what is downbearing?

[JIMRPT@aol.com]

In a message dated 20/02/04 7:11:23 AM, davner@kaosol.net writes:

<<  Supposedly.  Some pianos have no downbearing, yet still have plenty of

> volume and sustain. >>

Dave;
 What you say here is true in general much more than specifically....... :-)
Down bearing is a function of not just string pressure on the bridge/board 
but also of the upward pressure exerted by the crown of the board. A board that 
measured out as "flat" could still be exerting upward pressure on the 
bridge/strings and thus be a viable instrument in your "Supposedly" context.

 I am not 1000% sold, 999.44% sold though :), on Del's "compression set" but 
it certainly makes more sense than anything anybody else has come up with and 
I use his thesis as 'my' working premise...that being said even a board which 
has been 'damaged' by compression may be capable of providing very noice tone. 
I think this has to do with extent of damage, original downbearing, etc.

 A board which might measure "flat" while strung may display considerable 
crown when unstrung and it is this 'unstrung' crown which supplies the ability of 
that particular instrument to produce a very acceptable performance in the 
volume/sustain area.
 There are so many examples of pianos with little or no crown, including 
those which actually were made with reverse crown, which sound very nice that 
"downbearing" is just a portion of the total picture. Than there are the bridge 
agraffe thingees, like Ed's little Sohmer grand which actually have 'upbearing' 
in a portion of the scale and 'downbearing' in another portion of the scale 
and these were/are not bad sounding pianos...but they do sound different than 
what we are used to. :-)

 One of the things I appreciate about Baldwin's Accujust® sytem is that it 
has allowed me to experiment, non-scientificallly, with down bearing and the 
requirements therof. It always surprises me how little down bearing it takes to 
produce a wonderful, if not optimum, sound.

 I belive it is the interplay of upward pressure of the board in conjunction 
with downward pressure of the strings that is the main determinant of such 
qualities as sustain and volume and this can not be a function strictly of either 
downbearing or crown alone.
My thoughts.
Jim Bryant (FL)