According to CNS8753 test specification. As shown in the sketch, place the fan in a silent room with a background noise of less than 15 decibels, 1 meter away from the noise meter, measure the suction surface of the fan, and draw the data and sound pressure after collecting the measured data through a computer Level trend graph, octave band sound pressure level graph, etc.
The intensity of the sound heard by the human ear actually varies with the frequency of the sound. For example, the human ear is particularly sensitive at 1000Hz. Therefore, two different frequencies with the same sound pressure will prevent the 1000Hz frequency from being louder. Big. The so-called difference between noise and music is only whether it sounds comfortable or not, in terms of sound waves, it is no different. The intensity level (SIL) of the sound that the human ear can hear can be expressed by the following formula: SIL=log I/Io(Bel) or lO log(I/10*-12(W/m*2))Db Io: the smallest possible The intensity of the heard sound (10*-12(W/m*2)) I: the intensity of the sound
