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Audio Rack Construction

Happy New Year All!

I'm planning a rack with three wood (maple) shelves using threaded rod as the supports. This will be something similar to Salamander racks. Besides, the metal washers and nuts, I'm going to be using some type of isolation washer that will contact the top and bottom of each shelf.
So...shelf, isoloation washer, metal washer, and then nut.

Questions: 1. When passing the threaded rod through each shelf, should the holes in the shelves not allow the threaded rod to touch, so the only thing touching the shelves are the isolation washers? 2. Besides neoprene, what's a good material for the isolation washers? 3. After leveling each shelf during assembly, I'm planning to add aluminum tubing over the threaded rod and nuts between each shelf for a cleaner look. This would mean that the top and bottom ends of the aluminum tubing would also contact the shelves. Should I avoid this, or additionally add some isolation material between the ends of the tubes and the shelves?
kennythekey
rushton's avatar
rushton
2,445 posts
 
Alternative: don't use an isolation washer. Keep everything rigidly connected and couple the threaded rods to the floor with spikes. If you're going to uses tubing over the threaded rods, build it layer by layer and fill the tubes with lead shot for mass and damping. Countersinking the area around the hole to the diameter of the aluminum tube with keep the shot nicely contained. This generally is the way the Walker Audio rack is built.
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almonduck
11 posts
 
An inexpensive solution to the isolation washers are rubber O rings I got at a lawn mower shop. They were something like 7 cents a piece. Neoprene and larger flat rubber washers may be better, but it can get expensive when you need 8-12 per shelf.
buconero117
2,311 posts
 
Check out some of the acoustical parts manufacturers web sites. If I recall, they make some isolation hardware that is used to isolate mechanical equipment from floors. I purchased some of these components in the late eighties when I wanted to quiet my basement furnace units from the floor as I had a media room that I wanted to keep quiet. They were very inexpensive and really worked.
kennythekey OP
593 posts
 
I like the the ideas about filling the tubing but there seems to be different thoughts about isolating the shelves from the threaded rod. Rigid is very important but most of the better rack manufacturers use some sort of isolation between the shelf and the frame.

I am planning to drill and tap the bottom of the rods and screw in heavy brass spiked feet.
rushton's avatar
rushton
2,445 posts
 
Several people in my local audio group have built racks similar to what you're proposing. In each case, removing the isolating washers made an improvement. Take a look at the systems of Audiogon members Sbank and Slipknot1.
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