Which cone's or platforms have helped?

Fiddler, if I go to local Home Depot I can buy various sheets of foam insulation that have different densities and thermal properties. Do you have a more detailed description of type of foam you used....color, density etc. Some are quite dense/stiff and some are much softer.

What were you previously using under gear? Are component feet resting on foam, or just underside of case?

I can add this to JD's bubble pack tweak and get it all with one trip to Home Depot, heh heh.

Trip to home depot at lunch shows that 4x8 sheets of polystyrene foam (for insullation) are two basic types:
-white foam, less dense softer foam
-pink foam, rigid dense foam

Got a sheet of the 1.5" pink foam @$13, thickness available are 1/2, 1, 1.5 inch (no 3" foam) The pink foam is preferred I believe, if you check the foam inside Nueance or
Symposium platforms it is closer to pink foam density. Cut some bricks 8 inch x 4 inch with razor knife to position under gear and avoid feet or any vents which must remain clear. The 1.5 thickness is good because it easliy clears existing feet without raising too much (I could double up bricks for 3" height)

I am happy with existing brass cones and bearings, but this is a cheap, easy thing to try for reference, although will not win any interior design awards.

CDC, the Russians built the ALFA subs out of titanium because its strength allowed them to dive to greater depths. FWIW, the Alfa subs were notoriously noisy, hence the need to operate at greater depths. My point is that I have not seen any scientific evidence that indicates that titanium controls resonances r vibrations better than other metals.

Having tried sorbothan (spelling?): warm, soft highs, loose bass. "Black Diamond" cones: hard, quick. Concrete block: dead, dull, turbid. Large hunk of steel: solid image, stable pitch."Audio-Resolution" platforms: open mids, dynamic, quiet backgrounds. These mostly seemed evident under the CD player.

This was just regular old white Styrofoam. The hard stuff. Well, it's not really hard, you can dent it with your finger, but I had several blocks that were used as packing material in a box that was just shipped to me.

My suspicions as to why it works so well is that it is mostly air with thousands of cells joined randomly.

I placed the components on the Styrofoam bases without the component feet attached to the component. Just the bottom of the component sitting on top of the block.

Sorry I can't be more descriptive of the Styrofoam, but I thought there was only one basic kind.