There’s crawl space under my floor. SOTA has came up many times for my situation, but I do really like this TT and want to make it work. Even if I wall mount I feel that the flexible floor vibration will creep into the wall.
Well, you could still do it, just not as easy. Dirt or gravel floor in the crawl? Or concrete? If dirt or gravel, you could get 12x12 concrete block as a simple ‘footer’ sitting on top the dirt or gravel, and then brace the 2x’s off of that.
Your problem is the floor joists were undersized for their span, or at the limit of acceptable design, which equals ‘bounce’. Not unusual in an older home. Fine for most folks, but not for most turntables, except the SOTA, of course. 😁
if you can brace the floor, your solution at the table will be greatly minimized.