I got a couple questions. Number 1 if I wired 1 EQL to the front input of the 3XS and the other EQL to the rear input of the 3XS, would the eqaulizer points on the EQL wired to the front input control the front output and the rear input control the rear output? Second what would be good crossover points?
if you're using a 3XS as a 3 way crossover for front/rear/subs, you can use an EQL on the front channels and rear channels each, which would dedicate one EQL full range to fronts, and one to rears, but no EQing for the sub channels unless you put the EQLs before the 3XS. then you'd EQ the full range from fronts and rears at line level coming from the head unit.
in my case I just used an EQT on each channel before the crossover and amps.
as for XO points, that entirely depends on the system you're running, the vehicle, etc. best way to tune the EQLs and 3XS is on an RTA.