JL Audio d110 vs e110

it has a crossover network inside. cables go from preamp to subwoofer, then from subwoofer to amp. amp only gets non deep bass signals to send to main speakers.  therefore main speakers get signal from sub's crossover, not always a good thing.  proper set up of sub can be quite difficult, some say impossible... 

and then there can be all kinds of settings and placement...

but can be fun too