<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body text="#000000" bgcolor="#FFFFFF" link="#0000EE" vlink="#551A8B" alink="#FF0000"> Since I am a fan (at least to some degree) of Ed McMorrows book on pianos, I thought I might inject what he has to say on the subject matter. I will take his opening paragraphs only for now. Crown     There is much discusssion amoung piano technicians about soundboard crown. Crown is the curve of the soundboard towards the strings. I should be a gentle belly-shape. Achieving this curve is what technicians refer to as "bellying the board." Crown has two main purposes: to make the soundboard stiffer (hence more acoustically responsive) without adding any weight; and to function as an expansion joint for the wood as it reacts to humidity changes.     One could ask: "Since a high stiffness-to-weight ration is desireable, and crown increases stiffness, why not put as much crown as possible into the soundboard, since that will make it stiffer without additional weight?" The piano may sound good for five minuets, five weeks, or if you're lucky, five years, before the natural elasticity of the wood is ruined by this exaggerated tension. The piano maker must not crown the soundboard beyond the limitys of the wood's elasticity. A soft spruce soundboard cannot take much internal load without collapsing in a short period of time; if an extreme curve is forced into the board, the elastic limits of the wood will be exceeded.     The most important factor in achieving tone quality and long-term stability seems to be the elapsed time in the bellying process. If the soundboard panel is dried too quickly, it will lack longevity once crowned, due to the reduction in the elasticity of the wood. If the newly crowned board is fitted to the rim and plate too soon, it may continue swelling to the point of internally crushing the wood. If the installation fo the final plate and bridge elevations are rushed as well, one risks haveing too much downbearing on an internally crushed soundboard. This will inhibit the sone significantly and in a few years could result in loss of crown, which will cause the piano's tone to become even more lifeless.     The best piano makers take enough time in assembly for all the parts to reach relative equilibruim. If a piano maker has already invested time and money into makeing an finishing a plate and rime, it is hard to resist the cash-flow pressure to pop that board in, string it up, slike the action in and ship out the piano. But building a fine piano means playing a waiting game. from Ed McMorrows "The Educated Piano" side 10   Richard Brekne I.C.P.T.G.  N.P.T.F. Bergen, Norway </body> </html>