Getting granite tomorrow.

Here's our poor man's isolation setup. Of course it helps that I have a PhD materials scientist at home to dummy-check my stupider ideas. This explanation may help demonstrate how breaking a complex project into its discrete elements helps inform workable decisions.

Step 1. Our rack and components weigh ~450lbs. The first job was to provide this whole pile some isolation from our somewhat excitable wood floor. That was easy and cost <$50. All I did was buy sorbothane pucks in the appropriate size, durometer and quantity needed to isolate 450 pounds. This was simple to calculate with the information on the manufacturer's website, or on McMaster-Carr's site. One puck beneath each of my rack's eight feet plus two more beneath the heavy end of the rack and voila! I won't claim it matches a Minus-K, but I can jump up and down next to the TT and it never skips.

Step 2. was to isolate each individual shelf within the rack. That was also cheap and easy because I followed the same strategy: small, sorbothane hemispheres or Vibrapods beneath each shelf, of a size, durometer and quantity suitable for the weight being supported. I won't claim this equals a Vibraplane, but it did improve the sound and cost peanuts.

Step 3. was to isolate each individual component from the shelf it sits on, and this is where the DIY/cheapskate model broke down. After trying several things we settled on Symposium Rollerblocks + tungsten bearings, cryoed. Four sets were not cheap, even bought used, but the improvements beneath any component with a large transformer, power supply or tubes were remarkable.

Step 3(a) was the TT, a special case. Any compliance directly beneath a TT has both positive and negative effects. It's a tradeoff between lowering the noise floor (due to better isolation) and dulling dynamics and bass response (due to unwanted TT movement). After trying spikes (no isolation, great dynamics) and compliant materials (good isolation, sleepy dynamics) we settled on Stillpoints with Risers and Inverted Risers. These provide a nice improvement in the sound floor with only a minor loss in dynamics and bass. A reasonable compromise.

Note, the Stillpoints were nowhere near as effective as the Rollerblocks beneath our amps, power supplies, etc. Similarly, Rollerblocks beneath the TT were a disaster. Different applications require different solutions. Further, everyone's TT and sonic priorities differ so YMMV definitely applies.

And then there's speakers... :)

Doug, that is a very nice explanation of the various steps and results. I had a different experience with my unsuspended turntable. I did put a Vibraplane pre-loaded with 136 lbs of steel plate ballast under my unsuspended turntable. Interestingly, I found that the noise floor was lowered AND dynamics and bass response improved.

It just goes to show, as you wrote, that everyone's TT is different and thus solutions may work in some situations and not in others. I will shortly be trying out a suspended TT on the Vibraplane, and I may find the added isolation is not needed and perhaps even detrimental to the sonics.

So Doug, what are you using under the speakers? Since I moved a couple of years ago from a nice concrete floor to a suspended wooden floor (albeit decently solid), I've come to realize (despite my best efforts) that some type of decoupling is going to be needed at the speaker/floor interface since too much mid bass energy is being directed into the substructure. And, it probably isn't going to be cheap. I've tried the Herbie devices and they were abysmal in my application. The next step is something like Stillpoint Ultras or the Track Audio decoupling spikes, but now we're talking quite a bit of cash for eight feet. I'd be curious as to your approach. Cheers.

Granite Rings....not a good idea

Peter,
That's really interesting that a Vibraplane beneath your TT improved both noise floor and dynamics. I don't know how they function but I've heard good things from many people. We haven't gotten around to trying one ourselves... so many vibrations, so little time!

Richard,
We've had the shaky floor thing going from when we first got speakers big enough to go below 40Hz. I once tried isolating the floor from them by placing the speakers on butcher block boards, with the boards just sitting on the carpet. When Paul saw this setup he asked what I was doing.

"The speakers excite vibrations in the floor and that's undoubtedly getting to the components in the rack. I thought I'd try isolating them from the floor."

He gave me the pained look scientists reserve for children and idiots (I've seen it before, and since).

Well, we were both right. The isolation worked and the floor got quieter, woo-hoo. However, Paul's scepticism was justified because it sounded like crap.

Think about it. Isolating/decoupling requires allowing a component to move, and let's recall Newton's laws of motion. If a speaker cabinet is free to move then some portion of the energy from each cone excursion, which ought to be 100% dedicated to displacing air forward, will instead displace the cabinet backward. Result? Slurred transients, reduced dynamics, dopplered waveforms and general sonic muck. Decoupling is disastrous for speakers.

Stillpoints do decouple so I'd expect them to be a net negative beneath speakers. OTOH, those Track Audio speaker spikes look similar to the (very effective) Audiopoints spikes we now use. But it's an error to say they de-couple. Spikes couple, that is their purpose. A solid coupling improves speaker performance but as a side-effect the floor will shake more, not less. That problem must be addressed elsewhere, not at the speakers.

Recommendations:
Spike, bolt or glue your speakers to the floor as rigidly as possible. Perfect rigidity, if we could achieve it, would result in 100% of each cone excursion moving air and 0% moving the speaker cabinet. That's the goal.

If a floor's excitable then two approaches suggest themselves:
1. reinforce the floor to resist/dampen/absorb energies
2. isolate sensitive gear from the floor