Just in case the following query did not come through the list when I posted it last week, here is a repeat. If it did come through and there were simply no takers, my apologies for wasted bandwidth. (SK) >Since David Roberts' book, The Calculating Technician, was published some >years ago, I have programmed his formulae into a spreadsheet and plugged in >the appropriate data from each piano I rebuild. The data from the various >functions he developed (Loudness Factor, Hammer/String Contact Time, >Inharmonicity of the 4th Partial, Tension and Percentage of Breaking >Tension) creates some impressive graphs of each function, but I haven't yet >learned how to manipulate this data to optimize the scale on a given piano. > >I understand that others use Dr. Sanderson's formulae for scale analysis >and some feel that they are more accurate, at least as far as calculation >of tension and breaking percentage go. > >Although I have been told that the scaling software that is currently >available is suitable (at least for those of you with Windows based PCs), I >would like to take the discussion of Do-It-Yourself scale analysis to the >next level. > >Would those of you who have modelled their own spreadsheets with either >Roberts' or Sanderson's formulae care to comment on your procedures? Which >functions take precedence? Smooth tension curve? Smooth inharmonicity >curve? How do you actually manipulate the data? Do you identify problem >areas on the graphs and just empirically change wire diameters to see if >there is any improvement? > >There is a fascinating article in the June 1988 Journal on 'Rescaling the >1905 Steinway Upright' which involves replacing the lowest 2 tenor trichord >plain wire unisons with copper-wound bichord unisons. The article mentions >the Sanderson formulae and gives the reasons for recaling but doesn't >actually get into the procedure. > >Suggestions? Experiences? > >Best regards, > >Stan Kroeker >Registered Piano Technician > >Kroeker & Sons Piano Experts >59 Quiring >Winnipeg, Manitoba >Canada R2G 1Y5 > >Ph. 204-669-5881
This PTG archive page provided courtesy of Moy Piano Service, LLC