Granite Boards for Isolation?
- Thread starter Lee T
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Helen Bach
if it ain't Baroque ...
Lots of audiophile misconceptions here. Granite (and stone in general) do NOT damp. They have very little damping ability. Damping factor for marble is 0.009, I measured; granite will be very similar. Look for Ashby plot 'Loss coefficient against Young's modulus'. And thicker means higher resonance frequency, NOT lower. And where to put the 'feet' is also important, it depends on how the support is supported. HTH
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Helen Bach
if it ain't Baroque ...
slate damping factor 0.017, slightly better than marble (and probably granite) but woefully inadequate as a damping material. If vibrated, at resonance, it will multiply the resonance peak/s by 42 times. But if you like vibrations...
Personally I think a thick granite slab works well, apparently it’s some type of corrugated suspended floor and feels fairly solid to a thump! I’m not sure Bamboo would work as well, but I’ve seen some on EBay for a reasonable fee, but still don’t feel it’s worth a try. I would like to try some different feet on to the carpet as if anything the granite and super spikes do lift the speakers quite a bit
rontoolsie
pfm Member
As pointed out elsewhere, granite is more mass loading than damping. It may shift down the resonant frequency, but there will still be a high Q (and maybe even a higher one).
Proper damping converts most vibrational modes into harmless thermal energy, and there are more ways to achieve this than there are to curry a lamb.
Spikes were once considered the magic bullet to kill vibrations, but it turns out these are far less effective than previously thought, and sometimes (me for example) are a way to shoot oneself in the footers.
Proper damping converts most vibrational modes into harmless thermal energy, and there are more ways to achieve this than there are to curry a lamb.
Spikes were once considered the magic bullet to kill vibrations, but it turns out these are far less effective than previously thought, and sometimes (me for example) are a way to shoot oneself in the footers.
Sounds like a good start. Granite is nice and dense so it will resist movement, and I'd be experimenting with various rubber feet. Small bike inner tubes give great isolation and cost very little. You do have to blow them up now and again, and they work best when almost completely flat.
Helen Bach
if it ain't Baroque ...
and so the misconceptions are propagated. I'll give up now...enjoy your vibrations.
Mullardman
Moderately extreme...
I have two HNE Granite bases which I used to use under big valve monos. Would have to dig them out to check sizes. They have cylindrical bosses underneath with threads for spikes.... 6 mm I think.
rontoolsie
pfm Member
HNE...very late 1990s.
Inspired by them I contacted a local tombstone maker to get a price for some Custom granite bases for my DBLs. I think it was close to $800 back then.
But I ended up going down the Mana Soundbase route, which was a big improvement over the spikes on Naim Chips.
If you've got nothing constructive to say then we're better off without you. Enjoy your snarky comments, and your own company.and so the misconceptions are propagated. I'll give up now...enjoy your vibrations.
The upshot of all this is that it's experimental. Hifi bods get hung up about material types, when what's important is the structure you design. Carbon fibres of themselves are brittle, polyester resin is weak. But laminate them up and you generate a bike frame, a racing car chassis that outperforms either material. So statement s like "marble is good, wood isn't" are useless unless you know the structure they're going in.
And spikes were never any good at isolation. They don't absorb any energy, they just transmit it. Isolate your hand from a hammer blow by putting a nail between the hammer and your hand. Is that better?