>However, I am asking myself if a soundboard always needs crown in order to >work properly? Define "properly". Soundboards are typically crowned to provide more stiffness for the given mass. They become stiffer as the crown is depressed. That stiffness and spring resistance against the spring downbearing load of the string plane provides the impedance match for what we occasionally consider to be good tone in a conventionally built piano. There is no single one thing you can point to, nor will there ever be, that accounts for piano tone production. This includes soundboard crown. >I heard about some old pianos with no measurable crown that sound very good. >I have even seen some where no crown seemed left, yet the performance was >very good. Everyone has heard of these pianos. Most of them are owned by the guy who bought the new Corvette for $100 because someone died in it. How many have you actually heard for yourself, and what was the condition of the other dozens, if not hundreds of factors involved in this assessment? >So, why is a crown necessary? To provide the necessary stiffness under load - if it was designed that way in the first place as most of them were. >Would a flat board, but with enough downbearing for teh strings, work or >not? If it is still stiff enough to provide the required impedance to the strings, through accident or design, yes. Can you assume that a flat board will be fine if you just add downbearing (as has been done many thousands of times for many years by rebuilders lowering plates on old flat boards), no. Ron N
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