In addition to noise testing, there are several ways to improve the noise performance of brushless DC water pumps:

1. Optimize motor design

- Use low-noise motor technology, such as optimizing motor structure and materials, improving magnetic field, reducing electromagnetic noise, etc.

2. Optimize pump body structure

- Optimize the design of pump impeller and pump casing, reduce fluid turbulence and pulsation, and reduce fluid noise.

3. Improve mechanical parts

- Improve the manufacturing accuracy and assembly quality of bearings, couplings and other components to reduce mechanical vibration noise.

4. Add vibration reduction measures

- Add vibration reduction pads and other measures at the connection between the pump base and the pipeline to absorb vibration transmission.

5. Use silencers

- Add silencers, mufflers and other devices to the inlet and outlet pipes to absorb and isolate noise.

6. Choose low-noise materials

- Choose low-noise materials to manufacture water pump parts, such as low-noise plastics or engineering plastics.

7. Optimize pipeline layout

- Use flexible connections for water pipes as much as possible and avoid rigid pipes. Reduce excessive noise sources such as elbows and valves.

8. Reasonably adjust pump parameters

- Properly reducing pump speed, flow and other parameters can effectively reduce noise.

9. Increase sound insulation measures

- Add a soundproof cover around the pump or place it in a soundproof room to block the spread of noise.

The combined use of these methods can better control and reduce the noise level of the pump in actual application and improve the equipment use experience.