Compression ridges ... Clark and Dean

[Richard Brekne]

Hi you two.. First let me say to Dean that the few posts that came 
through since more or less confirm my last to you... tho the closest 
that comes to a direct answer is RonN in

http://ptg.org/pipermail/pianotech.php/2008-February/216955.html

What is not mentioned is that the entire assembly needs to have at least 
a certain degree of stiffness or it will not be able to vibrate well as 
a whole.. breaking up into small individual bits loosing the ability to 
drive low frequencies and loosing power in general. 

Clark... I'm going to go on record recommending you start with an RC&S 
board.  All the discussion about criticisms directed against compression 
reliant boards aside.. I think its very safe to say that an RC&S board 
is an easier place to start.  I'd also advise you to get either 
Nossaman, Overs, or Fandrich to do the basic design work... and pump 
them for whatever you can all along the way.

As for being confused... join the party.  There is a lot of seemingly 
conflicting statements to sort out.  Some RC&S discussions for example 
declare that downbearing on a CC board does not increase its 
stiffness... several discussions along those lines I ran into  last 
nite... yet Del can be quoted several times saying the exact opposite.  
Most of this I think comes from the difficulties in dealing with this 
particular media (i.e. the list) to exchange ideas, ask questions and 
get answers. Basic talking past one another.  Stick with it... lights go 
on... and off... and on again :)

For you others out there.... grin.. dont think for a second this means I 
have changed colors.  I think all three basic (actually four) approaches 
are perfectly sound.

Cheers
RicB


    Clark writes:

    I have been following this exchange about soundboards very intently,
    as one who wants to start building them.  Which brings me to a
    question.  I was tuning a Yamaha GA-1 grand the other day, which is
    famous for having a terrible bass-tenor break.   I made a comment to
    Del at one time about how I
    thought that the board in these small grands was maybe too flexible
    at the lower end, as they go out of tune so much there with humidity
    changes, and he said to me that most people complain that the board
    is too stiff there, on these pianos.  I seem to remember a while
    back that David Love (I could be wrong) posted something about
    adding mass to the tenor end of the long bridge on an M, and how
    that made the tone so much better.  I am no scientist, but I wonder,
    as I bet many others do about this stiffness and mass question. 
    More stiff, less stiff, more or less mass, the effects of these, and
    how does one "design" these into a board one is contemplating
    building?  How do they interact?  What effects do these have on
    tuning stability, tone, etc.  I hope I haven't attributed past posts
    to the wrong people,  just  questioning how this all fits together. 
    Recommended reading, just experience, or what?  Does adding weight
    to the bottom of the bridge just add mass, or somehow decrease in
    increase stiffness, 

    I'm so confused.

    Clark A. Sprague, RPT