Vibration isolating rollerballs

bdiament · July 4, 2015

There's no benefit for the purpose of isolation that the ball is kept centered. On a flat surface, it could still be off-center and the isolation would remain operational (and optimal).

Hi YashN,

I would very strongly caution against this. Wait 'til you actually do it. I say, on the contrary, there is no benefit to having a flat surface. The ball *must* be in a curved bowl if you want to set up the resonance that will result in the isolation. On a flat surface, the ball meanders, and nothing else happens. Try it and see.

Best regards,

Barry

bdiament · July 4, 2015

Won't happen if there is a curve at the very end.

Hi YashN,

With a flat surface, neither will isolation happen. The bowl is *necessary*.

Try it and see.

Best regards,

Barry

JohnSwenson · July 4, 2015

Hi YashN,

With a flat surface, neither will isolation happen. The bowl is *necessary*.

Try it and see.

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

Hi Barry,

the bowl shape is not necessary for the isolation to happen, however without it the system is like a pencil sitting on its point. If the system is not PERFECTLY level gravity will cause the top to just roll right off. The bowl shape adds some restoring force to keep the top centered.

John S.

Daudio · July 4, 2015

the bowl shape is not necessary for the isolation to happen, however without it the system is like a pencil sitting on its point.

John,

If the bowl is unnecessary, and there is no slope for the ball to push against, where is the isolation occuring ?

Somewhere in the 4 tiny contact points ?

Fine Forth,

Dave

JohnSwenson · July 4, 2015

John,

If the bowl is unnecessary, and there is no slope for the ball to push against, where is the isolation occuring ?

Somewhere in the 4 tiny contact points ?

Fine Forth,

Dave

Go back and read the thought experiment post I had in the big thread.

The basic idea is that if you have two slabs with zero resistance between them, the bottom slab can move around from side to side as much as it likes and there will be NO transfer to the upper slab if there is no resistance. The top's own inertia will keep it from moving. A hard ball between two hard surfaces comes pretty close to that. It has very low resistance in the horizontal direction and very high resistance in the vertical direction.

The two flat slabs have a problem, if they are not perfectly level, the top will just slide right off the bottom due to gravity, you need some sort of weak restoring force to keep the top from falling off the bottom. The more the restoring force the worse the isolation, the isolation works better the lower the connection between the surfaces.

The bowl is how the restoring force is applied. As the ball rolls up the sides gravity is applying a force to push it back towards the center. The shallower the slope the less coupling there is (and greater isolation) but it is easier for the top to fall off. So in general you want as shallow a curve as you can get and still keep the gear from falling off when you touch controls etc.

The bowl shape is essentially a necessary evil to get the concept to work in the real world, it is NOT the primary reason there is isolation.

Notice from the above that this provides essentially no isolation in the vertical direction, so other methods need to be used to get vertical isolation.

John S.

AnotherSpin · July 4, 2015

You are the only one who has ever provided a drawing! I'd be happy if you converse with Mike [email protected] and come to an understanding of what is possible given the constraints of what he's ordered in terms of material and reasonable price. Mike wants to make something that we like. I'm happy to go with either the spec Barry gave us already, or yours if that meets the manufacturing constraints or something in between.

Jon, I wrote to Mike with question and drawing enclosed. I think we could use my design with one change - inner curvature diameter should be 2" as in Barry's idea. In fact, this is the most important part, and I believe we should go with Barry here.

zerung · July 4, 2015

You are the only one who has ever provided a drawing! I'd be happy if you converse with Mike [email protected] and come to an understanding of what is possible given the constraints of what he's ordered in terms of material and reasonable price. Mike wants to make something that we like. I'm happy to go with either the spec Barry gave us already, or yours if that meets the manufacturing constraints or something in between.

I have pledged 3 sets.

About the design, if you see Mike's website, he has one that has edges chamfered. This will possibly give some visual oomph.

Some possibilities:

1. Small radius on the edges.

2. 4mm of the bottom of the disk could be left un-mirror finished. This will give some definition to the disk.

3. Else we could have some lathe groove at the 4mm mark, that would be cool too.

4. Or the bottom 6mm could be provided with concentric groove every 1.5mm, hence 4 parallel groove.

5. The top should definitely be mirror finished to allow for full isolation.

Can do cadd drawing if required.

BTW, Carbide Ball can be sourced from China. ~5 USD each for 12mm dia.

bdiament · July 4, 2015

Hi Barry,
the bowl shape is not necessary for the isolation to happen, however without it the system is like a pencil sitting on its point. If the system is not PERFECTLY level gravity will cause the top to just roll right off. The bowl shape adds some restoring force to keep the top centered.

John S.

Hi John,

While I understand your point, as you said, in the absence of a perfectly level system, things will not work out so well.

For all practical (as opposed to theoretical) purposes, I would consider the bowl necessary. I have always suggested *minimal* damping, but not zero damping. Just my perspective of course. As always, I suggest folks try things out and see/hear for themselves.

Best regards,

Barry

jabbr · July 4, 2015

I have pledged 3 sets.

About the design, if you see Mike's website, he has one that has edges chamfered. This will possibly give some visual oomph.

Some possibilities:

1. Small radius on the edges.

2. 4mm of the bottom of the disk could be left un-mirror finished. This will give some definition to the disk.

3. Else we could have some lathe groove at the 4mm mark, that would be cool too.

4. Or the bottom 6mm could be provided with concentric groove every 1.5mm, hence 4 parallel groove.

5. The top should definitely be mirror finished to allow for full isolation.

Can do cadd drawing if required.

BTW, Carbide Ball can be sourced from China. ~5 USD each for 12mm dia.

I would like to have a mirror finish on both sides of the bowls -- that way they can be used either against a flat top or inverted.

Where can you get carbide for $5 12mm bearing? That's an excellent price!

InfernoSTi · July 4, 2015

There is the question of "grade" with the balls, not just material. G25, G10, G3, etc. The more expensive balls have much lower tolerances (i.e. they are more true to perfect round).

The Grade 3 Superball

My thought is that folks will "tweak" with the balls anyway, so perhaps we should start a separate purchase of several types and let folk get bulk discounts if they go in together. Tungsten is also a popular material.

Additionally, there are a lot of fraudulent balls on the internet...just labeled as the higher grade/material. If the price seems better than it should be, it probably is. Just saying...

One thing: they all look similar so keeping them properly labeled is key!

zerung · July 4, 2015

I would like to have a mirror finish on both sides of the bowls -- that way they can be used either against a flat top or inverted.

Where can you get carbide for $5 12mm bearing? That's an excellent price!

For general information:

Taobao is a Chinese sales portal (Part of AliBaba), larger than Ebay and Amazon put together. They sell almost everything, if you know the name in Chinese.....

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YashN · July 4, 2015

I would very strongly caution against this. Wait 'til you actually do it. I say, on the contrary, there is no benefit to having a flat surface. The ball *must* be in a curved bowl if you want to set up the resonance that will result in the isolation. On a flat surface, the ball meanders, and nothing else happens. Try it and see.

On the contrary, it seems you misunderstand why the isolation happens.

You should re-read John Swenson's thought experiment post on the other thread and do the thought experiment to see why.

A flatter surface is more optimal for isolation in the horizontal plane.

YashN · July 4, 2015

Additionally, there are a lot of fraudulent balls on the internet...just labeled as the higher grade/material. If the price seems better than it should be, it probably is. Just saying...

Good point.

bdiament · July 4, 2015

On the contrary, it seems you misunderstand why the isolation happens.

You should re-read John Swenson's thought experiment post on the other thread and do the thought experiment to see why.

A flatter surface is more optimal for isolation in the horizontal plane.

Hi YashN,

In terms of understanding or misunderstanding, I can only offer what I've learned from experience and hope it is of use. I much prefer empirical data, i.e., direct experience, to theory. There are the theories being expounded and there is the practical, real-world reality. Once you move on to the latter, understanding of why isolation happens and when (and when not) in actual use with audio and video gear will dawn.

If you read what John said, notice the mention of needing PERFECT leveling. Based on my experience, I believe even with perfect leveling there will be more issues but by all means, I would never tell you to not try what you might be interested in trying. If you've read my posts so far, you know I always suggest folks try things for themselves. Actually trying these things out will tell you more than I ever could. (Even in the post you quoted, I said "Try it and see.")

Have fun!

Best regards,

Barry

Gilles · July 4, 2015

I found a Delaware supplier of half-inch TC balls at US$3.25 per ball, see https://www.craigballsales.com/1-2-12.700mm-lot-of-10.html.

I do not know them and have no idea of the grade of the balls, i.e. G25 or else.

My apologies if that has been covered in other threads, and I do not recall it has, but is there a benefit in having the ball and the bowl, cup, or disk as I call it, made of the same material of the same grade? My quasi non existent knowledge of metallurgy makes me think that having both made of the same material of the same grade should produce better results than otherwise. The probability that the desired properties of one be limited or defeated by those of the other of another material would be minimized. Does this make any sense? Am I splitting hair here?

I posted this while I had time today but will not have much time later today and tomorrow to read your replies, if any. I will of course catch up as soon as I can either late Sunday night or Monday at the latest.

Many thanks in advance, and have a great weekend. Happy Independence Day to our US friends!

Gilles

YashN · July 4, 2015

In terms of understanding or misunderstanding, I can only offer what I've learned from experience and hope it is of use. I much prefer empirical data, i.e., direct experience, to theory.

There are the theories being expounded and there is the practical, real-world reality. Once you move on to the latter, understanding of why isolation happens and when (and when not) in actual use with audio and video gear will dawn.

Go ahead and try it yourself: you've gone half-way by removing the upper cup. Remove the cup below and the isolation is further improved.

Try it on smaller piece of equipment and set up some material it can 'roll' or 'fall' on to at extremes of motion, said material being of dimensions slightly smaller than the diameter of the balls.

If you read what John said, notice the mention of needing PERFECT leveling.

That is correct. Use a level surface, Or as close to level as is possible, in conjunction with the 'safety' devices I mention above.

If you've read my posts so far, you know I always suggest folks try things for themselves. Actually trying these things out will tell you more than I ever could. (Even in the post you quoted, I said "Try it and see.")

In reality, you oscillate between repeating for others to try things and discouraging others from trying anything that is different from your own current setup, at least that's what I've noticed.

No need to repeat to me to try things for myself, I think there's sufficient evidence I am already doing that (and not just for vibration isolation!)

Cheers.

bdiament · July 4, 2015

Go ahead and try it yourself: you've gone half-way by removing the upper cup. Remove the cup below and the isolation is further improved.

Try it on smaller piece of equipment and set up some material it can 'roll' or 'fall' on to at extremes of motion, said material being of dimensions slightly smaller than the diameter of the balls...

Hi YashN,

You may have forgotten but while isolation may be new to you, I experimented with *all* of this well over a decade ago. That is how I arrived at what I decided to use. I'm at loss to figure out why you'd think I hadn't already been there and done that. No matter.

In reality, you oscillate between repeating for others to try things and discouraging others from trying anything that is different from your own current setup, at least that's what I've noticed...

This is not true. Perhaps that is what you inferred but the evidence of my posts would not support such an assertion. I made *recommendations* and even advised that certain approaches would not, in my opinion, work very well. That is not the same as discouraging others from trying. On the contrary. Always, always, I have said folks should *not* simply take my word for anything I report but should try things for themselves.

Perhaps it is best if I just don't reply to your posts. In all honesty, the last few from you are feeling less than friendly.

I hope you find the same joy I have found, however you decide to implement it. Good luck!

Best regards,

Barry

YashN · July 4, 2015

You may have forgotten but while isolation may be new to you, I experimented with *all* of this well over a decade ago. That is how I arrived at what I decided to use. I'm at loss to figure out why you'd think I hadn't already been there and done that. No matter.

If you think you've 'been there and done that', then it seems you have settled for a largely sub-optimal implementation.

This is not true. Perhaps that is what you inferred but the evidence of my posts would not support such an assertion.

The last exchange where you keep speaking about your speakers where mine as different is what makes me say this.

Perhaps it is best if I just don't reply to your posts. In all honesty, the last few from you are feeling less than friendly.

Your impression that it is the curvature of the bowl that makes the isolation is wrong. That is a simple fact, and having the wrong understanding of how it works may lead you to settle on a sub-optimal implementation.

If someone not agreeing with you is what you call 'feeling less than friendly', then feel free to ignore what I told you, knowing that John Swenson said the same thing.

The CA forum has an 'Ignore' feature. Use it.

bdiament · July 4, 2015

If you think you've 'been there and done that', then it seems you have settled for a largely sub-optimal implementation.

The last exchange where you keep speaking about your speakers where mine as different is what makes me say this.

Your impression that it is the curvature of the bowl that makes the isolation is wrong. That is a simple fact, and having the wrong understanding of how it works may lead you to settle on a sub-optimal implementation.

If someone not agreeing with you is what you call 'feeling less than friendly', then feel free to ignore what I told you, knowing that John Swenson said the same thing.

The CA forum has an 'Ignore' feature. Use it.

My, my, someone got out of the wrong side of the bed this morning, didn't they?

1. Curvature of the bowl doesn't make the isolation. Curvature of the bowl makes for *practical* (as opposed to theoretical) isolation.

2. I have no problem with disagreement. It is incivility that is the issue. Actually, it would seem *you* are the one with the problem regarding disagreement, evidenced by how quickly--and often--you've forgotten your manners. Again no matter. And given your previous posts, no surprise.

I wish you happiness. And perhaps one day, if not knowledge, at least a modicum of maturity.

My apologies to other readers of this thread.

Barry