1.Difference of test environment: the noise test in the specification is usually carried out in an ideal and relatively quiet laboratory environment, but in the actual use environment, there may be other noise Confounding. These noises will mask the noise of the fan, causing the actual sound to be heard to be louder than the specifications.

2.Different measurement methods: different manufacturers may adopt different testing methods and conditions, so the same fan may have different noise values in different specifications.

3.The problem of the cooling fan itself: the fan itself may be defective or damaged, resulting in increased noise. This can be due to quality problems that occur during manufacturing or damage caused during transportation.

4. Improper installation position and method: if the installation position is not suitable, such as at the resonance point, near walls or other obstacles, it will cause poor air flow and increase noise. Or if the installation method is incorrect, such as imbalanced installation, it can cause fan vibration and loud noise.