How to isolate turntable from footstep shake or vibration


Even while the Oracle turnable that I use has a built-in springs suspension by design there is a low or even sub-low frequency boom every time someone walks in a room. This becomes really bad with the subwoofer’s volume set high as the low frequency footsteps make straight to subwoofer where they are amplified shaking everything around. It seems the cartridge is picking up the footsteps very efficiently as even a lightest foot down becomes audioable. What can be done to attempt to isolate the turntable from the low frequency vibrations? Interesting, that the lower the volume of the subwoofer, the less the footstep shake is evident and with the subwoofer turned off it is a barely a problem at all. 
esputnix
Who’s jumping on the floor when you guys listening to your records? 
I have been using a Sota since 1981 and have had it on everything you can think of playing through ESLs. I have not found anything to be as important as using a dust cover during play attenuating airborne vibration by as much as 20 dB (not sure how accurate the meter was). Like protective earmuffs for your cartridge. And, everyone thinks this is poison (except Mark Dohmann). I guess like guitar amps everyone likes listening to distortion? With subtle differences I guess people prefer sticking with mythology than really listening? Boggles the mind.
@mijostyn  I had a dust cover for my Sota as well. When I added the custom stand and platform the improvement was instantly audible- it was not subtle, and it was also measurable- the latter being done by playing a test tone and cranking up the volume- you could easily see on the oscilloscope how much less 'disturbed' the waveform was prior to the volume control (we had the 'scope on the tape outputs).


We had a modified Empire 208 (which was the platform for what later became our model 208; at the time the 'mods' where a damped platter and an SME5 mounted to it). As you turned up the volume the Empire 'fell apart' sonically compared to the Sota. But when either one was placed on the stand with platform neither one fell apart- at that point the Empire sounded better since it was so much more speed stable (the early Cosmos machines had a stability problem that was later fixed) and had a more massive platter that had more damping. Both machines used the same platter pad as I mentioned earlier and both used the same arm and cartridge.


It was thus very easy to show that the anti-vibration measures were having a profound effect on the system when the volume was cranked up.


Tube guitar amps provide a range of tone from very clean to smooth, controlled distortion. Microphonic tubes become very obvious in a guitar amp, yet rarely occur. Read a review of any tube guitar amp and you can learn something about them.
Wolf, as you probably know better than I, if you actually play guitar, guitar amps are distortion generating machines. The distortion is intentional. This is one reason why overstressed tubes are preferred by the cognoscenti in guitar amplification, unless you disagree. One form that that distortion takes is due to the microphonics of the tubes adding to the other distortion generating characteristics of the circuit. Don’t you think? Speaking for myself, when I hear a really prominent electronic guitar solo, I think I can hear components of the distortion that are due to tube microphonics or are very characteristic of distortion caused by microphonics. I just don’t think there is much effort to avoid microphonics from guitar amplifiers in general. 
Furthermore, I and others have been saying all along that microphonics are more or less of a problem with certain tube types and with tubes used in circuit in different ways. Hi gain tubes that have a large glass envelope tend to have the most problems with microphonics. Small nine pin miniature tubes like mijostyn‘s 6922s are perhaps a bit less prone to microphonics, but Atma-sphere seems to disagree. Tubes used as cathode followers, i.e., to convert voltage into current and add no gain are less prone to microphonics. If one cannot hear a certain kind of distortion or noise in one’s audio system, that does not mean it is totally absent. It just means you can’t hear it. Which often is good enough.
A wall rack is a good idea. A rack on a load bearing wall even better. When I was just out of college I put my Sota table on a granite slab that was pried off the front of a building that was being torn down. The slab was placed in a window ledge with rope suspending/anchoring the front of the slab to the top of the window sash. PARTAY!  The cool thing about the Sota tables is that they are reverse sprung - the spring doesn’t compress, it is suspended. Good luck