I've put out a similar thread several years ago but I figured I'd try once more and try to keep it simple this time.
I've got two 15" subwoofers weighing 110 lbs. each solidly anchored to the subflooring using my own custom points. With mass-loading each subwoofer actually weighs about 160 lbs. In the center is my custom rack weighing about 250 lbs. with my custom points fastened at the bottom to ensure it too is solidly anchored into the subflooring.
The distance side-to-side between the nearest subwoofer points and my rack's center point is about 24-inches. The front-to-back distance between the subwoofers' closest point and the rack's center point is maybe 4-inches. It's entirely possible that one or both subs and the rack are sharing the same sheet of plywood (subflooring). The probability that the two subwoofers and rack are sharing the same floor joist is extremely high. Everything is also extremely rigid including their mounting to the subflooring.
For those who've strived all their lives to squash or quell floor-borne vibrations, isn't my configuration the biggest no-no ever? Am I not defying some law of high-end audio physics here? If so, why don't these recordings sound like mashed potatoes? Why isn't the resolution swinging high and low with every deep bass note? Why does there seem to be a tremendous consistency in articulation whether it be a high note or low note? If there's any truth whatsoever to the evils of floor-borne vibrations, none of this should be happening. Yet, everything I throw at it, the articulation and level of musicality remains consistent and IMO extremely musical.
I think of the millions others have spent trying to isolate their equipment from floor-borne vibrations. With so much dogmatism about the evils of floor-borne vibrations, surely there must be somebody out there somewhere that can provide an in-room video or two demonstrating how much more articulate the bass and overall musical presentation can be when floor-borne vibrations have been "isolated" from the playback system.