Why does my bluetooth audio quality lower when using the phone?

[Salpa]

I have LG G Flex 2 running android 5.1.1 and with it I am using Jabra Wireless bluetooth headphones. Pairing and everything work just fine, but the sound quality lowers when I'm actually using the phone, there's a lot of static noise and cracking (almost seems like some kind of battery saving). When i put the phone back to my pocket in 10 to 30 seconds the sound restores back to high quality.

I tried looking into setting, but can't find any solution to this problem. Since I am a music lover this is really driving me crazy.

Can anyone help me?

 

[RogMoore]

Every device has different bluetooth performances, all the device does not have same volume.