What does a stand do?
Posted by: Harris V on 29 January 2001
Components produce mechanical vibrations internally but are also subject to external sources. I assume that neither of these affect the operation in a good way but is it possible for a stand to dissipate internally produced energy whilst isolating from external sources?
Are components designed to cope with vibrations they produce themselves? If so, is all we need an isolating stand?
If everything is microphonic, do we need a material that itself has a resonant frequency well away from the audio spectrum? I don't think either wood or metal is good here. Is air not the best support below a component with something else shielding it from airborne vibrations?
I don't blame you for asking this basic question. I thought I understood what a stand was for but having read a couple of threads in this forum I realize there is more to this than meets the ear. I'm refering to component stands here rather than speaker stands. Here are my thoughts:
What is a stand for?
To make your hifi sound better
A place to store your kit so you can vacuum more easily and keep your home looking tidy
What does a stand actually do?
Costs a shed load of money
Creates acrimonious debate in this forum
Makes some peoples' hifis sound better
Upsets room styling in some homes
3 reasons why mechanical noise may affect your hifis sound:
1. If you are using a mechanical transducer in the signal path. Eg: a turntable cartridge. This is a relatively big affect.
2. If your semiconductors or valves (tubes to US folk) or electrical components or cables or connectors or solder joints have microphonic characteristics. In other words their electrical properties are affected by mechanical noise. Barring poor construction, then except for some valves this is a relatively small effect.
3. If part of your system is meant to respond to mechanical noise and in so doing creates electrical noise that finds its way into your signal chain. Eg: CD motor servo system creates electrical noise. The size of this affect can vary a lot depending on the design of your player.
Note that a CDs lens system is controlled so well and the digital error correction coding is so robust that the recovered bit stream is, except under extreme conditions, perfect. Sound improvements due to stands are NOT because the recovered bit stream has fewer errors.
How do stands help?
Technically they present a 3D mechanical transmission line to the object that sits on them. Descriptively, they have a certain feel and echo when tapped.
Mechanical noise propagates through things and when it meets a discontinuity (like a new material) some of it keeps going and some of it bounces back. So if you put your CD player on a thick, granite block, noise travelling through the feet would meet the granite and much of it would reflect back into the CD player (like a dull mirror). If you match the materials all the noise will travel into the table and keep going until it hits another boundary or is dissipated.
Dissipation is when the noise is turned into heat by the material as it travels through it. Also called damping.
As you can see the design of a table in not trivial. The "feel" that will work best for a particulary component will vary. It depends upon what in the component is causing the sensitivity and what frequencies are most important and so on.
In some cases a well-damped wobbly table may be best because the table is then absorbing the mechanical shocks rather than the internals of the component.
I suspect the generic table is trying to be stiff (like granite) but minimizing reflections back into the equipment and highly dissipative of noise that flows into them. Also, they want to resist noise flowing into them from the floor. This is what I suspect. But I'm not a table designer so let's see what other people think.
BAM
Few rich and bored manufacturers thought how can they bring people to tough argues in Naim forum.
Two examples are JW and Hutter.
And they succeeded.
Arie
what does a stand do??
i am also very keen to get a better understanding of this subject. i am frustrated that no clear, coherent theory on this subject has ever been published, to my knowledge. i think we are all started wanting somewhere nice to put our treasured hifi.
then we began to notice that different stands sounded different. the half backed theory is that various vibrations -- internally and externally generated, affect the performance of your hifi components. mechanical feedback affecting electrical properties.
the point is that all the various bits and pieces in a hifi component have their natural frequencies of vibration, which interact with airborned and stand borne vibrations. sometime this interaction produces desirable effects, this is probably why some stands are considered "better" than others.
what i find curious is how a hifi manufacturer can ever calibrate the sound of his equipment, independent of the stand to be used. what is this "naim" sound that is independent of equipment support?? os it is that this "naim" sound is no intrinsic that it dominates, regardless of what stand is used??
my current theory is rather academic -- the best stand is NO stand at all... float your equipment in air... i am working on ways to achieve that...
enjoy...
ken
1. Isolation of equipment from external vibrations is part of the story, but only a relatively small part. This tallies with people finding that the effect of their chosen supports is also manifest when listening through headphones, or in situations where the speakers are in a different room.
2. Allowing the equipment to handle internally generated vibrations more gracefully is a big factor. Thus, connecting the equipment to a structure which is more easily-excited than the equipment itself (theoretically allowing easier disipation) might be one approach, albeit riddled with caveats and potential problems. Obviously, the connection between the equipment and the support then becomes much more crucial (hence the CDX foot issue).
3. The material(s) from which a support is made create a (sub)concious expectation of what type of effect the support will have. We therefore expect a metal/glass support to sound "hard, spiky, glassy, brittle", a wooden one to sound "softer, more organic, damped", and granite to sound "fast, impeturbable, permanent". I think all this is bunk – it seems virtually impossible to predict what a given material will sound like. How the material is used seems to be a much more important factor.
4. Like everything else, a suppport will work well (or not) according to the number of things it fails to bugger up. "Non-subtraction" would be a better design aim, rather than positive addition.
At the risk of instigating a degree of topic drift, there is one more thing which occurs to me. In the UK our AC supply is 230v at 50hz, and this must cause audio equipment to have some sort of anomalous behaviour around this frequency (or products thereof). Taking account of this is obviously part of the designers' brief, which must get interesting if you are also selling into 110v 60hz territory, albeit with appropriately specified boxes.
Recorded music will also have embedded in it the anomalies generated by all the audio and support equipment through which the signal has already passed before we buy it, and will (hopefully) have had some sort of subjective judgement made about "sound" before duplication (typically at mastering). Does AC frequency account for the phenomenon of US-recorded & mastered vinyl sounding a bit brighter than the same album mastered in Europe (50hz) from the same (60hz-recorded) tape? You can easily start to go mad if you think about this too deeply, as the permutations are staggering (DAT, glass master, etc.), but it could be that mains frequency is also a big factor in the variable behaviour of a supported system.
Best;
Mark
(an imperfect
forum environment is
better than none)
Here's a copy of my previous posting on the subject.
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It's all about energy, distribution and pathways. Vibrational energy needs to be directed away from the electronics to stop them from vibrating.
If you change the spacing between the plates of a capacitor, then you would be changing its capacitance and modulate the signal - which is what vibrations tend to do. If vibrations enter at different points of the circuit board, then you end up with vibrations at different phases affecting different parts of the circuit board, thus generating a random mess of modulation (affecting timing and so on).
To avoid this then, there has to be a loading mis-match between the circuit board and casing. The transformer and drive mechanism of a cd player generate vibrations - so the casing should be impedance matched to the support in order to divert the energy away (unless you use a rubber case!!!).
It is the frame of the stand that actually acts as a vibrations sink, including contributions from the equipment, floor and air. Note that the shape of the spikes diverge towards the frame (from the equipment and from the floor). This could mean the vibration get trapped into the frame (effectively re-bounding within the frame) until it dissapates.
How does it dissapate? Only really 2 ways - by transforming into heat, and transforming into sound. Of course, a high heat/sound ratio is preferrable - which could provide interesting research.
I guess that with Mana, more levels equate to more framework to trap and dissapate vibration.
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Also I reckon that spikes transmit vibrational energy more effectively from the tip to the flare (rather than the other direction). This is very similar to the horn-effect on a horn loudspeaker. If you look at the orientations of the spikes on the top and bottom of a stand, you can see how vibrations are trapped within the structure of the frame.
Andrew
Andrew Randle
2B || !2B;
4 ^ = ?;
Suppose you had the mother of all hammer drills in one hand and were drilling into solid concrete, and in the other hand you had a test-tube of nitro glycerin.
Which would you rather be standing on...Mana or Hutter?
Decide or die!
BAM
"The transformer and drive mechanism of a cd player generate vibrations - so the casing should be impedance matched to the support in order to divert the energy away (unless you use a rubber case!!!)."
Would it be enough to have the circuit board suspended on rubber mounts linked through the case to the feet by rubber?
I ask this because this seems very similar to the isolation 'technology' used by my beloved decks. You can upgrade DJ turntables by using what are essentially very soft, high rubber feet, the top and bottom of which are decoupled so that in a club the rubber feet wobble like mad but the turntable remains perfectly still.
CD mechanisms are lighter so maybe we could use some very soft rubber.
Seriously though, hats off to some sensible discussion on the subject - at last.
Not much point in spending serious money on stands until you have serious kit and have sorted out your room acoustics though (see my posings in the topic).
Cheers
Steve
In order to design the ultimate stand you need to know what impedance/reflectivity is optimum to minimize the affect of vibration on the electrical signal inside the equipment. This is a complicated thing to analyze. It is not a simple matter of designing "the perfect stand" for all equipment because it cannot be defined. To some degree it also depends upon the floor surface.
Eg: I don't believe for a moment that Mana have the means to measure the effect on sound quality of a CDII on one of their stands. I suspect Naim "may" be able to measure this, but Naim aren't stand designers. I think Naim are in the best position to recommend a stand because they ought to know the microphonic sensitivies of their equipment and be able to measure it. Maybe they don't.
So, I'm afraid that leaves us to merely speculate about what may be good or bad. Again, listening is the only measure that can be relied upon. But don't expect one stand to be optimum for all your equipment and everyones floors.
BAM
quote:
I think Naim are in the best position to recommend a stand ...Maybe they don't
The majority opinion here that Naim can't recommend a stand.
I still don't get the answer - why Naim can't recommend a stand and can recommend an interconect and it is quite easy to test interconnect.
For myself, I trust Naim and don't want to test inteconnects - but I'll feel the same if they'll recommend a stand.
!!! Please believe me, I know all the answers about stands by heart day and night !!! - so if someone wants to relate to inteconnects only, that will be interesting for me.
Arie
I don't want to go over all this again, because it's been done to death.
Stands are VERY room dependant. Stand X would suit one room better than stand Y. In another room stand Y will be better.
Naim do not recommend what type of furnishings, floor coverings or wall construction is best, in the same way that they can't recommend stands.
Try a few of the 'best' stands and make up your own mind.
That's it Arie, there is no way that Naim, me, the forum or anybody can tell you what stand is right for you. You must work this out yourself.
Bob.
Omer,
I agree totally. When we moved to our new home, try as I might ( & boy did I try) I couldn't get my PMC LB1's to work. They just boomed. I ended up with IBL's ( same as Arie I think ). The whole stand & speaker thing is very subjective. As they say... One man's meat is another man's poison.
As we seem to be on the same wavelength, maybe you could explain what I am trying to say to Arie in Hebrew next time you have a chat.
Hope you haven't got a sore head from last night's celebrations or commiseration's.
Best wishes,
Bob.
quote:
If the carpet was best then we would all use carpets to support our kit.
In your case Ian, only if the carpet was made by Mana. 
Just a joke. Seriously....stop being so defensive about Mana otherwise this excellent thread will disintegrate yet again into a Mana drone. No one is being defensive about anything else. This is a good discussion and Richard has some very interesting stuff to say. I for one will be very keen to see the weblink where I can find out more about the support he is using.
Brian
This type of demo is easy to do.
Take most any piece of kit and change the material it is sitting on. If it is on wood, changing to glass may very well change the sound dramatically. This is a fun and easy demo to do. Any 'ol cheap glass will work (but thicker sounds better to my ears).
But...
...if the system was sounding good to begin with, and was working in a way that I or the user has been happy with for a long time, then a jaw dropping difference raises a red flag for me. While the new settup may do some obvious things better (clearer, more open up top or whatever), there is also the substantial risk that something that is very different from what was long-term satisfying may, in the end, prove not to be long-term satisfying.
A quick hit, and maybe fun, but I'm cautious of large stand-induced changes when those changes are away from something that has been working well. There is a good chance something important was lost.
- GregB
I'm not sure you read my post, but leave it.
Arie
Arie,
I did read your post but only addressed the stand issue. I will now finish the other bit.
Think of Naim's integrated amp, the NAIT. Now think of a large Naim active amp set up. The difference between these two apart from the cost & performance level, is that with the active set up the amplifier has been spread over many boxes, not just one.
Think of all these black boxes as a 'dispersed' NAIT. Instead of all the connections being made inside one box they are external connections made between the black boxes. Naim will of course make interconnects for this purpose, with given values, just as they make internal connections inside their NAIT. After all you don't hear of anyone opening their NAIT & changing the internal connections.
I hope this has made things clear.
Now what you put your amplifier on is an entirely different matter.....
Best wishes,
Bob
I get your point.
Arie