On Apr 15, 2009, at 2:04 PM, Ed Sutton wrote: > Can't you turn this into some sort of equation or chart? > > Something like: > > Flexible board + low tension scale + low downbearing = low impedence > needs > Soft hammer + light strike weight + high ratio = fast, light impact? > > Stiff board + high tension scale + high downbearing = high impedence > needs > Hard hammer + heavy strike weight + low ratio = slow, hard impact I'm not qualified to do that, don't have enough experience and experimentation to go on. But I can talk about the some of the principles as I understand them. A lighter weight hammer will rebound more quickly, hence will damp less upper partials while dwelling on the string. (It will be "brighter" than an otherwise equal heavier hammer). A softer hammer will dwell longer on the string, hence will produce less upper partials. (It will be "darker" than an otherwise equal harder hammer). Hammer felt compresses (non-linearly - meaning the hardness curve becomes steeper the more rapid the impact), so a hammer that hits a string faster will produce more high partials. High ratio action is conducive to more rapid acceleration of a hammer (assuming appropriate mass), hence you can get more speed more easily, hence more high partials at "full force" and a larger range of difference, easier to achieve (difference in partial mixes along a spectrum of force applied to the key). Taking this together, a softer hammer with a higher ratio can probably produce a greater range of tone quality. It needs to be lighter as well, for logistical reasons (amount of mass a finger can readily accelerate at that ratio). The lighter hammer will also be brighter by nature (other things equal). It seems from experience that heavier systems (thicker boards and ribs) need heavier hammers to drive them and achieve power, and that they need harder hammers to achieve high partial mixes (perceived loudness, ability to penetrate and be heard through other sound, whether from the rest of the piano or other instruments). It also seems from experience that softer hammers sound brighter on lighter systems. Combining these things, it seems logical that for a lighter, more responsive board, a lighter, softer hammer with a higher ratio would make for a good match. I am speculating that lighter plus higher ratio would give an "easier expressive range" to the pianist. This is based partly on experience with some older instruments, and trying to make sense of what I experience. In any case, you need to have enough mass to drive whatever belly assembly you have. Then you can think about what ratio is most appropriate for that mass. And I should add that I am not really advocating for one thing over another. Rather, I am advocating for having a range of choices. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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