floating the soundboard

[John Delacour]

At 00:58 +0200 13/5/08, Stéphane Collin wrote:

>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 ?

The other Berlin maker, Görs & Kallmann, also did this round about 
the turn of the century and perhaps for longer.  It's difficult to 
say if they had a particular tonal objective but it does allow a 
slight reduction in the width of the piano.  When I put my special 
soundboard in one of these, a 5'2" grand, I left the treble floating 
and also floated the bass for about a foot.  The treble on this piano 
is very special and gives the impression of echoing round the rim, 
but the my soundboard is not standard at all, so it's hard to say if 
this was a characteristic of the original.

On Viennese Bösendorfer grands I have come across, the whole front 
edge of the soundboard is floating, heavily arched with a maple bar.

JD