what is downbearing?

JIMRPT@aol.com JIMRPT@aol.com
Fri, 20 Feb 2004 20:50:38 EST


In a message dated 2/20/04 5:56:09 PM Eastern Standard Time, 
collin.s@skynet.be writes:

<<  Problems arise in the 3 last
 octaves of most pianos I see, and there any reading (even string length) is
 subject to caution.  Help !
  >>

Stéphane....The problem in these octaves is more typically 
soundboard/impedance problems and no amount of accurate downbearing magic will cure it. :-(

<>

 Difinitely not "irrelevant" but it is not alchemy or sorcerers work either. 
What you are shooting at in adjusting for down bearing is a moving target not 
a static one. There is a range where any downbearing within that range, for 
one particular piano, will produce excellent tone...That is the range to shoot 
for and inaccuracies of  small magnitudes are not going to effect the overall 
result. Downbearing forces change with changes in temperature, humidity, tuning 
pitch, whether any strings are broken, etc........  So we are shooting at a 
moving target and no one is going to be able to give you the magic formula for 
"exact" downbearing force or downbearing angle which will work on all pianos 
and most times won't work optimally on pianos, of the same model, which come 
off the production line one after the other.


 << But I would like to change my views also, and know
exactly how much downbearing I should put on my next rebuild job, and how I
could accurately (enough) measure it.>>

 Great!!! When you get it worked out, patent it, and I will market it for 
you!! :-)
Until then, measuring each piano shaped thingee, and then making a SWAG, will 
get 
you in the ballpark.......... cause you won't forget your mistakes quickly! 
:-).
Jim Bryant (FL)

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