Problems with speaker

[Taadis Markevicius]

Hello, I have a problem with my Galaxy S4. When batery drains till 80%, then sound becomes distorted. But when I put it to charge, sound becomes normal again. Moreover, the sound is ok when I use headphones dosentmatter if battery is 10% or 100%. I tried to change batery and rear speaker, but it doesn't help. Any ideas? Here is the link s4 sound problem - YouTube

 

[Taadis Markevicius]

any ideas ?