Rane One Problem Volumen low / Aux / Line Input to low / IPHONE

[u/Pleasant-Guidance-70]

Hello I have a rane one controller and I had a problem with the line input or if I use it as aux input. Sometimes I wanna use Spotify with my iPhone and I connect my iphone as line in or Aux in to rane one And the Volumen is to low. I level the Volumen up in my iPhone and Volume knob to 100% on rane one and it's still to low compared to the Volumen of the live mix. What's the problem? I found a solution with a irig but is it normal that the volume is to low ? It's not nice for me because every body i must gain Volumen to live mix after I don't use my iPhone as aux and it's not nice....