Won't play loud when using Spotify on IOS 4

[Syphs]

When i play the music thats already on my phone, I can play extremly loud, but when I then try to play music through my spotify, it's sooo much more quite. Any fix to this?

PS. I don't cahnge sound settings when changing from the phones music libary to Spotify, and I'm using the same dock station.

[MichaelJerzak]

Do you have Spotify Premium?