@acman3 we get it! All of the responses you received were relating to external subsonic vibration. That is the problem you are trying to work with and that is what springs, Herzans and the like will deal with. You cannot use a bass trap -- it would have to absolutely enormous!
Our solutions are practical in so far as if it proves impossible to remove the source of the subsonic issues (which frankly it will be, subsonic vibration is present all of the time from mini earthquakes and the like) then the only solution is to isolate the audio equipment from its effect which the solutions we are suggesting will do.
Our solutions are practical in so far as if it proves impossible to remove the source of the subsonic issues (which frankly it will be, subsonic vibration is present all of the time from mini earthquakes and the like) then the only solution is to isolate the audio equipment from its effect which the solutions we are suggesting will do.