Caster Cups -Reply

[Steve Pearson]

Gregory wrote <As to quieting with foam, yes, a piano can be quieted
somewhat with foam under the soundboard and above the strings.>  

True, but it's more than a bit, depending on the foam.  The foam 3"
Markerfoam under the sounding board drops the volume of a grand piano
by 5db, which is perceived as almost half as loud, say, 40%.  A blanket
of 2" foam, drops it another one or two db.  For the sake of perspective,
raising the lid on a grand makes 1db difference.  
Steve 
Yamaha