A world first? Passive v active isolation platforms test

Stacore said:

Very nice thoughts Theo!

Contrary to what people think, concrete is a very good vibration conductor and is very poorly damped. It provides mass but little damping (unless extra measures are taken when preparing it).

Isolation vs sound modification - a very delicate and difficult issue. On one hand a proper isolation can optimize the performance of a component. So one perceives a modified sound but indeed it is the sound of the component. On the other hand, no iso device is 100% transparent, so to some extent it is always in the mix.

Center of mass - shame to admit for a physicist, but I realized its importance in the component placing not that long ago. Before I was just interested in an even load distr over the support points. But a quick aha moment and you realize that the CM must be in the most "quiet" place on the platform (in our case the geometric center).

Cheers,

Click to expand...

Jarek,

Do you want to know something? You are not the only person to mention Center Of Gravity in relation to isolation, but you are one of a very few(who could be counted on one hand to the best of my knowledge). I have had to tolerate all manner of skepticism and dismissal about the iso method I have implemented. I regard myself as inspired by Barry Diament with the twist that I decided to substitute mag-lev for the pneumatic element. I tried using pneumatic but wanted a method that didn't change its load carrying specifications due to the slow leaking of the air bladder.

I actually have so many thoughts about this subject that it is difficult for me to put words to my musings. It is a very complex situation. Because I have never seen any other person elucidate on the many, many vexed problems and potential solutions it is like being a pioneer into uncharted territory. To any person who has never visited this territory, descriptions of this strange new vista are essentially incomprehensible. I will acknowledge the incomparable words of Pierre Lurne for opening my eyes to the imperative of placing Center Of Gravity(COG) front and center as the principle which cannot be overlooked when investigating optimisation of any mechanical moving element. Pierre I salute you and Barry Diament.

The Clearaudio Magix that I use as the mag-lev element are, I now realise, not at their best when loaded at the uppermost of their rated load limit. I am still experimenting with this. I find the 'perfect' optimisation of the combined method of a vertical isolation method with horizontal cup and ball isolation method to be akin to trying to balance two needles point to point vertically. Any deviation from perfect level(ie the load atop the mag-lev being minutely off COG) will cause the ball to roll in that direction within the cup and take the load even more away from COG and even more off level. It's a bit like trying to hit a constantly shifting bull's eye.

I noted that with variation of the load on my support it seemed like there was a 'band of resonance' which changed(ie shifted) up and down the frequency range. This band of resonance sounded like a suck-out(notch) followed by a frequency boost/lift below the notch frequency. I find that the cups and balls seem to have more influence at the higher frequencies. I use Ingress Engineering #3 cups and substitute 3/8 inch grade 5 Silicone Nitride balls instead of the balls provided by Ingress.

I understand fully your point about concrete slabs. I've been telling people for years that rigid solids transmit vibration much better than less rigid less solid media. I also at one time progressed the development of my isolation support using only the insight provided by headphones. The improvements in isolation are readily obvious via headphone listening.

spirit, I totally understand why you are gripped by a determination to experiment with isolation as far as you can take it. It has been a huge focus in my listening life for easily 20 years.

I need to contemplate my thoughts and consider how to describe the hard to describe effects I hear when I fine tune my isolation.

theophile said:

Jarek,

Do you want to know something? You are not the only person to mention Center Of Gravity in relation to isolation, but you are one of a very few(who could be counted on one hand to the best of my knowledge). I have had to tolerate all manner of skepticism and dismissal about the iso method I have implemented. I regard myself as inspired by Barry Diament with the twist that I decided to substitute mag-lev for the pneumatic element. I tried using pneumatic but wanted a method that didn't change its load carrying specifications due to the slow leaking of the air bladder.

I actually have so many thoughts about this subject that it is difficult for me to put words to my musings. It is a very complex situation. Because I have never seen any other person elucidate on the many, many vexed problems and potential solutions it is like being a pioneer into uncharted territory. To any person who has never visited this territory, descriptions of this strange new vista are essentially incomprehensible. I will acknowledge the incomparable words of Pierre Lurne for opening my eyes to the imperative of placing Center Of Gravity(COG) front and center as the principle which cannot be overlooked when investigating optimisation of any mechanical moving element. Pierre I salute you and Barry Diament.

The Clearaudio Magix that I use as the mag-lev element are, I now realise, not at their best when loaded at the uppermost of their rated load limit. I am still experimenting with this. I find the 'perfect' optimisation of the combined method of a vertical isolation method with horizontal cup and ball isolation method to be akin to trying to balance two needles point to point vertically. Any deviation from perfect level(ie the load atop the mag-lev being minutely off COG) will cause the ball to roll in that direction within the cup and take the load even more away from COG and even more off level. It's a bit like trying to hit a constantly shifting bull's eye.

I noted that with variation of the load on my support it seemed like there was a 'band of resonance' which changed(ie shifted) up and down the frequency range. This band of resonance sounded like a suck-out(notch) followed by a frequency boost/lift below the notch frequency. I find that the cups and balls seem to have more influence at the higher frequencies. I use Ingress Engineering #3 cups and substitute 3/8 inch grade 5 Silicone Nitride balls instead of the balls provided by Ingress.

I understand fully your point about concrete slabs. I've been telling people for years that rigid solids transmit vibration much better than less rigid less solid media. I also at one time progressed the development of my isolation support using only the insight provided by headphones. The improvements in isolation are readily obvious via headphone listening.

spirit, I totally understand why you are gripped by a determination to experiment with isolation as far as you can take it. It has been a huge focus in my listening life for easily 20 years.

I need to contemplate my thoughts and consider how to describe the hard to describe effects I hear when I fine tune my isolation.

Click to expand...

Theophile, this is all fascinating and I commend you for your efforts and willingness to share some of your ideas. It has me thinking about trying to locate the center of gravity, at least in the horizontal plane of my turntable, motor controller and steel ballast plate, so that I can shift this assembly's location on my Vibraplane to see if I can hear a difference.

Regarding your twenty years of experimenting with isolation, do you have thought about isolation versus energy drainage? Are they mutually exclusive, is one usually more effective for the types of audio components that we are discussing, or is it possible that both can be employed in combination for superior vibration management. I have long thought that my SME turntable in particular makes good use of each method to optimize its performance. The motor is isolated from the platter and arm support by the compliant rubber belt and by the suspension towers, AND the vibrations from the cartridge travel along a very rigid arm, arm bearing, and armboard into mass. It seems to me that draining vibrational energy into a mass away from sensitive components is very effective, but then isolating that mass from environmental vibrations improves performance further.

Have you experimented with energy drainage?

PeterA said:

Theophile, this is all fascinating and I commend you for your efforts and willingness to share some of your ideas. It has me thinking about trying to locate the center of gravity, at least in the horizontal plane of my turntable, motor controller and steel ballast plate, so that I can shift this assembly's location on my Vibraplane to see if I can hear a difference.

Regarding your twenty years of experimenting with isolation, do you have thought about isolation versus energy drainage? Are they mutually exclusive, is one usually more effective for the types of audio components that we are discussing, or is it possible that both can be employed in combination for superior vibration management. I have long thought that my SME turntable in particular makes good use of each method to optimize its performance. The motor is isolated from the platter and arm support by the compliant rubber belt and by the suspension towers, AND the vibrations from the cartridge travel along a very rigid arm, arm bearing, and armboard into mass. It seems to me that draining vibrational energy into a mass away from sensitive components is very effective, but then isolating that mass from environmental vibrations improves performance further.

Have you experimented with energy drainage?

Click to expand...

Peter
A simple way to closely(maybe not perfectly but close) determine COG. Go to a hardware store by a section of half round moulding.



Mark each cut off end with a vertical line. Place component atop the moulding and re-position the component until you find the the balance axis. mark where this is. Turn the moulding 90 degrees and repeat. I place a piece of masking tape on the sides of the component so that I can mark this location on the component. This is not completely precise, but it gets one fairly close.

Peter as for energy drainage: I use an analogy; A bell is a very resonant object. If it is struck whilst held aloft it will continue to ring until the resonant energy dissipates. Now strike a bell and push the perimeter(the 'open' part) into a surface (table, floor, wall) and the ringing stops dead. Is that not mass damping? The energy in the body of the ringing bell drains.

Now remember that a turntable is essentially holding onto a 'microphone' of sorts(the cartridge which picks up all vibration and translates that into an electrical signal). Thus the draining surface needs to not be adding back into the turntable, vibration which is coming from elsewhere. What I do is have vertical isolation. Atop that a 'drain' object(metal, stone plate with a reasonable mass). Then I place the cups and balls atop the drain object and the bottom of the turntable into direct contact with the balls. The balls couple in the vertical(courtesy of gravity). The cups couple with the drain object via gravity. The vertical isolation below the drain object minimises the transmission of vibes from below into the drain object.

I wrote about it here with photos:

http://audiokarma.org/forums/index.php?threads/they-say-a-picture-paints-a-thousand-words.650778/

I have revised my support since I posted all that. I've taken away the granite(by way of further experimentation into the optimal mass atop the Clearaudio Magix) I am also not anymore using the ceramic incense burners as cups. Now I use the Ingress Engineering cups:

http://www.ingress-engineering.ca/resources/IMG_0379.JPG

I tell people to consider the principles being addressed in my method. Even when applying them to a different method. It is the principles (COG, coupling, decoupling etc) which matter. I feel that there would be a few methods which could work, but the principles always need to be considered and their effects taken into account.

You will note that in the AudioKarma thread I linked to above, I stressed that it is not the method which guarantees success, but the fine tuning of the total load on the vertical elements combined with proper leveling, COG tuning, etc. I said in that thread that I can make the situation deteriorate by sub optimal loading, deviation from COG, not leveling and more. It is not 'one size fits all'( like many IMO dubious products on the market). It requires effort, time and experimentation from the user to optimise.

Too many people want to purchase, place and do nothing more. That would in my mind require the manufacturer of the isolation product to already know the COG of your component, mark the exact place on the isolation product where the component needs to be placed to coincide the component COG with the center of the load bearing elements etc. I don't see any manufacturers doing this. Which makes me wonder about the isolation.

It is not as simple as it seems and there is much to consider. Too few people wish to consider and actively fine tune.

A few constants I have observed when all is optimally fine tuned:

Natural timbre of instruments/voices.

Dynamics

Low level detail/ sonic texture/ ambiance previously obscured, now emerging. Greater separation of the individual elements in the sonic 'mind's-eye picture'.

Natural Timbre

Instruments change their tonal character as the player explores the tonal frequency range. ie A piano for example can sound 'bell like' in it's higher keys/notes, but sound markedly different to the high notes in its middle and lower keys. The same applies to most instruments. Proper isolation seems to make perception of this 'character change' as the frequency range is explored, more obvious/less obscured/ more distinguishable.

Dynamics

With proper isolation there seems to be a greater range between soft and loud. Sounds will encompass greater peaks of loud/softer whispers of barely audible. Also between those extremes there will seem to be many more individual gradations/ tiers of nuance. Think of going from a six-inch ruler with quarter inch gradations. To a three feet ruler marked with sixteenth of an inch gradations. Also it will seem that individual elements within the soundfield have greater freedom/ mobility to swell and ebb with dynamics. Not just the entirety of the sonic picture, the elements of the sonic picture can now seem to have a more obvious 'dynamic life' independent of the dynamic life of the entire picture and the other sonic elements.

Low level detail

Now all sorts of tiny obscured minutiae seem to be easily audible which were cloaked. I have used the analogy of the cleaning of the ceiling of the Sistine Chapel art. Nothing was added to the art itself. By removing 'something', more detail becomes perceptible.

I am listening for all three of these parameters to gain simultaneously

Read that last sentence again. They must all improve simultaneously. I mark this as the proof that I am moving in the right direction with my experiments. So let me also talk about the other side of the coin; When the experiment is taking me farther away from the goal.

It is as we would expect:

Tonal greyness. Less natural timbre of instruments/voices. Yes you can still hear that it is a piano, let's say, but the bell like quality of the highs is less distinct. The purr of the piano bass notes diminishes. and the same with other instruments/voices

Dynamics. A flattening of dynamic range and less distinct tiers between the extremes. The individual elements within the soundfield lack individual dynamic freedom such that it only seems like the entire picture gets loud and soft. Not so much the individual elements of the sonic picture.

Low level detail. Minutiae now less perceptible or non-perceptible. Seeming homogenisation of the sonic picture. Obscuring of detail.

These are my 'Litmus Tests'.

theophile said:

Peter
A simple way to closely(maybe not perfectly but close) determine COG. Go to a hardware store by a section of half round moulding.

Mark each cut off end with a vertical line. Place component atop the moulding and re-position the component until you find the the balance axis. mark where this is. Turn the moulding 90 degrees and repeat. I place a piece of masking tape on the sides of the component so that I can mark this location on the component. This is not completely precise, but it gets one fairly close.

Peter as for energy drainage: I use an analogy; A bell is a very resonant object. If it is struck whilst held aloft it will continue to ring until the resonant energy dissipates. Now strike a bell and push the perimeter(the 'open' part) into a surface (table, floor, wall) and the ringing stops dead. Is that not mass damping? The energy in the body of the ringing bell drains.

Now remember that a turntable is essentially holding onto a 'microphone' of sorts(the cartridge which picks up all vibration and translates that into an electrical signal). Thus the draining surface needs to not be adding back into the turntable, vibration which is coming from elsewhere. What I do is have vertical isolation. Atop that a 'drain' object(metal, stone plate with a reasonable mass). Then I place the cups and balls atop the drain object and the bottom of the turntable into direct contact with the balls. The balls couple in the vertical(courtesy of gravity). The cups couple with the drain object via gravity. The vertical isolation below the drain object minimises the transmission of vibes from below into the drain object.

I wrote about it here with photos:

http://audiokarma.org/forums/index.php?threads/they-say-a-picture-paints-a-thousand-words.650778/

I have revised my support since I posted all that. I've taken away the granite(by way of further experimentation into the optimal mass atop the Clearaudio Magix) I am also not anymore using the ceramic incense burners as cups. Now I use the Ingress Engineering cups:

http://www.ingress-engineering.ca/resources/IMG_0379.JPG

I tell people to consider the principles being addressed in my method. Even when applying them to a different method. It is the principles (COG, coupling, decoupling etc) which matter. I feel that there would be a few methods which could work, but the principles always need to be considered and their effects taken into account.

You will note that in the AudioKarma thread I linked to above, I stressed that it is not the method which guarantees success, but the fine tuning of the total load on the vertical elements combined with proper leveling, COG tuning, etc. I said in that thread that I can make the situation deteriorate by sub optimal loading, deviation from COG, not leveling and more. It is not 'one size fits all'( like many IMO dubious products on the market). It requires effort, time and experimentation from the user to optimise.

Too many people want to purchase, place and do nothing more. That would in my mind require the manufacturer of the isolation product to already know the COG of your component, mark the exact place on the isolation product where the component needs to be placed to coincide the component COG with the center of the load bearing elements etc. I don't see any manufacturers doing this. Which makes me wonder about the isolation.

It is not as simple as it seems and there is much to consider. Too few people wish to consider and actively fine tune.

Click to expand...

Thank you Theophile. I like the idea of the half round dowel. I had considered using either a full round and then rotating it 90 degrees or a steel ball, but your suggestion is simpler and safer. Once the COG of the ballast plate and turntable/controller assembly is determined, the next challenge will be to locate the center of the isolation table as it has three feet instead of the four that products like Stacore have. Three feet complicates it because there is more load on the one foot than on the other two, so I think the COG is closer to the single foot but on the centerline of the platform. Any suggestions as to how I can find this?

Regarding energy drainage and the bell analogy: what you write makes some sense, however I think that by touching another surface, not only are you adding mass damping to the bell, but I think you are also changing the resonant frequency of the bell. Some of the vibrations are draining into the table top surface or whatever you are touching the open edge of the bell to, but it seems to me that you are also changing the bells resonant frequency at the same time. The bell continues to vibrate but at a lower, less audible frequency, and for a different duration of time. I do not think that all of the energy is simultaneously drained at the moment of contact. Some energy remains in the bell and it continues to vibrate. We just don't hear it as much. This is where the mass of something like a turntable platter or armboard comes into play. The more massive, the more it is able to absorb any vibration and change its frequency so that it is less harmful to the signal generated at the vinyl/cartridge contact point and that along the path down the arm and arm board.

This gets me to your second section that I highlighted. Depending on the specific turntable design, the cartridge does not in fact act as a microphone that "picks up ALL vibration and translates that into an electrical signal." In the case of my SME, the cartridige is only picking up SOME of the vibrations generated by the system. The amount of the motor's vibration which actually reaches the cartridge through the structure of the plinth/bearing/platter is dramatically lessoned by the clever design of isolating the motor from those elements, first by using teflon/nylon inserts at the motor mount, second, the location of the motor on a separate shelf isolated from the main shelf by suspension towers, and third by the rubber belt itself attached to the sub platter. Ground borne vibrations are also lessoned by the suspension towers although I have enhanced the amount of isolation by placing the entire turntable assembly on a Vibraplane pneumatic isolation platform.

Based on Marc's recent experiments with 1mm pads of various materials under the footers of his Stacore platform, I may look into this also as a way to filter the frequencies of the vibrations reaching up into the Vibraplane. I may also experiment with the ball/cup idea between the top of my Vibraplane and the bottom of the steel ballast plate on which the turntable and motor controller sit. I will be curious to learn if the three ball/cups should be placed directly above the three pneumatic footers in the Vibraplane or if they should be placed in the opposite orientation, with one on the side of and between the two pneumatic footers, and visa versa. Stacore must have experimented with the placement of their ball/cups.

You've been at it for twenty years. That is commendable. I am just beginning to consider what this may all mean and how sonics may be effected.

theophile said:

A few constants I have observed when all is optimally fine tuned:

Natural timbre of instruments/voices.

Dynamics

Low level detail/ sonic texture/ ambiance previously obscured, now emerging. Greater separation of the individual elements in the sonic 'mind's-eye picture'.

Natural Timbre

Instruments change their tonal character as the player explores the tonal frequency range. ie A piano for example can sound 'bell like' in it's higher keys/notes, but sound markedly different to the high notes in its middle and lower keys. The same applies to most instruments. Proper isolation seems to make perception of this 'character change' as the frequency range is explored, more obvious/less obscured/ more distinguishable.

Dynamics

With proper isolation there seems to be a greater range between soft and loud. Sounds will encompass greater peaks of loud/softer whispers of barely audible. Also between those extremes there will seem to be many more individual gradations/ tiers of nuance. Think of going from a six-inch ruler with quarter inch gradations. To a three feet ruler marked with sixteenth of an inch gradations. Also it will seem that individual elements within the soundfield have greater freedom/ mobility to swell and ebb with dynamics. Not just the entirety of the sonic picture, the elements of the sonic picture can now seem to have a more obvious 'dynamic life' independent of the dynamic life of the entire picture and the other sonic elements.

Low level detail

Now all sorts of tiny obscured minutiae seem to be easily audible which were cloaked. I have used the analogy of the cleaning of the ceiling of the Sistine Chapel art. Nothing was added to the art itself. By removing 'something', more detail becomes perceptible.

I am listening for all three of these parameters to gain simultaneously

Read that last sentence again. They must all improve simultaneously. I mark this as the proof that I am moving in the right direction with my experiments. So let me also talk about the other side of the coin; When the experiment is taking me farther away from the goal.

It is as we would expect:

Tonal greyness. Less natural timbre of instruments/voices. Yes you can still hear that it is a piano, let's say, but the bell like quality of the highs is less distinct. The purr of the piano bass notes diminishes. and the same with other instruments/voices

Dynamics. A flattening of dynamic range and less distinct tiers between the extremes. The individual elements within the soundfield lack individual dynamic freedom such that it only seems like the entire picture gets loud and soft. Not so much the individual elements of the sonic picture.

Low level detail. Minutiae now less perceptible or non-perceptible. Seeming homogenisation of the sonic picture. Obscuring of detail.

These are my 'Litmus Tests'.

Click to expand...

Great post. Thank you.

PeterA said:

Based on Marc's recent experiments with 1mm pads of various materials under the footers of his Stacore platform, I may look into this also as a way to filter the frequencies of the vibrations reaching up into the Vibraplane. I may also experiment with the ball/cup idea between the top of my Vibraplane and the bottom of the steel ballast plate on which the turntable and motor controller sit. I will be curious to learn if the three ball/cups should be placed directly above the three pneumatic footers in the Vibraplane or if they should be placed in the opposite orientation, with one on the side of and between the two pneumatic footers, and visa versa. Stacore must have experimented with the placement of their ball/cups.

Click to expand...

Peter, it's 2mm not 1mm And I believe they do quite opposite to prefiltering (which we were trying with various plastics before) - they send the vibrations straight to their hell - our CLD slate!
Place the cups above the bladders.

Cheers,

theophile said:

A few constants I have observed when all is optimally fine tuned:

Natural timbre of instruments/voices.

Dynamics

Low level detail/ sonic texture/ ambiance previously obscured, now emerging. Greater separation of the individual elements in the sonic 'mind's-eye picture'.

Natural Timbre

Instruments change their tonal character as the player explores the tonal frequency range. ie A piano for example can sound 'bell like' in it's higher keys/notes, but sound markedly different to the high notes in its middle and lower keys. The same applies to most instruments. Proper isolation seems to make perception of this 'character change' as the frequency range is explored, more obvious/less obscured/ more distinguishable.

Dynamics

With proper isolation there seems to be a greater range between soft and loud. Sounds will encompass greater peaks of loud/softer whispers of barely audible. Also between those extremes there will seem to be many more individual gradations/ tiers of nuance. Think of going from a six-inch ruler with quarter inch gradations. To a three feet ruler marked with sixteenth of an inch gradations. Also it will seem that individual elements within the soundfield have greater freedom/ mobility to swell and ebb with dynamics. Not just the entirety of the sonic picture, the elements of the sonic picture can now seem to have a more obvious 'dynamic life' independent of the dynamic life of the entire picture and the other sonic elements.

Low level detail

Now all sorts of tiny obscured minutiae seem to be easily audible which were cloaked. I have used the analogy of the cleaning of the ceiling of the Sistine Chapel art. Nothing was added to the art itself. By removing 'something', more detail becomes perceptible.

I am listening for all three of these parameters to gain simultaneously

Read that last sentence again. They must all improve simultaneously. I mark this as the proof that I am moving in the right direction with my experiments. So let me also talk about the other side of the coin; When the experiment is taking me farther away from the goal.

It is as we would expect:

Tonal greyness. Less natural timbre of instruments/voices. Yes you can still hear that it is a piano, let's say, but the bell like quality of the highs is less distinct. The purr of the piano bass notes diminishes. and the same with other instruments/voices

Dynamics. A flattening of dynamic range and less distinct tiers between the extremes. The individual elements within the soundfield lack individual dynamic freedom such that it only seems like the entire picture gets loud and soft. Not so much the individual elements of the sonic picture.

Low level detail. Minutiae now less perceptible or non-perceptible. Seeming homogenisation of the sonic picture. Obscuring of detail.

These are my 'Litmus Tests'.

Click to expand...

It probably takes two decades to be able to put all the immense variety of observations re isolation in such simple yet powerful words.
Thank you Theo!

PS We definitely come from the same background of Barry Diament.

Stacore said:

Peter, it's 2mm not 1mm And I believe they do quite opposite to prefiltering (which we were trying with various plastics before) - they send the vibrations straight to their hell - our CLD slate!
Place the cups above the bladders.

Cheers,

Click to expand...

spiritofmusic said:

I find it totally fascinating that with 95kg of slate mass loading and pneumatic isolation, such a difference in presentation can be had with four 2.5cm diameter S crew-in footers, each one only 1mm thick.
The Stacores have really been a revelation in my system, these footers are now taking neutrality to a whole other level.

Click to expand...

Stacore said:

Hey Peter!

1) We are pneumatic of course. Marc must have confused our suspension with the one in his beautiful Citroen

2) Our platform is a mix of several damping/isolating techniques as one solution cannot give it all no matter what you do. It is now a question how to combine those solutions so that they work best. My initial idea, implemented in our current platforms, was exactly like you say - prefilter at least something before the air bladders, so that less is transmitted higher up. That's why we were using industrial damping plastic, then experimented with the teflon. But it turned out that this prefiltering idea is not the optimal, at least not always and it seems beneficial to let the >50Hz vibs hit the bladder and then the CLD slate. It's a question of optimizing various elements to give the best broadband isolation. We will offer as a standard both hard teflon and the steel caps for the user to choose the best interface.

Cheers,

Click to expand...

Hi Jarek. Thank you for the clarification about the thickness of those washers. I simply read Marc's post, copied above, and assumed they were 1mm thick. Marc refers to them as "screw-in footers", but you refer to them as washers. I understand them to be the material interface making contact between your platforms and the top surface of the supporting rack below. Is this correct, and are they attached to the bottom of the pneumatic air bladders?

I also thought you were attempting to pre filter the vibrations as they hit your platform based on your post above. I now understand that you have moved beyond that. My Vibraplane footers/air bladders have metal bottoms which I suppose would allow vibrations to move straight up into the pneumatic footers where they are attenuated.

In your case, don't the vibrations also go from the rack support through the pneumatic bladders before they hit the CLD slate or are the bladders above the slate? The order of assembly of your various parts and where the pneumatic bladders are located relative to the bottom and top of the assembly and what is in contact with each side of them is not clear to me.

I had also thought that you have four bladders, one at each corner of the platform, but if your ball/cup assemblies are located above each bladder, it appears that you must have only three because there are three ball/cups in the image of the Stacore.

Regarding Theophile's comments about the importance of knowing where the center of gravity is, do you indicate where the center of gravity along the top surface of your platform is located? With three footers, it must not be in the center of the top surface of the platform but closer to the side with one footer and still along centerline from front to back of the top surface. Is that correct?

PeterA said:

Thank you Theophile. I like the idea of the half round dowel. I had considered using either a full round and then rotating it 90 degrees or a steel ball, but your suggestion is simpler and safer. Once the COG of the ballast plate and turntable/controller assembly is determined, the next challenge will be to locate the center of the isolation table as it has three feet instead of the four that products like Stacore have. Three feet complicates it because there is more load on the one foot than on the other two, so I think the COG is closer to the single foot but on the centerline of the platform. Any suggestions as to how I can find this?

Regarding energy drainage and the bell analogy: what you write makes some sense, however I think that by touching another surface, not only are you adding mass damping to the bell, but I think you are also changing the resonant frequency of the bell. Some of the vibrations are draining into the table top surface or whatever you are touching the open edge of the bell to, but it seems to me that you are also changing the bells resonant frequency at the same time. The bell continues to vibrate but at a lower, less audible frequency, and for a different duration of time. I do not think that all of the energy is simultaneously drained at the moment of contact. Some energy remains in the bell and it continues to vibrate. We just don't hear it as much. This is where the mass of something like a turntable platter or armboard comes into play. The more massive, the more it is able to absorb any vibration and change its frequency so that it is less harmful to the signal generated at the vinyl/cartridge contact point and that along the path down the arm and arm board.

This gets me to your second section that I highlighted. Depending on the specific turntable design, the cartridge does not in fact act as a microphone that "picks up ALL vibration and translates that into an electrical signal." In the case of my SME, the cartridige is only picking up SOME of the vibrations generated by the system. The amount of the motor's vibration which actually reaches the cartridge through the structure of the plinth/bearing/platter is dramatically lessoned by the clever design of isolating the motor from those elements, first by using teflon/nylon inserts at the motor mount, second, the location of the motor on a separate shelf isolated from the main shelf by suspension towers, and third by the rubber belt itself attached to the sub platter. Ground borne vibrations are also lessoned by the suspension towers although I have enhanced the amount of isolation by placing the entire turntable assembly on a Vibraplane pneumatic isolation platform.

Based on Marc's recent experiments with 1mm pads of various materials under the footers of his Stacore platform, I may look into this also as a way to filter the frequencies of the vibrations reaching up into the Vibraplane. I may also experiment with the ball/cup idea between the top of my Vibraplane and the bottom of the steel ballast plate on which the turntable and motor controller sit. I will be curious to learn if the three ball/cups should be placed directly above the three pneumatic footers in the Vibraplane or if they should be placed in the opposite orientation, with one on the side of and between the two pneumatic footers, and visa versa. Stacore must have experimented with the placement of their ball/cups.

You've been at it for twenty years. That is commendable. I am just beginning to consider what this may all mean and how sonics may be effected.

Click to expand...

Please regard my 20 years at this by way of analogy: If I'd said that I'd spent 20 years building a garden shed 10 feet x 8 feet x 8 feet high out of timber and corrugated iron, would you still be impressed? Most of that time I was trying cheap and hopeless methods which had almost zero effect. I bought a SAP Relaxa 3+ mag-lev stand about 11 years ago. This came after using innertubes for 4 or 5 years. I got sick of the never ending( and I mean never ending) leakage form the innertubes. The SAP Relaxa showed some promising signs but I still couldn't get the result I was hoping for.

My initial purchase of 8 'Clearaudio Magix 2' came because my Yamaha GT 2000 was too heavy for the continued use of the SAP. I wanted to have plenty of leeway in experimenting with the optimum load on the Magix. By that I mean that should it be necessary to load the Magix down to very close to their rated maximum load I could easily add weight, but should it turn out that the Magix were best at (say 1/2 or even 1/3 of the max rating) I'd need to have a lot more of them under the GT 2000 than 8. I tried 14 and then tried 21. Which is where it has remained for quite a while now.

When I initially had 8 and 14 Magix, I was just trying different arrangements of them by lining them up directly underneath the GT 2000. I still wasn't getting the results I wanted. There would be improvements but they were small or mixed. 2 steps forward one step back. My Eureka Moment was realising that I needed to get the COG of the GT 2000 in a place on the support where the individual Magix units all shared the load evenly. It was obvious that a circle of Magix with the GT 2000 placed such that its COG was dead center from them was the answer. The pictures in the Audiokarma Thread ( Here: http://audiokarma.org/forums/index.php?threads/they-say-a-picture-paints-a-thousand-words.650778/ ) show the arrangement.

I got some methylmethacrylate cut to specification. I had calculated that I'd need a circle with an outer diameter of 850mm. I got a 6mm circle cut upon which the Magix could stand in such a way that their outer edge touched the edge of the 850mm circle. That was a way of maintaining a strict circle. Atop the Magix I placed another 850mm diameter circle of methylmethacrylate, only this one was 15mm thick because it had to be able to support the 68Kg of the GT 2000 plus the 30Kg of the granite slab I hoped to use as the 'drain object'. I was at the time using 3 ceramic incense burners as the cup element. Within the cups were the 3 Silicon Nitride grade 5 balls. I used 5mm stainless steel plates flush with the bottom of the GT 2000 to act as the interface between the balls and the GT 2000. That is what you see in the AudioKarma pictures I linked in the last paragraph.

The serendipitous height of the incense burners allowed me to place additional weight directly underneath the GT 2000. Basically, everything that went atop the Magix( the methacrylate circle/ the granite slab/ the ceramic incense burners/ the GT 2000), had to be centered with regard to COG.

I have now removed the Granite slab 'drain object' pictured in the AK link and have placed my Ingress Engineering cups atop upturned ceramic coffee mugs. This as I said about the ceramic incense burners, allows me to place weight directly underneath the GT 2000, in order to fine tune the optimal load atop the Clearaudio Magix.

None of this is easy. All of it is painstaking. The results are(I feel) well worth it.

I would only recommend painstaking isolation efforts to the owners of excellent turntables and systems. Basically with lesser turntables or compromised systems, the inherent compromises of lesser turntables or the system itself, would swamp the benefit accrued by the isolation. In those instances, the purchase of either a better turntable of further system upgrades would be more advisable.

spiritofmusic said:

Theo, fantastic input from you.
Re centre of mass/gravity, I can’t disagree with you, but with assymetric loading of tts, I’ve always struggled to work out where this is, esp with cantilevered arm pods, seperate motors, rim drive pod (in my case).
The other thing is that the Stacore is more than simple pneumatic isolation, but uses uber mass loading and Jarek’s “secret sauce” constrained layer materials to additionally deal with vibrations and noise.
That’s why in the case of a “simple” single central spring and non-fancy steel top plate in the case of the Minus K, it was definitely essential to get central loading of the tt absolutely correct (nigh on impossible), but with the Stacore nowhere near as critical.

Click to expand...

Which is why I feel that you didn't eke out all of the potential of the Minus K.

I understand that Jarek has worked hard on his platform and since his method has broad points in common with mine, I understand what it is doing correctly. Jarek has admitted that he overlooked COG, but had his own Eureka Moment revelation that it was key to stability. The COG is where all the other forces 'null'. If you investigate the concept you will come to realise how crucial COG is to so many factors of, especially, turntables. It doesn't end there. Space flight. Motor car racing. So much of modern transport relies on the stability of COG being front and center of the integral design. I feel that you want it to not be important to the Stacore, but the Stacore doesn't exist outside of the Laws that govern our 3D physical world and COG is one of the fundamentals of motion.

Separate motors definitely complicate things. I would be inclined to put the entire turntable/separate motor on a rigid (7075 Aluminium or Stainless Steel) plate (say 10mm thick). Then get some half-round moulding and do what I suggested in the reply to Peter A. Place the turntable/metal plate atop the half-round moulding, Mark the balance point. Turn the moulding 90 degrees and mark again at the balance point. This the initial step. Not the end of the road. After this comes fine tuning the optimum load and fine tuning the COG, because the half round moulding gets you close but you have to be precise to get the entire benefit.

I'm going to let you consider what I have just written, because it will throw your preconceptions around a bit. I am not being critical of your efforts nor of Jarek and his product. I can see that he is a fine thinker and that he has put an immense effort into his successful product. OK? Principles are what they are. They are fundamental and nothing worthwhile proceeds to perfection without addressing them. I wish to provoke others to think more than I wish to provide them with answers. Jarek is a fine thinker. I'll wager that my conversations here have really got him picturing things in his mind that he would like to test.

I started my own thread here at WBF, which praised the posters/members for their embracing of isolation. Many here have deeply committed to embracing the concept and practice of superb replay of recorded music/ recorded sound. They have outlaid time, effort, money and mental focus to chasing superb replay of recorded music. This is how excellence is attained. It isn't just money. It isn't just time. There has to be a boatload of effort and logical application committed also. A superb system requires a lot of thought, a lot of consideration and needs to be treated as much like an art that, let's say, fine cooking is. Assembling a superb system is a skill.

spiritofmusic said:

Theo, I get this idea.
Unfortunately, I’m hamstrung by my setup.
My one piece tonearm wire is relatively short meaning I can’t position my Straingauge energiser box anywhere else other than right next to the tt, and now the whole width of Stacore taken up.
As a result, I have only latitude to move the tt/energiser backwards and forwards a few inches.
It’s not as if the Stacore is 30” x 24”, and I can really shuffle the tt position around with abandon.

Click to expand...

I'm going to bed now. I will reply tomorrow. I promise.

Hi Peter,

PeterA said:

Hi Jarek. Thank you for the clarification about the thickness of those washers. I simply read Marc's post, copied above, and assumed they were 1mm thick. Marc refers to them as "screw-in footers", but you refer to them as washers. I understand them to be the material interface making contact between your platforms and the top surface of the supporting rack below. Is this correct, and are they attached to the bottom of the pneumatic air bladders?

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Yes, they are at the bottom of the bladders and this is a screw-in element plus a washer to damp it

PeterA said:

I also thought you were attempting to pre filter the vibrations as they hit your platform based on your post above. I now understand that you have moved beyond that. My Vibraplane footers/air bladders have metal bottoms which I suppose would allow vibrations to move straight up into the pneumatic footers where they are attenuated.

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The air bladders work up to some 40-50Hz at most. Past that, vibrations travel on the surface of the bladders' elastomer (skin modes).

PeterA said:

In your case, don't the vibrations also go from the rack support through the pneumatic bladders before they hit the CLD slate or are the bladders above the slate? The order of assembly of your various parts and where the pneumatic bladders are located relative to the bottom and top of the assembly and what is in contact with each side of them is not clear to me.

I had also thought that you have four bladders, one at each corner of the platform, but if your ball/cup assemblies are located above each bladder, it appears that you must have only three because there are three ball/cups in the image of the Stacore.

Click to expand...

Of course the bladders are below the CLD slate. The topology of our pneumatic suspension is similar to other platforms, but we pushed it further with our own implementation.

Logically, so to speak, there are always 3 independent support points.

PeterA said:

Regarding Theophile's comments about the importance of knowing where the center of gravity is, do you indicate where the center of gravity along the top surface of your platform is located? With three footers, it must not be in the center of the top surface of the platform but closer to the side with one footer and still along centerline from front to back of the top surface. Is that correct?

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The point of support of equimpent's COG is platform's geometrical center.

Cheers,

spiritofmusic said:

(...) Re centre of mass/gravity, I can’t disagree with you, but with assymetric loading of tts, I’ve always struggled to work out where this is, esp with cantilevered arm pods, seperate motors, rim drive pod (in my case).(...)

Click to expand...

Quite easy to determine - you just need a fisherman scale with adequate range.

theophile said:

I understand that Jarek has worked hard on his platform and since his method has broad points in common with mine, I understand what it is doing correctly. Jarek has admitted that he overlooked COG, but had his own Eureka Moment revelation that it was key to stability. The COG is where all the other forces 'null'. If you investigate the concept you will come to realise how crucial COG is to so many factors of, especially, turntables. It doesn't end there. Space flight. Motor car racing. So much of modern transport relies on the stability of COG being front and center of the integral design. I feel that you want it to not be important to the Stacore, but the Stacore doesn't exist outside of the Laws that govern our 3D physical world and COG is one of the fundamentals of motion.

Click to expand...

Cannot agree more with a small caveat that we did not overlook COG issues in the design of course, but rather did not pay the attention it deserves with equipment placing on the platforms.
Here is another interesting instance of getting the COG correct. Or at least the hypothesis is so: http://www.tnt-audio.com/sorgenti/vta_e.html

theophile said:

I'm going to let you consider what I have just written, because it will throw your preconceptions around a bit. I am not being critical of your efforts nor of Jarek and his product. I can see that he is a fine thinker and that he has put an immense effort into his successful product. OK? Principles are what they are. They are fundamental and nothing worthwhile proceeds to perfection without addressing them. I wish to provoke others to think more than I wish to provide them with answers. Jarek is a fine thinker. I'll wager that my conversations here have really got him picturing things in his mind that he would like to test.

Click to expand...

Thank you Theo for the kind words! Physicist by profession, I move by the laws of physics. This is an amazing feeling when you sort of give up to the laws of Nature, follow them as a river follows its valley and then feel this fantastic outcome it gives you.
One of the key feature of our isolation method is it's stability - irrespectively of the component type being isolated (source, DAC, amp, SS, tube, speaker, etc) and the system it is in, I always know what to expect. To a bigger or smaller degree, but the positive effect is there and is not random. Amazing feeling.

Cheers,