Hey guys I'm not to sure about crossover's and slopes and all that?

I have a 3 way set (JL XR) that I'm running off a full range ADS amp, and I was under the impression that the crossovers that came with my components would take care of everything.

My question is what would adding an external 24 db crossover or EQ help my system? Is it needed? I really just want to keep the highs down a bit.

Anybody?

It would be most useful to highpass your fronts wherever your subs low pass. Ex: if your subs play 80hz an under, then make your mids play 80 hz and up. Less uneeded excursion and more power for amp.