So i was just put onto "reverend" guitars (link: http://www.reverendguitars.com/) and im wondering..... how do you do that bass contour knob that they have, cause i would love to do that in either one of the guitars im beginning to build. Or put it in any of hte guitars i currently have, i think its a great idea..... but being electronically challanged i dont understand how they can do that. Somone explain pls?