foam baffles and silencing a piano

[Brooks & Yumi]

Del Fandrich suggested that any insulating material will cut the sound 
coming from a piano.  "Natural fiber... will be more effective..." 
Del's post:
https://www.moypiano.com/ptg/pianotech.php/2001-September/093399.html

The question of course would be where to put it.  My wife's piano is a 
Mason & Hamlin AA (6'2") and is in a relatively small room.  I have put 
two blankets above the strings and cut the volume significantly.  The 
blankets are stiff enough that they never touch the strings. I have a 
piece of cardboard that keeps the material from touching the dampers.  
Something underneath the soundboard would help as well and as you have 
already been advised something insulating between the casters and the floor.
Of course this kills the tone/overtones of the piano but it does cut the 
volume significantly.

Brooks Weisman
Arcata, CA