How much difference does an anti-vibration audio rack make

Very good, you have to be able to find your hole.

You obviously missed my BDR diatribe. You get used to things after 15 years. 😀 

Trouble penetrating the carpet? Here’s a handy trick. Using a hole punch 🥊 and Hammer 🔨 punch a hole through the carpet and pad so the tip of the cone makes definite contact with the floor. 

Just to illustrate how much folks can strongly disagree on things I find carbon fiber to hurt the sound quite noticeably. Especially those BDR cones, both types. When BDR cones are compared to harder cones like steel or ceramic there is no contest, sonically. From my experience in isolation and coupling, more than the average bear, I think I can draw the following conclusions, no offense to anyone or any company.

The harder the material the better the sound. Hardness can be established from the Moh hardness scale where 10 is diamond which, by the way, makes great coupling device. That is why Shun Mook uses a Diamond tip on their Diamond Resonators. The Golden Sound DH (Diamond Hardness) Cones are NASA grade ceramic, next hardest material to Diamond. I’m not a big fan of brass cones, either, which by no coincidence fall rather low on the Moh scale of hardness, along with Carbon Fiber. I’m not saying the BDR cones don’t look good and have a nice sleek space age profile. 😀 By contrast, tempered steel is high on the Moh scale, so would make an excellent cone. The DH Cones are the best, by a considerable margin. Which reminds me, shape of the cone is important, too. For example the Jumbo DH Cone is an excellent sounding cone. The Super DH Cone, which is essentially the same weight and size, has a more ballistic shape, and sounds better than the Jumbo.

I recommend using very hard Cones with isolation stands, coupling the component to the top plate and coupling the iso device to the floor or rack. Do not (rpt not) place iso devices directly on carpets or use cones with rounded tips as the carpets act like springs and interfere with operation of the device. Some cones can penetrate the carpet. Use those.

Steve, good luck with that. And what about the rotational directions? Easier and better to use springs and roller bearings, most likely.

You need to get different friends. 😀 Just kidding, of course. Keep on truckin’! 🚶‍♂️

I built a magnetic levitation stand twenty five years ago. It’s the same idea used in the Verdier turntable to “float” the heavy platter. And similar to the air bearing platters and air bearing tonearms. The general issue with mag lev is that the sideways forces of the opposing magnets are very strong, such that the top plate always ends up pushed against the part of the structure, e.g., the column, that stops the top plate from flying off the stand.
This also prevents the top plate from moving freely in the horizontal plane, I.e., no isolation in the horizontal plane. Also, not good for isolation in the twist rotational direction.

So the top plate is not totally able to float and a transmission path is formed between the bottom part of the stand and the top plate allowing vibration to travel up to the top plate. The magnets themselves do not make contact if you do it right. A better solution to the problem overall is a combination of springs and roller bearing assemblies, as has been discussed many times, which can provide isolation in most or all of the six directions of interest, if you do it right.

Ironically perhaps and certainly counterintuitively solid rigid racks are not really good for the sound, especially if one assumes that solid rigid racks provide any isolation against footfall and other seismic vibration. On the other hand real isolation devices can be mounted on shelves of solid and rigid racks. The Flexy Rack of yore was the opposite concept of the rigid rack inasmuch as it capitalized on the fact that the best isolation is when movement is easier in a particular direction when impelled by an external force, I.e., seismic vibration. Since rigid racks do not allow ease of motion in any direction they have little if any value for vibration isolation. In fact they tend to magnify the effects of vibration. Like tall buildings. They look good, though.