How to isolate turntable from footstep shake or vibration

"The most cost effective answer will be if the Oracle feet can be replaced with Townshend Pods." I disagree---that still amounts to adding springs to a turntable with a spring suspension.

And that is why I above suggested using a set of the Townshend Seismic Pods, not under the Oracle’s base (the non-floating frame which provides the table’s structure), but in place of the table’s stock suspension springs. Remove the Oracle’s springs, and install a set of three or four Pods under the floating sub-chassis---the bottom of each Pod resting on the shelf the table sits on, the top of each Pod in direct contact with the underside of the acrylic floating sub-chassis. That will isolate the sub-chassis from not only the shelf the table sits on, but also the table’s structural frame and it’s dustcover, as well as it's motor. In that regard, the Pods will provide an improvement in the sound of your table in general.

The Townshend Seismic Pods may be used thusly with any number of spring suspension tables; I have done exactly that with my VPI HW-19 Mk.5 (a Mk.4 with it’s stock platter and main bearing replaced with that from a TNT-5).

@esputnix: Is your Oracle the Delphi model? If so, does it have the Brooks Berdan mod?

Brooks was an expert at turntable suspensions, bringing with him to hi-fi the knowledge he had acquired working in the field of race car design. He was an Oracle dealer in the 1980’s, and realized the mass of the Delphi’s floating sub-chassis was not evenly distributed around the bearing. As a result of that mass imbalance, when the sub-chassis was pushed down upon and then let free, the s-c would not rebound straight up and down, but would instead cant to one side and then the other. He devised a simple solution to the problem: add a certain amount of mass (in the form of a thick disc of stainless steel) at a specific location on the underside of the sub-chassis. With the added mass, the sub-chassis behaved in a perfectly pistonic manner.

Brooks’ mod was written up in TAS (I believe), and lots of Delphi owners sent their tables to Brooks to have the mod installed. Brooks is no longer with us, but his son Brian is (his shop in Pasadena, California is named Audio Elements), and he may still be offering his Dad’s mod. Oracle themselves eventually incorporated Brooks’ mod into the Delphi.

As others have stated, adding springs under a table having a spring suspension is a very bad idea (imagine a car having two sets of springs for each wheel!), even the superior Seismic Pod from Townshend Audio. Years ago Townshend made his Seismic Sink isolation platforms using an internal inner tube as the means of creating isolation, but I don’t know if their use was approved of for tables with spring suspensions. Max Townshend incorporated the Seismic Sink into the Mk.3 incarnation of his Rock turntable, the Seismic Pod into the Mk.7 version.

One way to consider going is to install Townshend Seismic Pods under not the base of the Oracle, but in place of the stock springs, with the Pods resting on the shelf, not the Oracle’s base. Will that solve your footfall problem? I don’t know. Shoot Max T an email.

Putting a table on a wall-mounted shelf has for years been the most commonly employed solution to your problem, an "outer" wall if at all possible.

Another possibility is installing a set of "roller bearings" under the Oracle’s base. That design is a ball bearing sitting in a shallow "cup" (made of aluminum), and is available from a couple of companies (most famously Symposium Acoustics). Roller bearings provide isolation in the lateral plane, but zero in the vertical. Some people have used roller bearings in conjunction with inner-tube type isolators, with great success.