Turntable isolation for bedroom floor

The easiest change that will make the biggest improvement is to place the turntable on the floor. This is because the floor is gonna move anyway. But the higher the rack the longer the lever arm and the greater the move the higher you go. 

You can try a wall mount. But floors usually are a lot more structurally sound than walls. 

Your most fool-proof and cost-effective solution is the tried and true sand box. Dirt (heh) cheap and hard to mess up. You could if you want experiment and see for maybe $10 if that. Simply buy a bag of kids play sand, dump it in a tote. Tamp it flat. Find something flat and around 3-4" diameter, place that on the sand, place the component on that. Then when you have proven this works (and it will) you can decide how to make it look better. Build a box out of MDF for example. 

The bigger/deeper/more massive you go the more it will damp and the lower it will drive the fundamental frequency. My table for example does move when I walk up to it. But its in the range of a few hertz, and only when I'm right there. That's with over 500lbs but also on a rack over 40" high. For years before the rack mine was right on the floor. The rack is even better. But look how much mass it took to compensate for being that high. That's why more often than not the best rack is no rack.

My Clearaudio turntable has magnetic bearing in the vertical direction - its benefits are limited to the reduced friction & wear; it doesn’t do jack to reject footfalls. In fact magnetic suspensions can sometimes make footfalls even worse (e.g. Clearaudio’s magnetic bearing arms). However a properly tuned spring suspension can work wonders. E.g. I have a SOTA Nova that’s almost immune to footfalls. Though I haven’t tried them, Townshend sells spring feet & platforms that get good feedback - I’d look into those.

And honestly I'd toss out those magnetic feet. 

@millercarbon  that's very interesting, thanks for the suggestion. 
How about placing the one rack with the turntable in the sand...?

@mulveling  thanks for your input. I'll certainly try removing the magnetic feet. Maybe try sorbothane hemispheres...??

The difference of course is that turntable magnetic suspension isn’t intended to decouple the platter or provide any isolation.