Wood blocks underneath components?? snake oil?

cdc,
1) Even if you rigidly couple all components in your rack, each component will still have a different resonant frequency due to differing mass, volume, materials which result in different natural frequencies. This based on scientific fact. A spring or an elastomer is typically used to reduce the amplitude of the wave that produces vibration in a medium btw. Rubber is used to isolate a jet engine from an aircraft frame. For the record, unless the component is bolted down to the shelf, it is not a "rigidly coupled" system to which you can apply the formulae from rigid body mechanics. A component on brass cones can very easily be disturbed compared to the rack it sits on.
2) Please read my earlier post on this subject. The only way to reduce magnitude of the vibrational force transferred from the shelf to the component is to have an isolator and damper in between. Increasing the mass of the platform helps in theory but for practical reasons can't be the only way to dissipate vibration. If the offending force can make it's way through concrete slabs of your floor, you will need a lot of mass to dissipate it if you do not want to use a real "isolator". BTW, what makes you so sure that by rigid coupling everything you have raised the natural frequency of all the components beyond the audible range? Glass ringing/resonance occurs at higher frequencies, why are glass shelves frowned upon by audiophiles in that case? Lastly, anyone in the isolation business ought to have measuring devices (that are readily available) and back up their claims with numbers. How many of them do?

Rotarius I agree with the Vibes article that:
"The goal of vibration control is to minimize the relative motion between different elements that comprise a system"

"Rubber is used to isolate a jet engine from an aircraft frame"

Sure but the engine will still be vibrating. It's a different objective - don't shake the plane apart vs. audio get the vibrations out of the CDP. Isolation won't do this.

" The only way to reduce magnitude of the vibrational force transferred from the shelf to the component is to have an isolator and damper in between"

No as in the Vibes article you can do this by raising the resonant frequency. Then you reduce these small amplitudes will good shelving or maybe some thin, relatively hard rubber like neoprene. As the Vibes article says, putting cones 22% in from the edges of a shelf will minimize amplitude as this is the first node of near zero displacement. Would you agree this would be a good thing?
Again, these values have to be calculated, I'm just giving the theory as I understand it.

"Increasing the mass of the platform helps in theory but for practical reasons can't be the only way to dissipate vibration"

I agree, a better goal is to inprove the stiffness to mass ratio as even granite will ring.

"what makes you so sure that by rigid coupling everything you have raised the natural frequency of all the components beyond the audible range"

That what engineering is for and why we pay all those audiophile companies big bucks.

"Glass ringing/resonance occurs at higher frequencies, why are glass shelves frowned upon by audiophiles in that case"

Nope, the Sound Organisation racks use glass shelves and were praised by What HiFi? for fooling them into thinking it was a wood rack. Manna used 1/4" thick tempered glass with outstanding results. Glass alone will ring but glass is not used alone. It's all in the design. It's complex and requires soem serious engineering expertise. These things are not always intuitively logical.

"Lastly, anyone in the isolation business ought to have measuring devices (that are readily available) and back up their claims with numbers. How many of them do?
"

And thats why audiophile industry has the reputation that it does. Of course you could always buy a Vibraplane for $5,000.

Cdc, FWIW, You are probably correct. I doubt that we will agree on anything when it comes to this subject.

But, FWIW, I would pose a question which no one has ever answered for me. Assuming, for the sake of discussion, that you are correct regarding the "drain" theory, and assuming that you have a component, or part with-in which is more likely because each component part will have its own individual resonance point, which resonates at, say 5000hz, exactly what amplitude must this resonance reach before it actually affects the SOUND of the component.

IMHO, it's only an esoteric theory unless one can establish that it not only actually exists in the minds of our scientists, but as pratical matter for audiophiles that advertised methods actually work to solve a real problem experienced in audio components and their use in the home.

It seems to me that if we have a problem based on something as well explored by the scientific community as resonances/vibrations that there must also exist a method of quantifying the amplitudes necessary to cause a deterioration in sound quality. IMHO this is not an area where 'subjective' observations have much meaning (to me at least).

IMHO, the 'drain theory' is on the same level as someone saying that we aught to provide for compensation in out TT set ups for the effect of the moon. I mean it (the moon) sure effects our invironment - no arguement can be made there - so it must effect our TT's operation which are infinitely suseptible to all sorts of things, and we should be able to make adjustments to compensate, shouldn't we?

FWIW, I get a real kick out of someone saying that a 'component' has a resonance point which can be moved by choice of isolation/coupling. As I suggested above, if a component has 100 parts, it has one hundred resonances within, one for each uncommon part. Do these somehow combine to make just one resonance for the whole component? Perhaps I'm just speaking from ignorance - I guess I'll have to take some physics course so I can understand this

As indicated before, I think the drain theory offers more commercial opportunities than it actually solves real world problems. IHMO of course.

Excellent point Newbee, I will begin design on a moon shield immediately :>)

Hi Newbee

exactly what amplitude must this resonance reach before it actually affects the SOUND of the component

I'm not going there. I will not put on the facade that I have all the answers to everything. Some people get sucked in though, including the Pope, with disastrous results.
While I don't know everything, doesn't mean I know nothing either :-).

BTW, where the heck did warrenh and all the other coupling pundits go? Geeeshhh I'm just out here swaying in the wind.

Question for you, my friend. Did you read my inset from the bad vibes article and how it explains how sorbothane
"can contribute to the subjective impression of a "mushy," "soft," or "boomy" bass response"?
Could be in your system/preference it works well. There are so many variables it's hard to say what will or won't work on an absolute scale, IMHO.
Good luck