FWIW I can feel vibration in the top of my Rega Apollo R that is currently playing Seventeen Seconds by The Cure through a pair of 15" Tannoys at about 80db av, one of which is about two feet from it. I guess I'd expect to with such a big and full-range driver so close. It doesn't seem to bother it in the slightest.
PS Loud enough that the f***ing postman has just carded me rather than ringing the wireless doorbell that I'd taken into the room.
This is what I expect, just as much probably more vibration getting into the equipment by the acoustic pressure acting upon its surfaces, rather than from the stand.