Music on Spotify is slowed and is impossible to listen only when the screen is locked

[Maxencerlt]

Hello everyone, 

Since I have bought my new phone for Christmas (honor 6c pro), I have a real problem!

The music is getting unlistenable when I lock the screen, it's getting really slow and there are a lot of crackling sounds (and sometimes even when the screen is unlocked)

Please help me I can't listen to music while I'm premium and had never been in front of such a problem!

Thx.