Problem

The user uses Bluetooth earphones to play music. They then disconnect the Bluetooth earphones and disable and enable Bluetooth again. After the Bluetooth earphones reconnect, there is a high possibility that the audio quality changes.

Cause

1. The sound quality change is caused by the difference between the sound quality of the voice protocol channel and that of the audio protocol channel.

2. The Bluetooth earphones automatically switch the audio channel.

Solution

1. Change the audio channel manually.
2. Reconnect the Bluetooth earphones again to see if this resolves the issue.