Thanks to all who answered. I am begining to think the mass is not terribly relevant. I have two independeant needs. The shelf to isolate the TT from the floor which will require some serious decoupling and isolation of some type and the Amp stands. The Amp stands are more or less just mass dampening even if it resonates it will take some energy to do so at 4 inches thick. As I said I just wanted to know if there was a real detriment which did recieve the knod from one post. Otherwise these cool looking wood platforms will be ready to grace the dedicateed listening and audio storage facility shortly. |
Why not tap the tubes gently with a pencil (top part with the eraser - don't break your tube!) and see you if you can hear anything out the speakers (with the amp on of course) - if you hear nothing then you have saved yourself a lot of worry! |
As I understand it from playing the mailing tube and the wine glass, anything will resonate, and at several frequencies from the fundamental up. The exact frequencies depend on the size and composition of the resonating object.
Musical instruments are made to take advantage of these resonances; audio racks, feet, platforms, cabinets et cetera are made to damp them out so they interfere as little as possible with the musical signal.
I suppose it's a losing battle when looked at from a distance, but the near-successes are nice enough that we keep trying.
My experience so far leads me to think that maple platforms are quite successful at damping out resonances when used in a specific way. They have to be sitting on resilient feet and the component on top of them has to be sitting on spikes which contact the wood directly. This is the setup that worked for me. |
Yes, everything resonates.
The way to avoid that is to have multiple layers of stuff that doesn't share a frequency. Hi or is that low? hysterisis rubber (whichever one doesn't bounce!) is a good layer to add to a resonant system.
Many years ago, I had a Duel 1209TT. The platter was a 2piece affair. 'Ding' it with a finger nail and it was pretty inert. Take it apart, and each piece rang like a bell.
Look up the Tesla stuff of resonance. He once claimed he could topple the Empire State building with 2 (or 20)HP. Quite a feat. |
Don_s, I will defer to your comment. I will refine mine by saying that thickness is irrelevant to the fact that any material will resonate. Making it thicker or thinner or longer or shorter will not stop it from resonating if you hit the right frequency. |
Isn't resonant frequency related to mass? More mass=lower Fr.
Also, wood being a 'natural' composit will have the resonant modes distributed so there will not be one 'bell like' peak.
You are correct that speaker builders take advantage of this.
However, a panel of wood used as an enclosure is different that a wood base for a component....for one thing, the pressure stress is applied fairly about all sides, not just the pressure from within an enclosure.
If you seriously want to damp out a wooden shelf, laminate on a sheet of something inert, a very hi density rubber/plastic over a sheet of metal....maybe 3mm of aluminum. Bond it together with a uniformly applied adhesive. Such panels are nearly inert. |
Markphd, I think you are wrong when you say "thickness is irrelevant".
Thickness will change the resonant frequency of a mass of wood. I am not saying for better or worse, just that it will change. |
I may be the exception, but I found 2 1/2" maple butcher blocks to be slow and muddy sounding. They made my system sound terrible. I would suggest trying them before you buy them if possible.
One thing is for sure. They definitely make a difference. This is not a tweak that you have to carefully evaluate to hear the difference.
I suspect they may be great in a SS system if one is looking for some warmth, but in my tube based system they simply didn't work.
I have three brand new John Boos butcher blocks if anyone is interested! ;) |
Krellman, thanks for asking. I actually haven't found anything I like better. My attempt at a joke, above, was meant to convey that 4 inches was a bit too much for me aesthetically. The Mapleshade site mentions even thicker ones as possible and effective, however.
I trust my supplier when he says 3 inches is better than 2, yet my personal audio guru says two is enough. I haven't done a test to find out who's right, since that would cost me a little cash. Instead my rule of thumb is, if it's two inches or more and stable, it's good enough.
As for "I had", that's in the past tense because I sold my Shanling amps to one gentleman and the platforms to another. I hope to have another pair of 3-inch platforms, sized for the new amps, in a month or so. When I get them, I'll report my impressions on my system page. |
Just being honest, but the amps are tubed monoblocks so the stands may cut down on the non existent microphony. Can you point to evidence that tube microphony is "non-existant". This is news to me. I know it is less of an issue than TT vibration but "non-existant" - I think not? |
Toby,
I realize that the question here is 'how thick', but would you please expound on your answer?
You said that you HAD 3" thick platforms, have you found something that you like better now?
Chuck |
All physical materials have a resonant frequency. If you excite that frequency, it will resonate. Thickness is irrelevant.
The problem with wood is that its resonant frequency is audible. Speaker designers often use this feature to tune their speakers.
You can certainly use wood. You just have to dampen the possible resonance through isolation or other vibration reduction methods. |
I had 3-inch thick maple platforms made for my Shanling tube amps. I set them up the way Mapleshade advises, with (factory) brass spike feet into the wood above and resilient feet (Isonodes) below. What an improvement that was--bass, midrange clarity, overall resolution. I plan to have similar platforms made up for my current Audio Space monoblocks.
3 inches is a bit thicker than my best-informed pal says I need. However the difference in price is small. My supplier (Arcadia Audio) says thicker is better. They also offer 4-inch platforms but... that's a bit thick. |
