Headphonevolume changes if i play Backingtracks

  • Hello.

    I recieved my Spark today. First i updated the Firmeware. But if i play over a backingtrag inside the app, the volume changes. Sometimes it gets louder (guitar and Backingtrack) and sometimes it gets quieter.

    is there maybe a setting to set the volume (not the little knob next to the Headphonejack) oder any other setting that i can change?

    Sorry for my bad english, i am from germany :)