What isolation feet to use??

I'm not sure about the audiophile stuff, but isolation in physics is a kind of decoupling, and the purpose is to absorb or cancel out vibrations. The ideal model for this is the spring and dashpot, the next best thing is a visco-elastic material. You need to have deflection in order to decouple; imagine a spring that "bounces" at the frequency of the vibration you want to isolate. On the other hand, if you apply pressure against a relatively hard/inert object, it absorbs none of the pressure, and actually transmits that to the other side. As an experiment, hold a brick and have someone push you, versus a pillow, and see which absorbs and deflects more pressure.

The same principle applies in audio. Rubbery visco-elastic materials, springs, dashpots, shock absorbers, hydraulics, tuned mass dampers, etc. are decoupling devices. Wood, brass, silver, metalic, and any hard surfaces, like compressed sand or shot, are coupling devices. Coupling devices will transmit vibrations from your equipment to the ground, and from the ground to your equipment. There's no such thing as having only one-way (Newton's law: for every action there's an equal reaction in the opposite direction).

I'll treat lightly, since I don't want to offend anyone, but there are a lot of ideas here that flies right in the face of science. For some no-nonsense literature, for one, go to sorbothane . com and read what they have to say, and they even have a nifty program where you plug in a couple parameters according to a formula, and figure out the ideal size isolation feet you need for the project (hint: depends largely on the weight, aim for the lowest frequency). Sorbothane manufactures a proprietary visco-elastic material that many of these other audiophile products source from.

Note: I have no affiliation with Sorbothane, but the program on its website really is just the easiest way to figure out the idea feet for your equipment

Funny how many approaches there are to coupling/decoupling/damping/etc. I personally hate sorbothane and firmly believe in Mapleshade's brass cone/maple platform (not butcher block)/Isoblock approach, but then I watched Pierre Sprey demonstrated the whole process before my very eyes (and ears) in my own system, so I know how well it works. Along the way I've also tried sand boxes, inflatable innertubes, bubble wrap (!), and dead balls (not bad at all), not to mention sorbothane (ugh). So, in all particulars, YMMV. Dave

Herbie's is a place to contact. Steve is very helpful. I use various isolation devices of his under different components including speakers and turntable.

When I had an Aesthetix Calipso Audioquest Sorbogel "Big Feet" worked the best in combination with the rack system (bad) I was using. I tried Mapleshade Heavyfeet(to bright), BDR #3 & #4 cones good but there were still vibrations (hash). A Calypso owner with a Salamander Synergy rack used AQ Big Feet in front and maple blocks in back until he tried a SRA platform that he felt outperformed all prior tweeks. Grand Prix Audio uses Sorbothane pads between the rack and shelf, Project TT's have sorbothane pads in the feet! I only use sorbothane under my EP15A's and Direct TV DVR presently.

There have been many reports of great success with maple, but it seems I may be the lone dissenter. I tried 2 1/2" cutting boards under my components and they were terrible. Depending on the component, they either sucked the life out of the music or everything became fat and bloated. If it works in your system, that's great - but in my system maple was an abysmal failure.