Hi Paul. Can I join my voice to yours, asking what's all about downbearing ? Every downbearing measuring system I am aware of (carpet thread, Lowell gauge, dial feeler of John Hartman's stick) seems hardly precise enough to be able to ascertain one of these four statements : there is some downbearing, there is alot of it, there is none of it or there is negative one (those euclidean geometry maths associated with each method should really inlcude a strict discussion on relative errors in measuring process and in subsequent calculations). I just experimented the influence of rear bearing on the sound of the string, while setting the plate height in a piano with a new board. On one single string with positive front bearing, I just could not hear any difference between negative rear bearing and positive one, that is : no difference in volume, in sustain, nor in timbre. (Front bearing influence was more difficult to test, so I didn't. But net downbearing depends on rear bearing, no ?). Now, this was on one single string, and I can imagine that the story is different when considering a whole stringing. But this makes me think that the downbearing has mainly influence on the board stiffness, foreseen that the board has positive crown. But I'll join my voice too when you say there are pianos with flat board, no apparent bearing etc. that don't sound like junkers, and where side bearing seems sufficient to provide the needed mechanical coupling between string and bridge. Regards, Stéphane Collin > Could some explain the purpose of downbearing, how > much downbearing where? I and others I'm sure, have measured > many a great sounding piano-even new ones-that had almost no down > bearing, or even negative downbearing. > > Paul C >
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