Isolation vs. Absorbtion

Sean, since you mention that your explanation of how cones do what they do was quoted at length by J Scull in Stereophile, can I ask for more explanation? No disrespect intended – for you are a sane poster whose views on AudiogoN I tend to pay attention to – but I did not find the S’phile quotation very enlightening. The diode metaphor of how cones pass vibrations one way has an obvious appeal to it, simply because cones look like arrows, but I’ve often wondered if there was a scientific explanation behind it. Your chain of thought about how cones work to drain vibrations in one direction and block vibrations in the other is quite logical and, as you say in your explanation, “it’s all quite simple.” However, in the end it all rests on the familiar proposition that cones pass vibrations one way – which, in my mind, you basically reasserted, rather than explained. ---------- Ideally, the contact area between a flat surface and the point of a cone that meets it is just that, a point. What difference does it make to vibrations on which “side” of the point there is flatness and on which side there is cone-ness? Again, the diode metaphor appeals in a visual way – vibrations get funneled through the cone in one direction but cannot squeeze into the point from a flat surface in the other direction; lower frequency (floor-borne) vibrations have more trouble than higher frequency (equipment) vibrations fitting through a small point – but I don’t assume that necessarily has any correlation to science. Is there any further explanation you can add for this proposition? ---------- BTW, this is a matter of intellectual curiousity, and I am not implying that I need to hear a scientific explanation before I believe that cones have an effect. Right now, I am comparing Mapleshade brass cones against the cones I currently have under my turntable, and there are differences to my ear. But, speaking of Mapleshade, that company sells higher-priced brass cones (Triplepoints) that have three “micro”-cones sticking up from the flat side of the cone. The cone is used point down, and the equipment rests on the points of the micro-cones rather than directly on the flat surface of the cone. The designer Pierre Sprey says that minimizing the contact between the equipment and the big brass cone improves the transfer of vibrations from equipment into the feet. Not that he gives a scientific explanation for this (though he might have one if I asked) ...just another example of differing points of view (no pun intended). -- Jayson

Dekay, or anyone, can you offer any comparison between the Mapleshade and BDRacing cones that you used? I'm looking for a cone... for a different application -- between a Rega Planar 3 and a sandbox... but any comparative info still would be interesting. BTW, at first I was disappointed in the Mapleshade Surefeet -- got new detail and better defined bass but also some aggressive highs and too-light bass. Then I discovered the cones weren't perfectly flat on top; they had a tiny nub dead center that prevented uniform contact. To bypass the nub, I got some tiny brass cap nuts (dome shaped) and stuck them on the flat top with double-sided tape, thus creating a poor-man's version of Mapleshade's triple-point cone. Now, I am favorably impressed with the Surefeet (tried under turntable and CD player). I will exchange this set for a good set and may try a set of the heavyweight triplepoints as well, but the capnuts may still figure into the mix.

Sean, just a thanks for your follow-up. Jayson

Please see my post "Not Sneaky Enough?" under Site Related.

Then, you might try the poor-man's triplepoints! (There might be a better substitute than double-sided tape, but the tape's not bad. Gives a pleasant golden sheen to the sound -- just BS-ing of course.) It's easy to see, intellectually at least, why the triplepoints, with their guaranteed positive contact and the greatly increased pressure at the small areas of contact, would accomplish better energy transfer.

Try the cones under a speaker, Dekay? Heck, why not. When my new order comes in from Mapleshade, I'll try it. I was really only looking for a cone that would sound a little faster in my turntable setup (and will try the Ultimate triplepoints there), but my CDP asked for a tryout, too, so why stop there? I put three cones under my cereal bowl this morning, and damned if the oats didn’t taste a little more like oats, and the corn a little more like corn. Seemed to stay crunchier, too. ...... Mapleshade is aware that every once in a while their cones have the tiny nib on top that wasn’t completely machined off. From my experience, you’d hear it if you had it. ...... My mind is on feet these days, so Brulee and anyone else, any further notes on feet comparisons are welcome.