I know this have been discussed many times before, and i did read the other threads but i still have some questions and i am still unsure about doing a active set up. So my current set up is pretty basic Right now and i was satisfied for awhile but now i want something else. So my system right now i have, an Alpine Cda-117 as my head-unit and 1 audison lrx 4.1k and Hertz Hi energy 6.5 Coaxial and a 12" Image Dynamics IDQ in a sealed box, i have no rear fill so im using the 4.1k to drive the front and my sub. And for my active setup i plan on getting a pair of used Hertz MLk 165's or picking up The hertz hsk 165 xl's and i hope to use my 4.1k for my front stage then use my HD 750/1 for my sub, and i know audison says that the 4.1k can be used in a 2-way active set up, but after reading the other threads it said that to do a active set up my amp would need a band pass setting but i dont see it on my amp, and other threads said that a active setup would need an external crossover, is it absolutely necessary? because i think the 4.1k crossovers are good enough what do you guys think?