I have just updated to powered speakers (mackie thump 215) and a non powered mixer (american audio), previously I was running through a power mixer (yamaha stagepas 400bt) , I am playing from an Iphone. I am now unable to get any volume playing tracks, I can faintly here the track through the speakers. I can play audio files from the phone and tracks from Youtube and it works fine, just unable to get any volume when playing though StageTraxx app. Are you able to help. Thanks Kev