Log scaling

[Joe Perkinson]

Hello Del,
 Hope you are well. Since we last talked early this year I have continued to
think about laminate soundboards. The cumbersome burden of making a living
continues to impede my progress however. 
 In talking with you, reading, researching and thinking, I have come to the
conclusion that before I can develop a different soundboard a thorough
understanding of the current type of soundboard design is necessary. 
 I am currently working on a M&H BB that was rebuilt by someone else with a
new board and bridge cap on the original root and a c-8 speaking length of
40mm. The bridge was in no way close to its original position and I will be
replacing the bridge cap and soundboard. I have always used the original
board to define the design of the new board; likewise I have always used the
original speaking lengths to define the scale. I believe that this method,
while somewhat safe and consistent in my experience, is not ideal despite
moderate improvements through rib crowning, addition of wound strings on the
treble bridge wire gauge changes, ect. Additionally this piano in its
already modified state provided no reliable information other than rib
placement. I am however concerned about redesigning the board, rib set and
scale with out a clearer understanding of what the hell I am doing.	
 I am hoping that I might call on you again for some consulting. I would
like to have a better understanding of log scaling and soundboard mechanics
so that I can confidently make judicious changes to this M&H BB. 
 Working with the scale has raised many questions (like: it this right?). I
would very much like to do all of the evaluations and calculations myself
but would at the very least need guidance in interpreting the results. I
have already determined a location for the original bridge root based on the
plate design and the known speaking lengths of notes 88 and 21. Based on
this placement I have attempted to create a semi-log scale on the original
bridge cap. I have a basic knowledge of scaling and can see that this semi
log scale produces results that are not comparable to other scales that I
have worked with. So I can see differences, some more marked than others,
but I do not understand what effect these differences will make in the
piano.
 If you are agreeable, I would like to send along the data I've compiled and
phone you at your convenience after you've received it.

Thanks very much

Joe Perkinson
dolce Piano
Decatur, Ga 30030
404-310-5939