Rescaling for older soundboards

[David Love]

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I think that's backwards.  As boards get older they get stiffness
challenged.  More loudness comes from being less stiff, lower impedance,
more energy is absorbed by the board rather than reflected back, so
louder and less sustain.  That's why the epoxy method works as it does.
It adds stiffness without adding much mass.  Anyway, I sent the post on
the spur of the moment without thinking it through.  People, of course,
do compensate for the change in stiffness, meaning inability to support
the string load, by easing up on the bearing-as Ron N. pointed out.  It
was just a thought.  Epoxy and ease up on the bearing, rescale to
correct and smooth out the scale is probably the better way to go.  
 
David Love
davidlovepianos@comcast.net 
-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Joe Garrett
Sent: Sunday, November 14, 2004 9:32 AM
To: pianotech
Subject: Re: Rescaling for older soundboards
 
David Love said: "Since an aging soundboard will presumably be less
stiff with less
available crown, does it make sense, when restringing over an old board,
to consider rescaling the piano with a lower tension scale.

David Love
 <mailto:davidlovepianos@comcast.net> davidlovepianos@comcast.net 
David,
Hmmmm? Older soundboards will be stiffer! The natural aging process of
lumber exemplifies this. If you live in an older home, try driving a
nail into the olde studs!!! Yeah, like w/o drilling a hole, first,
you'll be bending nails 24/7!!! However, you do bring up an interesting
point. My observation, on olde boards, is that the upper treble is very
"loud" and, with a decent bridge termination, is very clear. Why?
Because the board is stiffer. I think this is a very good reason to NOT
use hard hammers on an olde board! In years past, a lot of the OLDE
techs used to drop the entire scale, by 1/2 size! This approach, had
some validity, but, I persoanally think this is the wrong thing to do.
Of course, this practice came about, way before the Electronic Age of
easy accessability to an easy way of doing the formulae. Thank god for
the 'puter, in this case! I used to do scales on a TI! Talk about
tedious! One had to be really adamant about scales to persue that! (Let
alone, doing it with a Slide Rule. (you do remember those lovely
gadgets, don't you?<G>)
As for the scaling, in and of itself, all we can do is to smooth out the
inconsistancies of the original factory screwups/design. And, hopefully,
not overstress the original intent of the structure design. At least,
this is my approach to scaling. If we are dealing with a new board, then
it's a whole different approach, IMO.
Best Regards,
Joe Garrett, R.P.T.
Captain, Tool Police
Squares R I

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