SWARM / Multi subwoofer questions

So this is for the peeps that know what "SWARM" means not just loud but Headroom, Sound stage, and for Music only. I have an all sealed system and getting excellent results with two Hsu ULS `15's on opposite sides of my room and my Dunlavys. I will be adding a 3rd for Fathers day to myself. So question is who makes a bass EQ to help make it as perfect as it can get? I bought a DSpeaker 8033 and a mini DSP with questionable results... Actually like it better running speaker level off my Pass Aleph. Possibly I just dont know what Im doing actually really good possibility. but I would love an outboard X Over that actually works for a swarm set up. I know JL Audio makes a CR1 but it gives me angst to spend 2-3K and Im sure there has to be some pro Equipment out there especially given that Im running my speakers Full range and dont need a high pass. Any advice is greatly appreciated! 

Allgood

Here is a review of ULS 15's with specs supposed to be plus and minus 2 db from 20 to 100 hz. Speakers are Dunlavy SC 3's and annoying ruler flat to 50 or a lil deeper. Get the right gear and they are CLS, Avalon, Soundlab, Watt Puppy magic. least to me.  

https://www.audioholics.com/subwoofer-reviews/hsu-uls-15-mk2
https://hometheaterhifi.com/reviews/speaker/subwoofers/hsu-research-uls-15-mkii-subwoofer-review/