Wim, and others, This from David Love is the crux of the issue to me. The soundboard changing is certainly a factor, and I'm not disputing that. It's simply a matter of accepting that there are MANY things changing on pianos seasonally, and it is nigh on impossible to identify all the sources, let alone quantify them. If you need a simple explanation for your clients, it's this: "changes in humidity = changes in the piano, including the tuning." Then, if they really want more, you can start to dive in to the myriad of possible contributors. William R. Monroe SNIP > There are many factors that influence tuning stability and it’s difficult > without a completely controlled situation and experiments to determine the > exact input of each factor on any given piano. Fortunately, for us, the > many factors help contribute to our job security. > > > > David Love > > www.davidlovepianos.com > > > > > > > > > > If it isn't the soundboard going up and down, and I have trouble accepting > the concept of the string riding up on the bridge having an effect on > tuning, there is only one other factor that could be the culprit, and that > is the plate expanding or contracting. If you think about it, where is the > greatest change in pitch? I find the biggest change is at the first couple > of notes on the treble bridge. On most pianos, that is the longest distance > from one end of the plate to the other. If the plate expands from top to > bottom, (or front to back on a grand), it wouldn't take much to change the > pitch even a few cents. The reason the bass strings, and especially the > lowest few, don't change much is because of the big bass strut, which gives > the plate more stability. > > > > So perhaps the reason the piano goes out of tune with humidity and > temperature has almost nothing to do with the soundboard/bridge moving up > and down, but is primarily because the plate is expanding and shrinking. > Someone else mentioned something along this line, but it seems have been > lost in the conversations. > > > > Has anyone done an experiment or taken measurements of this? > > > > Wim > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100403/1dd70c93/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC