Look at Rel subs. They have multiple ways to hook them up. Their preferred way is to use their high level connection which is connecting their supplied speakon cable to you amp. You run your speakers full range and the rels integrate perfectly with your mains. I’ve used rel with monitors and now using full range floor standing speakers
Subs - Installation
I am in the process of adding 1/2 subs to our 2 channel system. I am not entirely clear how you install/connect the subs. I assume they connect to my preamp. Is the bass still going through my speakers (B&W 804/3) and the sub is adding or is the sub taking all the low frequency? What is the thought of placing subs next to the speakers. I am looking at JL Audio Fathom 112 v2. I see that JL Audio also has an external crossover I am not sure what this does. Thanks for the help.