Vibration Management

[DaveC]

Pretty cool little online calculator for Acoustic Impedance measurements showing the amount of reflection involved

https://www.nde-ed.org/EducationResources/CommunityCollege/Ultrasonics/js_apps/acousticImpedance/

Brief explanation of calculator function:

"The following applet can be used to calculate the acoustic impedance for any material, so long as its density (p) and acoustic velocity (V) are known. The applet also shows how a change in the impedance affects the amount of acoustic energy that is reflected and transmitted. The values of the reflected and transmitted energy are the fractional amounts of the total energy incident on the interface. Note that the fractional amount of transmitted sound energy plus the fractional amount of reflected sound energy equals one."

That's really interesting, not so intuitive either. I wonder if best transmission/least reflection would have any correlation to listening preferences. Alum > Steel reflects back 20%, a good bit more than other materials and it looks like identical materials are best if you go by least amount of reflected energy.

 

[stehno]

John, Im happy to talk online here or by PM
Was unsure of your preferred method of comms
Re my system and my journey, Im actually at a place Im pretty happy to step off re component upgrades, w poss exception of a new tt/arm and SGM server/Dac8
I've pretty much blown 2-3 years components upgrade budget on creation of my new room/bespoke electrical supply
The upstick w these has been so startlingly good that I'm off the gear change merry go round
The only area that I think could enhance things further might be vibration management, and to this end I'm going to trial active v passive to tt
If this is really fruitful, I could consider same solutions to each component
At a cost of $3k per piece of gear
Ie pre X 2, monos X 2, cdp, spkrs X 2
But, w no idea of what you're offering, the ball is in yr court to inform me of solutions further
Aims? Improved transparency, noise flr, microdynamics
Usual checklist

Hey, Marc. I'm not ignoring you as I'm just taking a little time to think of a sufficient solution for your requirements. BTW, how long/deep are those amps? They look to be about 24 inches deep or so?

 

[Folsom]

Show us some damn pictures Stehno. You're killing me. I read a little book of blah over and over, but I need to see it.

 

[stehno]

That's really interesting, not so intuitive either. I wonder if best transmission/least reflection would have any correlation to listening preferences. Alum > Steel reflects back 20%, a good bit more than other materials and it looks like identical materials are best if you go by least amount of reflected energy.

Acoustic impedance on its face would seem to have little legitimacy in this application as we're not talking sound waves reflecting off of component and racking system surfaces. At least not as a primary matter but perhaps a distant secondary one.

I pay close attention to the materials I use and like I've said before, brass is one a the metals I do not use because I've considered it too slow and impedes energy's ability to travel unlike some other metals.

As for mechanical energy traveling, I suspect just like the energy traveling between the tines after striking the tines of tuning fork, we're talking energy traveling within and along the surfaces of these disparacte objects and primarily creating a mechanical conduit between the disparate objects. Perhaps not unlike electrical current flowing thru and along the surface of a cable. Only slower.

Moreover, in this applicatioin I suspect the importance of mechanical impedance ratiings is going to vary to very good extents for at least several reasons. 1) There is a duration of time required for energy travel to be at its optimal (mechanical settling in) and the severity of the mechanical settling in is directly impacted by the amount of force applied to sandwich the two disparate objects.

In other words, I suspect mechanical impedance readings do not take this mechanical settling-in into account since it seems so few are aware of its existence. Also, once the mechanical settling in has reached its max, I suspect any impedence readings would change drastically.

For example. The impedence rating of a hammer striking the top of one silver dollar placed on top of another silver dollar would be quite different than if the two silver dollars are sandwiched tightly together in a vise and allowed to "settle" for one month (like a soft weld), and I suspect should be yet another quite different rating again if the 2 silver dollard were hard welded together.

 

[stehno]

Show us some damn pictures Stehno. You're killing me. I read a little book of blah over and over, but I need to see it.

Here ya go.

 

[treitz3]

Very nice!

Tom

 

[PeterA]

Edit: Just saw you posted images. Thanks for showing those.

Stehno, this clamping idea is pretty interesting. Which condition do you think would provide a better conduit for energy transmission: a very large solid plate the size of a component on both the top and the bottom plates of the component exerting fairly uniform pressure on the entire top and bottom surfaces (once footers have been removed), or a clamp that exerts its pressure on points arranged in particular locations on the top and bottom plates, or along the perimeter of the side plates? It seems to me that components generally have more solid side plates than top and bottom plates so the edges could take more compressive clamping force.

One issue I see is the deformation of a component's metal casework, dramatically reducing resale value. And with the larger plate clamp surface, ventilation might become an issue.

You were writing earlier about the advantages of three points forming a plane, preferred for stability. What about loading or clamping a component in such a way that the conduit travels to a single point or rod for maximum vibrational energy drainage? The component could be stabilized by different materials like wood or plastic that insulate and don't transmit the vibrational energy thus directing it toward the single conduit. The component could still be stable, not rocking back and forth while the mechanical energy finds the path of least resistance through a single spike, ball or rod under extreme pressure.

What do you think?

 

[DaveC]

Acoustic impedance on its face would seem to have little legitimacy in this application as we're not talking sound waves reflecting off of component and racking system surfaces. At least not as a primary matter but perhaps a distant secondary one.

I pay close attention to the materials I use and like I've said before, brass is one a the metals I do not use because I've considered it too slow and impedes energy's ability to travel unlike some other metals.

As for mechanical energy traveling, I suspect just like the energy traveling between the tines after striking the tines of tuning fork, we're talking energy traveling within and along the surfaces of these disparacte objects and primarily creating a mechanical conduit between the disparate objects. Perhaps not unlike electrical current flowing thru and along the surface of a cable. Only slower.

Moreover, in this applicatioin I suspect the importance of mechanical impedance ratiings is going to vary to very good extents for at least several reasons. 1) There is a duration of time required for energy travel to be at its optimal (mechanical settling in) and the severity of the mechanical settling in is directly impacted by the amount of force applied to sandwich the two disparate objects.

In other words, I suspect mechanical impedance readings do not take this mechanical settling-in into account since it seems so few are aware of its existence. Also, once the mechanical settling in has reached its max, I suspect any impedence readings would change drastically.

For example. The impedence rating of a hammer striking the top of one silver dollar placed on top of another silver dollar would be quite different than if the two silver dollars are sandwiched tightly together in a vise and allowed to "settle" for one month (like a soft weld), and I suspect should be yet another quite different rating again if the 2 silver dollard were hard welded together.

I think, and maybe cjf can confirm, that the applet is an idealized computation of a vibration in material 1 traveling to material 2. I'd also guess the interface is assumed to be perfect between the materials. So material 1 would be the chassis and material 2 would be the rack. I'd further guess that in real life the interface is imperfect and would cause the result to be more reflection, with your clamping system improving the interface and making it closer to ideal.

In any case I think most have found the rack material to be clearly audible but trying to correlate that with measurements might be difficult... like much of audio.

 

[stehno]

Edit: Just saw you posted images. Thanks for showing those.

Stehno, this clamping idea is pretty interesting. Which condition do you think would provide a better conduit for energy transmission: a very large solid plate the size of a component on both the top and the bottom plates of the component exerting fairly uniform pressure on the entire top and bottom surfaces (once footers have been removed), or a clamp that exerts its pressure on points arranged in particular locations on the top and bottom plates, or along the perimeter of the side plates? It seems to me that components generally have more solid side plates than top and bottom plates so the edges could take more compressive clamping force.

Peter, I'm an absolute minimalist in everything I do related to high-end audio and performance. As I like to say, you'll never see top fuel dragsters pulling U-Haul trailers down the quarter mile - and for good reason.

I wouldn't hesitate to use a large solid plate for a special condition but I suspect performance could suffer just a tad. Energy likes to travel but I prefer to control its direction rather than give it the opportunity to scatter over a wider area.

But I see what you're saying. It was my hope to one day see performance-oriented component mfg'ers modify their chassis' ever so slightly so that I could directly and tightly couple them to their assigned shelves without the need for universal clamps. It was my dream to one day see component chassis' done away with altogether and just have super constructed modules bolted directly to the rack with audio-grade electrical connectors to connect the modules. What can I say, I'm a dreamer.

I've been able to extract tremendous volumes of performance from the components but at some point the mfg'ers would need to adapt this same strategy to knock things outta' the park since no component is an island.

One issue I see is the deformation of a component's metal casework, dramatically reducing resale value. And with the larger plate clamp surface, ventilation might become an issue.

In the 10 years I've been clamping my components with tremendous amounts of compressive force, I've yet to encounter any crimping, etc of a chassis as I'm very careful and it's hand-tightening only usually just shy of using all my strength. Back when I was an in-home dealer I had even taken components out of the rack and shipped them to customers for auditioning, never having a scratch, etc. Though sometimes there might be a scuff or two on the bottom plate where it meets the pods bolted to the rack. But that's not supposed to count during resale anyway.

You were writing earlier about the advantages of three points forming a plane, preferred for stability. What about loading or clamping a component in such a way that the conduit travels to a single point or rod for maximum vibrational energy drainage?

What do you think?

Well, funny you should mention that. Though you may be implying something slightly different, one of my paper designs was where a single (and double) mast was anchored into a concrete floor with variable-height adjustable shelfs. In other words no bottom shelf, just upper shelves with vertical masts straight into the concrete floor. In my limited experience, concrete is a superior performing flooring system and makes for a wonderful foundation for this stuff. Another design was to have no shelf at all but just universal clamps anchored directly to a cement floor. Did I mention I'm a minimalist?

 

[KeithR]

If Stehno is a manufacturer, why is this not disclosed on his signature?

 

[KlausR.]

That's really interesting, not so intuitive either. I wonder if best transmission/least reflection would have any correlation to listening preferences. Alum > Steel reflects back 20%, a good bit more than other materials and it looks like identical materials are best if you go by least amount of reflected energy.

That's exactly what physics tells us and that's exactly what I said:

The higher the difference in impedance the more of the energy is reflected.

If you want to drain vibratory energy away you need materials with similar impedance. The first one you usually can't choose since it's what the audio component is made of. If the component has rubber feet a steel interface is not as good as a wooden interface. Placing a steel rack on a concrete floor isn't a good idea either.

Klaus

 

[stehno]

I suppose I should come clean and show what I'm listening to today. In the previous photo was my old system with an Esoteric CDP and a BMC int. amp and it showed nicely as I'm into aesthetics and even looked like I meant business. But I've not owned those components for 3 years now.

She may not look like much but I'm very proud of its level of musicality. And I cannot begin to tell you how vastly superior this OPPO / Wyred4Sound config is over the Esoteric / BMC combo when combined with some new alterations in the way I now mount my components. This was going from $17k in components down to $4k in components and when all said and done it was by far my best component upgrades ever experienced. Line conditioners are mounted at the rear.

There is no bling remaining so it's best listening in the dark.

 

[the sound of Tao]

That's exactly what physics tells us and that's exactly what I said:

If you want to drain vibratory energy away you need materials with similar impedance. The first one you usually can't choose since it's what the audio component is made of. If the component has rubber feet a steel interface is not as good as a wooden interface. Placing a steel rack on a concrete floor isn't a good idea either.

Klaus

Thanks Klaus, great info on material impedance and also your earlier perspectives on patent were also cool.

 

[KlausR.]

Acoustic impedance on its face would seem to have little legitimacy in this application as we're not talking sound waves reflecting off of component and racking system surfaces.

Acoustic impedance comes into play when there are interfaces across which energy has to travel. You want to drain vibrations away from audio components, do you not?

Speaking of sound waves hitting an amp with, for instance, aluminium housing: the impedance of aluminium is 42,500 times greater than that of air, so there will be no transmission at all, only reflection, and this only at frequencies where the wavelength is about 4.5 times greater than the dimensions of the amp. Please explain why the amp housing should vibrate when being exposed to airborn sound waves.

And since you're at it, please explain why steel should provide better draining than wood when the laws of physics clearly show that this is not the case?

As for mechanical energy traveling, I suspect just like the energy traveling between the tines after striking the tines of tuning fork, we're talking energy traveling within and along the surfaces of these disparacte objects and primarily creating a mechanical conduit between the disparate objects.

You can suspect whatever you want, but a mechanical interface is an obstacle, and the size of that obstacle depends on the physical parameters of the materials used, density and speed of sound, and not of the will or wishful thinking of the audiophile. Energy travel across interfaces is dictated by laws of physics and you can't bend those.

Moreover, in this application I suspect the importance of mechanical impedance ratings is going to vary to very good extents for at least several reasons. 1) There is a duration of time required for energy travel to be at its optimal (mechanical settling in) and the severity of the mechanical settling in is directly impacted by the amount of force applied to sandwich the two disparate objects. In other words, I suspect mechanical impedance readings do not take this mechanical settling-in into account since it seems so few are aware of its existence. Also, once the mechanical settling in has reached its max, I suspect any impedence readings would change drastically.

This would mean that you change either the density of the material or the speed of sound in that material. Do you have any evidence for that?

 

[Folsom]

stehno, price is no guarantee of performance. The biggest shame often comes from a manufacturer under valuing themselves so much that they price themselves out of business on such amazing gear. I know people that use things way cheaper than you'd expect, and some can literally afford anything that has ever been made. No sweat, you're obviously as obsessed with the best you can do, to the point of manufacturing your own pieces of the puzzle. I'm impressed.

Your photos mean so much more than you might have thought. I actually think your rack system is smarter than you even realize. I don't believe it entirely works the way you explain it, but you've arrived at the right places.

My highest curiosity would be if you'd get a better result from a flat coupling disc, made of a elastomer type material but pretty rigid, in the front, and not just cones in the rear but cups as well. I'm almost sure you would, but perhaps you've been there.

 

[stehno]

Edit: Just saw you posted images. Thanks for showing those.

Stehno, this clamping idea is pretty interesting. Which condition do you think would provide a better conduit for energy transmission: a very large solid plate the size of a component on both the top and the bottom plates of the component exerting fairly uniform pressure on the entire top and bottom surfaces (once footers have been removed), or a clamp that exerts its pressure on points arranged in particular locations on the top and bottom plates, or along the perimeter of the side plates? It seems to me that components generally have more solid side plates than top and bottom plates so the edges could take more compressive clamping force.

What do you think?

Peter, sorry I misunstood. I see what you mean now. Yes, one would assume that the sides and perimeter would be best mounting points, but I tried just that not long ago and surprisingly benefits were minimal. The heft of a solid top and bottom plates would most likely improve performance at least a bit. But without pressure point mounts, particularly close to where the power supply, a motor, etc, is located, performance benefits suffers much.

In essence, I think what you're suggesting is a bit of an external chassis with rigidity and heft surrounding and compressing the internal chassis. If the new outside bottom plate had some pressure points tight against the internal chassis bottom plate, particularly in strategic locations, and the whole new object was sufficiently mounted to the shelf as a single unit, then yes, it should work moderately to perhaps quite well. Then again, there needs to be some pressure points on top to sufficiently damp the top plate too - to ensure it no longer vibrates but hopefully transfer that energy there toward the outside perimeter.

As you seem to realize, there are numerous even extreme ways to skin this cat. But it's important to not forget the significance of completing the grounding of this energy to the sub-flooring system via the rack and its ability to continue that effort.

Early on, I used to say that the clamping was responsible for maybe 20 - 25% of the entire rack's overall performance. Icing on the cake is what I called it then. But with the way I do things today, I'd venture it's much closer to the 50 - 50 region. Definitely part of the cake.

When I launched my rack in 2010, I also granted Audio Horizons an exclusive license to just sell the clamps for customers to mount to existing shelves / racks. They didn't sell many, but of those who provided feedback, I think possibly every one of them said the clamps were the best kept secret in high-end audio.

But also bear in mind that whenever audio enthusiasts (including me) encounter a performance improvement that exceeds say 10 or 15%, it's often times interpreted as a life-changing experience and doing cartwheels in the streets.

 

[stehno]

stehno, price is no guarantee of performance. The biggest shame often comes from a manufacturer under valuing themselves so much that they price themselves out of business on such amazing gear. I know people that use things way cheaper than you'd expect, and some can literally afford anything that has ever been made. No sweat, you're obviously as obsessed with the best you can do, to the point of manufacturing your own pieces of the puzzle. I'm impressed.

Oh, I'm well aware and have been for more than decade. A good friend used to say about this hobby, "One must spend a lot of money to realize one need not spend a lot of money."

When I was marketing my rack, exhibiting at audio shows, etc. my friends would chew me out a bit if I had upgraded my system with a more costly component. Because the first thing people would say if they liked the performance would be, oh it only sounds good because he's using these components. So that, including some other things, was a bit of quandry for me. Another quandry was if I used inexpensive components, those who could afford the rack, wouldn't take it seriously.

Your photos mean so much more than you might have thought. I actually think your rack system is smarter than you even realize. I don't believe it entirely works the way you explain it, but you've arrived at the right places.

It's not possible for my rack to be smarter than I realize. I designed it. And yes, it does work pretty much the way I initially intended. But you on the other hand may be more astute than I initially thought. Thanks for the compliment.

My highest curiosity would be if you'd get a better result from a flat coupling disc, made of a elastomer type material but pretty rigid, in the front, and not just cones in the rear but cups as well. I'm almost sure you would, but perhaps you've been there.

Sorry. It's a dud.

 

[KlausR.]

Thanks Klaus, great info on material impedance and also your earlier perspectives on patent were also cool.

Thanks for the compliment. I for one prefer to approach these issues from a scientific and engineering perspective and do not rely on listening alone, without controlling the listening parameters.

http://www.aes.org/e-lib/browse.cfm?elib=3899
http://www.aes.org/e-lib/browse.cfm?elib=14393
http://www.aes.org/e-lib/browse.cfm?elib=6338

If interested in reading those, send me a forum mail with an email adress.

Klaus

 

[Folsom]

Sorry. It's a dud.

Which? not using cones on all 3? cup and cones? the combo?



Sometimes our subconscious understands things we don't, so we make things we aren't even 100% sure how to explain. I do this from time to time.

 

[Stacore]

When I launched my rack in 2010, I also granted Audio Horizons an exclusive license to just sell the clamps for customers to mount to existing shelves / racks. They didn't sell many, but of those who provided feedback, I think possibly every one of them said the clamps were the best kept secret in high-end audio.

This I find a very cool idea! While I'm more with Klaus re the mental picture why this type of a "skeleton" rack works,
clamping is a very clear and well practiced engineering idea and its sort of strange nobody used it before John in audio!
Clamping both damps some chassis resonances (the driving force has to work against the constraints) and moves them higher where
they can have a chance to be better damped, i.e. by the chassis material itself. Marketing apart, I would not at all be dogmatic with either clamping
or isolation. I don't see those techniques as mutually exclusive. To the contrary, I'd rather see them combined:
Equipment clamped to an isolation platform. Roughly speaking, clamping would take care of (some of) the airborne resonances in
the chassis, while the platform of the structure-borne. Just by plain physics, there is simply no chance for a single technique to be good for all.
We realized that at Stacore and combine different techniques to work for the target effects (repeatability of the sonical results is one of them).

Cheers,