Poor streaming quality through iPhone 6 to Bluetooth

[Amorosamente]

Hi all-

Just recently, when streaming playlists from my iphone 6 via bluetooth through my car sound, the quality has been absolutely terrible. To be specific, it's very, very quiet and has no depth of sound. In order to hear anything, I have to turn the volume in the car up to 50, and even then I receive only a thin, depthless sound. 

I am a Premium subscriber. 

Thoughts or ideas?