amp tuning?

what do the controls (like gain and LPF etc..) mean and how would i use them to get the best performance out of my amp?

The gain adjustment is just as it is called, a gain adjustment. It determines the amount of output you will achieve in relationship to the amount of input.   The LPF control, also known as the Low Pass Filter. This determines how much upper bass frequencies get to your woofers. Depending on your subs and your personal prefferences will determine where you set this control. Set it as high as it goes and listen to it a few minutes then set it at half way and listen again, you will have to determine where it sounds the best to YOUR ears.