At 09:44 -0400 15/6/10, pnotnr at aol.com wrote: >I used PSCALE to evaluate the existing strings, and while it shows a >reasonably smooth curve, it's at the bottom of the target for >tension, especially the bottom 3 notes which are around 26-30 >breaking % and between 107 to 120lbs. tension. And the tenor >section is right on the bottom line of the inharmonocity curve The tensions you have calculated concur very closely to the results I get using my own programme, averaging 140 lbs. The nasty break at 53/54 rather spoils things but there's not much you can do about it unless you want to make a bridge that crosses the bar properly. It's quite a common fault in German pianos of that era. >I played around with the wire sizes, and came up with a better >looking scale, but it would add about 850lbs to the overall tension. >Is this too much? (original scale total tension is 24703 lbs, and >the one I came up with is 25660 lbs.) It's not the most wonderful bridge line but with the plain wire starting at note 32 you can't go far wrong and the 142 lbs. on a No. 18 wire is fine, provided that the highest covered strings are designed to match and give a good break. Have you got covered trichords on the long bridge, or bichords, and how many notes have you on the bass bridge? What often happens, even today among well-known makers, is that the break between covered strings and plain wire has to be fudged because of design faults of two or three kinds. In the case of this piano I think you are not dealing with the worst kind and that the break can be managed well simply by string design. Of course, I'd need to have the lengths and type for the covered strings to be quite sure. You have brought up the tension of note 32 to a good level and so you now need almost certainly to bring up the tension of the highest covered strings, and how this is done will depend whether or not you have covered trichords. What you will almost certainly find is that the highest covered strings were designed to fall off in tension, maybe as low as 110 or 120 lbs in order to meet the too loose plain wire in the tenor and fudge a mediocre break. You can now have all your bichords (forgetting trichords for the moment) at a good tension, say 170 lbs down to, say, note 14. Steinways being Steinways, you almost certainly have 10 or fewer singles, and this was, and is, too few, so here you do have to fudge the break in a way that you would not need to if you had, say 14 singles. The few (thank goodness!) Steinway uprights I've dealt with have all had a very bad break between singles and bichords, but this can be greatly improved. Sends me the bass lengths, if you like, and I'll suggest a scale. JD
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