if you are using 57 aux out, you need to make sure your upfaders are 100% and your aux out is between 12 and 1 o'clock (mines stays at noon). also make sure your scratch live main out is at 12 o'clock. this will give you the best levels without clipping. also when you are building overviews, make sure autogain is on and set at 92 db. this ensures that the majority of your library plays near a constant gain. and when you initiate a recording in ME, you should see green levels from your macbook line in. if they peak past the middle then your levels are good. p.s. if you ever have to turn your aux out past 1 o'clock then your audio files are crappy.