Measuring soundboard thickness

Erwinspiano@aol.com Erwinspiano@aol.com
Mon, 3 Oct 2005 11:17:41 EDT


---------------------- multipart/alternative attachment
 
Vladan
  In my Opinion & under the scenario you  proposed  ie. same crown. I'd 
suggest if the board thickness are  the same & the bearing setup zaactly  the same 
way ie. if the  Same moisture content was present on the day the ribs were 
glued on  & on the day the bridge heights were cut for bearing & also  the MC was 
the same in each at that time  ,there would be little tonal  difference. The 
problem is factory compression crowned board & the  inherent inconsistencies 
that are & were allowed to exisit in the factorie  invironment create a wide 
variety of anomallys. There are no agreed on  thicknesses for boards in old 
Stwys ,as I've witnessed from model to model, but  just a parameter. 
 A too thick board even with appropriate amounts of crown  & bearing will 
cause a stingy sound as quick as any thing I know. But I  usually do not find 
this condition in older stwys.
   In the case you present it's always many things  that contribute to tonal 
constipation or freedom.
  Also different species of spruce  used in models  50 yrs apart contribute 
to some of the difference. Ie Sitka boards used in more  stwy models in the 
1970s & the overall skill of the bellyman. It's many  things.
  I have used the hacklinger gauge & it is  expensive & accurate
  Dale

Let's  say you are interested in piano design and you
come across a couple of  Steinways, same model, built
50 years apart.  One sounds great, the  other one
doesn't.  They look similar enough.  The scale is  the
same.  Both have the same amount of crown, the ribs
look  similar, even the grain is similar looking.  One
could simply say:  "The wood is different, they don't
make them out of that good old wood any  more."

On the other hand, what if the acoustic difference is
due  to soundboard profile changes (intended or not)? 
Maybe they have changed  the thickness profile in the
intervening years and that is the primary  cause of the
tonal difference.  You would not know this unless  you
measured.  One can save a lot of time by comparing
things that  others have already taken time to build.


 

---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/2a/11/c8/55/attachment.htm

---------------------- multipart/alternative attachment--

This PTG archive page provided courtesy of Moy Piano Service, LLC