John H pointed us to: >Continuing with the discussion about even balance weight verses even >inertia I have another contribution. Actually a clarification of a >comment I made before. Please see the illustration on the >technicians page of my web site. [link redacted at request of site owner - Jul 25, 2015] >I think this will show what I meant when I said that the key leads >help when you play softly but hinder when you play at louder >dynamics. I got started thinking about this a few years ago after >seeing a class given by Bob Holf. He described an experiment he did >using a large scale key model. The gist of the experiment was to >discover how the key reacted to varying force. The key's >acceleration as measured revealed the influence of inertia. John's illustration with the string and hanging weight is a nice one. Here's an alternative way of looking at the same phenomenon, including a demonstration of what happens if you vary the location of the lead: http:/real.uwaterloo.ca/~sbirkett/inertia.pdf Some years back when the list was still innocent we had a discussion of inertia. I recalI pointing out the discrepancy between static balance which depends on the distance to the fulcrum and inertia which depends on the square of the distance. Some might argue that the "assistance" provided by the lead in "soft" playing actually makes the action MORE difficult to control. Stephen -- Dr Stephen Birkett Associate Professor Department of Systems Design Engineering University of Waterloo Waterloo, Ontario Canada N2L 3G1 Davis Building Room 2617 tel: 519-888-4567 Ext. 3792 PianoTech Lab Ext. 7115 mailto: sbirkett[at]real.uwaterloo.ca http://real.uwaterloo.ca/~sbirkett
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