Option 1
The best and most reliable method for reducing interference is to move the Bluetooth device (the smartphone, the tablet, etc.) closer to the earphones. The further the distance between the device and the headphones, the more interference you are going to get.
Option 2
Try re-pairing your device with the headphones. Turn off the headphone, and shut off the Bluetooth on your phone or tablet for a few minutes. Turn the earphones back on and re-enable Bluetooth on your device. Finally, reconnect the two devices.
Option 3
If you are able to, try to use the earphones with a different Bluetooth device. The interference/sound quality issue could be a problem with your mobile device and/or your mobile network service.
Option 4
Reset the factory settings.
- While powered on, press and hold V+ and V- for 10 seconds.
- Press and hold the center button for 3 seconds.
- Turn on to re-pair.
I found that switching my phone to my right pocket helped improve the connection. I think it made it closer to the controls and Bluetooth receiver.