----- Original Message ----- From: "David Love" <davidlovepianos@earthlink.net> To: "Pianotech" <pianotech@ptg.org> Sent: September 24, 2003 11:46 PM Subject: Re: Heavy Hammers / High Ratio / Ric > Even if saturation were not an issue, it seems that the upper level that > the piano will produce is limited by the soundboard. Actually, no. The upper power level any given piano is limited by the hammer velocity X hammer mass equation. And that is limited by action saturation. If you can increase hammer velocity with a given mass, or increase the hammer mass without sacrificing velocity, most, if not all, pianos are capable of producing more volume. > > As pianists we know > that beyond ff, many pianos probably don't produce any more sound. The > board seems to reach a point where it simply cannot put out anything more > without the tone becoming distorted--it becomes just more noise. Now I'm getting into an area I've not actually tested, but.... I think the distortion heard at this point is coming from a hammer gone out of control. As you approach action saturation the motion of the hammer becomes increasingly erratic -- it ends up flopping all over the place. This can easily be seen using high-speed photography to slow down the hammer's motion so it can be studied in slow motion. >From my own tests with removing the compliance from various action components I do know that it is possible to increase sound volume without introducing any noticeable distortion if you can control the motion of the hammer more precisely. One easy way to do this is to simply change the shape of the hammershank. The currently in vogue hexagonal hammershank cross-section shape is not the best. In fact, it's not really very good at all. Many early action makers used a rectangular shape well out toward the end of the shank. Some of the Pratt-Read shanks we used in the 1970s started out with this rectangular shape extending out about 3/4 of the length of the shank in the bass, about half way through the tenor, and about 1/4 the length in the treble. Why this is no longer done is a mystery to me. I guess the idea didn't originate in Germany. Del
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