Young man, There is a difference between LOUD and power! Anything can be LOUD but it takes a lot more than 200W to be POWERFUL! You are using a 4x10 cab and a 1x15 cab together, each cab is sharing 100W's, My car stereo is louder than that and it's stock!!! Do not confuse loudness with power, you say you are at about six on your amp and you have headroom left? I think all you have is air left after that! 200-300W's is the bare minimum bass players need to start with to be properly heard in the audience you are maxing out you amp using two cabs just to get 200W's. Do yourself a favor, go to any music store and try out any 500W head and you will notice a BIG difference in what you call headroom, and believe it or not 500W's is not a lot of power! When you have a rig like yours and use two cabs to get 200W's anything after six is going to be DISTORTION! you are not sending the cabs anymore usable volume and if you turn up you bass knob I bet all you get are FARTS!!!