Shelf Material

As for Subaruguru's comment about the sitka spruce, if it does have a high Young's modulus, then it would be an excellent "shelf material". My original comment applied only to the selection of the shelf, as the title of this thread states. Once a shelf has been chosen, then a suspension system can be applied to decouple the component / shelf from the structure which it resides upon. The goal of the shelf should be to rigidly couple the energy from / to the equipment into the suspension system. The lower the mass (for the combination of the shelf and product), the lower the amplitude (and higher the frequency of the resonant system) assuming that the compliance remains constant. Another concept to consider is the "Q" of the suspension and the use of any damping (lossy) properties. A good field of study would be to take a look at what turntable manufacturers are doing. They have had to deal with suspension / decoupling systems and have a wealth of practical experience. Kevin Halverson

It seems to me that MDF would make a very good shelf material - low mass and high rigitidy. I use 3/4" instead of 1/2" with good results as a standard (non-suspended) platform. It also has no grain. Am I thinking correctly? I have a 5' x 2 1/2' x 2 1/2" maple glue-lam butcher block that I salvaged from a restaurant but would rather go with MDF based on the info in these posts.

What about carbon or carbon fiber?

I certainly don't like MDF in practise - a very muddy sound. I don't have the ability to try such things as the BDR or Polycrystal shelves before buying (since noone stocks them here), and hence this post. But I quite like the BDR cones and so bought some of the BDR pucks - and they sounded awful. If they represent the BDR shelf then no thanks. I have actually got a lot of good ideas from the above posts and am in the process of trying or acquiring some of the less expensive suggestions. I am happy to splash out on the expensive stuff, but would prefer to see a concensus of more than one before doing so. It looks like the Butchers block qualifies. I wonder if Kevin has a point. Caterham and I tend to concur that you want light and rigid, release the energy quickly but damp the main resonances. But Kevin is suggesting the light and rigid shelf, and then deal with the resonances with some form of compliance between shelf and component. This may very well be right, but I tended to think of the rack as doing the light and rigid task and that you would begin to damp the resonance with the shelf. I don't like two forms of compliance in a system and so I have tried to get "dead" sounding shelves and use cones. My theory may be right, but the practise is possibly too dificult to achieve - we will see. Kevin may have a more practical solution. Am I missing something Kevin?

Regarding the use of MDF for shelf material, experiment with two MDF pieces cut to suitable shelf/support size, try one "plain" and get the other one either hand lacquered or two-part spray lacquered in a piano black finish or similar. Use some type of "footer" above and below the MDF whilst you experiment. You may change your mind about using MDF. If you can try this and find that something is happening that you like with just this single "shelf" then let me know and I will let you have some drawings for a very cost effective support platform (we make our own similar, platforms but once shipping overseas gets involved they do not become cost effective - bit like shipping large loudspeakers all the way around the world, you end up paying to ship "air"). Hope this helps..?? Richard, vantageaudio.com