Using rigid devices to "drain" vibration is mostly audiophile voodoo, IMHO, and mainly espoused by those that sell products designed to "drain". Honestly, as someone who has tweaked ad nauseum with all kinds of isolation devices over the years, I am convinced that this is one of the most over-hyped areas of this hobby and one of the least beneficial expenditures of an audiophiles dollars (exceeded only by jitter reduction devices and followed closely by AC conditioning devices). I suppose a brass footer, for example, that reduces to a small point may help (or seem to), simply because it reduces the contact area between a component and its point of contact with the rack. On the other hand, absorbing material used as footers will definitely help prevent the vibrations generated by component from transferring to the rack, but obviously does not stop the source of vibration within the component. To stop the source of the internal vibration, you will have to open the component and damp the offending source, such as a CD transport or power supply. With well built and designed gear (which often equates to "heavy"), I haven't found much need for either internal or external damping. I put my gear on inexpensive absorbent rubber footers (Herbies) and after having thrown lots of money down the rabbit hole, I've discovered there isn't a true need for anything more.
