The Xiaomi Y-600 air purifier has different operating levels that influence the volume and performance. Here are some important points:

- The air purifier has several power levels that can be adjusted according to requirements and air quality.
- The volume varies depending on the operating level. In general, the volume is at a low level, especially in night mode, and can increase at higher power levels, but it usually remains below 68 dB.
- The operating levels also depend on the level of air pollution, as the air purifier can automatically adjust the power to optimise the air quality.

Therefore, the volume is not 68 dB all the time, but depends on the selected operating level and the current air quality.