Sub Stream Options

Hey all,
I have a couple scenarios where I am looking to add a subwoofer to the playback. I am hoping for a solution that provides the frequency crossover. The only product I can find that has the crossover is the sub amp, but that amp doesn’t have a low level output for amps already built in.

I am currently testing with an amp v4 connected to a kicker hi-lo converter, and that is feeding into a bass guitar amp. I’ve turned all the higher EQ nobs down but it isn’t a replacement for the crossover. For this kind of setup do I need to string a separate crossover into the mix?