Cooling fan noise control methods can be divided into the following aspects:

1. Fan design optimization: choose the right type of fan blade, such as large-size, low-speed fans. Compared with small-sized, high-rpm fans, these types of fans are not only quieter, but also more efficient.

2. Reduce the effect of fan imbalance: fan imbalance can lead to strong vibration and noise, and can be reduced by using high-quality fan materials and superb processing technology.

3. Adopt noise-reducing cover: Noise-reducing cover can effectively block fan noise and reduce wind noise. Wrapping the noise-reducing cover around the fan can isolate it from its surroundings and effectively reduce the noise.

4. Use soundproof material: Use soundproof material around the fan, such as sound-absorbing cotton, soundproof board, etc., which can effectively absorb and reduce the noise.

5. Adjust the fan speed: Fan noise can be reduced by adjusting the fan speed. Under the premise of ensuring the cooling effect, appropriately reducing the fan speed can effectively reduce the noise.

6. Use active noise reduction technology: active noise reduction technology is a new type of noise reduction technology, through the electronic control system to control the cooling fan active noise reduction device and cooling fan start at the same time, the acoustic sensor detects the noise, the signal analysis system analyzes the phase and amplitude of the noise and other information and simplify it, the speaker system works to produce the opposite phase and amplitude of the noise sound waves, thus forming a static zone behind the active noise reduction device, which can effectively reduce noise in the cooling fan. The static zone is formed behind the cooling fan active noise reduction device to achieve the effect of noise reduction.

7. Regular maintenance and repair: regular inspection and maintenance of the fan, and timely replacement of damaged parts can effectively reduce fan noise.

The above are some of the cooling fan noise control methods, you can choose the appropriate method for noise reduction according to the actual situation.