DIY racks and related discussion

So I mentioned before how I wanted to build my own rack to make sure my Ragnarok doesn't overheat. So it had to be breathable. Well, I finished it and this is what it looks like:


Some more pics on my website, link above.

So how does it sound?

In a word? Fast. It can also seem somewhat etheral. It took some time for the Gungnir MB to warm up again and in the beginning it did sound somewhat anemic with some glare, but I could already tell there was potential. Still, building such a lightweight rack goes against what most people end up liking.

I do think it sounds cleaner than my IKEA Lack rack. That one was a pretty standard build with wooden inserts in the legs and dowels between the layers, along with height adjustable metal feet on the bottom.

Now I'm using spikes on carbon footers. Spikes between the layers and polished alu rods. It took me some time to find something that was both breathable, sturdy enough and not made of metal. I wanted to avoid putting my gear on a ringy metal platform. There's thick foam between the supports and the platforms. All in a glossy white frame that I reinforced using metal angles.

It does sway a bit and also obviously there's give in the vertical direction from the foam. The resonance frequencies here I measured at 3Hz laterally and 13Hz vertically. I do think I like how the Turntable sounds, this is despite most people putting thick slabs underneath their turntables.

I gotta admit I was taken aback when I saw the Quadraspire SVT at High End, so that served somewhat as an inspiration. Only I wanted more decoupling.

Anyway, let me know what you think. Have you built your own racks? What are some good sounding racks in your opinion?

 

I realized I had to improve two things:

1. The platforms were sagging towards the edges. I added supports near the edges to deal with that.
2. It was hard to center the spikes on top of the screws, so I drilled a tiny hole into the center (well, to the best of my ability) that the spike would go into. Note that the top screws in the image below don't have tiny holes drilled into them - no need

Here's what the supports look like. Not the prettiest solution, but it is a solution.


I also tried to measure the resonance frequency again and now that I could get more tension into the feet without them moving off-center I had a somewhat higher lateral resonance frequency. 4Hz-ish.

Vertically I think my first measurement was just off. I got 5Hz now. But there isn't much movement here, the foam is quite stiff. So impossible to measure correctly, really.

Either way both should not interfere with tonearm and cartridge resonances.

By the way. Of course I did not build the frames myself. They're picture frames. And the center platforms are from IKEA. The spikes are height-adjustable and I spent about an hour meticulously leveling the thing.

 

Looks nice! How are the aluminium tubes mounted to the underside? Threaded tubes screwed onto a bolt? Any isolation material around the mounting point?

 

Yes and no isolation material. Just the wood MDF, if it even deserves to be called that.

 

Weird, I could've sworn we had a "post pics of your racks" thread started by shiazada long, long ago, where I'd posted this build... Here's the full Imgur album: https://imgur.com/a/0aNKZDt

Here's a couple pics:









I'll dig back through my emails for receipts, and post up the full BOM if folks are interested - IIRC, I got all of the hardware and 8020 extrusions from 8020.net and McMaster.com, and the baltic birch plywood was from a place that does CNC cut blanks. All of the shelfs sit on 20mm sorbothane domes, adjusting the number per shelf to account for the mass of equipment on each shelf. Total cost was around $300-$400, iirc. I'll edit/add more info if folks want to replicate this, or build something similar.

 

This is kind of a dump but I cleaned it up a little. I think I ordered a couple different footers from McMaster so not everything below was used. The plywood should be sanded and sealed; I used boiled linseed oil, 3 or 4 coats with a final finish using 000 steel wool.
________________________________________________________________________________
Order from Craft Cuts www.craftcuts.com

Square Craft Shape Cutout
SKU: cra_dimensionalshapes_shapes_basic_square
Material: Baltic Birch Plywood
Longest Dimension: 18 Inch
Shape Thickness: 3/4 inch
Quantity 2
Price $45.80

Square Craft Shape Cutout
SKU: cra_dimensionalshapes_shapes_basic_square
Material: Baltic Birch Plywood
Longest Dimension: 23 Inch
Shape Thickness: 3/4 inch
Quantity 1
Price $31.14
________________________________________________________________________________
Order from 80/20.net:
Price
Qty

SKU: 14122
M5 Slide-in Economy T-Nut Block $10.08 48

SKU: 13-5310
M5 x 10.00mm Button Head Socket Cap Screw (BHSCS) $11.52 48

SKU: 20-4119
20 Series 2 Hole - Inside Corner Bracket $24.64 8

SKU: 20-4118
20 Series 3 Hole - Straight Flat Plate $13.77 3

SKU: 20-4119
20 Series 2 Hole - Inside Corner Bracket $68.40 24

SKU: 20-2020
20mm X 20mm T-Slotted Profile - Four Open T-Slots $18.89 3
Length - 27.17 Inches (690 Millimeters) x $0.16
Cut To Length - 1 x $1.95
Unit Of Measurement Millimeters

SKU: 20-2020
20mm X 20mm T-Slotted Profile - Four Open T-Slots $24.36 6
Length - 13.19 Inches (335 Millimeters) x $0.16
Cut To Length - 1 x $1.95
Unit Of Measurement Millimeters

SKU: 12260
40 Series End Cap with Molded Push-In Stem $5.60 4

SKU: 40-4001
40mm X 40mm T-Slotted Profile - Single Open T-Slots $62.41 4
Length - 26.77 Inches (680 Millimeters) x $0.51
Cut To Length - 1 x $1.95
Unit Of Measurement Millimeters
________________________________________________________________________________
Order from McMaster.com:

Swivel Leveling Mount
Corrosion-Resistant, M8 x 1.25 mm Thread Size, 32 mm Thread Length
6301K87
4 each
13.16 each
$52.64

Load-Rated Adhesive-Back Bumper, Polyurethane, 3/4" OD, 3 lbs.Maximum Load, Soft
8215K9
24 Each
1.34 Each
$32.16

T-Slotted Framing, End-Feed Single Nut, M5 Thread, for 20 mm Single Rail, Packs of 10
5537T651
3 Packs
$3.73 Per Pack
$11.19

Threaded-Stud Rubber Bumper with Steel Base Plate, M5 x 0.80mm Size, 10mm OD, 10mm High, 13 lbs. Maximum Load
3810N181
4 Each
$2.16 Each
$8.64

 

I guess an alternative to the two poll options is sort of split the difference: couple the equipment to massive, heavy shelves and then decouple those from each other and the floor. That's what I'm envisaging when I get round to building a proper rack.

 

Hope I'm not disturbing this thread with a speaker stand, but I'm going to make some in a few weeks and would love input. These are for 24x18x42" 75-100lb enclosures, I need to get them about 5-6" higher and decouple from the floor a bit. The plan is to use 12ga 2" OD square steel tubing, with threaded teflon sliding feet on the bottom for easy positioning and minor height adjustment/leveling. I have a bunch of extra sorbothane hemispheres that I plan to put on the top of the stands to decouple the speakers. I'll also leave the tops of the vertical sections open with an open path to the cross members so I can fill the whole thing with kitty litter, and then cap with plastic caps. I did an amateur 2D top and front view drawing, wondering if it needs a center support or if it's fine as just a rectangular frame?

 

I think just for ease of construction I would make it out of 15 series or 40 series extrusion like yota ;/ I haven't got a welding setup. That said I bet the amount of expected deflection from 100 lbs put directly in the center of 24" of 12ga 2" square tubing is very little, nevermind spread around the whole perimeter.

 

That's typically the best way to go. Generally floors have some bounce to them (unless you're on concrete, and even then no guarantee) and vibrations can transmit from footsteps, traffic, fridge compressors, etc.

Couple your components to something big and heavy, which will lower the component's overall vibration etc. Slap something heavy on top of it to really compress it into the heavy thing. Then float the heavy thing away from floor vibrations.

 

Thanks, I like welding(for hobby projects, it sucked as a job) and just found a community metal studio, so this is my intro project there. I'm also planning to use these stands as the base of a PAP Duet 15 inspired open baffle using the same drivers as these speakers with a helper woofer once I get around to that.

 

Thinking about it my floor does have some bounce to it. I might try a heavy platform-thing as a base to see if it makes a difference. The TT on top is heavy enough.

Stone? Steel? I'll see what makes sense and what is feasible. A 60x60 marble tile comes to mind, although something thick meant for outdoors is probably a better idea. Or just a concrete slab.

 

Do you mean to put the heavy slab on the floor below the stand, or on the stand below the TT?

If the slab goes directly on the floor, the weight basically couples it and all you do is reduce the resonance if the floor but vibrations still go through. If you have an isolating layer (could even be carpet), then the slab will be a floating platform for your stand.

If putting the heavy slab on the stand, it makes a difference putting the weight on the bottom or top. On the top increases the wobble potential of the stand, though if you're using it to couple to the turntable then that reduces the the vibration of the turntable itself (maybe). Weight on the bottom of the stand potentially helps stabilize it more. Maybe. Physics are tricky sometimes.

 

Here's the latest DIY rack I made, design was stolen from Timbernation.

Twelve lag bolts, wood, wood-glue. EDIT: and leg levelers.

 

I was thinking directly on the floor. Possibly placed on disks where the spikes and disks of the rack are located. But most likely just directly on the wooden floor.

It looks like 20-30kg is easily affordable, not too thick, etc. I wonder if that does much, though. The rack should be in the 40kg range itself, I guess.

 

The title was pretty specific - turntable ... furniture. There's another one here. I think there used to be more than I can find, maybe some got lost in the hack.

What do people think of this one, physics-sophically? ~13 lb turntable with fairly rigid feet on a 20 lb marble + wood platform (the marble's feet are rigid), decoupled with sorbothane feet (1.25" 50 duro x 4, so rated load = 20 to 40 lb).

I guess it could be characterized as "load & stand of similar mass, load more-or-less coupled to stand, stand decoupled from base".

 

that's a Rega TT, no? Rega's have a specific schtick with regards to mass, and coupling/decoupling. The wood plinth Regas (with glass platters) are kinda too heavy to be entirely rigid and lossy at higher frequencies, but also too light to be effectively mass coupled, at least as much as I played around with them. One thing I'd at least try, or, at least for me was the most effective with the couple of MDF plinth Regas I had, was to remove the footers and isolate them from the stand using a 12" bicycle inner tube barely inflated to a couple PSI between the plinth and the stand. This worked better than any decoupling (squishy) or coupling (rigid spikes) between the table and the stand for me. It makes leveling the TT a complete PITA, but shoving playing cards between the inner tube and the table plinth ended up allowing for a fine enough adjustment/shim to get the table level through some trial and error.

 

Yep, it's an old one (1984 or 85), so yeah, MDF plinth with stuff laminated to top & bottom and wood trim on the edges.

'Air suspension', I might try that, thanks for the suggestion. I used to have it sitting on 3 of those round balls (can't remember the name now, iso-something I think) that don't bounce when dropped. I thought this current setup sounded better when I first put the sorbothane feet under the rack, but that was shortly after moving to a new room and I'm not sure I did enough listening with the balls first (as it were) to be confident.

 

I made an itty bitty one for headfi setup