Dealing with Vibration on 2d Floor of Home

Happy almost-Spring, A'goners!  I haven't visited in a couple years, but I'm back to ask for your help. 

By necessity, my audio room is on the second floor of my home.  I struggle mightily with vibration from my own footfalls those of others on the second floor while my turntable is playing.  Even my careful footsteps away from the turntable to my listening chair cause the turntable arm to jump.  Likewise, "normal" footsteps of other family members in the hallway or adjoining rooms cause the arm to move.  

I'm currently using a "flexyrack" with heavy 2" thick solid maple shelves. 

A couple years ago I purcahsed a Symposium platform to place under the turntable, but that only mitigated the issue caused by faint, distant footfalls.  It is ineffective against closer or heavier footfalls.  

Shy of spending $$$$ on a state-of-the-art isolation rack, is there a solution for isolating the turntable without altering the sound?