Forgive my density but... What is it about the 6-6.5%emc at rib glue-up that causes the panel to be supported, all else being equal in terms of rib crowning & rib dimensions, panel thickness etc.? Is it a question of internal friction, stress and/or compression? I've read notes from classes taught by Del and Ron N. and while I get the stiffer rib assembly, I don't get why the extra emc makes for a more stable soundboard? Please forgive me and refer me to the archives if I'm opening up a can of worms here! :) Jude Reveley, RPT Absolute Piano Restoration, LLC Lowell, Massachusetts (978) 323-4545
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