No vocal sound in 5.1 movies

There's no vocal sound when playing 5.1 movies, while other sounds are normal, why? 

Please check the 2.0-to-5.1 function and make sure it's switched off. Then the vocal sound will be normal.

There are three possible ways to help:

- Press the 2.0-to-5.1 button on the remote control to switch it off.

- Enter Settings>Image and sound>2-channel to 5.1-channel>Turn off

- User center>Turn on/off the surround sound

Note: Starloop has developed a 2.0-to-5.1 algorithm to help enhance the surround sound effect when playing 2.0 contents on stream media like Youtube, Netflix, etc. Please switch it off when playing 5.1 movies to avoid sound channel conflict.