[Carlman]

I've seen a lot of products that 'isolate' the equipment from whatever it is sitting on. Sorbothane feet, Vibrapods, expensive maple platforms, cones, etc.  They each have their own theories to support themselves.

My question is, what about the other 5 sides of the gear that's exposed to air vibrations?  I could have my gear on a mountain of pillows but it still gets plenty of vibration from the sound.  I can put my hand on anything in the room and it vibrates.... especially the top of my hifi gear.

So, what good is all this isolation on the bottom?  Wouldn't it also require other methods to be truly effective?  Like putting weights on it.. etc.

I'm not trying to start a debate.  I've heard some small differences with various rubber things under my gear and have found Vibrapods to be OK for most things.  They either do nothing or a little something.  The only bad thing I've ever heard was putting some little sorbothane feet under my DAC.  I don't understand that one.  The sound got ever so slightly murky or uncrisp.

I've got 'the' IKEA tables because they fit my room and gear fairly well... but I don't know that they're 'all that' or whatever.. I just don't understand isolation priniciples.  

Thanks,
Carl

[JoshK]

Carlman,

Good question.  I don't presume to know all the answers.  But through reading, some understanding of the science of waves, and through simple experimentation, I have come to my own conclusions.  I think we often say 'isolation' platforms, when we mean more than that.  

I think isolation [from external vibration], as you sucintly pointed out, is not enough, and only half the problem. You also need to damp the vibrations that are internal in the component, or transferred to the component via air.  I think these are often overlooked when considering isolation devices.

[Jon L]

This stuff is in its infancy.  We are just beginning to scrape the surface of it, but in a few years, "isolation" will be today's "power cords."

There are 2 different theories.  One camp wants to "drain" vibration from the component.  The internal vibrations and airborn vibrations within the component are somehow drained to another place and dissipated. Various hard cones (most metal, ceramic, graphite cones) are meant to drain, and various platforms (Ikea Lack table, Neuance shelves) are meant to dissipate this energy.  Unfortunately, most cones stink as "drainers" and most platforms stink as "dissipators."  They all either do a very poor job at what they are supposed to do and/or do other things that are detrimental.  

The other camp wants to "isolate" from the speaker vibrations and earth's slow rotational vibration.  These would include spring-based platforms like Machina Dynamica Promethean base and Silent Running Audio.  Also all the sand boxes, air platforms, etc, etc.  But since cones, footers between component and these platforms also change sound, "isolation" is not all the story.  The bearing devices would try to fit into this category, but the different bearing material sound different, so they are also acting as drains.  

But then there are devices you put on Top of components that change sound, such as Walker Audio discs, granite slabs, wooden blocks, etc.  I have tried sandboxes and Neuance shelves on the bottom AND top of components with changes that are in similar direction, which leads me to believe there's also an important third dimension to it all.  The component, the footers, platforms, whatever's on top, vibration from earth, from speakers, from interconnects, power cords, etc are combining together to form a vibrational equilibrium that effects sound.  You can try and try to change a couple of footers and platforms to try to push this equilibrium to sound you prefer, but it can never be perfect.  In fact, often you can get worse sound if you are not careful, i.e. A-B evaluate your tweak.  

The "perfect" solution would be something like a anti-gravity levitation chamber in vacuum atomically decoupled from surroundings.  Of course no interconnects, power cords can attach to the component inside the chamber since vibration travels on these, too.  So unless such a chamber is developed for home use and high-resolution wireless signal, power transfer is possible, we are all just shooting in the dark.

[WEEZ]

Yeah,

cables and isolation- it can drive you nuts.....

One idea that has worked well for my turntable is a wall shelf. Works better than any thing else I've tried so far. Sound is much clearer.

Solid wood rack shelves for my other gear has worked better than mdf shelves ever did. (Far from perfect, but better).

Next, my amp goes onto a separate stand-- on and on it goes--

Glass never worked for me, but others have had success.

What a hobby

WEEZ

[PhilNYC]

Jon L captures most of the thoughts I have on this subject.  For more in-depth explanations, I've found the Symposium USA website to have some good perspectives on topics of isolation, dampening, and drainage:

http://www.symposiumusa.com/technology.shtml

[John Casler]

I agree with Jon L.

The areas of Room Treatment and Vibration Creation and Control are an important part of recreating the recorded performance.

Vibration.... It makes sound, it changes sound and it destroys sound as we wish to hear it.

While Jon mentioned that the "perfect" situation would be specifically isolating/insulating/controlling those elements in the reproduction chain that are subject to sonic aberation, I propose something different.

Eliminate the chain of reproduction elements all together.  In the future, there will be "implants" to specific areas of the brain, so that the signals will be "directly injected" via "cellular type" (but were talking human cells) transmission to the Auditory Nerve.

But I digress, we are currently "stuck" with vibrations and they are what create sound, and their "by-products" are what degrade our sound.

In general, once we have received the signal from the source, we are done with that vibration and if it could be eliminated after that we would be partially done.

It is also relevant that sound vibrations (waves) also can be affected or gather artifacts on their way to us (in the form of early reflections and such)

Then the sum of all vibrations created continue on untill they are absorbed, by the enclosure we are in and its contents, or are released and directed out of that enclosure.

It is these vibrations that can cause "problems"

While I don't claim to be a Physicist or Vibration Specialist, it is my understanding that there are 3 basic vibrations we have to deal with:

1) Mechanically conducted vibration - that which is transmitted by direct or indirect tranmission via a mechanical connection

2) Airborne conduction - which is similar to "radiation" since it is transmitted via "sound waves" (same principle cooks your food in a microwave oven)

3) Self created vibration - that which is actually created by the component itself, as in the vibration of a speaker, or tranformer in an amplifier.

In most cases of electronics, we need to "damp" them to reduce their self produced vibes, and insulated or isolate them to not receive or dissipate any external vibrations.

In the case of speakers, we actually want to focus on making the cabinet and drivers as "stable" as possible, by "mechanically coupling" them to their surroundings or adding enough "resitive mass" to make them resitant.

So when the drivers create the soundwaves, the "reactive" forces against the speaker itself are met with a resistive forces that will not reduce the effectiveness of the drivers movement.

I think that just like all other segments of our hobby, that terms will be created and bandied about, that may or may not be accurate or relevant.  I read only in a post this morning how a "isolation device" for electronics had passive "titanium" parts, that were EMI and RFI resistant????

What wasn't mentioned was that the effects of passively absorbed EMI and RFI energy was probably more than offset by the fact that metals have a set "resonance frequency" (a tuning fork might be a good example) and that would probably do more harm than good.

I am really surprised that there are not more components featuring  the latest "wood" case, that matches the Wood Block stands that they are sitting on.

I think we'll see more focus on "vibration control" of key components, especially components of "compression connection" such as RCA/XLR/spade/Banana etc, type connections, where vibrations at various frequencies can affect the state of the connecting surfaces on a moment by moment basis.

In any event, I plan on keeping an open mind as to the effect specific vibrations might have on our sound as we perceive it in the listening position.

[Carlman]

Thanks for the replies... they confirm much of what I was thinking but wasn't really sure if there was something I was missing.  

Thanks again,
Carl

[Smeggy]

The other vibration areas aren't important until someone finds a way to cash in on it, *then* it'll be important, and no doubt flowing with hyper expensive snake oil like so-many other areas of hi-fi