Exactly my point.<G> AND, nothing is "really" a solid, (think about it.<G>) Joe Joe Garrett, R.P.T. (Oregon) Captain, Tool Police Squares R I ----- Original Message ----- From: Ryan Sowers To: joegarrett at earthlink.net;pianotech at ptg.org Sent: 4/2/10 8:20:47 AM Subject: Re: [pianotech] Soundboard rise/fall theory I tune quite a few p22s in schools. They go out of tune in a very specific pattern. One interesting phenomonon is that leading up to the treble break the pitch sometimes will get flatter and flatter, the flattest note being the last one before the break. The very next note will be quite sharp. The sharpness then will taper off over the next several notes. Depending on the time of year, it can be the opposite with notes getting sharper leading up to the break and then suddenly dropping in pitch. This tells me that: 1. This can't possible have to do with soundboard rise/fall. 2. There is some sort of twist happening in the structure, with the pivot being at the treble strut. How else could flat notes be right next to sharp notes? Ryan On Fri, Apr 2, 2010 at 9:41 AM, Joseph Garrett <joegarrett at earthlink.net> wrote: William said: "This may be the way we've been explaining it for eons, but this theory is certainly in question. Read Ron N.'s article in the April 2006 Journal which speaks directly to this. More, I believe it was Ric Brekne who wrote an article some time back which addressed the concept of pitch change due to soundboard crown increasing. When he isolated the one variable of rise and fall of the soundboard, it was pretty quickly apparent that the amount of soundboard rise required to affect a significant pitch change was absurdly large. The math just doesn't support the theory that soundboard rise and fall is responsible for major pitch changes. It is involved to be sure, but is likely not even the major factor. Lot's to chew on, and I apologize in advance if I've referenced the wrong author." William, It's not just the soundboard that swells in a higher moisture situation. The entire piano swells, which puts stress on the plate and the rest of the sound producing body(s). That's the way I tend to envision it. There must have been some experiments done by manufacturers some where? Anyone? Joe Joe Garrett, R.P.T. (Oregon) Captain, Tool Police Squares R I -- Ryan Sowers, RPT Puget Sound Chapter Olympia, WA www.pianova.net -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100402/252aa54c/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC