On Sat, 9 Nov 1996, Jerry Anderson wrote: > the following hypothesis: Altering the back check configuration > may be changing the nature of a similar impact sound > that is occuring just after the strings are excited, and is > resonating through the key and keybed. I would imagine > that the closer this impact approaches the moment when the > stings are struck, the more it would conribute to the general > power of the instrument. According to Del Fandrich's article, which I referred to yesterday, this key impact sound could very well occur at the same time as, or even before hammer/string contact. This "action saturation" or action parts bending was also referred to by R. Moody on Nov. 7. > > >If the backcheck does not touch the hammer on the way up to the > >string, it can have absolutely no effect on the tone of the piano. > >or far away, so it can make no decisions as to good tone or dead > >tone. Since the backcheck, under a medium to hard blow, can travel a considerable distance before the hammer aproaches the string (due to flexing of shank and other parts), isn't it possible for the backcheck to slightly contact the hammertail during louder playing. Would this momentary contact help propel the hammer in the same way that the upright's backcheck wire acts as an extra spring to help propel the hammer to the string? If so, then changing height of backcheck could alter volume and possibly tone. The hard thing to visualize is that the parts are in motion and are bending or flexing at different rates. I think that someone obtained high speed film several years ago showing that the upright action backcheck wires act like auxiliary repetition springs under heavy or fast play. There might be some type of analogy to the grand action. Fred Scoles, RPT
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