High Level Out from Dock Connector

[cubit]

I have a dock connector to RCA to my car stereo. Every app other than spotify works fine, no distortion.   With Spotify there is bad distortion like the audio level is too high.  Pandora, tunein radi, and songs on the ipod app play perfectly.

I've tried uninstal/reinstal og spotify, using extreeme settings and I get the same results. I've even tried it with my iPad instead of my iphone and I get the same thing. It's got to be the app.

Anyone else getting high levels from dock connector out on an ios and know of a fix?