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Hi,Has anyone tried the GR Research version of the Relaxa shelf that uses two pieces of lucite "magnetically resisting" each other?
http://www.gr-research.com/levitator.htm
It is cheaper, I was just curious....
Follow Ups:
Wouldn't magnets capable of holding 50 pounds have stray fields that play havoc with weaker signals like interconnects or dac's?
http://www-hfml.sci.kun.nl/Mlimages/sumo.gif
Interesting concept for certain. Nice looks. Yeah, sure. But I'm trying to figure out how your supposed to level the suspended shelf, seeing as I've met very few components whose mass distribution was equal, either front to back, or side to side.How's this accomplished?
,
seems to be self-leveling; and there doesn't appear to be any stops against which the top plate rests to prevent sliding -- very curious indeed...
seems to be self-leveling; and there doesn't appear to be any stops against which the top plate rests to prevent sliding -- very curious indeed...The reason that it's stable is because superconductors are diamagnetic (below T c that is). And with a diamagnetic material and a magnetic material, you can create an inherently stable levitation. I'm sure you've seen those superconductor demonstrations which have a small slug of superconductive material in a petri dish full of liquid nitrogen and then they take a small magnet and place it above the superconductor where it floats in a stable fashion, even when the magnet is made to spin. That's called the Meissner effect.
The sumo wrestler is standing on a big permanent magnet which is levitating above a big diamagnetic super conductor.
You can't achieve this kind of stability using static permanent magnets which is why the pseudo mag-lev platforms require some sort of stabilizing mechanism.
se
I also think the superconductor levitation device would be a poor isolation device, can you see why?
I also think the superconductor levitation device would be a poor isolation device, can you see why?Yeah, because there's a big-ass sumo dude in the way. Or did you have something else in mind? :)
se
I was thinking: the more stable a device is in a given direction the less isolation effectiveness. This is why rigid supports are generally worse compared to flimsy/shakey ones (for low freq vibration isolation). Thus, by inspection, the superconducting levitator cannot isolate in rotational directions: yaw, pitch, roll, maybe not even in lateral plane...otherwise the sumo dude would topple over or his feet would slide out...
I was thinking: the more stable a device is in a given direction the less isolation effectiveness. This is why rigid supports are generally worse compared to flimsy/shakey ones (for low freq vibration isolation).Well stable in this case doesn't mean rigidly fixed. Just that there aren't forces creating a constant instability as is the case with static arrays of fixed magnets. And rigid supporters versus more flimsy supporters has more to do with the fact that the more rigid body tends to have the higher resonant frequency and for resonant type isolation, you need the resonance below that of the vibration in question.
Thus, by inspection, the superconducting levitator cannot isolate in rotational directions: yaw, pitch, roll, maybe not even in lateral plane...otherwise the sumo dude would topple over or his feet would slide out...
Mmmm. But in the more typical demonstration, i.e. that of the small magnet floating over a slug of superconductor, the magnet can be freely rotated in all directions. A lateral centering force (which might be keeping the platform from sliding out from under the wrestler) may have something to do with the overall shape of the magnet's magnetic field and the shape of the diamagnet.
Dunno for sure. I think this will require a bit more research/pondering.
se
sounds right to me, thanks for pointing out; the diamagnetic properties of superconducting materials are explained at the web site where I grabbed the sumo wrestler pic. The site is interesting itself as they are building a High Field Magnet lab in Netherlands. The site URL is:http://www-hfml.sci.kun.nl/
sounds right to me, thanks for pointing out; the diamagnetic properties of superconducting materials are explained at the web site where I grabbed the sumo wrestler pic. The site is interesting itself as they are building a High Field Magnet lab in Netherlands. The site URL is:Thanks. Actually I think that's the same lab that was featured on the Discovery Channel show. I knew it was somewhere in that region and for some reason Switzerland popped into my head.
se
An interesting bit on the show (which I saw part of) was the demo of how an aluminum disc, which is essentially not magnetic, when spun up on disc drive will cause a magnet held over the spinning disc to move.
An interesting bit on the show (which I saw part of) was the demo of how an aluminum disc, which is essentially not magnetic, when spun up on disc drive will cause a magnet held over the spinning disc to move.Didn't catch that part. Though that doesn't seem terribly mysterious. While aluminum isn't magnetic, it is conductive. And whenever you move a conductor through a magnetic field, you induce a voltage which produces a current which produces a magnetic field. Of course in the case of the disc these would just be eddy currents but even eddy currents produce magnetic fields.
se
The Levitator is produced by Dodd Audio. GR Research did have some participation in development and is currently involved in distribution and marketing.Initially a version was made that used attracting magnets for centering and opposing magnets to keep them apart. This did actually levitate the top plate with nothing physically touching it. But if you were to bump it hard enough it would make a very quick 45 degree turn and snap together with finger breaking force.
For liability reasons it was decided not to pursue this method.
This method also allowed large magnetic fields created by the attracting magnets. With the current system the opposing magnets effectively cancel the magnetic field.
The first versions, using the pins for centering, did use linear bearings in the top plate to allow smooth up and down gliding.
It was later decided (by designer Gary Dodd) that the bearings were not necessary. A hole through the Acrylic with a few thousandths clearance allowed just as smooth and frictionless movement.
Wedging the top plate between multiple pins and using a roller bearing system actually locks the top plate to the bottom one. This does not isolate it from vibrations in the horizontal plane. It only dampens it in the vertical plane (up and down).
By allowing some clearance in the aligning holes in the top plate the top plate has a thousandth of an inch or so of play horizontally. It barely touches the pins. So it not only floats up and down but also has a some of float side to side. This effectively isolates it from the bottom plate and vibrations in the vertical and horizontal plane.
Vibrations are not transferred through the magnetic field any more than they are transferred through the air. The only vibrations that will be received by the top plate (and/or whatever is on it) is what hits it directly, and even those vibrations will have a minimal effect because the top plate is not rigidly mounted but floating.
Also the resonance frequency of the 1/2 thick Acrylic, while it has not been actually measured yet, should be down in the single digit range. So, there should be no problems of the platform itself causing resonance problems.
Does it work?
Listeners seam to unquestionable believe it does.
A Levitator was recently audition in a Dallas store. The owner, a tech, and Gary Dodd simultaneously noticed a difference when the Levitator was inserted under the CD player. The music was cleaner. It has a quieter noise floor, and better detail. Gary described it as having darker Blacks.
And yes, a levitating platform does have a high "cool" factor as one poster said. But, it gets even cooler. An optional lighting kit is in the works too. A small LED light is inserted into the back of the Acrylic to light up the whole platform. Any color can be used too. I was not all that jazzed over the idea until I saw one that had a blue LED light in it that was turned down kind of dim. It looked real good.
Considering the price of other isolation devices I think the price to be pretty good especially considering the high price of Neodymium magnets. Also considering the effectiveness I think these to be a real bargain.
For you die hard DIY'ers that never buy anything that you think you can make yourself.... I think this post just gave you guys a few really good ideas.
Further questions can be sent to Gary Dodd at Dodd Audio gldodd@attbi.com or to me here at GR info@gr-research.com
Danny Richie
Hello-I have toyed with a home brew version of this concept which I posted on earlier. I can therefore say with a fair amount of confidence, the following:
You correctly noted the torque produced by the instability:
> But if you were to bump it hard enough it would make a very quick 45 degree turn and > snap together with finger breaking force.
Yet, you also say:
> By allowing some clearance in the aligning holes in the top plate the top plate has a > thousandth of an inch or so of play horizontally. It barely touches the pins. So it not
> only floats up and down but also has a some of float side to side. This effectively
> isolates it from the bottom plate and vibrations in the vertical and horizontal plane.This is simply not possible as a result of the torque (which you acknowledge) which exists that is trying to turn the platforms relative to each other. As a result, there will always be contact between the top platform and the guide posts, the front surface of one post, and th rear surface of the other post. The best one can do is to reduce the friction at these points to a minimum. Therefore, teflon and linear bearings are preferable to acrylic and whatever you are using. They are by nature lower in friction. You will never achieve "free floating" of heavy items with simple magnets in all three axes as it is contrary to the rules of mother nature (see what's his name's theory...) without alot of extras (superconductors, control circuits, etc.)
A few other things....I have found these platforms do improve the sound of my system noticably, but only when used in conjuction with a rollerbearing between the platform and the equipment. This allows you to utilize the z plane damping of the mag-lev, with the X-Y damping of the rollerball. The best of both.
Now, as to the spring "constant" of the mag-lev system, it is indeed different from a "normal" spring, in that it is NOT linear, but a second order system. A normal spring produces a force which is a constant (depending on the spring) times the displacement distance, so a with a spring constant of say 10, a displacement of -1 produces a force of of -10, a displacement of -10, a force of -100. With magnets, the force is proportional to the inverse square of the distance between them. This means the closer the magnets get, the "stiffer" the spring seems. Therefore, with magnets, the forces would be something like -10 and -1000. The effect is large displacement vibrations are damped more quickly...
Any second order system would behave the same way. Adding dampers to simple springs creates 2nd order systems....The magnet system creates a second order system without multiple components, so in this way, they are unique. And, they do look cool...
Hope this helps some....
> But if you were to bump it hard enough it would make a very quick 45 degree turn and > snap together with finger breaking force.This statement was referring to the model Gary produced that had magnets attracting as well as opposing.
Yes, he did make one that "free floated".
I also originally thought the linear bearing would be needed to reduce the friction, but I was surprised at how little friction there was with the clearanced hole through the Acrylic.
The torque motion of it trying to twist is almost non-exsistent (I could feel none). You actual have to let it move quite a bit off center for there to be any real force to the sides. The guide pins keep it centered enough to allow it to float without it forcing the top plate in one direction.
Thanks for adding the good information of your experience to the subject.
Danny Richie
Vibrations are not transferred through the magnetic field any more than they are transferred through the air.Vibrations are indeed transferred through the magnetic field. Any change in the relative distance between the opposing magnets also changes the force acting between them. So any force acting on one set of magnets is effectively transferred to the opposing set.
A magnetic isolation device is fundamentally no different than any other spring/mass isolation device. And the effectiveness of each ultimately depends on the fundamental resonant frequency and Q of the spring/mass combination.
The only vibrations that will be received by the top plate (and/or whatever is on it) is what hits it directly, and even those vibrations will have a minimal effect because the top plate is not rigidly mounted but floating.
I guess it depends what you mean by "effect." Because it's floating, it will have a higher Q resonance which means it will not only store more energy but it will dissipate it over a longer period of time (which is why musical triangles are suspended by a string rather than being rigidly mounted). Typically the goal is to keep energy storage to a minimum and dissipate what energy storge there is as quickly as possible. Apparently that's not the goal here.
I also notice there's no damping with respect to the magnetic "springs" (other than what little friction there may be between the top panel and the stabilizing posts) which means that the platform's resonance will also tend to have a high Q with lots of energy storage and long dissipation times.
Is this what you're actually shooting for? Underdamped high Q resonance?
se
Hello Steve,I have not had an exchange with you here in a long time. Of coarse I have had little time to post anymore either.
I have agreed with your input here on many occasions, but not today.
You said: "Vibrations are indeed transferred through the magnetic field. Any change in the relative distance between the opposing magnets also changes the force acting between them. So any force acting on one set of magnets is effectively transferred to the opposing set."
Now Steve,
If vibrations were indeed transferred through the magnetic field it would not work now would it.
You know if it did not work, and it did not represent a genuine value for what it accomplishes I would not indorse it or sell it.
Look at this a different way.
You said some key words, "change in the relative distance".
Vibrations that occur through the floor, the equipment rack, etc do not act in a way as to move anything to any measurable distance. Now before you disagree with that and you can, let me define that.
A vibration does not occur only in one point and time like a bump or hit.
It is thousands of small movements spread out over a given distance.
Think of the Levitator as a boat in the water. Add more weight to the boat and the level that it sets in the water changes (the boat sets deeper) just like adding weight to a Levitator.
For a small wave to hit the boat this would be like you taking your finger and lifting up one end of the lower platform of the Levitator.
If thousands of tiny waves hit the boat it does not change the level of the boat. The boat will remain flat as it averages the wave height of each wave.
In the same way the Levitator will maintain the same height as it keeps an average height.
So you see a force acted on one set of magnets is not necessarily transferred to the other. Magnitude and arrival times are spread out in distance and time and an average distance is maintained.
This method of isolation is quite different from a spring/mass isolation device.
I spring while being very good at storing energy, and changing a time arrival of a shock (store/release), a spring can be very good at transmitting energy. A spring is good for carring a load but not good at controlling resonances or vibrations. This is why our cars not only have springs, but shock absorbers as well.
I am sure that a rubber bicycle inter tube is more effective than any springs. It's just not real attractive to hold that $2,000. CD player up with a bicycle inter tube now is it.
While the idea of sandwiching components between heavy masses can also be effective it is only a function of its mass. The greater the mass the more effective it can be. How much is enough? A heavy rock can not be used in all applications. My CD player for instance is a top loader.
Think about this: If one does not understand the effect of grounding components or ground loop problems they may question the need for a $650. Interface.
But the proof is in the pudding isn't it?
If it works. It works. If the average person can hear a difference and that difference has a value it could be that the value is worth the cost for the difference.
Danny Richie
Hello Steve,I have not had an exchange with you here in a long time. Of coarse I have had little time to post anymore either.
Howdy, Danny.
Yeah, it must've been a while since I don't recall the first time. :)
I have agreed with your input here on many occasions, but not today.
Ok.
You said: "Vibrations are indeed transferred through the magnetic field. Any change in the relative distance between the opposing magnets also changes the force acting between them. So any force acting on one set of magnets is effectively transferred to the opposing set."
Now Steve,
If vibrations were indeed transferred through the magnetic field it would not work now would it.
You know if it did not work, and it did not represent a genuine value for what it accomplishes I would not indorse it or sell it.
Huh? NOWHERE did I say it didn't/wouldn't/couldn't work. I thought I made that quite clear with my statement which followed (and which you conveniently left out here) what you quote above, which was:
A magnetic isolation device is fundamentally no different than any other spring/mass isolation device. And the effectiveness of each ultimately depends on the fundamental resonant frequency and Q of the spring/mass combination.
I was responding to your statement in which you claimed:
Vibrations are not transferred through the magnetic field any more than they are transferred through the air.
And I responded because this statement strongly implies that a magnetic isolation device behaves in a fundamentally different way than a spring/mass resonant system when in fact it fundamentally behaves EXACTLY as a spring/mass resonant system because that's EXACTLY what it is.
I was only pointing out that any spring/mass resonant system is only effective at vibration isolation above its natural resonant frequency, at or below which it's quite effective at transferring vibration.
Look at this a different way.
You said some key words, "change in the relative distance".
Ok.
Vibrations that occur through the floor, the equipment rack, etc do not act in a way as to move anything to any measurable distance.
Well, then there's no need for isolation is there? :)
Now before you disagree with that and you can, let me define that.
Ok.
A vibration does not occur only in one point and time like a bump or hit.
It is thousands of small movements spread out over a given distance.
Yes.
Think of the Levitator as a boat in the water. Add more weight to the boat and the level that it sets in the water changes (the boat sets deeper) just like adding weight to a Levitator.
Why think of it as a boat in the water? Why not think of it as what it actually is? A mass coupled to a spring. When you add more mass, you change the resonant frequency of the system.
For a small wave to hit the boat this would be like you taking your finger and lifting up one end of the lower platform of the Levitator.
If thousands of tiny waves hit the boat it does not change the level of the boat. The boat will remain flat as it averages the wave height of each wave.
In the same way the Levitator will maintain the same height as it keeps an average height.
That would remain true even if the component were not sitting on the Levitator unless whatever the component were sitting on were significantly more rigid than the acrylic and MDF platforms that make up the Levitator. So in that regard, the Levitator changes nothing.
So you see a force acted on one set of magnets is not necessarily transferred to the other. Magnitude and arrival times are spread out in distance and time and an average distance is maintained.
First, that's not what I meant. And looking at what I said, I realize I could have stated it better. Here's what I said:
So any force acting on one set of magnets is effectively transferred to the opposing set.
I confused what I was trying to get across by using the word "set." What I meant was that any force acting on any of the magnets will be transferred to any of those magnets' opposing magnets. This doesn't change whether each of one set of magnets are moving synchronously or asynchronously.
This method of isolation is quite different from a spring/mass isolation device.
I'm sorry, but his is simply patently incorrect. The method of isolation is EXACTLY that of a spring/mass system. Your opposing magnetic fields are the spring force which is coupled to the mass of the upper platform and the component which rests upon it and which forms a resonant system that isolates by way of behaving as a low-pass mechanical filter.
Simply because you're not using a mechanical spring does not change this fact one iota. It doesn't matter if your spring is magnetic, or hydraulic, or pneumatic, or mechanical. The method of isolation remains the same.
I spring while being very good at storing energy, and changing a time arrival of a shock (store/release), a spring can be very good at transmitting energy. A spring is good for carring a load but not good at controlling resonances or vibrations. This is why our cars not only have springs, but shock absorbers as well.
A spring is anything which behaves as a spring. It needn't be a literal mechanical spring. Your opposing magnets behave as a spring. The air within an acoustic suspension speaker enclosure behaves as a spring. The air in a pneumatic shock absorber behaves as a spring.
I'm sorry, but like it or not, the Levitator is a spring/mass isolator. There's simply no denying it. So please stop denying it. :)
Think about this: If one does not understand the effect of grounding components or ground loop problems they may question the need for a $650. Interface.
Certainly. By the way, for you, I'll offer my industry accommodation price. Only $649.99. :)
Anyway, you can't expect people to understand things unless you tell them what the thing really is rather than claiming it's something that it's not. And again, what the Levitator really is is a spring/mass isolation device.
But the proof is in the pudding isn't it?
If it works. It works. If the average person can hear a difference and that difference has a value it could be that the value is worth the cost for the difference.
Except that I wasn't arguing about proof, or value or cost or anything of the like. I've only argued that you're passing it off as something other than what it is. If this is unintentional and due simply to a lack of understanding, then that can easily be rectified. If it's deliberate, then you're being fraudulent in which case I hope you never make a dime off the thing. Seeing as I'm not entirely cynical, I'll place my bet on the former.
se
You think "A magnetic isolation device is fundamentally no different than any other spring/mass isolation device. And the effectiveness of each ultimately depends on the fundamental resonant frequency and Q of the spring/mass combination."It is still different Steve.
In a spring/mass system the spring is only carrying the load. The spring does not effectively perform the function of damping. The magnetic system can and does.
Case in point: Go out to your car and take off the shock absorbers and go for a ride. That will be a spring/mass system. By the way, you will be in for a bumpy ride.
When a shock absorber goes out on your car you can push down hard on the bumper and the car will bounce several times until coming back to a stop.
With a system using a mass (the weight of the component and top plate) and a magnetic field (the Levitator) the behavior is more like it is setting the mass on a piece of foam than a spring.
There is a level of dampening not achieved with a spring. The magnetic field is more like an air shock. With lots of pressure in the shock it can be a bit bouncy. The Levitator is also a little bouncy with no load on it, yea just like a spring. However an air shock with the right amount of air pressure can provide a pretty smooth ride. Once loaded the Levitator is pretty smooth too.
Springs are also directly coupled. They are connected. Opposing magnets are not coupled, and not connected.
Take two plates coupled with springs. Move the bottom plate forward quickly by .001". If this were happening continually it would be a lot of vibration. I guarantee you the top plate will follow that movement. There will be a delay in time, but not much, and the movement in distance will be exactly the same for the top and bottom plate. Plus, when the top plate arrives at that position it will do so with enough inertia that it will over shoot and bounce back and forth until bleeding off its inertia and coming to a stop.
Due the same thing to the Levitator and the top plate may not move at all. If and or when it does move forward to that distance that the bottom plate moved it will take a considerably longer time to float to that position. It is not acted upon with the same force that moved the bottom plate. Remember the Levitator does not have fixed coupling. There are several thousandths of an inch of clearance in the pins that keep them aligned.
And Steve, your assumption made in your last paragraph was out of line. You obviously don't know me very well.
Danny Richie
I don't wish to butt in here, but as a mechanical engineer with a little bit of experience in vibrational theory, both academic and professional, I whole heartedly agree with Mr. Eddy's assertation that these simple mag-lev platforms are indeed spring/mass systems. As I have said in an earlier post, they are in fact 2nd order spring/mass systems. A characteristic of these magnetic systems, as 2nd order, is that they are effectively, to put it into your terminology, a "spring and shock absorber" combined. One could model or copy their reaction to vibration with an appropriate spring and damper arrangement. An equation of their vibrational damping would look the same as that for a spring and damper system. There is no mystery or unique isolation here. Consult any elementary college vibration analysis/dynamic systems text. The beauty of the mag-lev is you need only magnets, not separate springs (of any sort, as Mr. Eddy had said) AND "shock absorbers" (dampers). Also, as many people have noted, including myself, they are cool!
You think "A magnetic isolation device is fundamentally no different than any other spring/mass isolation device. And the effectiveness of each ultimately depends on the fundamental resonant frequency and Q of the spring/mass combination."It is still different Steve.
In a spring/mass system the spring is only carrying the load. The spring does not effectively perform the function of damping. The magnetic system can and does.
I'm sorry, but that doesn't change things one bit. You still have a spring/mass resonant system whose behavior is governed by the same laws of physics as every other spring/mass resonant system. The presence of any amount of damping doesn't change this fact whatsoever. EVERY spring/mass resonant system will have some measure of damping. Even those which use mechanical springs.
You need to get over this mental block of yours as to what constitutes a spring.
Case in point: Go out to your car and take off the shock absorbers and go for a ride. That will be a spring/mass system. By the way, you will be in for a bumpy ride.
Even WITH the shock absorbers, it's STILL A SPRING/MASS RESONANT SYSTEM. And you'll only be in for a bumpy ride if the frequency of the bumps fall within or below the natural resonant frequency of the leaf spring/car combination. Vibrations above this frequency will be attenuated more and more as their frequency increases. Just as with any other spring/mass isolation sytem.
When a shock absorber goes out on your car you can push down hard on the bumper and the car will bounce several times until coming back to a stop.
So what? All that does is demonstrate that the Q of the resonance is relatively high. And a high Q resonance is not necessarily a bad thing. Depening on where your natural resonance frequency is, a high Q resonance can actually provide GREATER isolation versus a more damped, lower Q resonance as damping reduces the slope of the rolloff of the low-pass mechanical filter you create with spring/mass resonant systems.
With a system using a mass (the weight of the component and top plate) and a magnetic field (the Levitator) the behavior is more like it is setting the mass on a piece of foam than a spring.
So what? You're still left with a spring/mass isolation system. Again, damping doesn't change this fact one bit.
There is a level of dampening not achieved with a spring. The magnetic field is more like an air shock. With lots of pressure in the shock it can be a bit bouncy. The Levitator is also a little bouncy with no load on it, yea just like a spring. However an air shock with the right amount of air pressure can provide a pretty smooth ride. Once loaded the Levitator is pretty smooth too.
Will you please get over this silly notion that a "spring" is limited to a coiled up piece of wire. I made it clear in my previous post that when I use the word "spring" as in "spring/mass" that I'm NOT referring to some literal mechanical spring. I'm beginning to think you're being intentionally dishonest here in order to continue your denial of the fact that the Levitator is a spring/mass isolation system.
Springs are also directly coupled. They are connected. Opposing magnets are not coupled, and not connected.
ONE LAST !@#$% TIME! I'M NOT REFERRING SPECIFICALLY TO ANY LITERAL MECHANICAL SPRING! I'M REFERRING TO THAT WHICH BEHAVES AND FUNCTIONS AS A SPRING, WHETHER IT BE MAGNETIC, PNEUMATIC, HYDRAULIC, MECHANICAL, OR OTHERWISE! NOW STOP MISREPRESENTING WHAT I HAVE BEEN SAYING!
Take two plates coupled with springs. Move the bottom plate forward quickly by .001". If this were happening continually it would be a lot of vibration. I guarantee you the top plate will follow that movement. There will be a delay in time, but not much, and the movement in distance will be exactly the same for the top and bottom plate.
Nonsense. The movement of the top plate will depend upon the frequency of the vibration with respect to the resonant frequency of the spring/mass combination of the spring and top plate. The top plate will move the greatest amount when the frequency of the vibration is the same as the resonant frequency. It will move less and less (i.e. greater isolation) as the frequency of the vibration increases above the system's resonant frequency.
This is how all spring/mass isolators function. This is also how the Levitator functions as it too is a spring/mass isolation system.
Due the same thing to the Levitator and the top plate may not move at all.
How much the top plate moves is governed by exactly the same physics as explained above. It will move the greatest distance when the vibration's frequency is the same as the resonant frequency of the spring/mass combination of the Levitator's magnetic springs and top plate. It will move less as the frequency of the vibration increases above this resonant frequency.
If and or when it does move forward to that distance that the bottom plate moved it will take a considerably longer time to float to that position.
How long it takes will be determined by the same physics that determine the time for every other spring/mass isolation system.
It is not acted upon with the same force that moved the bottom plate. Remember the Levitator does not have fixed coupling.
Nonsense. The forces acting between the top plate and bottom plate are no different simply because one force is a magnetic field and another is a mechanical spring. The same force applied by either will have the same effect.
With apologies to Mr. Ed:
A force is a force of course of course
But who ever heard of an invisible force?
That is of course
Unless the force
Is a strong magnetic field.There are several thousandths of an inch of clearance in the pins that keep them aligned.
I'm sorry, no. It's NOT clearance that keeps them aligned. It's the inevitable CONTACT beween the top plate and the pins that keep them aligned. The small amount of clearance simply reduces the amount of wobbling versus a larger clearance.
And Steve, your assumption made in your last paragraph was out of line.
My only assumption was that you were NOT being fraudulent. If my assuming you were not being fraudulent was out of line, am I then to assume that you are being fraudulent?
se
You say now "I use the word "spring" as in "spring/mass" that I'm NOT referring to some literal mechanical spring."Am I not calling it the right thing now Steve? Is that what I am guilty of? Or were you not calling it the right thing?
"ONE LAST !@#$% TIME! I'M NOT REFERRING SPECIFICALLY TO ANY LITERAL MECHANICAL SPRING! I'M REFERRING TO THAT WHICH BEHAVES AND FUNCTIONS AS A SPRING, WHETHER IT BE MAGNETIC, PNEUMATIC, HYDRAULIC, MECHANICAL, OR OTHERWISE! NOW STOP MISREPRESENTING WHAT I HAVE BEEN SAYING!"
I think this is the first time you have said you are not referring to a mechanical spring, and there is no need to shout. So what are you talking about now? Never mind. Don't even answer that. This is getting old fast.
I try to make something so simple it's anal, illustrating the de-coupling of the two plates by referring to one simple movement in one direction and you come back with.... "will depend upon the frequency of the vibration with respect to the resonant frequency of the spring/mass combination of the spring and top plate, blah, blah, blah...
You must be that guy, and there is always one out there, that will try to find fault with something or bring it down so you can feel better about yourself.
My apologies for misunderstanding your intentions in the last paragraph of your earlier post. I misread what you wrote and thought you were accusing me of being fraudulent. You were actually just trying to call me stupid. When isn't very polite, but not as out of line as the "former".
This is the last I will post of this. Sharing of knowledge is not taking place here. I think you are more set on winning an argument. Sorry, but there is no prise for you.
Call it whatever you like. This product really works. It's simple in design. It's not to expensive, and it's way cool too. Let what it does speak for its self and quit over analyzing it.
Danny Richie
You say now "I use the word "spring" as in "spring/mass" that I'm NOT referring to some literal mechanical spring."Am I not calling it the right thing now Steve? Is that what I am guilty of? Or were you not calling it the right thing?
What you're guilty of is claiming that the Levitator's method of isolation is something OTHER than that of a spring/mass system. To wit:
This method of isolation is quite different from a spring/mass isolation device.
Those are your words. And that claim is simply false. As I have been saying throughout, the Levitator's method of isolation is EXACTLY that of a spring/mass system because that's precisely what it is.
"ONE LAST !@#$% TIME! I'M NOT REFERRING SPECIFICALLY TO ANY LITERAL MECHANICAL SPRING! I'M REFERRING TO THAT WHICH BEHAVES AND FUNCTIONS AS A SPRING, WHETHER IT BE MAGNETIC, PNEUMATIC, HYDRAULIC, MECHANICAL, OR OTHERWISE! NOW STOP MISREPRESENTING WHAT I HAVE BEEN SAYING!"
I think this is the first time you have said you are not referring to a mechanical spring, and there is no need to shout. So what are you talking about now? Never mind. Don't even answer that. This is getting old fast.
The first time I said it was when I was responding to your claim which I quote above. To reiterate from two posts ago:
This method of isolation is quite different from a spring/mass isolation device.
I'm sorry, but his is simply patently incorrect. The method of isolation is EXACTLY that of a spring/mass system. Your opposing magnetic fields are the spring force which is coupled to the mass of the upper platform and the component which rests upon it and which forms a resonant system that isolates by way of behaving as a low-pass mechanical filter.
Simply because you're not using a mechanical spring does not change this fact one iota. It doesn't matter if your spring is magnetic, or hydraulic, or pneumatic, or mechanical. The method of isolation remains the same.
In this last paragraph I make it quite clear that I'm saying doesn't matter WHAT comprises the spring. A spring/mass system is a spring/mass system. And the Levitator is a spring/mass system.
I try to make something so simple it's anal, illustrating the de-coupling of the two plates by referring to one simple movement in one direction and you come back with.... "will depend upon the frequency of the vibration with respect to the resonant frequency of the spring/mass combination of the spring and top plate, blah, blah, blah...
You didn't make it simple. You made yet another erroneous and misleading claim. To wit:
Take two plates coupled with springs. Move the bottom plate forward quickly by .001". If this were happening continually it would be a lot of vibration. I guarantee you the top plate will follow that movement.
The "blah, blah, blah" part was explaining why your claim was in fact erroneous and misleading. But apparently you've no interest in whether your claims are erroneous and misleading.
You must be that guy, and there is always one out there, that will try to find fault with something or bring it down so you can feel better about yourself.
No, I'm the kind of guy who doesn't care to see people making erroneous claims and trying to pass things off as something other than what they are.
My apologies for misunderstanding your intentions in the last paragraph of your earlier post. I misread what you wrote and thought you were accusing me of being fraudulent. You were actually just trying to call me stupid. When isn't very polite, but not as out of line as the "former".
No, not stupid. Just a lack of understanding of the basic physics which govern the behavior of a product you represent which caused you to erroneously claim that it is something other than what it is.
This is the last I will post of this. Sharing of knowledge is not taking place here. I think you are more set on winning an argument. Sorry, but there is no prise for you.
No, that's not it at all. There is indeed a sharing of knowledge taking place here. You're simply not receptive to the knowledge being shared and would rather remain in denial of your own lack of knowledge on the subject at hand. You're the horse who can be led to water but can't be made to drink.
Call it whatever you like. This product really works. It's simple in design. It's not to expensive, and it's way cool too. Let what it does speak for its self and quit over analyzing it.
And at NO TIME have I said ANYTHING CONTRARY TO THAT! I'm quite content to have the product speak for itself which would be preferable to the erroneous and misleading way in which you have spoken for it.
se
No false claims have been made.It appears that we have different views of what a spring/mass system is.
By your definition just about any load carrying device using any type of suspension over a solid surface can be a spring/mass system. I guess this would include cars, motorcycles, etc, and of coarse the Levitator.
I guess to you a new Corvette is simply a load carrying device or maybe just transportation.
At least kuribo has called it a spring/mass/damper system. This at least encompasses another function of the device.
If you need to be so broad in your definitions then the Levitator can be a spring/mass system.
My contention is this broad term does not adequately categorize the Levitator or define its functions. It is much more than just a load carrying device and you know it. It is also unique in contrast to other isolation systems.
I also contend that it is superior to a literal spring in that it is not directly coupled like a spring.
I suppose you would like to debate that too?
My guess is you would not call it a debate or discussion. You would contend that any person whose views are not in parallel with your own makes false and erroneous statements if you can by definition prove some fault?
I am sure everyone appreciates the job you do here of being the truth police.
Loose the attitude Steve. Life is too short.
Danny Richie
No false claims have been made.Yes, there have. This is a false claim:
This method of isolation is quite different from a spring/mass isolation device.
It appears that we have different views of what a spring/mass system is.
Yes. And you should do a bit of research and learn just what they are.
By your definition just about any load carrying device using any type of suspension over a solid surface can be a spring/mass system. I guess this would include cars, motorcycles, etc, and of coarse the Levitator.
Any mass coupled to a spring creating a resonant mechanical low-pass filter for the purpose of vibration isolation is a spring/mass isolation system. And yes indeed, the suspension systems of cars and motorcycles as well as the Levitator are EXACTLY that.
I guess to you a new Corvette is simply a load carrying device or maybe just transportation.
I would call a Corvette a Corvette. I would call its suspension system a spring/mass vibration isolator.
At least kuribo has called it a spring/mass/damper system. This at least encompasses another function of the device.
Again, the presence or absence of damping does not change a spring/mass system into something other than a spring/mass system. The method of isolation is EXACTLY the same; that of a mechancial low-pass filter.
If you need to be so broad in your definitions then the Levitator can be a spring/mass system.
The Levitator is a spring/mass system even in the narrowest sense. Again, the presence or absence of damping doesn't change that fact. Even a literal mechanical spring spring/mass system has damping. That's inevitable due to the fact that there's no such thing in the realworld as a frictionless spring. Any amount of friction results in damping.
My contention is this broad term does not adequately categorize the Levitator or define its functions. It is much more than just a load carrying device and you know it. It is also unique in contrast to other isolation systems.
It's function is that of a spring/mass isolation system. At no time did I say it was simply a "load carrying device" so please stop putting words into my mouth. And it's only unique in its implementation. It's not at all unique in terms of its method of isolation.
I also contend that it is superior to a literal spring in that it is not directly coupled like a spring.
I suppose you would like to debate that too?
Yes, I will debate that becuase it is indeed directly coupled. The top plate is directly coupled to the bottom plate via the stabilizing pins. There's no way to avoid mechanical contact between the pins and the top plate as any static array of magnets is inherently unstable as per Earnshaw. So to claim that there is no direct coupling in the Levitator is simply false.
My guess is you would not call it a debate or discussion. You would contend that any person whose views are not in parallel with your own makes false and erroneous statements if you can by definition prove some fault?
These aren't my views. They are the views of well-established physics. So you're not arguing with me. You're arguing with a large body of science which quantified much of this centuries ago.
I am sure everyone appreciates the job you do here of being the truth police.
More I hope than appreciate the erroneous claims and other misinformation you've been trying to pass off.
Loose the attitude Steve. Life is too short.
Lose the denial, Danny. Life is too short.
se
Why can't you play nice?It certainly loooks like one of the reasons that you are arguing with him is that you think that the magnetic levitation platform is not good, or at least, no better than a simple spring loaded platform.
If someone were dissing your transformer based device by saying it was no good because it had transformers in it, I have no doubt you would get riled too.There is one thing that the magnetic levitation platform will have less of than a mechanical coiled wire spring loaded platform: HF vibrations transmitted directly through the spring metal itself.
Given that the resonant frequency of such a magnetic levitation system when loaded with a component will probably be quite low, what Danny is saying about the platform not reacting to HF vibrations is an accurate and correct portrayal. While there is indeed a "spring system" in action, it's loaded natural frequency will be very low, and tend to average out the HF vibrations that are attempting to bridge the magnetic gap.
Yes, I am aware that such things could be graphed, modeled, etc., I have worked with isolation platforms before, units similar to the now popular Vibrapods, and have pesonally taken many measurements of various isoaltion syustems in all three axis. Yes, I know that the HF vibrations are not actually all gone, just way way down on the curve. So spare me the lecture along those lines too.
Be aware that if you start calling names yet again, with yet another inmate, such posts will be deleted, and I will be forced to submit your name for consideration to be permanently banned.
Jon Risch
Why can't you play nice?I think I'm playing quite nice under the circumstances.
It certainly loooks like one of the reasons that you are arguing with him is that you think that the magnetic levitation platform is not good, or at least, no better than a simple spring loaded platform.
That's your delusion, Jon. The ONLY thing I have argued is that it is a spring/mass resonant system. And I've only argued that because it's been claimed to be something OTHER than a spring/mass resonant system. Here's a direct quote from Danny:
This method of isolation is quite different from a spring/mass isolation device.
This claim is flat out incorrect. The method of isolation is EXACTLY that of a spring/mass system.
If someone were dissing your transformer based device by saying it was no good because it had transformers in it, I have no doubt you would get riled too.
Except that that's not what I'm saying. It would be like if I were erroneously trying to pass off my transformer-based isolator as something other than a transformer-based isolator, claiming that it isolates by some means other than the means by which every other transformer isolates.
And if I were foolish enough to do something like that then I should be taken to task just as equally as I'm taking Danny to task for his erroneously claiming that the Levitator isolates by some means other than that of a spring/mass system.
I have absolutely nothing against such isolators as the Levitator. Like others, I also think they're pretty cool. I'm only taking issue with it being passed off as something that it's not.
There is one thing that the magnetic levitation platform will have less of than a mechanical coiled wire spring loaded platform: HF vibrations transmitted directly through the spring metal itself.
So? Please tell what this has to do with anything I've said.
Given that the resonant frequency of such a magnetic levitation system when loaded with a component will probably be quite low, what Danny is saying about the platform not reacting to HF vibrations is an accurate and correct portrayal. While there is indeed a "spring system" in action, it's loaded natural frequency will be very low, and tend to average out the HF vibrations that are attempting to bridge the magnetic gap.
Again, so? Again, please tell me what this has to do with anything I've said.
Yes, I am aware that such things could be graphed, modeled, etc., I have worked with isolation platforms before, units similar to the now popular Vibrapods, and have pesonally taken many measurements of various isoaltion syustems in all three axis. Yes, I know that the HF vibrations are not actually all gone, just way way down on the curve. So spare me the lecture along those lines too.
Ditto.
Be aware that if you start calling names yet again, with yet another inmate, such posts will be deleted, and I will be forced to submit your name for consideration to be permanently banned.
Oh Christ, give it a rest, Jon. Go polish your badge or something.
se
Mr. Risch wrote:"There is one thing that the magnetic levitation platform will have less of than a mechanical coiled wire spring loaded platform: HF vibrations transmitted directly through the spring metal itself.."
Yes, the mag-lev system will not transmit the HF vibrations as would a simple metal spring. That is because it is a second order system, and not a simple linear spring system. By using an appropriate metal spring in series/parallel with a damper (viscous, air, etc.), these HF vibrations can be similarly damped. Vibration isolation technology has clearly gone beyond the simple steel spring, and thus stating this as a benefit of the mag-lev platform seems rather trivial.
Mr. Eddy's point is, as I understand it, that this mag-lev device is nothing special or unique, that it is in fact a spring/mass/damper system and as such can do nothing more (or less) than any other spring/mass/damper system. He is correct here. I also believe he is taking issue with the description/claims made by the individual promoting this device as something other than a spring/mass/damper system. If it is indeed being promoted as something superior to a spring/mass/damper system, I believe the individual promoting the device should be held accountable to explain and back up his claims with scientifically sound arguments. Mr. Eddy is an outspoken advocate for the truth. I, for one, appreciate the truth. Based on the comments made by both individuals, I think it is clear who has the clearer theoretical understanding of dynamic systems and vibrational behavior. Until personal attacks are made, let the chips fall where they may.
[ Mr. Eddy is an outspoken advocate for the truth. I, for one, appreciate the truth. ]Well, you are talking about the truth as Mr. Eddy sees it, which is not necessarily THE TRVTH.
He can remain puzzlingly dense at times regarding his admitted level of understanding of various phenomenon, and his refusal to "let things go" once it is clear that it is no longer a dialog, but two monologs, is a large part of the problem, as is his propensity to be judge, jury, and attempted executioner.
Jon Risch
Yes, the mag-lev system will not transmit the HF vibrations as would a simple metal spring.Only if there were no mechanical coupling between the panels. Both of the pseudo mag-lev systems I'm aware of employ mechanical coupling as a consequence of Earnshaw.
Now if we could develop a material that's highly diamagnetic, we could have true mag-lev and eliminate all mechanical coupling. At least for static systems. Currently the most highly diamagnetic materials (namely graphite and bismuth) are too weak to be of any use as a component support.
se
"Only if there were no mechanical coupling between the panels. Both of the pseudo mag-lev systems I'm aware of employ mechanical coupling as a consequence of Earnshaw."Yes, that is true. I was speaking strictly of the magnets themselves, without the necessary stablization mechanism.
"Now if we could develop a material that's highly diamagnetic, we could have true mag-lev and eliminate all mechanical coupling. At least for static systems. Currently the most highly diamagnetic materials (namely graphite and bismuth) are too weak to be of any use as a component support."Someday....maybe....in a galaxy far far away....
Appreciate your vigilance for the truth. Keep it up....
Kuribo
"Only if there were no mechanical coupling between the panels. Both of the pseudo mag-lev systems I'm aware of employ mechanical coupling as a consequence of Earnshaw."Yes, that is true. I was speaking strictly of the magnets themselves, without the necessary stablization mechanism.
Ah, ok. Gotcha.
"Now if we could develop a material that's highly diamagnetic, we could have true mag-lev and eliminate all mechanical coupling. At least for static systems. Currently the most highly diamagnetic materials (namely graphite and bismuth) are too weak to be of any use as a component support."
Someday....maybe....in a galaxy far far away....
Hehehe.
The Discovery Channel here aired a show last night on levitation actually. It included mystical levitation such as "Yogic flying" but the last feature was on realworld magnetic levitation. They featured two labs doing research in this area, one in the US and one I think in Switzerland.
They used extremely powerful electromagnets (which required enough energy to power a small city) which produced a very powerful concentrated magnetic field in a cylindrical chamber a little over an inch in diameter and perhaps a foot long.
They took advantage of the fact that most every substance is at least weakly diamagnetic and were able to float plastic beads, drops of water, etc. in the chamber. The lab in Switzerland was doing this with spiders and baby frogs.
Prety wild.
Appreciate your vigilance for the truth. Keep it up....
Thank you. I will. It'd be nice to see a bit more of it. My arms are getting tired. :)
se
nt
Hi Steve,I could probably look in a book, but perhaps you can answer this quickly - is the magnetic "spring" a linear system? IIRC, the field falls off at 1/r2, but what about the force it exerts? What I'm trying to determine is whether it will track any vibration you give it, and whether it will ever go unstable.
I am just thinking about this intuitively - the transfer function of the magnetic repulsion system is such that the system acts as a high pass filter for mechanical vibrations, quite similar to an elastic spring such as a bungee cord or coil. High frequencies are attenuated tremendously (with gain of at least 60 to greater than 100dB). The system will easily track low frequency oscillations such as a 1Hz sinewave with slight damping due to gravity, and resonance is probably something very low, I bet below the audible range. The thing that affects DACS and tubes is your typical microphonic vibration, which is high in frequency and low in amplitude. You are achieving your goal whether or not you go resonant, due simply to the frequency-dependent filtering. The issue of energy storage would then be moot, since the system would appreciably store/release energy only at low frequencies that do not affect the audible band.
It probably wouldn't be very difficult to calculate the resonant frequency of the magnetic system, but I only know how calculate it if the transfer function is linear. Anybody with a maglev table have a mechanical oscillator that they can tune to generate a Bode plot of the table?
What I think would be way cooler is to have a dynamic electromag-lev system. A set of neodymium magnets and a feedback system using simple RLC/op-amps that maintains the same back EMF in the deflecting coils no matter what. Much simpler to implement than things such as magnetic bearings, which have been done.
-Chris
I could probably look in a book, but perhaps you can answer this quickly - is the magnetic "spring" a linear system? IIRC, the field falls off at 1/r2, but what about the force it exerts? What I'm trying to determine is whether it will track any vibration you give it, and whether it will ever go unstable.The force follows the same square law function, making it exponential rather than linear. The force will track vibration, just not linearly. And not sure what you mean by unstable. Could you clarify that a bit?
I am just thinking about this intuitively - the transfer function of the magnetic repulsion system is such that the system acts as a high pass filter for mechanical vibrations, quite similar to an elastic spring such as a bungee cord or coil. High frequencies are attenuated tremendously (with gain of at least 60 to greater than 100dB). The system will easily track low frequency oscillations such as a 1Hz sinewave with slight damping due to gravity, and resonance is probably something very low, I bet below the audible range. The thing that affects DACS and tubes is your typical microphonic vibration, which is high in frequency and low in amplitude. You are achieving your goal whether or not you go resonant, due simply to the frequency-dependent filtering. The issue of energy storage would then be moot, since the system would appreciably store/release energy only at low frequencies that do not affect the audible band.
It's actually a low-pass filter, not a high-pass filter. And the goal is to get the natural resonant frequency as low as possible into the subsonic region as the transmissibility of vibration is greatest at resonance.
It probably wouldn't be very difficult to calculate the resonant frequency of the magnetic system, but I only know how calculate it if the transfer function is linear. Anybody with a maglev table have a mechanical oscillator that they can tune to generate a Bode plot of the table?
Don't look at me. :)
Though I might point out that the resonant frequency will depend in large part on the mass of the component you're loading the isolator with. So on top of the non-linear nature of the magnetic springs, you've got a component weight which can vary considerably from one to another.
What I think would be way cooler is to have a dynamic electromag-lev system. A set of neodymium magnets and a feedback system using simple RLC/op-amps that maintains the same back EMF in the deflecting coils no matter what. Much simpler to implement than things such as magnetic bearings, which have been done.
There are active systems such as that available, though none targeted toward audiophiles that I'm aware of.
se
The force follows the same square law function, making it exponential rather than linear. The force will track vibration, just not linearly. And not sure what you mean by unstable. Could you clarify that a bit?What I meant by 'unstable' is uncontrolled oscillations to the point where the table will 'jump' off of its runners, or simply a sustained oscillation. In other words, is there a frequency in the audible band at which the system will blast itself into outer space or simply bounce up and down continuously forever if one gives it the proper signal? I suspect this does not happen in the audible band unless the amplitude of vibration is minute. A frequency sweep test using a simple but strong transducer affixed to the bottom plate would give us the answer.
It's actually a low-pass filter, not a high-pass filter. And the goal is to get the natural resonant frequency as low as possible into the subsonic region as the transmissibility of vibration is greatest at resonance.
Correct. I was thinking low-pass and wrote high-pass for some reason. My mistake.
Though I might point out that the resonant frequency will depend in large part on the mass of the component you're loading the isolator with. So on top of the non-linear nature of the magnetic springs, you've got a component weight which can vary considerably from one to another.
Right... that is a variable in the nonlinear equation. I wish I knew how to solve something like this. Intuitively, amplitude of oscillations is decreased if given the same system with higher load. Actually, come to think of it, a trace of the oscillations will look like the "trampoline" algorithm in Super Mario Bros. 1 (not sure if you've played that, but they're all over the place in the game), where one gets accelerated more quickly when close to the magnets, while farther away from the magnets, momentum imparted by the accelerating field is fighting gravity, and the platform stays at the peak for a considerable amount of. Anyway, all this is somewhat irrelevant.
There are active systems such as that available, though none targeted toward audiophiles that I'm aware of.
Would certainly be a fun project and not too difficult to implement if one used gross approximations when defining the system.
I think one really needs to understand the system to optimize its implementation. It obviously works, intuitively, and I guess also experimentally. But would love to see the frequency response given an 'average' load.
-Chris
Sorry, I seem to have overlooked this post in the flurry of the other sub-thread.What I meant by 'unstable' is uncontrolled oscillations to the point where the table will 'jump' off of its runners, or simply a sustained oscillation. In other words, is there a frequency in the audible band at which the system will blast itself into outer space or simply bounce up and down continuously forever if one gives it the proper signal?
Well I suppose if it were fed a continuous "signal" centered on the fundamental resonant frequency of the table you could come up with something like the Tacoma Narrows Bridge. :)
But then any effective isolator will have its fundamental resonance well below anything that will ever come out of your speakers.
I suspect this does not happen in the audible band unless the amplitude of vibration is minute.
More like unless the fundamental resonance falls in the audio band.
A frequency sweep test using a simple but strong transducer affixed to the bottom plate would give us the answer.
Yes. That or a waterfall FFT from an accelerometer after applying an impulse.
Right... that is a variable in the nonlinear equation. I wish I knew how to solve something like this.
I think to get the best picture would be via empirical measurement. No realworld isolation platform is going to be have as a simple ideal harmonic oscillator. The platforms will not be perfectly rigid so they'll have their own vibrational modes, etc. which will show up as peaks and dips in a transmissibility plot.
Intuitively, amplitude of oscillations is decreased if given the same system with higher load.
That's because adding mass lowers the resonant frequency which lowers the cutoff point of your mechanical filter which results in greater attenuation within the same frequency range. You can also lower resonance by using a higher compliance (i.e. less stiff) "spring."
Actually, come to think of it, a trace of the oscillations will look like the "trampoline" algorithm in Super Mario Bros. 1 (not sure if you've played that, but they're all over the place in the game), where one gets accelerated more quickly when close to the magnets, while farther away from the magnets, momentum imparted by the accelerating field is fighting gravity, and the platform stays at the peak for a considerable amount of.
I'd be embarrassed to say how many times I've played that game. :)
Would certainly be a fun project and not too difficult to implement if one used gross approximations when defining the system.
I think one really needs to understand the system to optimize its implementation. It obviously works, intuitively, and I guess also experimentally. But would love to see the frequency response given an 'average' load.
Hey, throw one together. McMaster Carr's got a good selection of electromagnets to choose from.
se
I don't think you should buy at face value that this results in superior isolation since the two slabs of plastic do, indeed, exert a force on one another. Contact via a magnetic field is just as "real" as a physical connection. I see no reason to think this is any more or less effective than springs, air cushions, sorbothene, etc. Looks cool, though!Also someone needs to talk to their website designer about scrolling and the pull downs along the top of the page.
I don't think you should buy at face value that this results in superior isolation since the two slabs of plastic do, indeed, exert a force on one another. Contact via a magnetic field is just as "real" as a physical connection. I see no reason to think this is any more or less effective than springs, air cushions, sorbothene, etc.Exactly. Force is force whether it's being applied via the force of a magnetic field or a mechanical spring.
se
This has been my experience with some of the tinkering I have done with my Forcefield magnets. These magnets are pretty strong and once they reach the point where they will support the weight, they are fairly resistant to any changes in movement (very little friction at the posts would help this some though).Having experimented with many other things like minimally inflated inner tube suspension systems, I had trouble getting my magnets to approach this kind of a low frequency rocking type motion. Maybe it requires a very closely matched magnet strength to component weight, etc.. I wonder myself if it really is a viable concept - but it is kind of fun to play with.
That's a good point, but I would think that the nature of the pushing forces of the magnets would allow great isolation. Just a guess, but I would think that the magnets would have a very low resonant frequency and there would be a significant hysteresis loss exhibited when the magnetic field changes.Perhaps a PhD physicist could work out the math on this, but intuitively, I would think the isolation would be excellent as long as the acrylic top plate is reasonable inert (or damped with lead bags).
More importantly, anyone with any listening comments?
The first production run is underway and they should ship in a couple of weeks.Cheers
Bob
My only concern about the GR platform is regarding the magnetic field. I remember a well known designer(Walker audio) who wanted to incorporate this concept into his turntable design over 8 years ago and abandoned the idea.It seems the magnets had to be too powerful to stabilize the platform and there might be some 'leakage' under some circumstances that could adversely effect the turntable mechanisms.
If you pulled it off without any side affects, my hats off to you.
Lou
If there was not enough field left to effect a TV screen when one was set on top of it then I doubt it will have much effect on a turn table.Danny Richie
This should not be a difficult DIY project. Here is a source for the magnets (see below). I recently bought some and have been experimenting.The trick is to reduce the friction of the 2 stabilizing posts. There was a suggestion here a couple days ago to use 2 teflon rods connected to the base with some "linear bearings" connected to the top platform (something like this link) -
http://www.msldirect.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=MD&Category_Code=FDBB
I have been trying to find a cheaper source for the linear bearing but no luck so far (any suggestions welcome).
Looks like they have some kind of rollers that glide along the four posts....???
http://www.bluecowaudio.com/SAP-RELAXA.HTMI can't really tell just by looking, but it looks like there might be less friction with the way that the Relaxa works...
What do you think?
When I've played with this idea, I always thought that the solution for the instability of magnets was-more magnets! You have magnets in four walls around the floating platform, and magnets around the base of the platform (MuMetal if you could source it), probably two per side.You make them fairly strong, the stronger, the more resistant to internal/airborne vibration it would be, the internal being problematic with such a system for transport devices. For a DAC, or something without large scale internal vibrations, you'd likely achieve better effects with weaker magnets (lower resonant freq)
Ah, resonance frequency. I think you've hit on something important.Assuming one could create a mag lev platform that actually worked (something I'm personally not yet betting on), what would the resonance frequency be?
The best isolation systems I know of all have resonance frequencies in the low single digits. This makes sense because isolation doesn't occur until approximately 1.4 times the resonance frequency. (The degree of isolation will depend on the damping at resonance, with less damping translating into more isolation.)
Has anyone who has experimented with mag lev (or spent money on a commercial product) checked the resonance frequency?
I'm wondering whether such a platform truly excels in isolation or merely in "cool" factor. Granted, coolness is quite high. For my money though, that's not enough. I'd want isolation at least as good as simpler means.
Happy Listening!
Barry
.
... Paul
While I tend to take a lot of these extravagant claim about tweaks with a grain of salt, Danny Ritchie is not prone to hyperbole. What an elegant solution to isolating components. It's perfect for turntables and CD players. Lemme see, where did I put that clump of neodymium magnets...?
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