----- Original Message ----- From: "Joseph Garrett" <joegarrett@earthlink.net> To: <pianotech@ptg.org> Sent: Saturday, April 26, 2003 7:41 AM Subject: Semi Log Scale > Del, > Please explain the term "Semi Log Scale".<G> > Best Regards, > Joe Garrett, RPT, (Oregon) Ideally, a string scale is calculated from C-88 down using a constant logarithmic exponent. This is easily done when working with a new stringing scale. The plate and bridge are simply made to fit. In the case of an existing instrument it is often impossible to achieve this. Or, if it is achievable, it compromises string lengths too much. Problems generally show up in the lower treble section and/or just below the tenor/treble break. If a log multiplier is chosen that gives you good top treble section scaling it may be that the plate configuration will not allow you to continue with this sweep--the bridge would run well into the plate. Still, if you use a lower (numerically) logarithm to give you clearance down in the tenor section--i.e., an overall shorter scale--you may find that your string lengths are much shorter than you want in the treble. So, you compromise. You use one log multiplier for the top treble, another for the lower treble and, possibly a third for the tenor. All chosen to give the least deviation from a pure log. Since the result is not a pure log scale I call them semi-log scales. Like much of life--a compromise. Del
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