floating the soundboard

[Stéphane Collin]

Hi John.

Your comment in this thread awakes an old question I had in mind for years.
On the Bechstein pianos from before 1875 that I encountered, the treble part
of the soundboard is floating.  Some have fanned ribbing, some have ribs
parallel to the grain, but all have the last treble rib parallel to the
small side of the piano, and ending the board which is not glued to the rim
there.  What is the idea behind this arrangement ?  I understand the
advantage of floating the bass side of the board grossly perpendicularly to
the grain, in order to ease large movements of the panel needed to transmit
low frequency vibrations.  But why float the treble ?
And yes, the arrangement sounds very well.  The treble is not that long
sustaining, but it seldom is apart from the capo-duplex arrangement, yet it
is very musical and dynamically way fun to play.

Best regards.

Stéphane Collin.

-----Original Message-----

My education comes 
from the great non-American makers from 1865 to 1914 and a 
significant proportion of their output had the soundboard floated in 
various ways for various reasons.  

JD