More on soundboard crown

[Delwin D Fandrich]

This is a multi-part message in MIME format.

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

  ----- Original Message -----=20
  From: Richard Brekne=20
  To: Pianotech=20
  Sent: August 18, 2003 10:38 AM
  Subject: Re: More on soundboard crown



  Now correct me if I am wrong.. but I understand this to mean that a CC =
board will be stiffer, both unstrung... and increasingly so when =
downbearing is applied.  Assuming that is correct,=20

Which it is not.



  and putting aside all other compression damage discussion for a second =
or two... I have a question about this long term so called compression =
set.=20

By this are you implying you don't believe the phenomena exists? Check =
The Wood Handbook (USDA) and Understanding Wood (R. Bruce Hoadley).



  Given the absolute ideal climatic conditions over many years... would =
a soundboard subjected to uniform compression set take on a permanent =
stiffness as a result of that, or is it exactly the woods resistance to =
being compressed that causes the stiffness ? Seems to me I also read =
something in one of Johns posts that hinted in this direction. That a CC =
board <<properly treated>> will eventually be pressed into a very stiff =
and permanent condition.=20

No. Compression set continues until some neutrality is reached. I.e., =
the point at which there is so little compression left within the panel =
that in practical terms the wood fibers no longer deform. At this point =
compression and crown and stiffness will be at their minimum point.=20



  On the side of this... and please forgive whatever lack of knowledge I =
display in the asking,  if compression from ribs being glued cross grain =
to the panel is such a problem...even in RB boards.. is there no way of =
contriving a rib such that it is a bit less constraining ?=20

I don't understand any part of this paragraph:
    -- What compression from the ribs? In a compression-crowned =
soundboard system the compression is in the soundboard panel, not the =
ribs. The rib-crowned system uses an entirely different technology that =
has been described in infinite detail numerous times in print and on =
this list.
    -- Compression from ribs is not a problem.
    -- Ribs, in a rib-crowned system, can be contrived to do just about =
anything you want them to do.
    -- What do you mean by "less constraining?"

Del

---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/f8/27/2e/4e/attachment.htm

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