What is vibration isolation for?


Where do these vibrations come from? From where I stand the earth doesn't shake too badly?! I would think that most vibrations would come via sound transmission through the air directly through the chassis of the components thus rendering the racks or other vibration isolation, uh, useless, no? (with the exception of actual thumping from walking etc)
neubilder
Pbb, strawmen, irony, apples, oranges, and lack of knowledge. Thus is a summary of your response, and that of your comments in general. Let me explain.

STRAWMEN
"The problem is you have nothing quantified."
If we consider the spectrum of [ Possible > Probable > Audible ], the thought experiment defines a nice sharp position, somewhere around the right side of the second >. We arrived at that point with incontrovertible logic, whereas your statement of the type ".. for no logical reason" places us somewhere left of the entire spectrum above, and worse yet, does not even define a spectrum.

IRONY
".. for no logical reason" is a statement made for no logical reason, or at least with no logical reasoning put forth. Nor is there any logical reasoning put forth to move the pointer back towards the left even a bit, even though your desired position requires considerable movement all the way to the left.

If by "quantified" you mean "assigned numbers", my thought experiment can be easily turned into a physical experiment. Here's one that requires no lab equipment: Fire up some music with a beat to it. Turn up the volume until you can just begin to feel the bass a little, in your chest (80-100hz does that well). Now, place your finger tips, very lightly, on the top metal plate of your CD player. Do we need to assign a number to that vibration which you will surely feel? If so, buy an accelerometer and a scope, and measure it yourself. Then you could tell us how small those numbers are, and how in-audible that should be. At least then, you could comment with SOMETHING. Something more than the strawmen that you stand up and kick down in such a definitive manner.

APPLES & ORANGES
"As an analogy (for what it's worth) the world is chockfull of bacteria and viruses. Their mere presence does not signify that the carrier is diseased."

Your analogy, upon any inspection, is not worth much at all. It completely fails to anologize the situation at hand. A more accurate analogy would be "someone who voluntarily exposes themselves to high concentrations of very particular bacteria and viruses on a daily basis, may or may not be able to tell the difference between two slightly different diseases."

With that more accurate analogy, you could at least argue numbers. I can imagine something like "if your intra-oral body temperature is exactly 102.6 F, when infected with the nemulo coccus as well as when infected with the nebulo coccus, then your headache could not possibly be different".

Now, the names of bacteria I did indeed make up as I went, whereas the rest is from experience. I find it much more usefull for a discussion to progress along some path, rather than be stifled by the same three mantras repeatedly repeatedly.

LACK OF KNOWLEDGE
"I will trot out the usual question-to-end-it-all (and will probably get the usual stock answer): why would the manufacturers of ultra-high-end transistor amps sold for kilo bucks not build the best isolated chassis possible if this is such a concern? "

That question "ends" only one thing: any shred of credibility of the argument that uses such a statement, simply because it shows the lack of knowledge of the very industry one is discussing. It shows that you have never looked inside a Rowland amplifier, nor a Conrad Johnson tube preamplifier. Nor have you placed the 1 lb mass on the CD in a CEC transport. Apparently, you have not even gone so far as to visit Aria Audio's website (Michael Elliot's new company), to have noticed the images of his circuits with bracing and dampening of the capacitors. Not having done ANY of the above (examples from my very limited knowledge), we can only assume that you have never actually put bubble wrap under your preamplifier, just to prove to yourself that it will not make a difference.

But I guess that would necessitate the owning of a preamplifier, or doing some research, or actually partaking in the hobby that you are so keen to debunk.

It seems you almost had a point with "I don't think we should worry ourselves sick over it...[cut].. When does attention to detail, to minutiae becomes more of a hindrance than a source of advancement? I truly wonder."

But the point is pointless, because "attention to detail, to minutiae" is the VERY definition of ANY hobby or enthusiasm, is it not? Car fanatics discuss the type of alloy used for the screws affixing their front brake pads. Fishing enthusiasts discuss the balance of their fly rod when casting with 10 lb line, especially on humid days. Shutterbugs discuss the dynamics of the sparkle from a car window, given a particular polarization of the filter, color temperature, and film speed. That is what hobbyists do, they pay attention to the details and discuss the minutiae.

What is rather UNUSUAL about the audio hobby is that it seems to attract so many NON-hobbyists, who receive so much satisfaction from constantly telling hobbyists they are barking up the wrong tree.
Audiofile9, it appears you and I posted answers to the Pbb posting at the same time.

Our responses from similar positions, hoping to explain what should be obvious.
Albert, indeed we must have been posting simultaneously. Interestingly, our thoughts were as harmonious as our timing :)
You cannot fight mother nature so the best thing to do, is to let it vibrate. I will be happy to tell you why.. later, but for now I have to meet a client. Great discussion...Tom
Tom.

We are not fighting mother nature, we are fighting one man made invention with another. If we could hear human powered music exclusively and not have to deal with electronics, the vibrations would be fun.