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Equipment isolation and vibration damping.


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I am in the process of building my isolation platform and devices. I am rather sure the results will be in the same vein as room diagnosis and physical acoustic room treatment, i.e. fundamental and quite a large effect, and necessary in order to properly even start to hear your gear.

 

Considering the air cushion and the cup and ball arrangements, the effects are the following:

 

1. Air cushion: predominantly deals with vibrations and isolation along the vertical axis.

 

2. Cup and Ball: only deals with vibrations and rotations in the horizontal plane. Does nothing for the vertical plane.

 

Hence, you can see people combining these to great effect. Some use Springs to reach the same total effect. The balls move in the cup surface and then, have to oscillate back to equilibrium. Thus, the vibrational energy which would otherwise affect the components or radiate outwards affecting other components and sound, is instead spent as kinetic energy and heat through friction mostly and a little through air conduction/convection.

 

The air cushion is usually done either with tire tubes or similar air-filled bags or else squash balls, raquetballs or tennis balls. These support a first platform on which the cup and ball arrangement rests, and then either the component bottom rests directly on the balls if it is smooth enough, or else another platform is used.

 

Going from the principles of both vertical and horizontal isolation, I am thinking of mounting each cup and ball arrangement on its own rubber feet. The rubber feet will then do the vertical axis damping.

 

Another thing I thought about after doing a simple fluid damping for the tonearm of my turntable is to add some oil in the cup and ball arrangement. Perhaps having a fluid filled cushion would be beneficial too.

 

Good ideas?

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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.

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I am in the process of building my isolation platform and devices. I am rather sure the results will be in the same vein as room diagnosis and physical acoustic room treatment, i.e. fundamental and quite a large effect, and necessary in order to properly even start to hear your gear.

 

Considering the air cushion and the cup and ball arrangements, the effects are the following:

 

1. Air cushion: predominantly deals with vibrations and isolation along the vertical axis.

 

2. Cup and Ball: only deals with vibrations and rotations in the horizontal plane. Does nothing for the vertical plane.

 

Hence, you can see people combining these to great effect. Some use Springs to reach the same total effect. The balls move in the cup surface and then, have to oscillate back to equilibrium. Thus, the vibrational energy which would otherwise affect the components or radiate outwards affecting other components and sound, is instead spent as kinetic energy and heat through friction mostly and a little through air conduction/convection.

 

The air cushion is usually done either with tire tubes or similar air-filled bags or else squash balls, raquetballs or tennis balls. These support a first platform on which the cup and ball arrangement rests, and then either the component bottom rests directly on the balls if it is smooth enough, or else another platform is used.

 

Going from the principles of both vertical and horizontal isolation, I am thinking of mounting each cup and ball arrangement on its own rubber feet. The rubber feet will then do the vertical axis damping.

 

Another thing I thought about after doing a simple fluid damping for the tonearm of my turntable is to add some oil in the cup and ball arrangement. Perhaps having a fluid filled cushion would be beneficial too.

 

Good ideas?

 

Hi YashN,

 

In my experience, proper isolation provides benefits in every area of sound I know how to describe. Well, it doesn't really add anything; what it does it prevent degradation. Having heard what it does, I'd never go back. Everything in my studio/listening room is isolated, including the speakers and subs. I use isolation for the gear during remote recording sessions too.

 

As with anything else in audio, there is a wide range of opinions on exactly what types of vibrations are of concern and just where they originate. Some folks are concerned with vibrations from the speakers reaching the rest of the gear. Some are concerned with "draining" vibrations out of individual components. My experience has been the it is the low frequencies *entering* the gear that are the ones to be concerned with... simply because blocking these is what showed me the benefits that made me isolate everything.

 

As to "draining" my take is that if something is being drained, there should be less of it in the place from which it is allegedly being drained. Personally, I have not heard any audible evidence to support the idea that anything is being drained or diminished. On top of this, any path out is also a way in. The ad copy speaks of "mechanical diodes" but this is pretty easily dismissed by moving the shelf on which a component on such devices sits. There is no delay in motion and in fact, the component responds directly and instantly to the motion. So such devices are acting as couplers -- the diametric opposite of isolators.

 

Now, what I've learned in my own experiments is that just about anything you put under (or atop) a component will change its sound. The operative word is "change" which should not be confused with "improve." Couplers like spikes and cones *will* change the sound but what I've found is the change is somewhat random and inconsistent from component to component. These are ideal for folks who want to play with the "color" of their components. But they aren't the same as isolating a component and freeing it to do what(ever) it can do. (By the way, in my view, the idea of an "isolation cone" is an oxymoron, like "jumbo shrimp" or "civil war.")

 

To your question, I would advise against a rubber base for the roller bearings. An isolator needs to have a resonance in the low single digits because it doesn't begin to become effective until about 1.4x its resonance frequency. In order to block low frequencies, it needs to take effect at as low a frequency as possible. Rubber, sorbothane, squash balls and similar materials have resonances that are way too high. They will allow low bass to pass as if they weren't there and they will not become effective until the mid-bass. This means the response will have a peak in the mid-bass, adding "bloat" to the sound and a loss of definition in the bass. (Some may like this sound but a proper isolator will not alter tonality, it will free it.)

 

For more info see Vibration control for better performance, which I hope will be of interest.

 

By the way, after isolating the CD player and other electronic components, I experimented with isolating the speakers (just on rollers as I don't want to risk a tilt and fall on an air bearing, which is much easier to control with a regular component). Once I hear the changes, I described the non-isolated speakers as "bound and gagged" by comparison. Max Townshend has spoken about this stuff for years and years. Clark Johnsen too. I didn't start experimenting until about 2002. It has all been "afloat" on isolators ever since.

 

Have fun!

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Isolation alone does nothing to deal with airborne vibration or vibration generated inside a component.

 

I think isolation works to some extent with airborne vibration. Some inherent vibrations inside a component (like crystals and capacitors) need something a little different. Some people use blu-tak or sand-bags or some other means of internal shielding or damping.

 

On the other hand, the vibrations generated internally (component A) and which could affect other components (component B), like when A is a CD or DVD reader or an HDD, are taken care of at the physical interfaces by the isolation in this thread.

 

This is not to say we couldn't investigate some additional means of internally damping too.

 

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.

 

Yes, ultimately I think this is the way to go. For the isolation in this thread we are not dealing with the inherent internal vibrations directly and this should probably be do

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In my experience, proper isolation provides benefits in every area of sound I know how to describe.

 

No doubt about it, I have read attentively some of your previous posts on the SH forum. I have also read Thorsten Loesch (of AMR/iFi) describing similar air cushions and others saying good things about the cup and bearing arrangements as well.

 

Some folks are concerned with vibrations from the speakers reaching the rest of the gear. Some are concerned with "draining" vibrations out of individual components.

 

Certainly. I think if we tame vibrations in all directions, then the gear can do what it is supposed to be doing to the best of its ability. If it's a CD player, then it's doing A/D internally and providing that digital stream. For the speakers, taming the vibrations out of the cabinet allow the drivers to provide the fullest sound, etc...

 

My experience has been the it is the low frequencies *entering* the gear that are the ones to be concerned with... simply because blocking these is what showed me the benefits that made me isolate everything.

 

Makes sense if you think that the lower frequencies have a tendency to travel and make standing waves. Typically, there is a lot of energy around the lower frequencies.

 

As to "draining" my take is that if something is being drained, there should be less of it in the place from which it is allegedly being drained. Personally, I have not heard any audible evidence to support the idea that anything is being drained or diminished.

 

For me, the analogy and term is correct. Take the example of a bookshelf speaker cabinet resonance. The issue is that all cabinets vibrate to some extent. When the cabinet vibrates, the sound waves will interact with those of the driver thus colouring the sound. In this case, what we need to do is dampen the cabinet vibration. So, by making a stand for the bookshelf speaker we plan to make the (speaker + stand) arrangement sound better. For this, we need coupling between the cabinet surface and the stand. Additionally, we also need the stand itself to lower the vibrations. This can be achieved by using a more massive/rigid/inert structure for the stand. A way to 'drain' here would be to use sand within the stand columns: the cabinet wants to vibrate, but as it's coupled to the stand below, the vibrations transmit to the stand. In turn, this displaces the sand particles against each other, and the vibrational energy is then spent in work done to move the sand particles and as heat, i.e. kinetic energy and friction + some conduction/convection around.

 

In other words, we converted that detrimental sound from the cabinet into heat. Essentially, we drained the cabinet's energy down to the stand and sand where the loss as heat makes it sonically harmless.

 

I have had very good results making my stands for my Fostex Studio monitors initally that I re-used for my current Totem Mites. The center pole isn't within sand yet: I would need quite a thick tube to be able to do that, so this is on the roadmap and should enhance the sound even further. So currently, in my arrangement, the stand and speaker is what vibrates, and since it is more massive than just the speaker, the resonance is lowered.

 

So, it could also be a very good thing to consider that 'draining' aspect in the isolation goal of this thread. Draining is also what's happening with the cup and ball arrangement (draining vibration into other motion and heat loss).

 

On top of this, any path out is also a way in. [snip] this is pretty easily dismissed by moving the shelf on which a component on such devices sits. There is no delay in motion and in fact, the component responds directly and instantly to the motion.

 

The immediacy of response is a good thing. I am a bit more concerned about the oscillation of the arrangement at low frequencies. I have manually and visually tested the air cushion and cup+ball this morning. I am wondering whether it would be better to dampen the ball motion further. Adding oil or some similar, perhaps more viscous material like silicone could help here.

 

When there is vertical motion, the air cushion dampens it to some degree. If there's simultaneous motion of the balls, there already is some vertical component of force in the cup+ball and this then can get exacerbated by the lower platform's vertical component.

 

So, ideally, what I would like here, is that the kinetic energy in both the lower platform (air-cushion) and the upper one (cup+ball) be killed as fast as possible, i.e. I'd prefer 3 oscillations until rest rather than a 12-oscillation motion until rest of the balls in the cups.

 

Maybe a steeper curvature of the cup can help here or adding the oil or silicone.

 

As for the air-cushion, I would take the enclosure, ensure it is hermetic and try to fill it with fluid as well (perhaps just oil).

 

 

Taking the example of sand above, where ultimately, energy is dispersed at heat, this morning, I was also wondering whether I could substitute either or both of our platforms with sand or bags or sand.

 

I've seen people mention a bed of sand as support, so this is of the realm of already tested and proven tweaks.

 

For the upper platform, supposing you keep the air-cushion, 3 little bags of sand in place of the cups+balls perhaps?

 

Now, what I've learned in my own experiments is that just about anything you put under (or atop) a component will change its sound. The operative word is "change" which should not be confused with "improve." Couplers like spikes and cones *will* change the sound but what I've found is the change is somewhat random and inconsistent from component to component.

 

Quite right, and I am trying to avoid running into this rabbit hole, and that's why I am thinking through what we are trying to achieve based on the Physics principles. That can be a time-saving strategy.

 

To your question, I would advise against a rubber base for the roller bearings. An isolator needs to have a resonance in the low single digits because it doesn't begin to become effective until about 1.4x its resonance frequency. In order to block low frequencies, it needs to take effect at as low a frequency as possible. Rubber, sorbothane, squash balls and similar materials have resonances that are way too high.

 

OK, we'll avoid rubber feet because their effectiveness at damping lower frequencies isn't up to par. I can live with that and the explanation.

 

For more info see Vibration control for better performance, which I hope will be of interest.

 

Yep, already read that before starting the thread, including some long threads at the SH forums. Thanks for sharing.

 

By the way, after isolating the CD player and other electronic components, I experimented with isolating the speakers (just on rollers as I don't want to risk a tilt and fall on an air bearing, which is much easier to control with a regular component). Once I hear the changes, I described the non-isolated speakers as "bound and gagged" by comparison. Max Townshend has spoken about this stuff for years and years. Clark Johnsen too. I didn't start experimenting until about 2002. It has all been "afloat" on isolators ever since.

 

Yes, the thought of my speakers falling is scary! Maybe replacing the air cushion with an enclosure where sand can be used is better.

 

Currently, my source is mostly digital: we have as source components the external HDDs, the Computer, the DAC.

 

I think I would need a platform to isolate all these components, although I initially thought of doing the isolation for the amplifier first and then the speakers.

 

Which do you think I should start with?

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Don't forget: A good roller bearing will also work in the rotational plane, not merely the horizontal.

 

I've seen you mention this a few times, but I cannot visualise it or translate it into normal mathematical/physical terms.

 

Let's take the horizontal plane of the upper platform, i.e. the one above the balls, and let's look at it from above. This constitutes a horizontal plane.

 

This horizontal plane can have a few types of motion which we want to dampen:

 

1. The horizontal plane can suffer translations along that plane, i.e. horizontal displacements, i.e. North-Sound, East-West, any direction and its opposite, really or outward-inward if you prefer.

 

2. The horizontal plane can suffer motion by rotating around a vertical axis, i.e. clockwise-anti-clockwise rotation. Even when rotated, it is still a horizontal plane.

 

 

Is 2. what you meant by 'rotational plane'?

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...Makes sense if you think that the lower frequencies have a tendency to travel and make standing waves. Typically, there is a lot of energy around the lower frequencies...

 

Hi YashN,

 

The second sentence says it: there is more energy in the lows... enough to disturb gear. (Standing waves can occur at any frequency and are, in my estimation, not part of what is of concern with isolation.)

 

 

 

...For me, the analogy and term is correct. Take the example of a bookshelf speaker cabinet resonance...

 

In other words, we converted that detrimental sound from the cabinet into heat. Essentially, we drained the cabinet's energy down to the stand and sand where the loss as heat makes it sonically harmless...

 

While you may like the results of doing this, in my view, nothing was drained. What occurred by coupling the cabinet to the stand is an alteration in the resonant characteristics of the cabinet. (The cabinet is still resonating, albeit with slight changes in the frequencies because it is not part of a larger assembly.)

 

 

...Draining is also what's happening with the cup and ball arrangement (draining vibration into other motion and heat loss)...

 

Actually, what is occurring is what I described with the speaker and stand: the roller bearing acts as a coupler in the vertical plane. The motion of the ball is due to horiztonal (or rotational) excitement and what it is doing is *converting* the motion to heat. Again, in my view, nothing at all is being drained.

 

 

...I am a bit more concerned about the oscillation of the arrangement at low frequencies. I have manually and visually tested the air cushion and cup+ball this morning. I am wondering whether it would be better to dampen the ball motion further. Adding oil or some similar, perhaps more viscous material like silicone could help here...

 

It is precisely the oscillation that is creating the isolation. Adding damping will work against this as it will diminish the steepness of the rolloff above resonance (that last *is* the isolation). In other words the *less* the damping on ball motion, the steeper the roll-off, i.e., the greater the degree of isolation. This is one reason why I do not recommend using a "bowl" on the top and the bottom of the ball--it adds damping, thus diminishing isolation.

 

 

...When there is vertical motion, the air cushion dampens it to some degree...

 

The purpose of the air bearing, as I see it, is to prevent such motion from being transferred. It should *block* it, not merely dampen it.

 

 

...So, ideally, what I would like here, is that the kinetic energy in both the lower platform (air-cushion) and the upper one (cup+ball) be killed as fast as possible, i.e. I'd prefer 3 oscillations until rest rather than a 12-oscillation motion until rest of the balls in the cups.

 

Maybe a steeper curvature of the cup can help here or adding the oil or silicone.

 

As for the air-cushion, I would take the enclosure, ensure it is hermetic and try to fill it with fluid as well (perhaps just oil)....

 

Why 3 oscillations? I would suggest creating different designs and comparing them yourself. What I found when I did this is that the greater the number of oscillations (i.e., the less the damping) the greater the isolation. I would not want to deliberately add damping and thus waste the effort spent trying to isolate by effectively minimizing the isolation.

 

A steeper curve on the "bowl" will add damping to ball motion. I recommend a shallow curve. I want the ball to move as slowly as possible (lowest resonance frequency) and for as long as possible (least damping on ball motion). In this way, isolation takes effect at the lowest possible frequency and the rolloff above resonance is as steep as possible (i.e., maximum isolation).

 

 

...Taking the example of sand above, where ultimately, energy is dispersed at heat, this morning, I was also wondering whether I could substitute either or both of our platforms with sand or bags or sand.

 

I've seen people mention a bed of sand as support, so this is of the realm of already tested and proven tweaks.

 

For the upper platform, supposing you keep the air-cushion, 3 little bags of sand in place of the cups+balls perhaps?/

 

In my experience, sand will dampen energy but it will not provide effective isolation.

If you have the inclination, by all means, try all these things out. That will tell you much more than anything I could say.

 

 

...I think I would need a platform to isolate all these components, although I initially thought of doing the isolation for the amplifier first and then the speakers.

 

Which do you think I should start with?

 

I'd definitely use a separate platform for each component being isolated.

While I've heard benefits with everything I've isolated, I would say the greatest benefits have been with digital gear (CD players, transports, DACs, ADCs) and with loudspeakers. Speakers were a revelation because I'd always heard that speakers should be mounted rigidly. Now I would say the *drivers* have to be mounted rigidly to the baffle, but want my speakers "afloat."

 

So between amp and speakers, I'd try the latter. If they are stand-mounted cabinets, I'd first try isolation between the speaker and stand, rather than isolating the whole stand. The reason is that I've found the closer the isolation is to that which is being isolated, the more effective it is.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Hi YashN,

 

I've seen you mention this a few times, but I cannot visualise it or translate it into normal mathematical/physical terms.

 

Let's take the horizontal plane of the upper platform, i.e. the one above the balls, and let's look at it from above. This constitutes a horizontal plane.

 

This horizontal plane can have a few types of motion which we want to dampen:

 

1. The horizontal plane can suffer translations along that plane, i.e. horizontal displacements, i.e. North-Sound, East-West, any direction and its opposite, really or outward-inward if you prefer.

 

2. The horizontal plane can suffer motion by rotating around a vertical axis, i.e. clockwise-anti-clockwise rotation. Even when rotated, it is still a horizontal plane.

 

 

Is 2. what you meant by 'rotational plane'?

 

First, per my previous post, I don't want to dampen anything. I want completely free, undamped resonance in the isolator in order to achieve the steepest rolloff above resonance, i.e., the greatest degree of isolation.

 

Actually, there is a difference between horizontal energy (front-to-back and side-to-side) and rotational energy. You've described the difference in your post.

I suppose you could see them both as horizontal in some respects. I see them as different.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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While you may like the results of doing this, in my view, nothing was drained. What occurred by coupling the cabinet to the stand is an alteration in the resonant characteristics of the cabinet. (The cabinet is still resonating, albeit with slight changes in the frequencies because it is not part of a larger assembly.)

 

You may not like the term 'drain' as people commonly use it, but that's correct and it's exactly what is happening. The proper terms in physics are certainly lowering resonance when using a larger mass, but additionally, energy conversion and heat loss. The coupling of the cabinet and the stand does make the cabinet part of a larger assembly. The addition of sand in the column then finished the conversion from the vibration of the (cabinet + stand) into kinetic motion of the sand particles and heat loss.

 

Hence the detrimental energy at the cabinet is drained into heat, if you want a shortcut.

 

Actually, what is occurring is what I described with the speaker and stand: the roller bearing acts as a coupler in the vertical plane. The motion of the ball is due to horiztonal (or rotational) excitement and what it is doing is *converting* the motion to heat. Again, in my view, nothing at all is being drained.

 

The conversion to ball motion and heat is the draining. With the ball motion, since it has to rise along the curve of the cup, there is also a vertical component to the motion.

 

 

It is precisely the oscillation that is creating the isolation. Adding damping will work against this as it will diminish the steepness of the rolloff above resonance (that last *is* the isolation). In other words the *less* the damping on ball motion, the steeper the roll-off, i.e., the greater the degree of isolation. This is one reason why I do not recommend using a "bowl" on the top and the bottom of the ball--it adds damping, thus diminishing isolation.

 

Now this is interesting, because in my visual and manual tests today, the freer the motion, the longer my upper platform oscillates. Much like a pendulum in air vs a pendulum in water: the oscillations in air will last longer than in water. In water, the pendulum loses more energy working against water and hence the oscillations die down quicker. In other words, the freer the motion of the balls, the longer the platform and component are oscillating. Do we want our component to oscillate? Or do we want our component to oscillate the least?

 

The observation about roll-off is I believe important but are we here looking to :

(a) tame the low-frequency oscillations which are particularly detrimental at a specific resonant frequency?

(b) to isolate from vibrations effectively across a large bandwith of frequencies?

 

These two seem different to me.

 

To summarise: when the balls are rolling about and oscillating, the upper platform and hence the component is still oscillating too.

 

 

The purpose of the air bearing, as I see it, is to prevent such motion from being transferred. It should *block* it, not merely dampen it.

 

It won't prevent it, only diminish it as it is transferred with loss to the upper arrangement.

 

 

Why 3 oscillations?

 

The number is unimportant, it was only an example, together with 12, to show what I meant when I said I wanted less oscillations: if the ball + cup arrangement has to work against a viscous material there, then the kinetic motion is lost to move the material and as hear, the oscillations are damped and hence the upper platform and my component comes back to rest more rapidly instead of continuing to oscillate with the balls.

 

What I found when I did this is that the greater the number of oscillations (i.e., the less the damping) the greater the isolation.

 

By isolation here, do you mean as perceived sonically, or as vibrations as measured through equipment? (I am not going into the usual debate here at all and want to avoid it, it's just to see if I can save time building on your experience or if I must for instance just hook up a little iPhone + motion-detection app).

 

I would not want to deliberately add damping and thus waste the effort spent trying to isolate by effectively minimizing the isolation.

 

Yes, except, people mean different things when they say 'isolation'. Here, if my component is oscillating in sympathy with the balls and for too long, to me, it's not isolated. Ideally, I want the ball motion to occur but I don't want the upper platform and the component to do the same in sympathy. In the ideal case, I'd rather the energy loss occur at the ball and cup the in the smallest amount of time, so that the upper platform and component move the least.

 

A steeper curve on the "bowl" will add damping to ball motion. I recommend a shallow curve. I want the ball to move as slowly as possible (lowest resonance frequency) and for as long as possible (least damping on ball motion). In this way, isolation takes effect at the lowest possible frequency and the rolloff above resonance is as steep as possible (i.e., maximum isolation).

 

I suppoer in this viewpoint, we can consider a low frequency of oscillation below what's considered acceptable for turntable's tonearm + cartridge, e.g. something like a frequency of <10Hz to be acceptable oscillation?

 

In my experience, sand will dampen energy but it will not provide effective isolation.

 

It amounts to the same effect: I don't think we can have perfect isolation. Damping is the working principle behind normal, imperfect isolation.

 

I think I will try some arrangements if I can get my hand on some sand (doesn't seem to be easy here). If not, I may try with cat litter.

 

I'd definitely use a separate platform for each component being isolated.

While I've heard benefits with everything I've isolated, I would say the greatest benefits have been with digital gear (CD players, transports, DACs, ADCs) and with loudspeakers.

 

OK, thanks for your feedback. I think space restricts me anyway to different platforms for the sources: I have my Kurzweil K2500XS right in front of my iMac, so there's not much space on the table for a single platform to hold all three components. It's massive.

 

So between amp and speakers, I'd try the latter.

 

OK, that sounds good to me, I already have some bamboo platform for the speakers to avoid getting the cabinet in direct contact with the balls as I don't want to spoil the Totem Mites' cabinets. I just need a few more cups (coming soon).

 

If they are stand-mounted cabinets, I'd first try isolation between the speaker and stand

 

That's the plan. I won't change the isolation between the stand and the floorboard because it is working as planned: I wanted the speakers not to directly transmit vibrations to the floor (wood). That works, and also successfully prevents motion of the floor to affect the speakers.

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Actually, there is a difference between horizontal energy (front-to-back and side-to-side) and rotational energy. You've described the difference in your post.

I suppose you could see them both as horizontal in some respects. I see them as different.

 

The motions are different: the correct terms are translations and rotations. But the plane is already defined: it is the horizontal plane and it doesn't change since it is delimited and constrained by the 3 balls.

 

This doesn't mean the horizontal plane itself cannot rotate: indeed it can because the lower platform could make it so temporarily until the motion restores it to equilibrium.

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A cool relevant article on Wikipedia.

 

Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in biological systems.

 

 

The damping of a system can be described as being one of the following:

 

Overdamped

The system returns (exponentially decays) to equilibrium without oscillating.

 

Critically damped

The system returns to equilibrium as quickly as possible without oscillating.

 

Underdamped

The system oscillates (at reduced frequency compared to the undamped case) with the amplitude gradually decreasing to zero.

Undamped

The system oscillates at its natural resonant frequency (ωo).

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You may not like the term 'drain' as people commonly use it, but that's correct and it's exactly what is happening....

Hence the detrimental energy at the cabinet is drained into heat, if you want a shortcut....

 

Hi YashN,

 

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

If you check that speaker cabinet, you'll find it is still vibrating. This is a characteristic of the cabinet, i.e. the speaker design, and it won't go away simply because the cabinet has been coupled to a larger structure like a stand. The energy conducted into the stand is *converted* to heat. No energy is lost.

In contrast, when I drain my kitchen sink of water, it ends up with no more water in it. ;-}

 

 

 

The conversion to ball motion and heat is the draining. With the ball motion, since it has to rise along the curve of the cup, there is also a vertical component to the motion...

 

You can see it that way if you want to. I would not agree as I differentiate between conversion (where no energy is lost) and the concept of "draining" as it is applied in the marketing literature (where energy is supposedly being removed -- which by definition, is what draining is). To my knowledge, no one making such claims has yet demonstrated that there is less of what is supposedly being drained in the place from which this is said to occur (i.e., the component).

 

 

Now this is interesting, because in my visual and manual tests today, the freer the motion, the longer my upper platform oscillates. Much like a pendulum in air vs a pendulum in water: the oscillations in air will last longer than in water. In water, the pendulum loses more energy working against water and hence the oscillations die down quicker. In other words, the freer the motion of the balls, the longer the platform and component are oscillating. Do we want our component to oscillate? Or do we want our component to oscillate the least?

 

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.

 

 

The observation about roll-off is I believe important but are we here looking to :

(a) tame the low-frequency oscillations which are particularly detrimental at a specific resonant frequency?

(b) to isolate from vibrations effectively across a large bandwith of frequencies?

 

These two seem different to me....

 

We want to block performance-degrading vibrations from entering the gear. In my opinion, these tend to be primarily very low frequencies coming up from the ground. (The higher frequencies of vibrating air in the listening room have *much* less energy than the low frequencies I'm speaking of.)

In order to block those low frequencies from interfering, the isolation must begin to take effect at a lower frequency. (The isolation will be effective from ~1/4x the resonance of the isolator and increase in effectiveness with increasing frequency. Think of a low-frequency resonant peak with a roll-off at frequencies above the resonance.

So, we *are* blocking transmission of vibrations across a wide bandwidth. The key is: At what frequency will the blocking begin? To be effective, this has to be as low as possible.

 

 

It won't prevent it, only diminish it as it is transferred with loss to the upper arrangement...

Technically, yes. Unless we have a perfect isolator with an infinitely steep roll off. But *effectively*, with a properly designed and properly implemented isolator, we're preventing those frequencies from harming performance. At least that is how it sounds to me in comparison to no isolation.

 

 

 

 

The number is unimportant, it was only an example, together with 12, to show what I meant when I said I wanted less oscillations: if the ball + cup arrangement has to work against a viscous material there, then the kinetic motion is lost to move the material and as hear, the oscillations are damped and hence the upper platform and my component comes back to rest more rapidly instead of continuing to oscillate with the balls.

 

Yes. And there is little to no isolation. Try it and see/hear for yourself.

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.

 

 

By isolation here, do you mean as perceived sonically, or as vibrations as measured through equipment?

Both sonic and measurable visually. No need to lab gear. Try it different ways and compare for yourself.

 

 

Yes, except, people mean different things when they say 'isolation'. Here, if my component is oscillating in sympathy with the balls and for too long, to me, it's not isolated. Ideally, I want the ball motion to occur but I don't want the upper platform and the component to do the same in sympathy. In the ideal case, I'd rather the energy loss occur at the ball and cup the in the smallest amount of time, so that the upper platform and component move the least.

 

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.

 

 

I suppoer in this viewpoint, we can consider a low frequency of oscillation below what's considered acceptable for turntable's tonearm + cartridge, e.g. something like a frequency of <10Hz to be acceptable oscillation?

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.

 

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*.)

 

 

It amounts to the same effect: I don't think we can have perfect isolation. Damping is the working principle behind normal, imperfect isolation.

 

Rather than repeat myself, I will suggest you try experimenting with sand vs. well-designed and well-implemented mechanical low-pass filters (with different amounts of damping). Sand if not a very effective isolator. Again, high damping = slow rolloff = little if anything in the way of isolation.

 

 

I think I will try some arrangements if I can get my hand on some sand (doesn't seem to be easy here). If not, I may try with cat litter.

 

Have fun!

 

 

OK, thanks for your feedback....

 

I hope some of it proves useful to you.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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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.

If you check that speaker cabinet, you'll find it is still vibrating.

 

Yes, but less, which is the whole point, hence we are draining the cabinet of its harmful resonance (nobody said we were draining perfectly).

 

More responses at length during the week :)

 

Thanks for the cool exchange of perspectives.

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Yes, but less, which is the whole point, hence we are draining the cabinet of its harmful resonance (nobody said we were draining perfectly).

 

More responses at length during the week :)

 

Thanks for the cool exchange of perspectives.

 

Hi YashN,

 

My point is that there is no less. Different, yes. But not less. In fact, I say exactly as much.

I note that no one using the term "draining" for audio has yet released any measurements to support the claim that anything is being drained (other than the customer's wallet ;-}).

 

Thank you too for the dialogue!

I hope you find the same pleasures I've found in isolating gear.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Hi YashN,

 

My point is that there is no less. Different, yes. But not less. In fact, I say exactly as much.

 

It would be interesting to see why you think it is so.

 

Based on Physics principles, when you couple the speaker cabinet with additional mass, it is the whole arrangement which vibrates, with a lesser resonance. The energy that the cabinet itself used to vibrate previously is now dispersed among both the cabinet and the stand.

 

It follows that the cabinet has less energy in its vibration than before. Hence, it has less deleterious effect in combination with the driver's performance.

 

I don't think anyone achieves complete vibration-less cabinets, but what we can and know how to do is reduce the extent of the cabinet's vibration at resonance.

 

Another way of proceeding is to do without the cabinet altogether: open-baffle.

 

If it is not less by your viewpoint, then it should be completely vibration-less, and then by your own standard of measure in the previous post, one should show it by measurements.

 

Now, if your speakers oscillate back and forth, what is it that happens to the soundwaves the drivers are supposed to send to you?

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Hi YashN,

 

It would be interesting to see why you think it is so.

 

Based on Physics principles, when you couple the speaker cabinet with additional mass, it is the whole arrangement which vibrates, with a lesser resonance. The energy that the cabinet itself used to vibrate previously is now dispersed among both the cabinet and the stand.

 

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

 

It follows that the cabinet has less energy in its vibration than before. Hence, it has less deleterious effect in combination with the driver's performance....

 

I would say it follows that the resonant characteristics of the cabinet have changed but in now way is there less energy. It is not a cup with a static amount of water in it. It is a dynamic system, always in "motion".

 

 

Another way of proceeding is to do without the cabinet altogether: open-baffle...

 

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

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

 

 

Now, if your speakers oscillate back and forth, what is it that happens to the soundwaves the drivers are supposed to send to you?

 

I would guess the question (a quite reasonable one) comes from the assumption that the motion of the drivers will cause the balls in the roller bearings to roll--a Newtonian reaction to the action of the drivers. A properly designed roller bearing will have a resonance in the very low single digits, well below any frequency edited by any speaker (or subwoofer) I know of. In effect, the rollers to not "see" the speakers. The drivers in the speaker move against the relative stillness of the baffle on which they are mounted.

 

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.

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.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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I feel terrible about injecting this very simple question into a conversation in which I really have no business being involved in, but Barry, what have you found to be the optimal "cup" for your roller bearing method? I am using furniture cups now but they are almost infuriating to work with, in that they don't hold the bearing securely enough to be able to move equipment even a 1/4 inch without the bearing moving to an area where it is no longer supported properly. The pictures in your first post look like a metal receiver for the bearing, any insight on where to purchase something like that or was it custom made?

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I feel terrible about injecting this very simple question into a conversation in which I really have no business being involved in, but Barry, what have you found to be the optimal "cup" for your roller bearing method? I am using furniture cups now but they are almost infuriating to work with, in that they don't hold the bearing securely enough to be able to move equipment even a 1/4 inch without the bearing moving to an area where it is no longer supported properly. The pictures in your first post look like a metal receiver for the bearing, any insight on where to purchase something like that or was it custom made?

 

Hi Todd,

 

Don't feel bad -- I think your post is entirely apropos in this thread.

To answer your question, after my initial experiments with "econo" rollers (using marbles and Easter egg holders -- which very easily outperformed a set of $400 "racing cones" -- for a total cost of under $2) I tried a number of materials. When I came up with the design I wanted I drew up a spec and found a local machinist to make some prototypes for me. I had some made in 6061 aluminum and in 7075, ultimately deciding on the latter. Then I went back and had enough 7075 sets made to support all the gear in the system, including the speakers and subs.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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what have you found to be the optimal "cup" for your roller bearing method? I am using furniture cups now but they are almost infuriating to work with...

 

Going for 'optimal' whether with commercial products, or having your own cups custom machined is going to involve some serious money, especialy for enough devices to outfit an audiophiles complete system.

 

I have never quite understood how the rough wood cups and imprecise marbles are able to deliver any audible performance at all, but Barry says he has heard it...

 

I looked for a middle route and found one. All my cups are acrylic moldings made for retail display purposes. They are available in an array of sizes, shapes and colors. And they are inexpensive ! I can put together a set of 3 for $10 - $15.

 

I was already a big fan of acrylic for its workability and good looks. In the application to ball and cup vibration control devices, the material is not optimal, but I think it is a good compromise. While the surface of the cast acrylic is nowhere as hard as steel, or some AL alloys, it is very smooth, which I think contributes to the performance of the system (assuming the plastic is not overloaded by too much weight, and goes into deformation).

 

These retail 'dimple blocks' do not have as shallow a cup as would be preferred, but a smaller size of the SS 'ball' (while still usable) can optimize the relationships of the curves to make the best of the situation.

 

I have my entire system, electronics and speakers, outfitted with these DIY Acrylic/Stainless Steel devices, and I clearly heard veils lift when, first the digital stuff and amp, and then the speakers and subs, were floated. No going back :)

 

I don't know what degree of sonic difference there is between my plastic hybrid devices, and Barry's 'Hip-Joints, and the commercial products. I hope to learn that one day, but for now I feel have achieved almost a 'Regen' level SQ improvement, for less then even that small cost.

 

Color me pleased as punch !

 

 

(P.S. the inspiration for me to do this experimentation came directly from Barry's BLOG and forum postings. Thanks BD)

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Hi Daudio,

 

Going for 'optimal' whether with commercial products, or having your own cups custom machined is going to involve some serious money, especialy for enough devices to outfit an audiophiles complete system...

 

When I had mine made I spoke with several machine shops before finding the one I ended up using. Some gave me silly quotes like $150 per piece (!) and added a $75 "setup" charge. Preferring to *not* be "set up" ;-} I thanked them and went elsewhere. The machinist I chose made me sets of three at well under $50 per set. Of course, this was over a decade ago, so one seeking a shop today would have to consider the degree to which the dollar has been devalued in the intervening years.

 

 

I have never quite understood how the rough wood cups and imprecise marbles are able to deliver any audible performance at all, but Barry says he has heard it...

 

Indeed, it was the initial Easter egg holder and marbles prototypes that convinced me the idea of roller bearings is so good that even a trio of 29 cent holders from a "crafts" store, with an ordinary marble in each very handily outperformed a $400 set of "racing cones." The former provided consistent and repeatable isolation--albeit not from an optimal frequency, with less than optimal surfaces, and "bowls" of less than optimal shape--while the latter allowed somewhat random color changes.

 

 

These retail 'dimple blocks' do not have as shallow a cup as would be preferred, but a smaller size of the SS 'ball' (while still usable) can optimize the relationships of the curves to make the best of the situation...

 

While they will certainly work--as you already know, 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.

 

 

I have my entire system, electronics and speakers, outfitted with these DIY Acrylic/Stainless Steel devices, and I clearly heard veils lift when, first the digital stuff and amp, and then the speakers and subs, were floated. No going back :)...

 

Sounds like your experience has been very similar to my own. Definitely no going back.

 

 

(P.S. the inspiration for me to do this experimentation came directly from Barry's BLOG and forum postings. Thanks BD)

 

You are very welcome! I'm so glad the writings were of use. It really is an easy (and for do-it-yourselfer's an economical) way to significantly up a system's performance.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Roller bearing devices are not always a silver bullet. It can be device dependent. A friend of mine put his SACD player on some (don't recall the brand) and they sucked all the life out of the sound. Replacing them with brass cones revived 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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Roller bearing devices are not always a silver bullet. It can be device dependent. A friend of mine put his SACD player on some (don't recall the brand) and they sucked all the life out of the sound. Replacing them with brass cones revived it.

 

Hi Allan,

 

Actually, properly designed and implemented, I think they are a silver bullet and utterly indifferent to the device. In the case you mention, it might be the particular devices, it might be how they were placed, and/or it might be the bottom of the SACD player chassis. If the life was sucked out of the sound, I would say something was wrong but would not blame the idea of roller bearings.

 

I speak for myself of course but I've never heard a component that was not appreciably freed to better performance when used with a properly design and properly used set of rollers. Basically, they prevent vibrations from entering the component via its support. They should not alter tonality and certainly not remove life. Again, I say something in the design or the implementation was at fault in that case.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

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Actually, properly designed and implemented, I think they are a silver bullet and utterly indifferent to the device.

 

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. :)

"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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