(page 3)

(Putting It All Together continued)

Once the shelves are assembled, push the four threaded rods through each, securing the nuts and washers one shelf at a time. You will find working with the rack placed on one of its sides easier in accomplishing this step.
Set the height of each self to your requirement by simply adjusting the corresponding nuts. Use a bubble level to ensure the shelves are flat. Once the height and the shelf spacing are set, tighten all the nuts firmly. Don't over do it otherwise the rubber washers will "bleed" out.
Attach the feet. Half fill each rubber doorstoppers with Blue Tack and push on to the bottom of each pillar.

Performance

The usual benefits of reduced vibration and increased isolation are sonically evident here as well. Compared to particleboard, the sound is more dynamic, livelier with greater snap and spring to it. Focus is improved carrying greater detail and the background is quieter allowing the individual instruments and voices to stand out more convincingly.

The "sandwich" shelves have a lot going for them and account for the majority of what this rack has to offer. First they are made out of three different materials, each material having different resonance and dampening characteristics. This has the effect of reducing the overall shelf resonance, not allowing the resonance to compound, build up and leak out. The bottom layer is a slab of MDF. Widely used for both shelf and speaker enclosure construction, it's still one of the most affordable ways to provide a relatively dead medium. We've introduced two variants for the middle layer: A cork sheet and Blue Tack. Both are known by Tweakers as having good dampening characteristics, and are widely used in many applications. Put all together these "sandwich" shelves are excellent in controlling vibration. They pass the knuckle test with flying colors.

In respect to the two middle layer variants, I prefer the Blue Tack one. With Blue Tack the shelf is sturdier, it's deader and has a better coupling effect than the cork sheet. On some of these photographs, if you look closely, you will notice a slight warping of the shelves. The layers appear closer together on corners than in the middle. This is normal because the tightening force is greater on the corners. In the case of the cork sheet this equates to a loss of adequate coupling. In the middle of the shelf there's actually a small amount of space separating the layers. Interlayer coupling is one of the things that works in favor of this shelf; therefore maintaining coupling throughout is key. There is no such problem with Blue Tack. Yes, some bits are squished more than others but they all continue to maintain contact. Suffice to say I've replaced the cork sheet variant with a Blue Tack one.

The pillars (i.e. the treaded steel rods) are less accomplished but never the less offer great flexibility in shelf adjustment. The rubber washers help a bit in decoupling the pillars from the shelf. The same maybe said in respect to the rubber feet, half filled with Blue Tack; they provide a fair degree of floor isolation.

Conclusion

This rack easily outperforms the standard (chip wood or particleboard based) audio shelf and has an edge over the majority of entry-level racks found in the industry. Entry-level racks are relatively cheep but they still cost more than this homemade version. A firm "Best Buy" ratting then!

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Comments (add)


Bryan	You might want change your steel all threaded rod out for aluminum as it is a inert metal.

Tony	Might it be worth considering a tri-support system offering better rigidity, less material and ultimately less conductivity for floor bound vibrations?

Doug	Hi - when you completed your flexy rack, was there any wobble to it? I basically followed your plan, but did the 3 leg version (the triangle), since I had trouble getting a 4th piece of 5/8 inch rods. My rack has a bit of a wobble. Also, where did you get the large rubber washers? The home depot and plumbing places around here only had small outer diameters. Thanks

Boris	Hi Doug, After you have put everything together don't tighten things yet. Make sure your shelves are leveled. Use a bubble level on each shelf to make sure they are perfectly horizontal. Adjust the nuts on each pillar (leg) until the bubble is in the middle of your leveling device. If you have done a three leg version then you should not have any wobble. If you have chosen to go with four legs then it's important that all four legs protrude the same amount from the bottom shelf. Try rotating the pillars/legs and not the nuts. This is not always easy but it will make the pillars/legs move up and down in respect to the entire assembly. Keep checking for wobble and adjust accordingly. Once everything is leveled you can tighten all the nuts but make sure you do not spoil your adjustments in the process. Regarding the rubber washers, I'm pretty sure I got them from Home Depot. If you can't find them there check other plumbing supply stores. You can also try ring type rubber washers.

John	I did this also. However, I purchased enough mdf for nine sheets of 24" x 24" x 1/2" inches. I needed three shelves so I glued and clamped three sheets together times 3. This provided me three shelves of 24x24x1.5 inches. Perhaps a bit more inert. Routed off the sharp edges, sanded, primed, and then painted. Added some nice casters that screw into the bottom of the 5/8" threaded bar. Spikes might have been better than the casters, but this rack weighs about 130 pounds empty. Fully loaded with three components the fully loaded rack weighs about 330 pounds. So mobility is a bit of a necessity. Costs: casters: $80, all else: $50, Total $130. Looks better than some professonally built racks I've seen and would appear to function better as well. Still the ultimate enhancement to this rack would be to use maple butcher blocks 24x24x1.75 or thicker.

Charlie	Maple butcher blocks approx. 15 3/4" x 18 1/2" x 1 3/4" available @ Ikea $24US

wcwarrell	Anyone ever tried suspending an audio rack from the ceiling? I've got a 55" RPTV, two bi-polar floorstanding speakers, and an audio cabinet along one wall in my family room, and it's a bit crowded. I'm considering building component shelves to suspend the electronics (receiver, DVD player cable box, etc.) from the ceiling, opening up floor space to let the speakers "breathe". My thought was to build two relatively short cabinets using maple butcher for the shelving (IKEA rules!), and tie them together & suspend them from the ceiling with nylon climbing rope. I'd then mount one cabinet on each side of the TV, suspended from the ceiling, with enough height under each to be able to move the speakers where I want them, and allow the bi-polar sound pattern to radiate freely. I had originally thought off mounting the cabinets directly to the wall with some sort of damping material behind them, but now I'm thinking suspending them from the ceiling will better isolate the equipment. I could then just run a channel down the wall on each side for the wiring and have a neat cabinet to show-off the equipment, with an reasonable WAF (GFAF, in my case). ;o) Has anyone ever seen this type of a set-up? Any ideas, pros or cons, as to how this might work?

The Audio Component Rack