I see this as a design failure. In my own design from 20 years ago and which is downward firing, I have NO BUZZ or vibration. I KNOEW that with Bass frequencies that the BOX must be stable and weigh enough to prevent vibration @ frequency.
Of course my BOX (case) is 1/2 in PVC and weights in at about 80 lbs.
You can easily place your favorite family photo on top and never worry about it sliding off the top.