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Equipment isolation and vibration damping.


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Hi Barry:

 

Then it sort of becomes Catch-22, doesn't it? If the device doesn't improve the sound, then it is "not properly designed and implemented". One could argue that, if the component itself was properly designed and implemented, these devices wouldn't be necessary. :)

 

Hi Allan,

 

I don't see a catch-22 here. It is simply a matter of approach.

As to these devices not being necessary with optimally designed components, agreed 100%.

It is nice to see some designers (notably Carl Marchisotto with his Nola speakers) incorporating seismic isolation into their products.

 

Back to outboard devices, if the sound isn't improved by isolating devices, any one or more of the following might be true:

 

1. The device isn't a particularly good isolator.

Many devices sold as isolators are actually couplers - the diametric opposite. Other devices sold as isolators have resonances that are too high, often in the mid or upper bass. Their isolation does not take effect at a low enough freqneucy to be effective. And these devices result in bass bloat to boot.

 

Among rollers, some are sold with "bowls" to be used above the ball as well as those used below it. My experience has been that the second bowl adds damping, which diminishes the rolloff above resonance, i.e., diminishes the degree of isolation.

 

2. Assuming a well designed isolator, placement becomes important. With good rollers, I've found it is important to place them in an equilateral arrangement to allow for the greatest freedom of motion. With air bearings, I've found it is important to inflate them *only* enough to achieve air support -- to lift the load so it isn't resting on the inflation valve. One pump too many and the resonance goes up, bass bloats, and isolation diminishes.

 

Rollers need a *very* smooth surface resting on them. If the bottom of the component to be isolated has a textured surface or has ventilation holes, motion (and hence, isolation) is impeded. With such components, I use a dead marble tile, smooth side down against the roller bearing balls. The component sits atop the tile on its own feet.

 

Back to air bearings: Some folks use multiple small air bearings to achieve balance (so the gear doesn't tilt). This alters the function of the air bearing from isolator to level. Once that is done, it isn't such a good isolator. Better, in my view, to use an air bearing (aka inner tube) that describes a large enough circle to accommodate the component to be isolated. In this way, components where the bulk of the mass is off center, can be placed off center atop the platform atop the air bearing. In other words, if an amp's left side is heavier than its right side, I'd place the amp to the right of center atop the platform, thus achieving balance without having to alter the minimal inflation of the air bearing. (This means the shelf on which the air bearing sits, as well as the platform between the air bearing and the component being supported, needs to have adequate size.)

 

3. As I noted in my article on the subject, it has been my experience that certain other things must be attended to before the benefits of isolation will be plain. Among those other things are clean AC power and proper routing of system cables (signal cables separated from power cables, etc.).

 

As with any system setup, there are priorities. The smaller things won't be audible until the larger things (starting with speaker and listening position placement) are properly addressed. Once all is in order, the benefits of isolation become clear.

 

A last thought: In my experience, not everyone will like the results of increasing the neutrality of a component or system. Some folks prefer certain colors in their gear (such as can be achieved, albeit somewhat randomly, with spikes and cones) and I'd never argue with whatever brings anyone their listening pleasure. That said, for those who have taken great care in their system setup and want to hear their gear do even better at what I call "getting out of the way" I recommend trying some good seismic isolation techniques.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Among rollers, some are sold with "bowls" to be used above the ball as well as those used below it. My experience has been that the second bowl adds damping, which diminishes the rolloff above resonance, i.e., diminishes the degree of isolation.

 

FWIW, the devices my friend used were of this category. The difference heard when they were replaced was both immediate and significant. My friend's wife, who was in the kitchen, noticed and commented on it.

"Relax, it's only hi-fi. There's never been a hi-fi emergency." - Roy Hall

"Not everything that can be counted counts, and not everything that counts can be counted." - William Bruce Cameron

 

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FWIW, the devices my friend used were of this category. The difference heard when they were replaced was both immediate and significant. My friend's wife, who was in the kitchen, noticed and commented on it.

 

Hi Allan,

 

I'm not surprised.

The larger contact surface presented by a "top" (vs. the ball) also tends to alter tonality, adding brightness and sometimes, outright "chatter." I would not think the difference would be subtle.

 

Like I said, "properly designed and properly implemented." The fault was not at all in the concept of roller bearings for seismic isolation. It was in the approach.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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The machinist I chose made me sets of three at well under $50 per set. Of course, this was over a decade ago,

 

 

Barry,

 

A decade ago in an craft that is going more to the big CNC shop and less to the 'old lathe guy' kind of thing, I used to see a lot of around the 'Motor city'. Not so much anymore :(

 

Anyway, how many units did you buy at that > $50 per set price ?

 

 

I would not agree that changing the size of the ball will do anything significant with regard to the curve. (Well, maybe if the ball was so small, it no longer protruded from the top of the "bowl" -- but even then, I say still no significant effect in terms of resonance frequency or damping. That's basically all in the bowl.

 

OK, how's about we put some numbers to them ? What diameter are your bowls (the full negative space, not the block intersection) and bearing balls ?

 

I'll figure out my variations.

 

 

It really is an easy (and for do-it-yourselfer's an economical) way to significantly up a system's performance.

 

So true !

 

Reminds me of barrows signature: "everything matters". Attending to vibration control, contact treatment, cable dressing and routing, AC power, and such, will get the most out of whatever audio hardware one happens to have hanging around :)

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Hi Daudio,

 

Barry,

 

A decade ago in an craft that is going more to the big CNC shop and less to the 'old lathe guy' kind of thing, I used to see a lot of around the 'Motor city'. Not so much anymore :(

 

Anyway, how many units did you buy at that > $50 per set price ?

 

That was "well under $50 per set."

I made enough for everything, including the speakers and subs. If I recall correctly, probably 12 sets.

 

 

OK, how's about we put some numbers to them ? What diameter are your bowls (the full negative space, not the block intersection) and bearing balls ?

 

I'll figure out my variations...

 

Iteration #1 uses a .96" diameter bowl that is a section of a 2" sphere. Bowl 1/8" deep at the center.

Balls are 1/2" chrome steel. I auditioned Tungsten Carbide and they clearly sound even better -- but $9 per ball was more than I chose to spend. A bag of 100 chrome steel balls was a couple of bucks at the time.

 

Iteration #2 to come. I have some ideas.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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So, this is all great reading, and I just happen to be playing with my old sets of Daruma 3 mkII roller bearing isolators on a pair of Omega Super Alnico monitors.

 

Sounds like I should attempt to remove one of the brass pieces and just use the ball with the brass cupped piece. This will be on my "must try soon" list!

 

And finally the question has to be asked.... What is the "best" ball material?? Brass? Titanium? Maple - other hardwood?? I do have a couple of sizes of maple balls coming this week to play with; either will fit into the cupped brass end of the Daruma... Cheap experiment!

 

Keep the great commentary coming!!

Metrum Onyx DAC, Matrix X-SPDIF2 DDC, Snake River Boomslang Digital cable, Verastarr Nemesis USB cable;

Backert Rhumba 1.2 Preamp; Coincident M300B Frankenstein mkII SET monoblocks

Omega Super Alnico HO Monitors (Cherry finish) / Martin Logan Depth i Subwoofer

Macbook Pro (mid-2012, 2.3GHz i7, 16Gb RAM, 512Gb SSD), HQPlayer, Tidal, Roon;

Cabling by Cerious Tech (Graphene SC, Blue PCs), Verastarr (IC and PC) and Teo Audio (GC IC)

 

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So, this is all great reading, and I just happen to be playing with my old sets of Daruma 3 mkII roller bearing isolators on a pair of Omega Super Alnico monitors.

 

Sounds like I should attempt to remove one of the brass pieces and just use the ball with the brass cupped piece. This will be on my "must try soon" list!

 

And finally the question has to be asked.... What is the "best" ball material?? Brass? Titanium? Maple - other hardwood?? I do have a couple of sizes of maple balls coming this week to play with; either will fit into the cupped brass end of the Daruma... Cheap experiment!

 

Keep the great commentary coming!!

 

Hi 1markr,

 

In my view, the best ball will be the hardest and the smoothest.

The best I've heard are Tungsten Carbide but the price resulted in my deciding I was quite happy with Chrome Steel.

 

I would not deem wood an optimal material for such. Not hard enough and not smooth enough.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Thanks Barry.... good to know about the Tungsten Carbide and Chrome Steel. I will have to check Grainger or similar if they have them in 3/8", 7/16", or 1/2" diameters. Any other known sources?

 

As for the maple, it cost me $6, after shipping, for 12 balls of two sizes, so mehhhh, we'll see what happens!

 

Cheers,

Mark

 

 

Hi 1markr,

 

In my view, the best ball will be the hardest and the smoothest.

The best I've heard are Tungsten Carbide but the price resulted in my deciding I was quite happy with Chrome Steel.

 

I would not deem wood an optimal material for such. Not hard enough and not smooth enough.

 

Best regards,

Barry

Soundkeeper Recordings

www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

Metrum Onyx DAC, Matrix X-SPDIF2 DDC, Snake River Boomslang Digital cable, Verastarr Nemesis USB cable;

Backert Rhumba 1.2 Preamp; Coincident M300B Frankenstein mkII SET monoblocks

Omega Super Alnico HO Monitors (Cherry finish) / Martin Logan Depth i Subwoofer

Macbook Pro (mid-2012, 2.3GHz i7, 16Gb RAM, 512Gb SSD), HQPlayer, Tidal, Roon;

Cabling by Cerious Tech (Graphene SC, Blue PCs), Verastarr (IC and PC) and Teo Audio (GC IC)

 

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... Tungsten Carbide and Chrome Steel. I will have to check Grainger or similar if they have them in 3/8", 7/16", or 1/2" diameters. Any other known sources?

 

Mark,

 

I got 3/4", 1/2", and 3/8" SS G25* balls off of Amazon. At the time they were very reasonable. I agree with Barry that the Tungsten Carbide balls are 'a bridge too far' :)

 

 

* (G25 - concentricity accurate to 25 millionths of an inch) (good enough for me)

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Perfect! Thx Daudio...

 

 

Mark,

 

I got 3/4", 1/2", and 3/8" SS G25* balls off of Amazon. At the time they were very reasonable. I agree with Barry that the Tungsten Carbide balls are 'a bridge too far' :)

 

 

* (G25 - concentricity accurate to 25 millionths of an inch) (good enough for me)

Metrum Onyx DAC, Matrix X-SPDIF2 DDC, Snake River Boomslang Digital cable, Verastarr Nemesis USB cable;

Backert Rhumba 1.2 Preamp; Coincident M300B Frankenstein mkII SET monoblocks

Omega Super Alnico HO Monitors (Cherry finish) / Martin Logan Depth i Subwoofer

Macbook Pro (mid-2012, 2.3GHz i7, 16Gb RAM, 512Gb SSD), HQPlayer, Tidal, Roon;

Cabling by Cerious Tech (Graphene SC, Blue PCs), Verastarr (IC and PC) and Teo Audio (GC IC)

 

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Thanks Barry.... good to know about the Tungsten Carbide and Chrome Steel. I will have to check Grainger or similar if they have them in 3/8", 7/16", or 1/2" diameters. Any other known sources?

 

As for the maple, it cost me $6, after shipping, for 12 balls of two sizes, so mehhhh, we'll see what happens!

 

Cheers,

Mark

 

Hi Mark,

 

At the time, I got them from smallparts.com, which I believe has since been absorbed into Amazon.

Grainger may be a good bet.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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That was "well under $50 per set."

I made enough for everything, including the speakers and subs. If I recall correctly, probably 12 sets.

 

Hi Barry,

 

Ok, so we're talking about less then $500 for a 'system set' (as opposed to a 'device' set of 3). Ten years ago. And access to custom machining services is variable. Unless some enterprising job shop got setup to make, a nice, simple design... (Alex, are you listening ?) :)

 

I spent about $200 on blocks, balls, and inner tube stuff. Some was experimental, and wasted. But I ended up with about the same quantity.

 

 

Iteration #1 uses a .96" diameter bowl that is a section of a 2" sphere. Bowl 1/8" deep at the center.

Balls are 1/2" chrome steel.

 

All right ! So you have 2.00" dia bowl, and a .500" ball. 4 to 1 curvature ratio.

 

My 'medium' size Ball Block has a 1.300" section of a sphere, and the ball is 3/8" - just enough for a nice low profile device.

 

So the DTA DIY do-hickey, is 1.30" to .375", for a 3.47 to 1 ratio.

 

That doesn't sound like a huge difference, to me :) And I'll bet that your upcoming 'Iteration 2' will have a larger sphere diameter bowl, right :)

 

Cheers,

Dave

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Hi Dave,

 

Hi Barry,

 

Ok, so we're talking about less then $500 for a 'system set' (as opposed to a 'device' set of 3). Ten years ago. And access to custom machining services is variable. Unless some enterprising job shop got setup to make, a nice, simple design... (Alex, are you listening ?) :)

 

I spent about $200 on blocks, balls, and inner tube stuff. Some was experimental, and wasted. But I ended up with about the same quantity.

 

There are still local machinists to be found. There are also on-line services some folks I know have used.

We spent different amounts but didn't you say you are using off-the-shelf acrylic "bowls"?

I think that might account for it as I brought a specification and drawings to a machinist and had them made per my design, out of the material I chose.

 

 

All right ! So you have 2.00" dia bowl, and a .500" ball. 4 to 1 curvature ratio.

 

My 'medium' size Ball Block has a 1.300" section of a sphere, and the ball is 3/8" - just enough for a nice low profile device.

 

So the DTA DIY do-hickey, is 1.30" to .375", for a 3.47 to 1 ratio.

 

That doesn't sound like a huge difference, to me :) And I'll bet that your upcoming 'Iteration 2' will have a larger sphere diameter bowl, right :)

 

Cheers,

Dave

 

Sorry if I wasn't clear but that is not correct. As I said, "Iteration #1 uses a .96" diameter bowl that is a section of a 2" sphere."

That's a .96" diameter bowl, not 2". Further, to look at the bowl diameter to ball diameter ratio without looking at the shape of the bowl is, in my opinion, to miss the mark entirely. As I said earlier, from my perspective, it is all in the bowl.

(Iteration #2 will have to remain close to the vest for now.)

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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didn't you say you are using off-the-shelf acrylic "bowls"?

 

Yes, a place called 'World Plastics of Michigan'. I was very happy to discover that they were located about 5 miles from my house, but turned out they only did large fabrication there, and the factory was in Arizona. And ordering was online only.

It was more like 'wait a month+ for my order to be made', then off-the-shelf :)

 

 

Sorry if I wasn't clear but that is not correct. As I said, "Iteration #1 uses a .96" diameter bowl that is a section of a 2" sphere."

That's a .96" diameter bowl, not 2". Further, to look at the bowl diameter to ball diameter ratio without looking at the shape of the bowl is, in my opinion, to miss the mark entirely. As I said earlier, from my perspective, it is all in the bowl.

 

I'm not sure we're in sync with our words here.

 

Imagine you have a big steel ball that fits perfectly into the bowl, touching on all sides and on the bottom of the bowl. The size of that 'ball' would be what I call the spherical diameter (or radii). and it would be larger then the circle made by the intersection of the bowls concavity and the top surface of whatever it is carved out of (the block). The diameter of that intersection circle and the depth of the bowl in the block form a chord, and can be used to calculate the spherical diameter, but I forget the formula :(.

 

It is not so easy to measure the bowls spherical diameter, since there is nothing there to lay a rule on ! My bowls diameter was larger then any of my radius gauges, so I went looking for thin disks (could be washers) till I found one that fit perfectly. It was 1.3" in diameter. One could draw, and cut out, paper circles to do the same thing. I don't think tight tolerances are necessary here :)

 

So where you are saying 'the shape of the bowl', I think I am saying 'the spherical diameter', and I believe both boil down to the curvature of the bowl, as expressed by a diameter or radius.

 

Does that work for you ?

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Hi Dave,

 

...I'm not sure we're in sync with our words here.

 

Imagine you have a big steel ball that fits perfectly into the bowl, touching on all sides and on the bottom of the bowl. The size of that 'ball' would be what I call the spherical diameter (or radii). and it would be larger then the circle made by the intersection of the bowls concavity and the top surface of whatever it is carved out of (the block). The diameter of that intersection circle and the depth of the bowl in the block form a chord, and can be used to calculate the spherical diameter, but I forget the formula :(.

 

It is not so easy to measure the bowls spherical diameter, since there is nothing there to lay a rule on ! My bowls diameter was larger then any of my radius gauges, so I went looking for thin disks (could be washers) till I found one that fit perfectly. It was 1.3" in diameter. One could draw, and cut out, paper circles to do the same thing. I don't think tight tolerances are necessary here :)

 

So where you are saying 'the shape of the bowl', I think I am saying 'the spherical diameter', and I believe both boil down to the curvature of the bowl, as expressed by a diameter or radius.

 

Does that work for you ?

 

I'm not sure either.

If you place a 2" diameter spherical ball into the bowl of one of my Hip Joint roller bearings, it would fit into the bowl touching it on all surfaces.

But I wasn't thinking of spherical diameter when I described the Hip Joints. Well, perhaps this is what came to your mind when I mentioned the shape of the bowl is a section of a 2" sphere. ? (I didn't have to measure this because the number came from my head during the design phase, as I made a drawing of what I wanted.

 

When I refer to the diameter of the bowl, I'm talking only about the top edge of the bowl. The whole Hip Joint is a 2" circle, 1/2" thick.

Hip Joints.jpg

 

Not sure if I'm any more clear than before. I hope so. ;-}

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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If you place a 2" diameter spherical ball into the bowl of one of my Hip Joint roller bearings, it would fit into the bowl touching it on all surfaces.

But I wasn't thinking of spherical diameter when I described the Hip Joints. Well, perhaps this is what came to your mind when I mentioned the shape of the bowl is a section of a 2" sphere. .

 

Barry,

 

How about we call the bowls spherical diameter (size of the imaginary ball that fits into the bowl), the 'bowl curvature diameter', or just 'bowl curvature' ?

 

 

When I refer to the diameter of the bowl, I'm talking only about the top edge of the bowl. The whole Hip Joint is a 2" circle, 1/2" thick.

 

OK, so we refer to the opening of the bowl as "bowl diameter"

 

I'll only use those terms so we should be in sync :) Bowl curvature is the measurement I'm interested in here, to compare with the ball diameter, as I did eariler:

 

Barry's Hip-Joints = 4.0 to 1 curvature/ball ratio.

DTA DIY Ball Block = 3.5 to 1 curvature/ball ratio.

 

Do you think that 12% difference might have have a significant effect on my devices's resonance or rolloff ?

 

I wish I had a better idea of which characteristics are more important for the bowls and balls: hardness, smoothness, curvature, concentricity, or ? ??

 

 

 

(good night)

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Barry,

 

How about we call the bowls spherical diameter (size of the imaginary ball that fits into the bowl), the 'bowl curvature diameter', or just 'bowl curvature' ?

 

We can if you like. I prefer to describe the curvature I used as "a section of a 2 inch sphere" since that is the geometric term I've always heard.

 

 

OK, so we refer to the opening of the bowl as "bowl diameter"

 

I'll only use those terms so we should be in sync :) Bowl curvature is the measurement I'm interested in here, to compare with the ball diameter, as I did eariler:

 

Barry's Hip-Joints = 4.0 to 1 curvature/ball ratio.

DTA DIY Ball Block = 3.5 to 1 curvature/ball ratio.

 

Do you think that 12% difference might have have a significant effect on my devices's resonance or rolloff ?

 

I wish I had a better idea of which characteristics are more important for the bowls and balls: hardness, smoothness, curvature, concentricity, or ? ??

 

(good night)

 

Again, I do not think the ratio of bowl to ball diameter is an adequate criterion for comparison.

To answer your question, in my opinion, the difference is significant.

 

In my experience, hardness and smoothness are key for both the bowl and the ball. Add shape (or curvature) and size for the bowl, which I consider #1.

Concentricity in the ball is icing on the cake. But I'd trade some perfection there before I traded bowl geometry, smoothness, and hardness.

 

As always, my best suggestion is to try out different geometries and materials. There's nothing like direct experience to find out how *you* would rate the importance of each of these.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Just want to add some facts from my own experience. I use privately machined bowls, measures are close to those from Barry. Initially I used first steel balls that I found in a store, slightly smaller than Barry suggest. After couple of months I bought on ebay chrome steel 1/2" balls (posted from US to Ukraine). Even though they are slightly bigger, and slightly better in quality, the change in sound was immediate. Enclosed is a picture with ball 1 (left) and ball 2 (right)

 

ball1-2.jpg

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I would like to give some (hopefully) insight into what these roller devices are doing which might help in understanding where various compromises are.

 

First off what I am describing is an isolator designed to prevent low frequency seismic noise from getting into your audio equipment. My experience matches Barry's, blocking this low frequency noise is the most important aspect of vibration control. There are others, and they need different approaches, but blocking the low frequency noise seems to be by far the biggest improvement.

 

First a thought experiment. First take a large flat board that is infinitely rigid and has a top surface that is completely frictionless, then place your audio component on top, for now no wires connected to it. Then start moving the board side to side, to a frow etc. (NOT up and down). What happens to your gear? Absolutely nothing, it just sits there. The board can move around as much as it wants at whatever frequency it wants and the gear just sits there completely ignoring what is happening to the board.

 

Why? because the surface is frictionless, there is no "resistance" between the surfaces. There is no way for any energy in the board to couple to the device. This is what we want, complete isolation of the gear from movement underneath it.

 

There are some problems with this isolator, if the board is not completely perpendicular to the local gravitational field, the gear just slides right off. Not very useful. THAT is why a shallow bowl is used in the devices mentioned, it provides a DC restoring force to prevent the gear from just sliding right off. But this is now providing some coupling between the board and the device, so it is not a prefect isolator any more. This is a tradeoff that is made to alleviate the effect of two parallel surfaces, the gear just slides off.

 

Note that the bowl shape is not part of the function of the isolation, it actually hinders the isolation somewhat but is a necessary evil for a practical implementation. So for the best isolation you want the shallowest "bowl" you can get away with that still provides enough restoring force to keep your gear from sliding off. This is also important for cables, the stiffer your cables are they steeper your bowl will have to be so the cables don't fling the gear off the shelf. This may be a good incentive to go with very flexible cables, so you can go with shallow bowls, which work better.

 

The other aspect of the bowl is that it adds a resonance, in order for the isolator to be effective that resonance has to be significantly lower than the frequencies you are trying to isolate. The seismic noise in question seems to have most of its power in the single digit Hz range, so a resonant frequency below 1Hz will usually be quite effective. The "steepness" of the bowl also affects the resonance frequency, so again a shallow bowl is a good thing.

 

As has been noted it can take a long time for this resonance to damp out. This is a GOOD thing, it means there is low resistance to the motion. Refer back to the original thought experiment, it is the lack of resistance that makes the isolation work, so anything you do to damp this very low frequency resonance defeats the whole purpose of the system. The resonance is so low in frequency it will never be excited by any normal music activities, the only way to normally excite it is to push the gear, thus applying a VERY low frequency very high amplitude stimulus to the system. It is not an issue for normal playing music, which has much higher frequencies than the resonance of the isolator.

 

This CAN be a problem for devices you need to push buttons on, this can cause the gear to move a lot if you use a shallow bowl. Think carefully about using remote control for these functions, or using a rotary control rather than push buttons.

 

As has been mentioned the lowest resistance is the goal, this is achieved with hard round surfaces rolling on hard smooth surfaces, so things like chrome steel etc are pretty good choices. For my attempts I use machined stainless steel, highly polished, and flat polished stainless steel for the other side. I found camping shaving mirrors work great for this, they are polished stainless steel and inexpensive $5 at my local sporting goods store.

 

That is it for the horizontal plane, the next post will cover vertical isolation, which is much harder to achieve.

 

John S.

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If something is being drained, I expect there to be less of whatever was drained in the place from which it supposedly was drained.

 

The energy conducted into the stand is *converted* to heat. No energy is lost.

 

I wouldn't get too stuck on the term if I were you: there is a Law of Conservation of Energy, but there is also something called 'Heat Loss'. When someone says 'drain', they do mean the conversion into heat or some other form of energy, thus less energy at the point where it is 'drained' from or converted from.

 

Thus, the cabinet vibration is diminished or drained in sand motion and heat. Yes, it is conversion and overall conservation, but the energy which would otherwise have been used for vibrating the cabinet only is now partially going elsewhere, so both are correct. It is a fact of Physics.

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I wouldn't get too stuck on the term if I were you: there is a Law of Conservation of Energy, but there is also something called 'Heat Loss'. When someone says 'drain', they do mean the conversion into heat or some other form of energy, thus less energy at the point where it is 'drained' from or converted from.

 

Thus, the cabinet vibration is diminished or drained in sand motion and heat. Yes, it is conversion and overall conservation, but the energy which would otherwise have been used for vibrating the cabinet only is now partially going elsewhere, so both are correct. It is a fact of Physics.

 

Hi YashN,

 

I hope we can agree to disagree.

Again, to my mind, nothing at all is being drained unless one can demonstrate there is less of it in the place from which it has supposedly been drained. This is by definition of the term.

 

Converting energy is not draining anything. It is converting it. By the way, in your example, it is the sand that is heating up, but the cabinet is still vibrating.

 

Anyway, as I said, rather than go round and round, let us agree to disagree on this.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Hi John,

 

Great post!

 

I'd differ on two things though:

 

...Note that the bowl shape is not part of the function of the isolation, it actually hinders the isolation somewhat but is a necessary evil for a practical implementation...

 

The other aspect of the bowl is that it adds a resonance...

 

To my mind, these two statements are at odds. I understand that if we had a frictionless flat surface, we wouldn't need the bowl, but in practical terms, the bowl--more specifically the rolloff ensuing from the resonance created by motion of the ball in the bowl--is exactly what provides the isolation.

 

...The "steepness" of the bowl also affects the resonance frequency, so again a shallow bowl is a good thing...

 

In my experience, the steepness of the bowl primarily affects damping on ball motion. I see the diameter of the bowl as affecting the resonance frequency. Hence a wide, shallow bowl is the idea.

 

Or perhaps I'm misunderstanding and we're saying the same thing with regard to both of these.

 

By the way, with regard to front panel buttons of devices on rollers, I've often said one must develop a gentle touch. A few fingers on top of the device while pressing buttons with the thumb -- or one hand to steady the device and the other to push the button, will work when one is at the equipment rack. Of course, the remote works just fine too.

 

I've also mentioned folks should be wary of pets and people near the gear, especially loudspeakers "afloat" on roller bearings. (Though for some reason my dog, who loves to join me in the studio/listening room, has not presented any issues at all.)

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Yes, exactly: the freer the motion, the longer the item oscillates. Less damping, manifesting visually as longer oscillations, equals a steeper rolloff above resonance, manifesting as a greater degree of isolation.

 

I gather by this we are OK with oscillations that are sub-10 Hz or so, assuming these are not modulating the audible spectrum? If we are looking to maximise the oscillations for longer, then why aren't we using very large and very shallow cups?

 

The key is: At what frequency will the blocking begin? To be effective, this has to be as low as possible.

 

I've seen some commercial products managing just that for Lab equipment. Concerning our DIY arrangement, do you find that the amplitudes we are isolating for are rather small? That is, in normal use (without touching or pushing the component), do you find them oscillate visually at all?

 

I can see the upper platform move around at low frequency when testing manually (providing a large impulse by hand), so in that case, the platform moves, our component is moving as well as around, say 10Hz for several seconds. Can we live with that?

 

Taken to its logical extreme, it you damp the motion completely, there is no oscillation at all. And no isolation. Again, it is precisely those oscillations that provide the isolation. The goal is more of them, not less.

 

Depends on the nature of the damping (c.f. the Wikipedia extract above). I have seen a couple of contradictory messages about isolation/damping around the web. Perhaps someone whose Physics is less rusty than mine can chime in.

 

All I can tell you is what *I* mean by "isolation" and that is that ground borne vibrations do not impede the performance of the gear because they are effectively blocked from entering the gear. The only point of the ball motion is to impart that motion to the component being supported.

Put another way (and this is something only you can determine whether or not you want), isolation = oscillating gear. More isolation = more oscillations.

Fewer oscillations = less isolation. The relationship between the two is direct and will not change.

 

OK, that answers my questions above. So here again, assuming we have a ground wave of 10Hz which is making our speaker oscillate front and back through the cup and ball. Doesn't this modulate the drivers' sound? Can we live with that?

 

Complete different things. A cartridge/tonearm resonance needs to be ~10 Hz so that it is above the frequency of typical record warps, yet below the audible range. We're not trying to block anything there. The cartridge/tonearm (or more specifically, the cantilever/tonearm), being a compliant structure is going to have a resonance. Isolation, while also involving resonance (of the isolator, if we're using a mechanical low-pass filter like a roller bearing or an air bearing) is something else.

 

Both these cases have resonance and frequencies that we want to have at less than audible. We are indeed trying to block something in the turntable example: we do not want the tonearm/cartridge assembly's resonance to impact what we hear. So these two cases are similar, not different.

 

A good isolator will have a resonance in the low single digits. Something like 2 Hz or 3 Hz would be great. (That's why that roller ball needs to oscillate *slowly*.)

 

If this is the case, that's not what we're doing here: the cup's curvature is too steep and the cup is too small. You'd need a much shallower and larger cup and allow the ball to move as far as possible before returning.

Dedicated Line DSD/DXD | Audirvana+ | iFi iDSD Nano | SET Tube Amp | Totem Mites

Surround: VLC | M-Audio FastTrack Pro | Mac Opt | Panasonic SA-HE100 | Logitech Z623

DIY: SET Tube Amp | Low-Noise Linear Regulated Power Supply | USB, Power, Speaker Cables | Speaker Stands | Acoustic Panels

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But there is not a static quantity. It is constantly being replaced.

 

Nobody said it was static. Doesn't matter in the least: it is continuously being converted or 'drained' away.

 

My speakers (Magnepans) are boxless. They still benefit a great deal from blocking vibrations from entering the speaker (and crossover).

 

I think we are mostly crazy to allow our manufacturers to put the crossover circuits inside speakers :P Additionally, we use the crossovers after the amps (crazy as well :P )

 

I make no attempt to drain anything; only to block seismic vibrations from entering the gear.

 

Yes, you are draining or converting the ground energy at the interface before it reaches the component.

 

So what I hear happening with speakers that *can* oscillate due to being isolated on roller bearings, is the speaker now sounds like it has been unbound and ungagged. Performance in every area of sound I know how to describe is improved: extension (at both ends), dynamics (at both ends), low level detail, bass pitch definition, soundstaging expands (in all three dimensions, provided the recording contains the information), images are more "solid", and overall "focus" improves appreciably.

 

Thanks for that. Knowing what to listen for can help greatly when tweaking.

 

Townshends Seismic Speaker Stands accomplish the same thing. I've heard different speakers demoed on the stands vs. off the stands and found the improvements on the stands were not subtle.

 

Haven't been able to find more info yet, but I sure do know my meagre DIY stands had improvements which are not subtle at all! My first large woodworking project - I learned along the way. Never built one before. Time-consuming, but fun, and very, very worthwhile: tamed the wood-floor vibrations, and totally re-defined the attack transients and soundstage.

Dedicated Line DSD/DXD | Audirvana+ | iFi iDSD Nano | SET Tube Amp | Totem Mites

Surround: VLC | M-Audio FastTrack Pro | Mac Opt | Panasonic SA-HE100 | Logitech Z623

DIY: SET Tube Amp | Low-Noise Linear Regulated Power Supply | USB, Power, Speaker Cables | Speaker Stands | Acoustic Panels

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Hi YashN,

 

I gather by this we are OK with oscillations that are sub-10 Hz or so, assuming these are not modulating the audible spectrum? If we are looking to maximise the oscillations for longer, then why aren't we using very large and very shallow cups?

 

Sub-10 Hz is not good enough. The resonance needs to be in the low single digits.

Wide, shallow bowls are what I recommend.

 

 

I've seen some commercial products managing just that for Lab equipment. Concerning our DIY arrangement, do you find that the amplitudes we are isolating for are rather small? That is, in normal use (without touching or pushing the component), do you find them oscillate visually at all?

 

I can see the upper platform move around at low frequency when testing manually (providing a large impulse by hand), so in that case, the platform moves, our component is moving as well as around, say 10Hz for several seconds. Can we live with that?

 

The only time I see motion is when I physically push a component atop a set of rollers.

In normal use, the amplitudes and frequencies are so small, I have not seen anything. Again, in my opinion, 10 Hz is way too high for the purpose of an isolator.

 

 

Depends on the nature of the damping (c.f. the Wikipedia extract above). I have seen a couple of contradictory messages about isolation/damping around the web. Perhaps someone whose Physics is less rusty than mine can chime in.

 

I don't know about Wikipedia. There is no dependence. Degree of damping is inversely proportional to the steepness of rolloff above resonance. More damping = less steep rolloff. Less damping = steeper rolloff. This does not change.

 

 

OK, that answers my questions above. So here again, assuming we have a ground wave of 10Hz which is making our speaker oscillate front and back through the cup and ball. Doesn't this modulate the drivers' sound? Can we live with that?

 

In my opinion, no. In order for the isolator to be effective, it has to have a resonance in the low single digits. I'm talking more than two *octaves* below 10 Hz. Lower is better.

With a proper resonance, there will be no impact on the drivers, which even with a subwoofer, are well above what the isolator will "see".

 

 

Both these cases have resonance and frequencies that we want to have at less than audible. We are indeed trying to block something in the turntable example: we do not want the tonearm/cartridge assembly's resonance to impact what we hear. So these two cases are similar, not different.

 

Here again, I hope we can agree to disagree. We're not trying to block anything with a phono cartridge. We want it to be immune to record warps. This is not the same as blocking the warps because we're setting up a resonance that will not "see" the warps but will still be low enough to get out of the way of the audible frequencies.

 

 

If this is the case, that's not what we're doing here: the cup's curvature is too steep and the cup is too small. You'd need a much shallower and larger cup and allow the ball to move as far as possible before returning.

 

Perhaps this is true of whatever you've tried so far. It would seem so if you see oscillations on the order of 10 Hz.

It's what *I'm* doing with my Hip Joints design though. Some of the commercial rollers are doing this too.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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