I definitely like the free bass around 16hz! I’m fact, I’ve almost been inspired by your experience with the HSU’s to buy some myself. For a really long time, my sights were set on a pair of fv15hp’s by rythmik. Then they dropped the 18’s. Damn!!!
However, after struggling to finish my Atmos upgrade, I’m thinking about a pair of HSU’s like yours instead. $$$
My PCs are great in their own right, but like you, I’m on concrete, sunken living room, vaulted ceiling, open concept...blah blah blah...
I need more subwoofage without being afraid of winding them up.