Score Encore!

Well, after sourcing the shelves, I got a move on and got my rack design down on paper. Took it to a local welding shop, talked it over with them, and they're going to fabricate the frame for me for £60.

Thus for a three shelf 30mm granite and HEAVY steel frame (which will be sand damped) rack to my own design, I'll have paid a total of £75. And the rack can take a fourth shelf when I source one. This is significantly less than your basic glass-shelved rack from a hifi shop... Any bets on which will resonate less?

 

sounds like a Bargain! There's been a few DIY rack thread on the DIY boards. What sort of frame shape are you going for? 3 or 4 legs?

Sand damping?

 

My design has 4 legs in a 3-leg arrangement. The back legs are only 100mm apart, whilst the front legs are 500mm apart.

The uprights of the rack are tubular steel, which I will fill with sand (much as people, myself included, do with speaker stands). The sand damps the stand, and absorbs resonance, as the vibration in the sand causes the grains to rub against one another, converting the energy to heat.

The sheer weight of the stand will mean that the amplitude of vibrations is extremely low.

There will also be sorbothane or something similar between each shelf and the rack, so there will be plenty of energy absorbtion in the rack.

 

oops my bad.

When you said sand damping I didn't think you meant simply mass loading. I've seen others use a sort of bed of sand (like a sand pit!) under their racks. I thought you meant you were going this route, or even individual "pits" on each shelf.

Sounds like it's going to be rather heavy!

Do you intend to have the legs joined in any way? As in further framing welding them togeather? Or the flexi way where they're just bolted to the shelf?

 

The legs will form the corners of the rack, connected by 16mm steel bars, three per shelf. The shelfs then sit on these purely by gravity.

I'll get pics once it is built in a few weeks.