Best type of metal for turntable platform?

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.

Look... I'm not knocking the SOTA (except for its looks :). If I dont solve this, then I might consider it. I just didnt want to be limited to ONE turntable in this room. I was considering a VPI Prime Signature in a year or two as the next TT. But with this room the way it is, I dont see that happening. the concrete blocks/wood as a footer does sound like the logical thing to do... So there's noooo other way to deal with a footfall im assuming? Is this why im getting woofer flutter/pumping with almost anything I do?

The point is, you might have to spend a lot of money on a localized audiophile bandaid solution instead of a few bucks by minimizing the actual problem. 

You don't need CNC, unless you yourself make it a requirement. What you need to eliminate footfall problems is a two stage approach. First stage, mass eliminates large amplitude low frequency footfall type vibrations. Second stage, springs isolate the turntable from the smaller amplitude higher frequencies that get past the mass. 

With a superior product like Townshend Pods your table will probably be fine even with your existing rack. People who have PM'd me about problems like this tried Pods and they work great in situations much like yours. They work even better in situations like mine, which is why it is still a good idea for you to build a sturdy low profile rack with a massive sand bed. As described above. 

You really should as a general principle ask the question you want answered. You came here asking about metal when really it is about footfall problems with your turntable. At least that is what it seems to be. Until it changes yet again....?

@best-groove:     A plinth could be more a work of art*, made of that.        If cleverly equipped with an air bladder; very efficacious against footfalls.                                                               * Some Panzerholtz laminates are leg-wetter gorgeous!