Why the voice of Mi Bluetooth Headset Basic is intermittent and noisy?

1. The battery level of the device or the headset might be low, try fully charge the headset then try again if the sound is normal.
2. The distance between headset and device might be too far, or there's some other signals interferes the Bluetooth signal, like Wi-Fi. Try to reset the headset and re-do the pair process at a non-interference location then try again.