crossover

First let me say i have looked all over this site and there is lots of info on crossovers but i cant figure out what i need to know. My head unit and amp both have crossovers built in and im sure they help filter as best as they can. but the way i see it is you can only ask an amp to do so much. I got my hands on a sherwood crossover network xn-5000. Im only using it for my sub amp to see if it actually makes a difference. My question is what is the difference between an active and passive crossover? Is it even wort my time to mess with? any help would be great. thanks

An active crossover is an electronic crossover, the crossover in an amp, a radio and in your Sherwood unit are all active devices.   A passive crossover is simply a combination of capacitors and inductors.  Passive crossover does not require 12 volts to power it.   Passive crossovers connect between the amp and speaker.  Active crossovers are in the path between the signal source and the final stage of amplification.

The ONLY thing you may gain from the outboard crossover is going to be the adjustable bass boost. (If you think that is a plus)