Soundboard Installation & MC

[Erwinspiano@AOL.COM]

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.>                     Del& Ron
> > >>>>>And this really was my main point that it does  stiffens up 
> considerably
> > which is certainly some part of the dynamic equation for its ablity to
> > produce tone.
> > Perhaps not stated very well but in our ongoing discussions about the 
> rims
> > and board function this one little piece of the pie seems to be ignored 
> or at
> > least not considered as important. 
> >     No it isn't germain to the tension resonator argument and I wasn't
> > supporting it although that's where the discussion  started. I was merely
> > making the point that this stiffening from gluing the panel to the rim is
> > important. Although I'm calling it a supporting agent I don't /didn't 
> imply
> > that this is how the crown in the board was derived in the first place 
> nor
> > will it keep it from going away over time. Perhaps I was unclear.
> 
> 
> Hey Dale,
> Then why the mention of the flying buttress, which isn't exactly an edge 
> clamp?
> OK though, that's cleared up.

>>>>>>>>Well almost. Is it your opinion that none of the downbearing load is 
transfered down our gloriously precrowned rib./board stucture? or is it just 
an almost  negligable  consideration because of the absorption of bearing 
force from  the panel itself? One thing I didn't say was how stiff these 
boards are even when they are being dry fit and pre stressed for bearing. 

    I have more observations and questions. The glued
> edge does obviously stiffen the assembly, but the *additional* crown support
> from the beveled rim surface is what you're after. I'll try to make sense 
> of
> this, but no guarantees. 
> The rim bevel only aids crown support as long as the bevel angle is greater
> than the landing angle of the crown.
>>>>>> I agree and the  critical word is"Aids"

         The landing angle (or what would be the
> landing angle if the panel wasn't glued down) depends on the crown radius,
> length of the ribs, and deflection under load. If the bevel angle is less 
> than
> the landing angle, the initial effect would be to depress rather than 
> support
> crown
          This is virtually always the case when installing a new board. In 
the
> case of a flat cutoff bar, the perpetual effect is to depress rather than
> support crown, but the assembly is still stiffened. Do you increase the 
> bevel
> angles to accommodate the tighter crown radii in the treble? What do you do
> with cutoff bars?

>>>>>>>>Point well taken. At his point I have not rebeveld any of these 
sufaces. But what. I do know is that at least on Stwys the bevel in the rim 
and belly rail seems to be adequate enough so as not to flatten out all the 
extra crown I'm applying to the treble.
  This I have determined from Measuring the crown after installation and 
after stringing as well.

           The degree to which the rim bevel supports, or depresses crown 
depends entirely
> on how much crown there would be without it. In either case, the stiffness 
> is
> there. I don't think there's any substantial tonal benefit to this levered 
> up
> false crown, though I do think it gives a false impression of functional 
> crown
> to the rebuilder when the strings are off, even though there was precious
> little if any measurable crown under string load. For me, that puts it in 
> the
> negative benefit category.

   >>>>>>>> This is the false crown measured by piano techs that is mistaken 
for real crown values. 1/8" crown on the logest ribs isn't really crown. As 
you know  this false crown disappears as soon as the board is released from 
the rim bevel.

>  On a different note since some of the old compression crowned boards
> > survived for longer than they should have based on our experience with 
> them
> > it will be disappointing not to be around to see just how long the modern
> > variety rib crowned board will survive tonally by comparison.
> > >>>>>>>>>Dale Erwin>>>..
> 
> 
> Yea, too bad we'll miss it. One thing we can count on though is someone out
> there in the future a hundred years from now will be saying "Sure some of 
> them
> still sound pretty good now, but how can we know what they sounded like 
> new?" 
> "They had wood back then, you know, and special tone wood at that." "The 
> secret
> lacquer formula they used still has us stumped too." "If only they had 
> written
> down their secrets instead of taking them to the grave..." "We'll never 
> prove
> anything now."      ------ Ron

>>>>>>>>>You Mean you're not writing it Down dude?
                     Thanks for the post. My tone woods better than yours any 
day
         >>>>>>>>>>>>Dale>>>>>>>>>>>>>

> 
> 


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