It's not hard to do a simple test of bridge height change and accompanying change in pitch using the nose bolts of a given piano that has them. By lowering the plate a measured amount you can effectively calculate a change in the in the bridge height (using bearing measurements as well) and then measure the change in pitch. It's not a perfect test but it can give some idea. While I can't comment on Ric B's calculations not having done them I can say that even modest changes to the nose bolts create quite a difference in pitch when compared to the normal seasonal change we experience. I'm not convinced that the soundboard/bridge rise and fall isn't a significant part of the pitch change even if it is not the entire story. Certainly compression soundboards change enough during seasonal swings as to impact the tone, that they should impact the pitch would not be unexpected. For purposes of client communications and simplicity I think it's not an unreasonable offering. David Love www.davidlovepianos.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Ryan Sowers Sent: Saturday, April 03, 2010 10:09 PM To: pianotech at ptg.org Subject: Re: [pianotech] Pitch Change (was: Grey market pianos, seasoned pianos, etc.) It sure looks like the sun is going around the earth too, and people had a hard time wrapping their brains around the fact that the opposite is true. I really think the rising/falling soundboard theory (RFST?) fits in the same category. Actually, geocentrism actually makes more sense because the theory at least seems to fit our direct observation. Nobody really observes the soundboard rising and falling. Maybe because we know there is supposed to be crown in a soundboard and the tuning drifts in a crown like pattern in response to humidity change makes the RFST make sense. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100404/a996f4d0/attachment.htm>
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