Hi Cy I can believe that, tho I did find a measurable pitch change when doing an experiment with strong (neodymn) opposing magnets under the treble section while back. I agree, a good deal of real world measurements and experimentation. All part of a good days "woik" as it were... I should have a spreadsheet which charts expected changes of pitch for both soundboard rise/fall and strings climbing up the pins in a couple days. On the side... I cant get over the fact that this string climbing bit has been a very large part of this discussion with no one seemingly wondering why string climbing is suddenly like magic not only possible but a matter of course. I cant count the times this has been plain discounted as possible due to the large clamping strength and friction levels involved when the string seating subject comes up. A couple interesting points on that subject matter have had light shed on them by this one I think. First, that strings can and do climb pins after all, and secondly and perhaps more interestingly... a consequence of this climbing due to pressure from a swelling bridge surface is that the indentation becomes wider because of the increased sideways excursion of the string path on the bridge. This has to be a partial explanation then for why the indentation is so much more evident towards the bridge edges then at the midpoint. The indentation is not necessarily so much deeper at the edges after all..., as I have always assumed it was. Cheers Cy RicB At North Bennet Street, David Betts told me they once put a jack under a piano they were about to tear down, and put pressure on the soundboard from below. Even with significant force, no pitch change was detected. Time for more Real World experiments, methinks... --Cy--
This PTG archive page provided courtesy of Moy Piano Service, LLC