Subwoofer suggestions for budget system?

Experiment with lowering the crossover and volume if things are getting unwieldy when you turn up the volume as that shouldn’t happen with proper setup. What Dynes do you have and where do you currently have the crossover set? You might also try placing the sub in one of the other places you found to be good for a sub while you were crawling around like a baby audiophile. Heh heh. Seriously though, nice work and you’re clearly benefitting significantly from all your efforts (and I’d think probably learning a lot too — always good). I think you’re now seeing why the SB1000 Pro is desireable with its integration app that you can use from your listening chair to make adjustments. That said, if you haven’t already it’d probably be a huge help to have someone else slowly adjust the crossover/volume/phase while you sit in the listening position. I could see that being pretty tough to do on your own.

I keep the crossover low (50-ish) since the Dyna's claim 40Hz–23kHz
I need to figure out if the phase change helps, if only my CFO would do the nob turning for me :)
I'd say the best part is, when the SVS works right, the 3D effect really kicks in. I am all about vocals so my main concern is to keep it bright, forward as if the singer was right in front of me, not behind the drums and I sense that deep bass can swallow the room easily

Evoke 20s on my custom stands
 

Maybe try reducing crossover closer to 40Hz and see what that does at higher volumes?  Sounds like you might be getting too much overlap between sub and speakers as volume increases.  Just a thought, but I totally hear ya on the 3D imaging thing.  It’s amazing what subs can do in that regard.  Try turning it off in the middle of a song and watch how everything collapses.  Crazy. 

so I just listened to Bohemian Rhapsody and I was like: wow, it's finally come together. And then I noticed the sub wasn't on. Baby steps....

@soix so I was confused about the SVS, and went out and picked up a Klipsch Reference R-120SW sub and I am glad I did. It’s a much bigger box and sounds profoundly different. If the SVS is a bobcat, the Klipsch is a lion. It makes the room feel much bigger. However it’s very raw, aggressive, a bit tiring. I feel like I was in a DISCO for an hour and I just spent 20 minutes with it, my head is buzzing. So the ideal solution must be somewhere in between. (And I am still not a Klipsch fan but I appreciate the scale)

It feels like it’s absolutely possible to live without a sub but may not be worth all that much without it :)