At 2:08 PM +0200 8/23/03, Richard Brekne wrote: >Whats is more important to the <<heaviness>> of the action, the inertia >of the hammer and top action, or that of the key. I'd vote for inertia in the top action. From a design standpoint, and a mechanical one. First, someone setting up the action has far less control over it than key inertia. To elaborate, what determines top action inertia is SW and the ratio of hammer shanks and wippens. Once those parts have been selected, there is a limited extent to which top action inertia can be adjusted. (As for as SW, maybe if your lucky, .75g downwards. KR, which I'd call bearing directly on top action inertia and not on key inertia, provides more of a means of adjustment but at great extra effort.) The only reason to adjust key inertia would be in meeting the requirements of top action inertia. So from a design standpoint, I'd say that top action inertia is the one to pay attention to. Key inertia is the tail on the dog which wags when its's happy with the weight of the rest of the dog. Mechanically, I'd also vote top action inertia. The top action is the driven portion of the system and the key is the driver. If the driven portion is lighter than the driver, there is the good chance in some circumstances that he top action will "fly away" from the key. (Have you ever had a pianist talk about "fly-away" hammers?) On the way up the top action inertia needs to be greater than the key. Otherwise coupling (and as a result, control) will be weakened. In effect, the driven needs to act like a brake on the driver. >Or if there exists a >kind of border condition where one becomes more important then the other >and vice versa.... what is that condition ? You mean like Steven Birkett's soft and hard zones? There would be two ways to determine this. 1.) happen to be Steven Birkett, with all his years of physics, math and the analysis of mechanical systems. of 2.) do a massive survey of pianists under the controlled experimental circumstances proposed by David Anderson. Mind you, the existence of such a cross-over zone/point is only speculation at this point, and the variables which would cause that cross-over are as yet unproposed. At 4:32 PM -0700 6/14/03, David Andersen wrote: >Let's have a test with 10 fabulous piano players from different genres playing >the same piano, but really PLAYING it, for as long as it took them to know the >spielart, over a 48-hour period where the tuning, voicing, and regulation can >be kept consistent to a very high standard. Bill Ballard RPT NH Chapter, P.T.G. "We mustn't underestimate our power of teamwork." ...........Bob Davis RPT, pianotech '97 +++++++++++++++++++++
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