On Dec 6, 2009, at 2:53 PM, Ron Nossaman wrote: > Now, I'd like to state once more that none of the formulas anyone > has are absolute gospel. None of them. The closest thing I have to > truth here is from reports I've read through the years from > facilities having done empirical testing on wire stating that break% > doesn't change with wire size, if you average in enough batch > testing. Zero change falls in the middle of the bell curve. Once > again, the formulas that we use to calculate tension, inharmonicity, > impedance, and break% aren't, and can't be, absolutely accurate. > This doesn't render them less useful for their purpose, but picking > two at random (which themselves don't nearly agree) isn't a useful > indicator of an absolute premise. > Ron N Thanks. Obviously I have been relying on false data to come to my conclusions. Just for the sake of completion, and maybe to make it clear to some others, I'll recap a couple things. We will all agree that on any working real scale, which means that length increases at less than two times per octave, if you string with one gauge, the tension goes down as you move down the scale, and up as you move up the scale. Since the breaking point stays constant (since you are using the same gauge), that means break% is higher at the top and becomes lower as you move down. More to the point, though, given a single note, meaning a speaking length and a target pitch, if you increase the diameter of wire, the tension increases (and, obviously, the inverse: decrease diameter, tension decreases). So the question is whether the strength of the material increases at the same rate, to keep up with the increase of tension. I had thought, based on the information I had, that it did not keep up. Apparently I was wrong. Of course, the measurement of breaking point tension is not an absolutely precise science, and so it is likely that my information was based on sampling that happened to slant in a particular direction (that is, the breaking point figures selected by the spreadsheets I used tended to show more relative strength in narrower gauges). So, bottom line, I am convinced. Again, thank you for going to the trouble. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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