Please refer to the following troubleshooting steps:
1. Slide up on the touching control area to adjust the volume individually;
2. In your phone's settings, enable Absolute volume (or Keep volume consistent) and adjust the volume using the phone's volume buttons;
3. Alternatively, in the Xiaomi Earbuds APP settings interface >> [Gestures] >> set double-tap to increase volume, then press the earbuds to adjust the volume;
4. It can be due to the low battery on your phone or earbuds. Charge them fully and check again;
5. Reset the earbuds and pair them again;
6. Test with another phone. If the problem persists, please apply for the after-sales service;
7. Check if the sound outlet of the earbuds is blocked or if there are foreign objects. Clean them promptly.
Note:
Sound will be reduced in high wind conditions or noisy environments like subways, which is normal.