Equipment isolation and vibration damping.

[YashN]

Pretty cool, it would have been fun to test this on top of the ball and cup method - but at $2000 it's too expensive for testing (at least for me). Normally the little vertical rods that it uses to keep the levitating platform centered could be a source for vibration, but if it were sitting on a properly implemented ball and cup arrangement then any horizontal displacement would be absorbed and not transferred to the little vertical rod. This would be a good x-y-z solution if someone can figure how to DIY one for way less $$$.

 

Or below it!

 

The rods, if properly implemented can be very interesting even for supporting two flat surfaces with ball in between: we could use little springs or little Euler springs (on second thought, I don't think Euler applies here, just normal springs could do) that really kick into action if the lateral displacement starts to reach a threshold.

 

Symposium also uses magnets in its ISIS racks, but not for levitation, but rather as a friction-less way to move the balls back to a central position.

[YashN]

Now of course my first thought is while good for mechanical de-coupling, what does a rather strong magnetic field in the vicinity of an electronic piece of gear do? Is it better or worse than the vibration? Though the shelf will allow small movement to decouple vibration it also necessarily will move the magnetic field an equal amount which will induce currents anew in the device on the shelf.

 

Good point.

 

I am weary of magnetic fields, and anything having to do with EMI (weary of RFI too), unless that is, you specifically need a magnetic field to solve a particular problem in audio (which I have in one of my newest designs - for different goals than this thread - which is far from implementation for now).

[YashN]

https://en.wikipedia.org/wiki/Earnshaw%27s_theorem

However, servomechanisms, the use of diamagnetic materials, superconduction, or systems involving eddy currents allow stability to be achieved.

 

In some cases the lifting force is provided by magnetic levitation, but stability is provided by a mechanical support bearing little load. This is termed pseudo-levitation.

 

Exactly, rotation can stabilise arrangements, and is actually part of what makes the Levitron possible:

 

The Physics of Levitron.

 

 

 

 

We receive numerous queries from LEVITRON owners asking for an explanation of how the LEVITRON works. Many express puzzlement that it works at all, often citing a theorem due to Earnshaw (1,2) as proof that it should not work.

[YashN]

Come on now, you have to admit, the levitating shelf looks cool as h*ll.

 

Here's another fun audio contraption:

 

 

You wanted floatin', here's floatin' for ya.

[YashN]

I did some experimentation a couple days ago trying to get a low frequency suspended spring systems. It seems my original calculations were quite wrong, you CAN get a low enough frequency without much height. I tried a bunch of different springs and found out a slinky works great for this purpose, it's easy to select different numbers of coils to change the spring constant and it has a huge extension ratio.

 

Very cool, John.

 

The upshot is four Slinkys suspending a platform actually do a very good job of isolating in both horizontal and vertical directions. It only takes about a foot of extension to get it working well. A practical implementation could be built with a framework going up a a foot or so above the "bottom", with the platform (I prefer thick aluminum) suspended by Slinkys (juniors are thinner so probably look better, I have not done any testing to see which is better). If the platform is suspended a half inch or so above the bottom, then to push buttons etc just push the platform down into contact with the bottom, do your thing, then slowly release.

 

I hope to have something built along these lines this summer.

 

Nice. The thing to look out for here is the resonant frequency of the combined Slinkys and other parts of the arrangement, right?

[YashN]

Just got my ball and cup isolation solution - the cup has a wall to restrain the ball.

The video below shows the balls oscillating nicely in the cup.

 

Note: This is not Barry's design but appears very similar conceptually.

 

 

 

 

 

Now to wait for my shelf design to arrive before testing it under my DAC.

 

Looks great, Nikhil.

 

If one day you can get some of the flat shallow steel dishes, try those too.

 

What's the cup?

[YashN]

I haven't tried it, but I foresee some issues:

 

If you affix the top plate to the entire circumference of the top end of each slinky, it will be quite stiff horizontally, so you won't get much isolation from horizontal forces.

 

Conversely, if you attach each slinky to the top plate at only one point, the entire mechanism will be free to swing horizontally like a child's swing.

 

You need some resistance to damp the springs' vertical oscillation.

 

This reminds me I had a question which has been popping up in my head from time to time: Townshend's pdf only illustrate P-waves and it looks like it is implicit that his spring+air+rubber also does isolation/vibration-damping in the vertical direction.

 

Is it also implicit that his solution also deals successfully with tilt as the spring+rubber comes back to equilibrium position?

[YashN]

More:

 

https://www.youtube.com/watch?t=172&v=XCfhdmC7oMY

[YashN]

Did a few tips today from CDs, so took the opportunity to float the iMac on a cup-and-ball, using the Mac's existing aluminium base, as well as the DVD reader/writer.

 

Connected the DVD reader/writer through my AC filter box as well...

 

Only the amp remains for the stereo setup.

 

Then I'll probably extend the same to the sub, the centre channel, the Blu-Ray player, the SET Tube amp when it's repaired, etc...

[YashN]

Partsconnexion has these magnetic levitation dampers in sets of 4 for $150 for those who can afford them:

 

 

Supposed to be focused on vertical isolation, but deals with some horizontal displacement as well.

[YashN]

Not sure the company is still active, but here's a review of the SAP Relaxa 1 levitation platform:

 

There are several ways to escape from Earnshaw's limitations: you can use a spinning system (gyroscopic effect) like the ones used on magnetic bearings, you can make the whole system "active" by means of electromagnets controlled via software and position sensors (and feedback), more or less like on MagLev Japanese trains and/or you can make use of superconductors (Meissner's effect) at temperatures near the absolute zero or near -100 C with high critical temperature superconductors.

 

[YashN]

I think you are better looking at curved cups both above and below the ball rather than a flat surface.

 

Not if you want to maximise isolation.

 

A flat surface is just going to cause headaches to no end.

 

Not headaches, just its own set of design and practical implementation constraints.

 

I suppose if you wanted an active system, you could have rods at each corner driven by the equivalent to a voice coil which received signals from a sensor to maintain active leveling and decoupling. I also remember some carmakers had fluid filled dampening pads on engine mounts. The viscosity could be varied by an electric signal sent through the fluid. Sensors allowed that to damp engine motion and vibration. None of that sounds easy as DIY project though.

 

Could be easy to work something with Arduino, relays and motors. I had actually planned to build a whole CNC machine with those. You could do a 6-DOF active isolation platform.

[YashN]

A more affordable alternative to Stillpoints. They look good:

 

$90 each for the smallest ones.

 

He also has racks.

[YashN]

Craig balls has 1/2 inch tungsten carbide for $3-4 each.

 

Great price for TC.

[YashN]

2. Where to find the steel pucks. If we need to get them made, then what is the depth of the dimple, and what should be the radius of the curvature (that will give the diameter of the circle on the puck) of the dimple. Alternatively, I think a flat indentation will provide least contact area between the ball and the puck and would be lot easier to fabricate, unless there is another reason. I know equipment will sort of float in flat surface, but I think cables will provide restraint (that is another question if cables are connected then how we say it is isolated, but if works, that is good for now). Anyone found a steel cup with flat recess?

 

InfernoSTI covered a good reply. Here some additional thoughts: do take the time to read the whole thread or you may miss some good info (some others obviously did).

 

A flat surface would be better for isolation but comes with its own set of practical constraints. I would favour this for smaller, lighter components. Curvature isn't needed for isolation.

 

As a concave base, you could look for drawer 'pulls' which are so-shaped (or drawer knobs or handles for more British-oriented audiophiles). What you're looking for here is ideally the shallowest curve possible and the hardest, smoothest surface possible.

 

For a flat surface, I tested manually a very shallow pancake pan. Something similar to that would work as a flat rather than curved surface. If I could source some large, shallow dishes made of steel or aluminium, these are the ones I would look for.

 

For the platform, some people suggested metal, and wood. The important thing here is that the component is well connected to the upper surface and that the lower surface is smooth enough for the rolling of the ball below it.

 

3. I have found tungsten carbide balls on Amazon; Tungsten Carbide Sphere, Grade G25, Precision Ground, Precision Tolerance, Inch: Tungsten Metal Raw Materials: Amazon.com: Industrial & Scientific

4. 3/8” are the largest on this site for about $6.42 each; are they big/small enough.

 

TC is very good for the ball material: it's very hard and durable, the only thing is that they're usually very expensive relative to the others.

 

I think Symposium describe why they settle on 1/2" balls instead of other sizes.

 

5. In my HQ Player setup I have an HQ Player PC, another NAA PC, DAC, pre-amp, and amp. I cannot float the speakers, too dangerous. Which is a good place to start, DAC or NAA pc?

 

The danger with the speakers is because the air-cushion will deflate with time, and an imbalance can wreak havoc. You could test solely the cup-and-ball with them but you will still need to be careful: the three points of contact describing the plane doesn't withstand a rotational imbalance around an axis within the horizontal plane, especially at the two back corners. After a threshold of this type of imbalance, the structure above will fall unless you have set up in place some safety fall-back support at the edges.

 

While measuring the speakers floating of the cup-and-ball I saw a 10x more motion readings along the driver axis compared to rest. This could be inducing some euphonic colouration.

 

Your setup is very good, I would certainly try with the Player PC, the NAA and the DAC first, then follow up with the amps.

[YashN]

I know equipment will sort of float in flat surface, but I think cables will provide restraint (that is another question if cables are connected then how we say it is isolated, but if works, that is good for now).

 

You will want the cables to not cause undue drag on your floated component, maybe by supporting the cables themselves with some other way (or as I suggested, trying to float them too).

 

As an example with my experiments here: tried floating my DAC with the cup-and-ball, but my USB cable is relatively way too heavy and large so that it is actually keeping my DAC in place. This means that isolation of the DAC currently isn't effective.

 

I will need to build a new, smaller and lighter USB cable to make the DAC float effective.

[YashN]

It seems that the most effective resonance control solutions all claim to provide a path for drawing energy out of components in addition to providing isolation. I'm thinking Stillpoints, Nordost Sort Kones and Symosium with their couplers and maybe HRS too.

 

Isolation alone does nothing to deal with airborne vibration or vibration generated inside a component. That's not to say that isolation alone won't deliver big benefits. It's just that maybe a combination of strategies might be the best approach.

 

I am coming back to Kenny's short but important post indeed, having seen a video of the Nordost Sort Kones as well as thinking of another thread where a member was identifying the chips in his DAC so as to do internal vibration damping. The third related thing that came to mind were the Wave Kinetics feet with spherical balls which are said to also isolate from airborne vibration and the balls settle rapidly in place after such vibrations (taking into account that once we floated the speakers here with the c-and-b, airborne vibratins were perceived to be much louder).

 

So, let's assume the cup-and-ball successfully isolates the component from seismic P-waves for now, and we have a solution similar to the air-cushion or an alternative for the S-waves or vertical ones. Thus we have prevented the external vibrations from coming into our components.

 

However, these do nothing at all for vibrations which are internal (and I wonder how much the airborne vibrations affect components which have just been floated with the cup-and-ball too) to our components.

 

As additional strategies, we could resort to a couple of solutions:

 

1. Feet like Nordost Sort Kones and Waves Kinetics for lossy disruption on internal mechanical vibrations.

 

2. Internal damping with constrained layer or blu-tak on the chips or clocks or capacitors or some anti-vibration paint like that other member mentioned in the other thread (approximately 3 or 4 weeks ago).

 

I missed attending this time, but he Nordost Sort Kones demo at this show sounds convincing to my ears:

 

[video=youtube;NdND5c-VNl8]

[YashN]

I have read the whole thread now

 

Well done.

 

Don't forget the papers!

[YashN]

Are you awarding a Ph.D. to me if I do that

 

Not yet, but I will get to those. Thanks.

 

No but there are two very interesting Doctoral Dissertations you can read, on top of many other links and papers.

[YashN]

Maybe the mini-slinky could be fashioned with a 90ohm impedance, could itself serve as the USB cable and would then require 4 regens:)

 

My next USB cable build will be more than just a USB cable, no joke.

[YashN]

I'd suggest hanging the USB cable from a sling. Easy to make from 2 - 3 of those Velcro cable ties stuck together end-to-end, to make as long a sling as needed. Then, some means must be found to suspend the sling over the cables center of mass. I use a spring clamp attached to a higher shelf. The sling is looped around the USB cable, then tie a rubber band to the top of the sling, and hang it over the clamp wings. You can adjust the lift by the lengh of the sling, and Velcro is very easy to adjust.

 

Not sure it would work in my case: my current DIY USB cable is too long, too bulky and too heavy - just finding the space to let it rest normally is difficult, so imagine balancing it on another implement.

 

I have resorted to designing the next iteration which will solve the floating issue as well as improve on two enhancements already, and one of these enhancements is actually linked to the solution to the floating issue. Big win!

[YashN]

I was describing hanging/suspending the unattached parts of the cable. Nothing about balancing it on anything ???

 

Never mind that: it's not practical for my current cable in any case.

[YashN]

I was thinking to use plywood instead of marble tile and put something hard between plywood and ball.

 

Give bamboo a try as well if you can.

[YashN]

I meant to ask, where you find bamboo boards.

 

I'm not sure what I'm using for the speakers is available in your area, but it's just a very simple small-size chopping board with green rubber lining on two sides, and an area hollowed out as a handle (also lined in rubber). The rubber can come in different colours. They cost $2 each or so.

 

It's probably easy to find larger chopping blocks.

 

Gilles' suggestion is a good one, I have seen a few reviews and feedback posts online mentioning it.

[YashN]

One other hint about inner tube air bearings. The plate or shelf that sits on top of the inner tube needs to have a hole in the center to equalize the air pressure in the middle of the ring of the tube. Otherwise there will be a pneumatic resistance to vertical movement reducing the isolation effect. If you can't put a hole in the plate (like if its glass), a small straw laid along the top of the ring somewhere along its circumference, will do the equalization job.

 

That's an interesting point: it's similar to what Townshend does in his latest devices, and there are isolation tables used in Scientific Research that use the principle of an air diaphragm with a valve inside for isolation.