<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; = charset=iso-8859-1"> <META content="MSHTML 6.00.2600.0" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Dear List-</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>This discussion of MOI in piano actions = has been one of the great moments on this list.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Throughout this discussion I have been = trying to find an answer to the question "How can I tell if it matters enough to = do something about it?" and "Is there a point of diminishing return where = we should stop worrying about key lead placement?"  As practicing piano technicians, this is the question we are all seeking to answer.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>The act of playing a piano is so = complex, the demands are so varied, and the techniques, sizes and shapes of people = who do the playing are so varied, that while analysis of the physics of the action = give us insight, I don't believe it can give final answers.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Ultimately the answers will have to = come from empirical performance tests using real musicians.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I have been trying to think of some way = to test this that doesn't require an immense budget and research lab, since I = have neither!.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>So I've done various thought = experiments, looking for something feasible.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Here's the best I can imagine so = far.  I would appreciate critical comments:</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>1) Start with a piano with a well = designed and regulated action.  It should have strikeweight and frontweight continuities, even balance weight and friction as low and even as = possible, and presumably wippen assist springs.  The keyleading should be as = consistent from key to key as possible.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>2) Add extra key leads to certain = keys.  Add these leads in pairs equidistant from the balance pin hole, one lead to = the front, one to the back.  In this way the measured parameters of = frontweight and balanceweight should not change, but the MOI of various = adjacent keys would be very different.  If, for example, one large lead is added, = front and back at 8" from the balance pin hole, the relative MOI difference = between keys will become greater from bass to high treble.  </FONT></DIV> <DIV> </DIV> <DIV><FONT face=Arial size=2>3) Have pianists play the piano and = report on what they feel and how it influences their playing.  Compare their = reports with actual locations of extra lead.</FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Thanks for your comments.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Ed Sutton</FONT></DIV></BODY></HTML>