To isolate or not to isolate, that is the question

HI Guys,

I'm sorry about the Shakespeare misquote.
I've had some really good advice from this forum so I thought I'd run something else by you. I live right down in the south of Spain in and old house built of stone and concrete. It is all open plan with high ceilings and marble floor. My hi-fi currently sits on an old glass multi shelf rack from the nineties.
I'm in the process od doing some renovations and was thinking of building a couple of marble shelves to put the Hi-fi on, but I have a couple of questions.

1. Should I make the shelf as solid as I can or should I try to isolate it? I have some silicon feet it could sit on and I've been told that sitting it on half a squash ball would work.

2. Will it make any difference?

3. If I listen to equipment in a dealers with carpets, soft furnishings etc am I right in thinking that it might then sound a little bright when I get it home due to the acoustics of my house?

Thanks again and keep the excellent advice flowing.
Glass shelves are generally not a good idea. You might look at stands made by reputable audio companies, like Adona and others I cannot recall, at least for an idea about proper shelves.
You want the stand to be as solid as possible. If your marble flooring is sitting on an earthen slab (no cellar/basement underneath, just solid ground), then you don't need to isolate the shelving, in my opinion.
Yes, obviously, your house will be "brighter" than almost any audio emporium; you might consider hanging some carpets here or there to soften up the reflections. Absent such decorative carpets, there are commercial products for room acoustic treatment.
First you need to listen some Paco de Lucia and after that
consider the situation ;)

1) I´d not isolate the marble selves, just put them sit on
metal spikes with metal washers (coins) underside. This
transfers mechanical energy/vibrations into the heavy wood

2) The other way worth to try: put the selves on magnetic
feet (and all the equipment too, if you like). This is
called magnetic isolation. I have excellent results of
magnetic levitation with my TT. This is Physics of Today.

Happy experimenting.

"Solid" and isolation are not necessarily opposing designs. I have first-hand experience with other components but have only read (a lot) to find a good design for a stand for my own turntable. The possible issue with isolation techniques you are considering is that the resonance frequency of those items may be too high, not to mention how the questionable amount of damping they have (too much or too little).

High rigidity stand/shelves will decrease the vibration amplitude prior to the resonant frequency and increase the resonance frequency - as will a low mass - which is desirable. High mass is inversely proportional to vibration amplitude above the resonant frequency, so there is a trade off.

Kuzma as an okay pdf for setup, although the information they have about mass and "stored energy" I don't think is perfectly correct: all depends on the design of the turntable. A suspended turntable (Linn) should be on a light shelf, whereas a VPI should be as solidly anchored to the center of the earth as possible.
Symposium Ultra Stealth will improve your sound any were in the world!!