sound power level
P: pressure
Pref: a reference pressure
Wref: an acoustic reference power
Semi-Anechoic Room