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In Reply to: Re: Suspending a component is not sufficient... posted by Tim G. on June 03, 2004 at 12:20:15:
Attention to vertical coupling is very important, even in cases where vertical isolation will be implemented. Due to gravity, we can't truly float our components, therefore our gear must be coupled to the ground in some manner, even if thru a vertical isolation device - you must couple your gear to the device, and the device to the rack or floor.If you're going to go the string suspension route, then I think you have the right idea in using something like cones to couple the component to the suspension cradle. You should also make the cradle as light and stiff as possible. Aircraft (7075) aluminum would be the best material (short of carbon fiber), next would be 6061 T6 aluminum. If you're going to use steel, you may want to consider swiss-cheesing it by drilling lots of holes in it - it's definitely more important for it to be stiff than to be light - you'll need to find the best compromise within your budget. You should also consider damping the structure if you make it out of steel (Mortite, or rope caulk, works well). Even better than a metal cradle, however, would be some type of constrained layer platform. As Barry Kohan hit on earlier in this thread, a platform would help out with some of the other types of vibration that the string won't addrress.
You will also want to pay attention to how you mount the string to both the support and cradle/platform. Minimizing static friction is very important in maximizing the effectiveness of any spring/pendulum suspension. As I stated ealier, if the suspension isn't put into motion, it's no more than an elaborate coupler....
Have fun,
Pete
Follow Ups:
> > "if the suspension[strings]isn't put into motion, it's no more than an elaborate coupler..."Rollers too I might add...
Maybe now would be a good time to ask a couple of questions...
ONE: In IYO, how is horizontal isolation benificial?
Two: Can you dispute any of the following?
Roller balls do not dissipate vertical vibrational energy by rolling.
Roller balls are fully coupled while rolling (so long as they maintain traction with both surfaces).
Airborn resonances cannot overcome the static friction of a roller ball (much less with the added weight of a component).
--
Now also, I would like concede...
A component on rollers sounds better when it is allowed maximum freedom of movement in every direction.
I agree...I do not however agree that this is because of horizontal isolation; but rather balanced coupling.
Given that the surface is level; it is at THAT POINT, that the weight of the unit (against all opposing forces, such as the weight of a cord etc...) has been perfectly, and evenly distributed to each individual coupler(roller). That is to say; perfect balance has been achieved.
This, IMO is a pos effect, which some are contributing to 'horizontal isolation'. IMO, horizontal isolation has no benifit w/ relation to conductive, or airborne resonances.
...prove me wrong?
fc
Please take the time to read the linked article. Although it is long, it will give you a much better sense of where people like me, bdiament, and David Aiken are coming from. Although the three of us have slightly differing opinions, we all got the basis of our beliefs on the topic of audio and vibration from this article:
Hi Pete,"we all got the basis of our beliefs on the topic of audio and vibration from this article"
Just to clarify a bit, speaking for myself, I wouldn't put it exactly that way. While I find the article one of great interest, have read it a number of times and would recommend it to anyone with an interest in the topic, I wouldn't say I got the "basis of my beliefs" from this.
There are a number of articles and authors whose works have had a greater influence on the evolution of my own audio perspectives. Also, my personal experiences in the early years of "high fidelity" (before it became "hi end") and in more than three decades as a professional audio engineer (recording both purist and multi-track, overdubbing, mixing, editing, mastering) had a lot to do with where my perspectives are today.
Happy Listening!
Barry
The statement of mine which you quoted was a bit careless, and I certainly didn't mean to imply some of the things that I now see could be implied from it.-Pete
Hi Pete,No sweat.
I just wanted to clarify a bit.B
The "Bad Vibes" article is excellent but was written in 1995. This at least ten years after my early experiences that convinced me that isolation is urgent(only tube gear was used and no CD players at this point as they all sounded like, well you know...) if you want the best from your system. Granted we didn't have all of the products or ideas to experiment with that are around today. Some of what we first used were VPI bases and their springs(which had 3 tiny cone points on one end) in combination with Audioquest's big sorbothane feet. The number of springs was adjusted to support what ever weight of the component(The slightly souped up CJ Premier One came in with it's fighting weight at about 120lbs and needed far more springs that the Preimier Three we were using for a pre amp at the time). The orientation of the sorbo feet was alternated. Some feet facing up with the spring on the bottom and some with the sorbo on the bottom and the springs small cones in contact with the VPI base. We used quite a few VPI bricks to mass load and tune the set up. There were a few Mod Squad "Tip Toes" thrown into the mix. All of the decisions were based on what sounded best(read, sounded the most like live music to us)after quite a bit of testing. A Sota Star was used(with an ET 2 and then a SME V) as the table with threaded tall Tip Toes( if I remember right) under it and it also used springs as you know. So I have to say that springs, sorbothane, and aluminum cones were more or less the order of the day.
Please check out the linked post on the bottom for my thoughts on rollers and horizontal isolation versus vertical coupling. As you've suggested, there doesn't seem to be any data other than anecdotal (that I know of, at least) relative to what percentage of the benefit of rollers is due to the isolation versus the coupling.I wholeheartedly agree that if the normal vibrations to which a roller is subjected do not overcome the static friction of the bearing system, then any benefit is 100% attributable to vertical coupling.
"Maybe now would be a good time to ask a couple of questions...
ONE: In IYO, how is horizontal isolation benificial?"
This is a question that I believe has no generally accepted answer (in other words, it's pretty controversial). I don't claim to know the answer, but I'm willing to speculate. There are obvious reasons something like a CD player or turntable would benefit from reduced vibrations, so let's consider something like an amplifier. You've got lots of wires in there, all generating their own magnetic fields as current passes thru them. Now, what happens as a wire passes thru a magnetic field? A current is induced. Although we can't see circuit boards and wires move in a typical amp in a typical listening environment, the fact is that any material will deform to some degree when subjected to force, and vibration is simply an oscillating force. Consider that vibration travels thru an amp much like a sound wave thru air (in fact, it's really much the same thing, and often at audible frequencies, the only major difference being that sound travels thru solids much more quickly than air - vibration is really nothing other than sound travelling thru a solid), so the different parts of an amp are constantly moving relative to one another when vibration is present - quite chaotic. This would mean that the magnetic fields that any one wire is subjected to, even though minute in most cases, are constantly changing when vibration is present. Reduce vibration, and you reduce the effect. I don't think this is far-fetched, but I'm sure there will be disagreements.
"Two: Can you dispute any of the following?Roller balls do not dissipate vertical vibrational energy by rolling."
I'd never dispute that. Search for some of my posts on the topic and you'll see that I've always described roller balls as a horizontal isolator and vertical coupler, and I'm the only person I'm aware of pushing the notion that vertical coupling is critical in any isolation system, whether horizontal or vertical.
"Roller balls are fully coupled while rolling (so long as they maintain traction with both surfaces)."
This is true in the vertical. Roller balls are horizontally decoupled when in motion (At input frequencies below 1.4 times the resonant frequency of the roller system the isolation is less effective, and isolation becomes completely ineffective at and below the resonant frequency of the roller system).
"Airborn resonances cannot overcome the static friction of a roller ball (much less with the added weight of a component)."
I once again agree, but I also wouldn't ever claim that a roller ball would do much to manage airborne vibration. Roller balls are only effective at helping to manage floorborne vibration. The one role that roller balls can play in helping to manage airborne vibration is their vertical coupling properties. If you use the roller balls to couple an equipment chassis to a constrained layer platform, for instance, the vertical components of the vibration present in the chassis due to airborne effects can travel into the platform where they can be converted to heat. This also helps with self generated vibration, such as that caused by transformers and transports.
"This, IMO is a pos effect, which some are contributing to 'horizontal isolation'. IMO, horizontal isolation has no benifit w/ relation to conductive, or airborne resonances.
...prove me wrong?"
I can't, and I'm not so sure anyone really can (if the last statement of yours I quoted was meant to be confined to airborne vibration only, read no further; if it was meant to cover floorborne vibration, then read on). I've given you my best guess as to why vibration negatively affects audio electronics, and reducing vibration at all frequencies and in all directions without amplifying any of them makes audio equipment perform better (I should point out that I've always believed that an effective vibration management scheme consists of both horizontal and vertical isolation, as well as damping, with particular attention paid to the vertical coupling between any two pieces in the system).
So, you see, I think we might actually agree more than you may have realized at first....
Cheers,
Pete
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