Again, thanks for the advice.
I already changed fuses. I meant when I said I'd tried the basics. I have tried bypassing in the past, unrelated to this issue, and I always thought it sounded terrible. The fuses are brand new and I've changed those out, anyway.
Good to know about the Behringers and DBX's. I won't waste the time.
I found one called Sublime acoustics. $500. Not inexpensive. Looks to be decent quality, although the plasticky rca connections in rear don't look to be the best.
But, since I've been wanting to migrate to active crossovers for my bi-amping for around 15 years, now might be the time to just try it.
Regarding your speakers, what are those dividers? Do those come with the speakers? I've always found that when I do that with Magnepans, they sounded better. I used to put another pair of Maggies on the outside of both the ones I was listening to. Unless I was in a great room already, which I used to have. Now I'm listening in my apartment and it's not ideal. 17x19 for the 3.5's would be fine in a square, but this trapezoid, along with the opening in the room where it splits into another room just makes a mess of the sound. I have taken a lot of steps to control it and get it to a respectable level. And now this bass issue.
Thanks for trying.