hey guys, was wondering if anyone new how to corectly set the amp gain?

Sure.

turn your amp gain all the way down. Go to your head unit and turn the volume up to 3/4 way. Then go back to your amp and turn the gain up until you hear the speakers distorting, then back it down until the distortion goes away. You have correctly set your gain.

Some people will tell you to turn it up almost all the way. Some day 3/4. I say turn it up to the loudest you will ever listen to it. If you listen to it all the way up then there is a good chance you should tune your amp to that volume so you dont risk blowing your speakers.

http://www.bcae1.com/gaincon2.htm

Basic and very detailed.