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Want to build a rack with sandwich layered dampening

Hi all,

I considering constructing a very basic, small, low two shelf rack to accommodate my somewhat compact components to replace my rather resonant Pangea rack. Lower, not as deep and a bit wider to accommodate access, but also keep it low to preserve stage between the speakers in my smallish listening room. 
 

I’ve found some perfectly sized and precut maple (I think it’s maple will have double check). 3/4 to 1” boards that I’d like to sandwich together with screws, and place some sort of elastomer material between to control resonances. The legs would be basic but thick, and I’d probably just put spring isolators under them. Rack would be sitting on a raised hardwood floor. 
 

My question: would using a sheet layer of sound absorbing butyl or some type of elastomer in between help or potentially harm sonics? Reason I’m asking, I’ve found sorbothane to actually have an adverse effect under components, with say stack audio pucks instead a purely delightful improvement. I know we’re talking about a different application, but still would like to get some experienced thoughts on anyone that has done - or purchased - something similar. 
 

Big thanks in advance for anyone’s help! 
 

John 

riccitone
scotandholly's avatar
scotandholly
48 posts
 

Vibrapods can be used between shelving for an effective isolation device. The illustration is from the site. Results may very.

There are a lot of viscous materials that can used between your boards for constrained layer damping. If it is necessary to keep the profile as low as possible, I like bdp's suggestions. The green glue concept could be held together with a couple dowels. Press fit into bottom board, slip fit into top board.

 

 

Vibrapod Isolator Installation

danager's avatar
danager
983 posts
 

another option is bubble wrap

mashif
378 posts
 

I used 1/4 inch neoprene in between all the joints in my rack as I assembled it. There's no direct contact between wood and metal parts except screws that also go through the neoprene. 

terry9
2,354 posts
 

Constrained layer damping works by having two materials of different acoustic impedance in intimate contact.Wood and elastomeric glue are quite different, but you may fare better by using one layer of wood and another layer of metal, joined by elastomeric glue: aluminum and lead are two of the best choices.

When I built my music room a few years ago, I looked at many of the elastomeric products, and found M1 from Chemlink to be a good all-round choice. They also have a product which has marginally better adhesion - but look at the specs of anything you use, because some of the stuff called 'glue' really isn't.

Good luck!

terry9
2,354 posts
 

By the way, lose the screws! Metal fasteners transmit energy very efficiently from one layer to the next, undoing most of the good which constrained layer damping can do. Other fasteners connecting the two layers aren't much better.

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