After a little more playing around I find I agree with yamahaSHO. My room (AKA the basement) is crap; the electronics work fine. Adding the second sub just made it more obvious.

Now I just need to figure out why my room is absorbing/cancelling 50 and 100 Hz.
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975/7075/SMS-1
Aperion Verus Grand Towers & Bookshelves, Verus Forte Center, Infinity Surrounds, Ultra-X12
Oppo BDP-203, XBOX360, Xbox One
LG 65" OLED
RR2150 w/Klipsch SCR-2