If you are experiencing poor sound quality when using soundcore Sleep A10 in music mode, there are a few things you can try to improve the audio performance:

1. Ensure that the earbuds are properly inserted into your ears. 

The ear tips should create a tight seal to block out external noise and improve the bass.

2. Check the volume level on your device and the earbuds. 

Make sure that the volume is not too low or too high, as this can affect the sound quality.

3. Try using a different sound source or music app.

4. Adjust the equalizer settings on your device or in the soundcore app. 

You can experiment with different EQ presets or create your own custom settings to improve the sound quality.

5. Reset the earbuds as follows.

- Place the earbuds in the charging case and leave the case open. 

- Press and hold the button on the charging case for 10 seconds until the LED indicators on the case flash white 3 times and then flash in sequence. This confirms that the reset was successful and your earbuds can be connected normally.