Jim and I said: ME: "Now, I'm really confused! Did you rescale it to tensions relevant to 425cps? Or, just arbitrarily change the tension scheme? And,..are you going to tune it to 440cps? If not, then why change the scale. All...most confusing Jim! JIM: Nah, just poor communication on my part. It takes me time to write coherently. Plus I'm working with some design assumptions that might be considered a flavor other than vanilla. Lets try again. It will be tuned to 425. ME: O.K. IF, the scale remained the same! JIM: Set scaling program to 425. If the wire sizes and core/wrap configurations remain unchanged, the 425 will automatically reduce tensions a bit, but not a heck of a lot, just a couple of %. ME: Totally wacked idea Jim, imo.. Based on some earlier tension dropping experiments I've been messing with in the bass, I wanted to go further than this...simplified bass tonal spectrum. Add to that reasoning the structural reasons for wanting more than a couple % reduction in tension. However, though there were structural concerns, the bass tensions clearly do have a tonal goal, and are defined in concert with elevated but safe BP% curves. Bass inharmonicity ends up somewhat reduced, but treble inharmonicity ends up being increased a bit as well. In this case, that means the treble ends up being pretty close to the original scale values (which were high). Thinking about your comment, and going back over the spreadsheet, I could have achieved the above simplified bass and tenor tonal goals at 440 (the back and forth on this list always teaches me something). I would have had to reduce plain wire cores a bit more in the treble to compensate, and that would have reduced inharmonicity up there a bit...probably would have been a good strategy. But the bass strings have been designed at the 425, so for this one, I think I'll keep things there. What I'm interested in seeing is, though the lower tensions create higher treble inharmonicity values relative to higher tension modern scales, what audible effect this higher inharmonicity has. Will it have any audible effect at all, in the the big picture? Power will be reduced, but what other effects will or will not be audible? ME: IF your are using this instrument to just fool aroun with possible/perceptable differences in scaling, I can't think of a worse example to use as a basis. Here is the way I've been doing this sort of thing, (using all of the initial criteria you have given me<G>): 1. Record all scale data and structural stats. 2. Evaluate w/scaling program, set at 425cps, (this is an arbitrary setting due to the age and country of origin. Since I am assuming that it is an English piano or a pre 1870's American piano. German or such would be set at that country's average pitch, as found in the back of Helmholz.) 3. Once, the original perameters are established, Change program pitch base to 440cps and re-run all notes trying to get each note back to the limits of the original scale @ 425cps. This will allow the piano to be, (actually), tuned to 440cps w/o exceeding the original tensions. Doing it this way, you get the harmonics of the original scale, etc. w/o taking the chance of causing any additional stress on the structure. Of course, this is assuming that all STRUCTURAL problems have been repaired and/or reinforced. 4. IF there is an extreme scale anomoly, that you percieve as detrimental to the overall safety of the instrument, then and only then should you make a radical departure from the intent of the designer, imo. All of this is with the idea of making the instrument PLAYABLE/TUNEABLE & to, hopefully, have it continue to be a useable instrument for an indeterminate amount of time.<G> Well, that's my take on it. And...it's served me well over the years Regards, Joe Joe Garrett, R.P.T. Captain of the Tool Police Squares R I
This PTG archive page provided courtesy of Moy Piano Service, LLC