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Sandbox Design Advice

I understand the recommended design is to build an open wooden box plus a loose lid (possibly granite) which is slightly smaller than the internal perimeter.

Fill the box with kiln dried sand, float the lid on top of the sand and then component on top.

Heavy duty sorbothane feet for the box.

There were a few design details i couldn’t find on the forum and so pl can anyone advise on:

  1. what size should the gap be between the lid and the perimeter?
  2. how deep the sand should be for a 52 kg power amp (114lbs in old money 😀)?
  3. i am going to use a carpenter to make it for me (pine?) and would like a professional finish in black - any suggestions? 

thanks very much - advice is much appreciated.


soma70
dgarretson
2,609 posts
 
I elevated the heavy sandbox on five large, relatively soft springs from McMaster Carr. If you find the correct spring rate for the mass of the sandbox platform, the sandbox oscillates at around 1-3hz resonance when touched. This insulates the turntable system from the rack and any earth-borne vibrations. The sandbox then acts solely as a dump for vibration propagated from the turntable. It’s a bit eerie to give the box a visible push while a record is playing, or furiously jump up and down on a sprung floor, and experience absolutely no mistracking or skipping.
So far I've only used this approach with unsprung turntables.
millercarbon's avatar
millercarbon
12,531 posts
 
That is a good point and what I meant about understanding the details of your particular situation. Since there is no such thing as isolation its all controlling/tuning instead its important to understand that is what suspended tables are doing as well. All you're really doing is tuning or controlling the vibration down into a less bothersome range, like your 1-3 Hz. This is in other words the resonant frequency of your rack or box or whatever. If that also happens to be the resonant frequency of your arm, or your suspended turntable, oops, problems!

One more reason in favor of unsprung tables.
geoffkait's avatar
geoffkait
23,365 posts
 
Soma70, would I hot dog you? 🌭 
asvjerry's avatar
asvjerry
4,861 posts
 
If one Must pursue sand infill....

Let the sand dry out Thoroughly...it has a tendency to retain moisture.
Plays hell with MDF....caulk the seams....

If you absolutely want weight....lead shot.....

You don't need as much, either.....

Don't forget the appliance cart.....you'll need it....
jtcf's avatar
jtcf
1,620 posts
 
I've used Bright Star sandboxes for years.If I refill them ever I would choose lead shot or stone rather than sand.It's not easy to level.To thoroughly dry the sand I heated it on the stove in a large stock pot,stirring it and watching the moisture steam out.After cooling overnight it's ready to fill and level.

If you go with birch a wood stain is one choice.There are some very interesting metallic or stone look paints available also.
Good luck with your project!

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