Gregm,
When I tried a similar project I discussed the results with Ken at Neuance, Arnie (Audiogon founder) and a couple Agon members privately. It appears that the inner tube does fine at isolation, but the problem with this type of isolation, including air blotters, is the upper shelf is still able to roll on the air suspension. If you recall when you tried this project, the shelf was quite easy to move in a sideways motion. This motion, no matter how small will create smear of the leading edge of the note. Its effect in tempo is this smear. A second possibility is the thickness of the rubber has potential to dampen in a place we do not want dampening. We are trying to drain or isolate vibration at this point; using a dampening product may be effecting tempo too and being counterproductive.
My bubble wrap does not have this effect, and Ive theorized its because each bubble is in tension, and the motion of one bubble is in opposition to the bubble next to it. Thus the 100 or so bubbles are canceling each other to the degree that it is not possible for any movement. Now add to this the sidewall thickness if each bubble is so thin that the dampening effect described above is essentially eliminated. It turns out to be an ultra light weight, absolutely neutral suspension (at least in my opinion). If you try a bubble wrap sandwich and weight it by pushing down on it, try moving it sideways, its virtually impossible. Now try it on a blotter or inner tube type product, it moves all around.
So you might be wondering, why do Aurios or similar bearing products work so successfully when they move sideways too. Well again its my opinion and a theory that Arnie came up with one night when we were chatting over the phone. We were discussing the fact that I had placed Aurios under my speakers, and that I was amazed that the entire speaker was totally vibration less. This was on six foot tall speakers that had quite a large amount of vibration prior to the Aurios. Arnie theorized that the lack of vibration was due to the design of these bearing type products. The bearings are in a trough or cupped shape base. This means that for any vibration to create sideways movement, it must be of significant force to push the bearing uphill well the speaker is 200 lbs, so even the enormous force created through the bass drivers, a force strong enough to allow the listener to feel the vibration in the air, is still not adequate to push up hill or lift my speakers. Without this lift there is no sideways motion. We then theorized the bearing must vibrate at an ultra high speed as it tries to move, thus releasing the energy as heat????
Now then, take this same theory to a CD player or a turntable. These components might weight as little as 25 pounds or so, but the source of vibration within the component is far less severe, again the vibration is not of a great enough proportion to move the component uphill. That makes sense, but I have a second theory that effects the result, the bass waves within the room do have enough force to move 25 pounds on a bearing uphill, if only so slight. I believe that is why my SCD-1 player that weights 58 pounds sounds better with the 15 pound plate on top of it. I think the bass waves are significant enough to move even 58 pounds. The improvement is slight with the weight, and it appears in clarity, thus smear. My amps also benefit from these bearing products; they are 80 pounds each and are not helped with weight. In actuality the pace and tempo is slowed and the definition is muddied with weight. This may explain one of the points of contention between the light rigid and the mass loaded camps.
Im kind of thinking out loud now in that Ive never really thought about all of this to this degree, but this all might explain why my pre-amps have never benefited from bearing products. The pre-amp has always been a relatively light component. The Aesthetix Calypso is.39 pounds. If the magic weight is something around 70 pounds, as per my SCD-1 experience, then I would need to add some forty more pounds of mass to the units top. This would be a massive storage unit for vibration and would no doubt product a slow, muddy and fat sound. Without the weight the pre-amp would be allowed to move on the bearing product, creating a smear that would result in a lack of focus and a sense of tempo change.
On my system I guess these are the results of my findings. Again Im only theorizing with no science, but it makes sense to me. In my design; I have isolated the racks from the floor vibration with the bearings under sandstone slabs. These slams are hundreds of pounds and with equipment are even greater. Thus the actual movement of the floor is still not enough to lift the slabs on the bearings, so the bearings are isolating the racks successfully. The bearings used between the shelf sandwiches and components over 70 pounds are able to be isolated from further vibration that is picked up from airborne vibration through the rack its self.. The pre-amp does not benefit in the same way, which explains why my old Placette always sounded best on its factory feet. Today my Aesthetix is on a string suspension product, but after this discussion, I think I need further testing of other footer choices. The string product makes little sense given what Ive talked about above.
Hummm
..
Well back to the laboratory.
