At 1:52 AM -0400 5/30/03, Stephen Birkett wrote: >Well it's about time I earned those oatmeal chocolate chip cookies >which Bill very kindly sent mmmm. Thanks much Bill for the treat. You got the ones with the sodium pentathol. Next time it's the Haight-Ashbury recipe. <g> >The graphs I described are actually based on the formulas which are >easily derived, but I hadn't included those in the article to keep >it simple. It would be nice to have some values (maybe next time the green flecks AND the sodium pentathol). Knowing how the values are observed/measured would allow us to see what scale the graph is in, ie. are the breakpoints plotted in the neighborhood of a "mp" or a "ff". Then we'd know over how much of the pianist's dynamic range, the application of counterbalancing mass works for or against pianist's control. At 1:52 AM -0400 5/30/03, Stephen Birkett wrote: >Yes. This is one certainly possible interpretation - I added some >comments on the subject of control in the article version. I did say >in the original slides that the question of "more or less difficult" >control was "arguable" ["some might believe" etc.] It really depends >on whether it's easier to control smaller absolute forces over a >shallower slope vs larger forces over a steeper slope [this in the >soft zone]. One could view the pianist's ability to control the speed of the parts as measured by a minimum unit/increment of force applicable by the pianists. Then the acceleration yielded by this minimal increment of force would be the minimal increment of acceleration. The question then becomes, is the size of the change in volume/timbre useful to the pianist as a minimal incremental of tonal variation. If the curve is too steep, he minimal increment of tonal variation will be to large, and the action will indeed be too "touchy", as Phil describes. Too shallow, and the pianist's minimal increment of force will go unnoticed by the inertia in the system. That is the speed of parts (hence, tonal attributes) will not show a noticeable response to the pianists' minimal touch. >The answer is not unequivocal and needs investigation. As the mathematicians say, complex. I think the engineering studies are going to have to remove the pianist from the piano, to avoid contaminating variables and unknowables. Maybe, Stephen, you've been there done that already..... At 12:45 PM -0700 6/2/03, Phillip Ford wrote: >1. The steepest slope is the most desirable. ><snip> >2. Something other than the steepest slope is most desirable. That's the choice, but we don't know how to make it yet because we don't know how significant the advantages and disadvantages of each are to a pianist's performance. Jerry Lee Lewis or Little Richard, that's one thing. >This gives us a predicament. We then have to choose between biasing >towards optimizing soft zone play or optimizing hard zone play. The original choice is not between steep or shallow, it is between choosing or not choosing. Like the original sin, it's not which sin you'd pick, but whether you're going to be a "sinner". >Or we have to come up with a new action design or balancing scheme >that allows us to have a different slope in the soft zone and the >hard zone. A two-speed transmission, the second taking over after the breakpoint. this whole system begins to resemble a torque converter. At 12:45 PM -0700 6/2/03, Phillip Ford wrote: >Another point to come out of this slope investigation - if it turns >out that the steepest slope is most desirable, then this would >indicate that we would get some return from reducing the inertia of >the key itself. Some clever engineering of the keys might yield >positive results. Don't forget the rep and the shank. If you don't want mass in the key, you don't need it in these either. I would like to see a real hammer out on the business end of this action. >If it turns out that something other than the steepest slope is most >desirable, this would indicate that the time and expense of doing >this would probably be wasted. As soon as the optimal slop has been decided upon, designing the action should be straight forward. At 12:45 PM -0700 6/2/03, Phillip Ford wrote: >Also, on the next revision of your article perhaps you will include >the idea of magnetic balancing and compare this to lead balancing. >I think balancing with magnets should keep the slope of the line the >same as the line for the unbalanced key but shift it to the left a >bit. If the steepest slope is the most desirable, then this would >appear to be a good way to go. If not, then perhaps leads would be >better. Here, here. Phil, let's both send him cookies. I have two concerns with magnets. 1.) As long as it is a Fazioli action being set up, one could trust that the work being asked of the magnets moving conventional amounts of weight in the action. With Mr. Chris's Aeolian grand, the magnets could also be pressed into service on inertia problems which should have been dealt with mechanically (ie., SWs, Fws, SBRs etc.) 2.) I don't know how the coupling of parts operates during the return stroke. This a complaint similar to that of helper springs, in that both introduce a counterbalancing force with is separate from (and independent of) the forces based on mass (gravity and inertia). During the down stroke, the key is the driver and everything above it is coupled by gravity and inertia. On the way back, the force of magnets (as does force of springs) is working against the mass-based forces. BTW, both the helper springs and the magnets grow weaker, the higher the hammer lifts, and stronger as the key returns. At 11:35 PM +0200 6/2/03, Richard Brekne wrote: >One point I'd like to get clear pretty quickly tho... just what >level of play can we expect to be able to expand the so called soft >zone too by configuring the keys intertia appropriatly ? Is this >limited to some level of pianismo ? Or can this feasably include mf >perhaps even forte play ? I must admit I've not really thought of >these musical concepts for play level in terms of actual input force >in grams. I couldn't agree more. We lack a correlation. And I'd be willing to bet that the combination of pianist and piano is an unknowable.
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