Isolation systems

As pointed out too many variables to predict.
 

I would not attempt further whole rack isolation but concentrate on individual component isolation. For one thing it will be easier to analyse and compare. You’ve already got a pretty good base. Nobsprings under individual legs would be unstable as an experiment, then a lot of work to upgrade as you point out. But a perfect start to experiment under individual components. I use a Different approach to each component. So, I have a Silent Running custom isolation platform under my turntable and Townsend feet under my DAC and Nobsprings under my streamer.

I luckily own 3 sets of Ganymede Vistek Isolation pucks, they have a bearing inside and when set up correctly your components "float" ... They are awesome like a equipment upgrade, so smooth, analog, musical etc... BUT they are out of business and you can’t get them anymore...

I also have Golden Sound DH cones too which are also really good but not in the league of the Ganymedes... And they are also gone and no longer available, but I’m a true believer, it really is super important to isolate your great from tiny micro vibrations, it takes you to another level

@sidog1460: The article linked by @dituse is well worth reading. The first point made in the article dispels the myth that spikes provide isolation. They do not; spikes couple, they do not decouple (thereby providing isolation).

The anti-resonant material applied to the underside of your shelves may very well damp the resonance of those shelves, and would in no way interact negatively with the Townshend Audio Seismic products, which actually do provide excellent isolation.

I do have isolation devices under all my components. I have Symposium platforms and rollerblocks(some w superballs and double stacked) under all my equipment. It could be overkill adding isolation footers under the rack itself, but in order to open up more space between my rack and speakers, I’m moving my rack back. And, if I add footers to the rack this would be the time. Sounds like some think of you isolate the components the rack doesn’t require anything additional. Definitely will finish reading link sent by @ditusa. Thanks

@sidog1460: The question of whether to isolate components individually vs. install Townshend Audio Seismic Corners on a rack is an interesting one. The Corners isolate the rack and everything it supports from floor-borne vibrations, but do nothing to isolate each component from the rack (and it's shelves) itself, and from the other components resting on other shelves.

But since you are already using the excellent Symposium Rollerblocks and Platforms (which---unlike spikes---do provide isolation for each component), the addition of the Townshend Corners would be a good way for you to access the effectiveness of the Townshend Seismic products. And there is no reason the Symposium and Townshend isolation systems cannot be used together. I have owned the Symposium Rollerblocks (and the very similar version of same made by Ingress Audio Engineering in Canada), and currently employ both the Ingress and Townshend isolation products in my Solidsteel racks.