Audio Rack Construction

I would fill the "tubing" with a material to dampen it.Mine touch the shelving (brass).Be sure to leave enough threaded rod to attach footers.

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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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.

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.

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.

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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Thanks Rushton, I will take a look and get back.

Well, there you have it nice and simple.

I know that brass is a coveted material, but it appears that Slipknot is using steel but that's hard to see. Brass gets expensive especially with all those nuts and bolts. I was thinking about using 5/8" steel rod and fasteners, and then covering it with the aluminum. I was first thinking 3/4" but nuts at that size are special order where I am.

For the top shelf I was going to use brass nuts/washers to match the bottom feet. I've been looking for a flat brass end cap for the top nuts but no luck.

Try boltdepot.com for your source, also mcmaster carrs
they both have a wide range of parts at industrial prices

I had an old Mike Green rack. Very good in its time. I did learn to replace all the steel with brass for much improved sound. Don't try to isolate with rubber or any other type of suspended material. If you couple all the way thru and then mechanically couple all the componets to the shelves and couple the rack to the floor with audiopoints or stillpoints then you will have a decent sounding rack. Last thing is to look away from pressed materials such as mdf..lotsa mass and glue for that over damped and dead sound. Vibration can be given direction away from components and a damped shelf or component will disrupt direction and slow the transfer of energy away from the device your trying to enhance. If you can manage to use solid wood shelves this would be better than a non directional material like mdf. Think of the rack as a musical instrument in that you want it to be active {though rigid] and with more playing time it will create its own vibrational direction and become even more open and coherent. Place your most active components on the middle shevles. The center area will give your tubes, your turntable and your transport the greatest stability and audible coherence. In the end you want to provide a path and direction for all of these vibrations to pass thru and out and be coupled [discharged] to the higher mass of ground..the floor. Tom

Thanks guys for the source information and excellent advice. Does anyone have an idea on how to finish off the ends of the rods for the top shelf? I've seen round nuts and end caps on manufactured racks but am having problems locating.

Kenny, I like the Salamander rack; it is a well-made, affordable product for basic use. But if you are rolling your own you can probably do better. IMHO the main problems with the Salamander racks are that the light weight and rigid design work against the geometry: that is, small movements at the bottom of the rack result in larger movement at the top. This can make it especcially problematic for use with a turntable, for example, if you are on a suspended wood floor. The (optional) spikes are terrible, and I would like to see Salamander offer a floating shelf option for the line.

If you are determined to copy the Salamander design why not just but a unit and make your own maple shelves for it? You could resell the stock shelves and probably recoup most of the cost of the unit. Just a thought...

I got a lot of helpful suggestions on a similar topic here:

http://forum.audiogon.com/cgi-bin/fr.pl?htech&1158841915&openmine&zzJdoris&4&5#Jdoris

BR3098 - Thanks, I'm just copying the threaded rod concept from Salemander and will be using heavier maple shelves and as recommended, shot inside the external tubing around the rod. The end result should be a lot heavier and more rigid. I'm not placing my turntabl;e on this rack.

Jdoris - Thanks for the link I will check it out.

Wow, tons of info from the link provided by Jdoris. The original thread was back in 2006, and the raw materials have gone up nicely since then. That still won't stop me.

Lots of stuff to go through and I'm taking off for vacation. Will be back next week and will re-focus then.

Thanks everyone!

I'm back from vacation and had time to contemplate all of your good information.

I've decided to abandon my wall mount ideas for my Table, and place it on the new rack. My Target wall shelf was a failure, so why shell out big bucks for a Finite wall shelf? The Finite was maple with an aluminum anodized back plate, so I was going to add silver aluminum anodized tubing to the new rack. I don't need to do that now.

I have an old Farmhouse, so I would like to hide the industrial look of the rods and nuts. Looks like I will be using an anodized tubing with a colored powder coat instead. I found a local source for this and if their product is decent I will let everyone know becuase it's so inexpensive.

I will also add shot to the tubing but in the end I'm hoping that this eliminates any potential ringing and does not make the sound less lively. Any thoughts on that?

Hi Kenny.

I've got a 1905 home, and the industrial look of brass and maple has grown on me, esp. as they've picked up some patina.

Since you're thinking of covering the the rods, will you still go brass? Some favor the sonics of brass (I'm not confident I could detect a difference), but I'm pretty sure you would save a a good bit on the rods by going stainless or galvi.

I suppose that filling the rods could reduce the possibility of ringing and the like. Note that filling the rods may, depending on the amount of fill needed, add significant weight; my 4 shelf rack is pretty heavy as it is.

One more thought on the visuals: Boos block is now offering walnut and cherry blocks (at a price), which gives more options for matching decor. Again, some favor the sonics of maple, but I'd not be surprised if their ears were much better than mine.

John

Thanks John,

I've already purchased the maple shelves and hardware thanks to the help from everyone.

The 24" X 18" 1.75+" shelves were $69 each and ony $1 to ship all due to holiday pricing from Overstock.com. I am very pleased with the fit and finish. The 3/4"-10 rods and hardware I got from McMaster. Everything is brass.

I remember when reading your thread from 2006 that you were getting used to the look of the nuts and rods. If I wind up using the tubes I will post a picture. Maybe, you and others will want to use/add them since they come in Slver Satin Aluminum, Black, Dark Green, and Rust Brown. The cost is very low so I don't want to release the source until I first check one out.

We're all concerned about sound, that's why I'm trying to find out if I'm sacrificing some by using the tubes, or if I'll be okay if I prepare the tubes properly.

Finish question. Regarding maple shelves, does it make any difference for finish...oil, laquer, stain, etc.? For preservation and sound? I just plan to use a mineral oil.

I used multiple coats of tung oil, each one rubbed with fine steel wool, then a thin layer of polyurethane, for gloss and hardness, finished with a buffed out coat of paste wax.

Check out the Charles Altmann Dac site..mother-of-tone.com. He describes his use of tone woods in audio the effects of finishes to musical instruments and how they carry forward to his DAC and his use of acoustic treatments. Information to be stored and used when needed.
Tom

I thought there would be no leaf unturned when it comes to this hobby. Good info. Thanks.

Kennythekey
Hi,I am in here late,noticed you bought your hardware already.I built salamander archetype racks a long time ago.
1.You can buy the top flat caps for 5/8 rods from audio advisor that's where I got mine back then,just tell them you need replacements for your lost caps due to dismantle/relocation!!!!!
2.For an upgrade you could buy uprights from C.R.Laurence in solid stainless stell,oh yes!!!.Price $$$$$$$$,quality top of the line with 5/16" internal threading and 1-1/4" diameter at various lengths from 2" up to 12" in multiples of two inch.
3.For the ultimate think Samson by Mapleshade oh yeah!!,you can buy their hardware but too costly OR you can get 1-1/4" solid brass threaded rods from mcmaster.com and then go see a machinist to make for you the donut shaped nuts as in SAmson racks and the footers.
The sky is the limit.If you need advice assistance to build or fill the tubing ,e-mail privately.I know a few tricks being in the trade.
Best regards
George
Enjoy the tunes!

Thanks George.

Yes, I've got everything but the tubes and they'll be here soon. I'm going to have a machinest cut them because they need to be precise and I don't have a band saw or lathe.
Everything is brass and maple but the tubes are anodized aluminum with a powder coat. I'm going to fill them as advised with lead shot for mass and no ringing. I bought the acorn nuts for the top, so I'll see how they do for now.

I have a Mapleshade platform with IsoBlocks for my table, so I'll use that on top and take it from there. I'm using the HeavyFeet with a 3/4"-10 tap for the supports. I won't use the feet for leveling but will level the shelves instead, so the feet will get maximum thread. I'll only be using two of the four shelves right away. I was going to get a headphone amp but the rack has delayed that purchase.

I'm really enjoying this and get to make it look the way I want while still saving money. From the good and consistent advice from everyone out there, I'm pretty sure it will sound real good as well. You can't ask for more than that!

Hi Kenny. I like walnut oil for the finish. In general, I'd go for oil for ease of application and touch up; walnut oil seems to create a hard finish. John

Thanks John, from the paper that Theaudiotweak provided the link to, it appears that you should steer clear of plastic based solutions.

I'm ready to drill my shelf holes but have a question. What's a good way to support the heavy maple shelf on the drill press for the corner holes? Right now, my drill press is only set up with the standard (small) metal work base.

If you are going to fill the space between the tube and allthread, I'd use an expanding foam.
Lead is toxic and a nightmare to work with. The expanding foam has the advantage, from a physics standpoint, of coupling the rod to the tube which increases rigidity. This may actually provide better damping than simply adding mass.
In my stand, I use Teflon washers. A hard, slick material. I also make sure the allthread does not touch the wooden shelves, which are also of a unique composition / construction.

Thanks for the info Magfan.

I'm am debating over the tubes at least for now. I will be expanding my rack pretty soon and I would not want to disassemble/re-assemble. I'm also adding new components and don't know the height yet. This means that the tubes would be a pain right now and I would have to cut new ones if there are any height changes.

By the way, the tubes I received are really nice and inexpensive. We're talking 0.22 and 0.28 cents per inch. For those that are interested here's the link http://www.landmarkflyrodtubes.com/Tubes/aluminum.htm

Hey Kenny. Regards the drill press table size, could you affix a piece of .75" furniture grade plywood? if the table does not have holes that could be exploited for mounting, you might even drill some. I gather no add ons from the manufacturer (eg, some kind of outrigger, or a larger table) are available, or cost too much?

Kenny
I would advice to make a jig.I am not sure how big is your drill press,mine is floor standing and big,but you could make a 3/4 thick plywood base the size of the shelves with one corner blocked by using 1x2 cleats screwed down in square and spaced away enough,that will act as a nest for the shelves to get a consistent and accurate but easy hole location every time.Use a Forsten bit and also the plywood base will protect the underside from wood splitting when the spinning forstner bit exits.
Best of luck
George

Thanks guys.

I got it done and it's perfect...whew!!!

I mean perfect in my mind, you know?

I got lucky. Home Depot had pre-cut acrylic exactly the size of my shelves (24 X 18"). I made a template to fit over the shelves and marked/drilled small holes from the corners. Then drilled the 13/16" holes with my drill press. I simply attached a board to the base of the drill press that supported the shelves just fine. Later, I stacked my shelves and all of the holes lined up perfect. A little anxiety can go a long way!

Anyway, I just got my Walnut Oil, but still have to wait on the feet. I'm having a local machine shop drill and tap my Mapleshade Heavy Feet to 3/4"-10. Still waiting, so more news later.

Hi All!

Jdoris had suggested using Walnut Oil and I like the idea and have it. I also checked out some of your rack pictures and saw that many of you have a redish tint to your wood.

Have you accomplished this using Maple, or are you using Cherry instead? I'm asking because my shelves are Maple and the Walnut Oil looks like it will leave a greenish tint.

Hey Kenny. I've not gotten anything like a greenish tint. I think Walnut Oil won't add much color, and will stay pretty "true." The maple for my rack was pretty dark to begin with, with some tints running to reddish. This summer, I refinished the butcher block work table in my study, which is quite blond maple, and it stayed that way with Walnut Oil. Not much of greenish tint on my cutting boards, either. Of course, with wood finishes (even more than audio!) the results depend a lot on the particulars of the situation. John

Thanks, John.

I already went at it with the Walnur Oil, and it looks nice. The instructions aren't clear, so I suppose I'll give it a few coats and plenty of time to dry. I found a penetrating oil stain in Cherry but it used urethane as a hardening agent and I don't want that.

I also found a spray-on clear laquer that's not made from plastic. Instead, it's nitrocellulose based (cotton). I'm considering using this on the brass to prevent oxidation because I prefer a bright brass look over a patina.

Yes, I'd go several coats, rubbed hard with four ought steel wool, followed by soft rag, final coat with soft rag. I rushed my table, and the wood is underprotected. The brass will patina if not treated. Not sure what to use, though.

Thanks, I just rubbed the oil in with a cloth. I'm in Colorado where it's pretty dry, so I better look into the steel wool.

The worst part of this project, is cleaning the brass rods that I got from McMasters. I spent about twenty five minutes last night on one rod and I'm still not quite done. I did the two-stage dishwasher soap/Brasso cleaning that produced many blackened rags. Makes me want to seal the rods instead of letting them oxidize again. For me, it's always most difficult to finish those final details, but I am looking forward to the assembly.

The only negative I see with the nitrocellulose based laquer is that it's highly flamable as it's a relative of dynamite. Windows open, turn off the electric heat...and it's winter!

Finally finished the FlexiRack!

I'm very happy with the way this project turned out. Thanks everyone for your help and suggestions.

Here's a picture...no surprise that it looks like others in the forum. http://cgim.audiogon.com/i/vs/i/f/1265411095.jpg

Absolutely beautiful work. The only question I would have is why didn't you match the trim on your speakers.
I'm in the process of building my own speakers stands and the first thing I thought of was matching the stain color on my speakers.

Nicely done! Thanks for the picture.
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Thanks, I do have one issue but it's not the rack.

The rack is rock solid when the shelves are perfectly leveled. You almost don't need a level because as you adjust the nuts, as soon as the next shelf finds level...you can feel the rack lock-in like it's cemented in place. I love it.

The problem is when I put my Mapleshade turntable platform on top. The platform is not level but the top shelf is. Either the platform isn't true or the Isoblock feet aren't exactly the same height...hmmm. If I adjust the top shelf to compensate for the platform then my rack is not quite as solid as it was. I don't want to adjust the feet on my turnatable because it sounds best with the feet screwed in all the way in. Any ideas?

Markeetaux...you should do that! I didn't stain my shelves because I like the natural maple and I'm considering new speakers. If you look at my pic you'll see that the cabinet to the right is yet another finish! Well, I'm replacing that cabinet as well. Maybe in the end it will all be maple.

Nothing like a 3 point suspension such as Sistrum. Nothing like a proper mechanically grounded metal shelf that won't warp and will maintain consistency. Tom

Kennythekey
If you like I'll send you a photo of my speaker stands
when they are complete. I expect they will be done early next week. Nice job Kenny.

Markeetaux
By all means, I'd like to check them out.

Well Done, Kenny. On leveling the top shelf: There a school of thought that says that you don't want the nuts on your rack completely tight, and that some feeling of play is better. Can't remember where I heard this, but you might look around; I have mine that way. Whyn't you level the top shelf for your TT, and give a listen? I'd certainly be keen to hear your results on an a/b: tight v. loose rack. John

Thanks John.

Okay, so I started listening and I was mesmerized. Not that everyone would have such an experience, but I realized just how poorly I treated the support of my components in the past.

Every audio attribute was bettered. It sounded like I did a full system upgrade and it costed what, $700? I will never underestimate the rack as a true component again.

Oh, and I eliminated my foot-fall problem. Did I ever really have a foot-fall problem or was it just the crappy rack I used in the past? The energy that this flexi-rack directs outward is awesome. I lightly pound on a shelf and I can hear my table in the middle of my room rattle. I jump up and down next to the rack, and the glass of water on top...nothing. Now, I can identify and fix room vibration problems using my rack...hah...hah...okay, I'm getting silly.

Yea, I'm happy. My rack is fully tightened but I may experiment with the nuts to see what's up with that.

Goodbye Target, goodbye old side table, goodbye Billy Baggs.

Theaudiotweak -

I have no experience with the Sistrum.

I did find out that my maple platform is not warped, but the Isoblock feet are different heights because they compress differently based on the component's weight distribution. This would then make it difficult to level a component without leveling feet or a flexiRack.

As you suggest, this should not be an issue with a rigid metal platform.

To be fair to Mapleshade, I spoke to Pierre and this is normal. He suggests using 2" X 2" manila paper squares under the blocks as a shim and twisting each block until the resistance is the same for all.