Dave, Check out Del Fandrich's article in the December issue of PTJ. I think he answers many of your questions about the function of mass and springs in both grand and vertical damper actions. Steve Brady, RPT "The most expert and rapid tuners are... University of Washington possessed of a highly excitable, sbrady@u.washington.edu nervous, and emotional temperament, verging on the border of insanity at times." -Daniel Spillane, The Tuner's Guide
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