MillerCarbon has shared some pretty well thought through opinions about just trusting your ears (assuming they’re any good) and not always searching for a scientific explanation for why something improves the sound-- but that does not mean that most or all of the "improvement" you hear with some of these products is not all in your head. After all, that’s where the music goes doesn’t it?
That said, with respect to vibration control, there is no question that quashing as many extraneous vibrations as possible will improve the sound of your system. I am committed to trying the nobb springs because of MillerCarbon’s writing on this subject.
I have two decent turntables-- a SOTA Star Sapphire VI with an Origin Live arm and Soundsmith Hyperion cartridge that plays at very loud volumes with little or no audible vibrational feedback-- played out to Genesis III floor-standing speakers and Genesis Servo-12 subs.
My other turntable, a MoFi Ultradeck, sits on a butcher block which sits on six Isoaccoustics Orea feet. This deck will cause some vibrational feedback above a certain volume level. This is the one I’m hoping I can improve with some nobb springs, or Townsend springs possibly.
Anyway, I try to focus on the obvious stuff-- most of that being my rooms deficiencies-- so vibration and reflection are the demons that I still wrestle with.