---------- > From: Stephen Birkett <birketts@wright.aps.uoguelph.ca> > To: pianotech@ptg.org > Subject: Re: "Oval or Round Shanks" or to bend or not to bend > Date: Friday, September 05, 1997 2:56 AM > > Richard wrote: > > Before time lapse photography, only educated proposals could be > > made. It was suggested that the optimum blow to the string would > > occur if the hammer rebounded at the moment the string was at the > > heighth of its vibration peroid. > > > We now have computer simulation to get a grasp on this. I wish I could > show you the graphs I have in front of me..showing hammerhead position, > string displacement and force during the impact period. Unfortunately > these aren't email-worthy. If they can be photocopied, I would pay for that and the snail mail, or if they have been published, perhaps some references I could input into a library computer system and maybe get on interloan. Richard Moody ps Of course Helmholtz's comments about the hammer leaving the string at it's apex could be view as predictions since he was before time lapse photography. On the other hand he didn't say what we know now that he could have known then is that the piano is a system of mechanical levers operating in a circular plane exciting a stretched wire into periodic motion. So fare thee well into the relms of trigonometry and analytic geometry those who wish to understand the piano through graphs, computer simulations and other mathematical constructs. Oh and don't forget the levers bend and flex, so it is also a system of springs. And just when you almost memorized the string tension formulas, including the gravity correction, don't forget piano wire is also a spring. You will need that for your rebound variables. If you have all of that under equation, then you can procede to the soundboard, if you can factor in the bridge. Now you are ready to have the old masters tell you where on the string the hammer of such and such composition should strike.
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