Hi Christian,
Understand in your video you have actually connected your Macbook Pro thur the aux in of the Amplifi.. Care to share what kind of volume level (high or low) you need to set from the Mac in order to achieve a balance tone with your guitar? I suppose in this setup , you will have to adjust the Macbook volume (for backing track) and Ipad volume (for guitar level) to balance the mix as the the large volume knob is to control the overall output level...