>From Sy Zabrocki When tuning aurally for many years I seldom seriously thought much about = inharmonicity. When tuning a good piano the temperament beat rates, = tests etc. came out good and you were aware the piano had low = inharmonicity. When on a "funky junky" the beat rates needed compromise = all the over the place and you were aware of high inharmonicity. When = learning this work we all receive the usual dose of information = concerning inharmonicity and live with it the best we can. Six years ago I purchased a Sanderson Accu-Tuner (SAT). Now we are = accurately measuring for stretch factors, intervals, octaves etc. You = began to become more aware of inharmonicity. About nine months ago I had = Sanderson update my SAT to the FAC feature. During the last few months = I've become even more curious about certain aspects of inharmonicity.=20 During this post I would like to talk about only the (F) number and not = the (A) or (C). The stretch number of F3 is defined as the difference = between the fourth and eighth partial. This number can vary from #4 to = #25, more than the A and C. Consider the F3 stretch numbers I've found on the following pianos = recently. No. 1--Baldwin Studio 243 Built 1976 Stretch #25.5 No. 2--Baldwin Studio 243 Built 1976 " 21.5 No. 3--Everett Studio Built 1979 " 11.0 No. 4--Baldwin Studio 243 Built 1955 " 11.0 No. 5--Acrosonic Spinet Built 1954 " 11.0 I'm not sure these numbers are constant on all of these models. These = are some I measured the last week or so while thinking about this topic. I became curious why the newer Baldwins have a higher number than the = 1955 model. Can we assume the older scale was a better scale? The string = length couldn't have changed much. String length on the Baldwin and = Everett would be about comparable. Why would the Everett have a lower = number? Why would the older Acrosonic have a lower number then Baldwin = studios? Consider the older and new Baldwin which would probably have the same = string length. What factors would cause so much difference? Wire size = and tension difference could probably cause this difference. Only the = Acrosonic has wrapped strings on F3. Wrapped strings I believe have = lower inharmonicity in this area.=20 As stated above, using the SAT causes you to become acquainted with = various pianos and their amounts of inharmonicity. It causes you to = think about inharmonicity more often. It's amazing how the SAT can do a = pretty good job on one of the funky junkies. You know it jumbled up = those beat rates as best as anyone could do and you're glad you didn't = have to do it. I treasure that little blue box. Sy Zabrocki RPT Billings, MT
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