Some have said they set the Threshold to barely audible. I've also read that you can miss hits through the threshold if it's not loud enough. Should I be lowering the threshold or the volume of the machine? Is lowering the threshold just lowering the threshold volume or does it affect the machine differently? Also, can someone explain the Iron Mask a little bit? I'm confused on how it works compared to the Smartfind screen, or do you use them together?