Marble or Granite shelfs in a hifi rack?

To take the subject admittedly but interestingly off-topic for a sec, I once bought an unusual gift of a windchime made from shards of a particular kind of obsidian (natural volcanic glass) that forms in 'fingers'. Dangle these pieces from monofilament and they ring like bells, with a very pleasing overtones structure.

Anyway, although I have not experimented with this myself, many audiophiles and manufacturers seem to prefer one of manufactured granite or marble substitutes that are used in kitchen countertops, such as Fountainhead (hope I got that name right?). Presumably these are fabricated using bonding resins that act as damping agents.

Well Brulee, I may not have yet made the plunge to begin seriously investigating alternatives, but I can agree with you about MDF. I suppose there may be worse materials one could employ, but on the whole I think the entire MDF paradigm is basically a scam rack makers (and retailers like Audio Advisor) have attempted to perpetrate on audiophiles in order to get away with using an easy and cheap shelf material.

Well, then there's always my approach: I invested about 1K in my Salamander Synergy Twin 40 solely for the reasons of convenience in having adjustable shelf heights, enough space for all my components, and the ease of system reconfiguring that comes with having gotten the Saturn caster option. The shelves are all MDF, the rack itself is fairly flexible and resonant by high end standards (though much better than some more makeshift solutions or mass-market stuff, and heavy as a bear), and way too tall for high rigidity anyway, and of course it isn't positively coupled to the floor, though the fact that the casters employ rubber treads does provide a little isolation.

Frankly, in my circa-$15K system, I've never heard enough differences from various support strategies with most components to place a higher emphasis on this subject. I do own some cones and isolation footers, finding the Iso-Bearings and such mildly useful with certain gear, and don't use the cones. I keep my TT on an original Symposium shelf, which in conjunction with sorbothane pucks underneath, does a very nice job of isolation from energy transmitted through the rack. But I'll tell you what, I'm lovin' life these days with all my gear on one rack and total accesss from all sides (no doors, sides, or rear panel installed) - I probably roll the rack out and make changes (most temporary) around back a few times a week on average, now that this is so quickly and painlessly accomplished. I have decided to replace all the regular corner shelf support brackets with the heavy-duty ones, which employ steel struts that runs front to back between the vertical pillars, for the addtional reinforcing effect they will have on the overall rigidity, but aside from that, I've experienced no objectionable problems in use so far, and I think I'm done with this aspect.

Could it sound better? What do I care - it sounds good enough for me to just relax and enjoy the music, and the ease of use I get with being able to raise or lower shelves and move the whole thing around at will. I personally doubt that any incremental sonic improvements I might get from compulsively obsessing over a more audiophile-approved and tweaked-out arrangement would be worth the candle to me in terms of livability lost. (Oh, and I also don't believe in the concept of "mechanical diodes", self-vibration being more of an issue than acoustically-induced vibration, or the existence of "PRAT", but those are probably issues best left for other threads! :-)

BTW, the preceding doesn't mean I'm in love with MDF any more than I implied two posts ago, just that although I have mused about experimenting with replacing a shelf or two with something else and seeing what turns up, so far I haven't felt compelled to go to this length. The rack probably doesn't justify it anyway. (Ignorance is bliss and all that... :-)