Richard Moody wrote: > I "rescaled" a Kimball upright from the same era. [...snip] > The idea was to get > a scale uniform in tension. I had read the book which was a reprint of the > piano maker's conferences of 1915 - 1918, (Piano Tone Building) and was > impressed by the fellow from American Wire and Steel who adovacated an > equal tension scale. His concern was that wide variations of tension would > result in tuning difficulties and tuning stability problems. He pointed > out that the tension should never excede the elasticity limit of the wire, > which was considerably under the breaking point of the wire. > I calculated the existing tensions, then fed in sizes to get a uniform > tension. In end I opted for a graduated uniform tension scale that went > from 155 lbs in the treble to 180 in the lower tenor. [...snip] > : ( It was my piano so I felt free to experiment. I was pleased with the > results. I'm glad you were happy with the results. My experience with that method has not been that good; the scaling calculations should take more than tension into account. The biggest problem with that approach is in the low tenor (the longest plain wire strings). Because there is usually a recurve or foreshortening of the bridge in that area, the equal tension method results in a very heavy wire size which has much greater inharmonicity than the wound strings below. In simple terms, it sounds bad. I asked a question about this about a year ago. There are others on the list more knowledgeable about this than me; some have written software for it. My only advice is something that Vince passed along--get a copy of "The Calculating Technician" by Dave Roberts (a PTG book). -- Tom Rush tarush@mindspring.com
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