hi Prof, REL takes a totally different approach to subs than JL. I am no expert and am not very technically literate, but one of my takeaways today was that REL does not like the outboard crossovers that do what the JL does. they want the speaker to receive the full range of signal and for the amp to send a full signal to the sub. i agree with Jafant, that the REL is not that hard to set up.