I've been misquoted twice this week. Ron Torella: I never advocated a Sharp "V" for the shape of the capo bar. Read February "Journal". Bill Ballard: I don't ever recall saying anything about the hammershank "whip"...somebody else. I will say that Baldwin made a similar type film back in the '70s where you could very clearly see this effect. Maybe Kent Webb would know where this film is. I believe the "zing" comes from nearly harmonic lengths in the capo section. See February "Journal" where Harold Conklin talks about this. Stability.... The steeper the angle going across the capo bar the greater the friction. Most mathematical models assume uniform tension throughout the speaking length of the string. This is assumed for ease of calculation. If nonuniform tension is the assumption then it is nearly impossible to find the function that will describe the motion of the string. The initial shape of the string upon impact, in reality, would indicate nonuniform tension that would be both a function of time and position. To make a long story short, as the initial pulse travels to the capo bar it would attempt to grab tension from the non speaking portion on the other side of the capo bar. The result would be a lowering of tension and frequency in the speaking length provided that friction at the capo bar was small. Each reflection would find the same thing occurring until finally when the string was fully dampened (not moving), forces would seek equilibrium and the speaking portion of the string would return to its higher pitch. I'm not sure that this is the correct model either. It is just what I'm thinking right now. I just started my second quarter on Partial Differential equations and Fourier Analysis and this is the sort of stuff it deals with. Hopefully, in the summer I will be able to apply some of this knowledge when I have leisure time. It has been a long time since I have seen or tuned a Steinway Upright but I'm willing to bet that the problem lies in too little friction at the capo bar or what ever that thing is. Michael Wathen College-Conservatory of Music University of Cincinnati
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