Hello, A friend of mine pianist (professional), have find very tiring the Fazioli fitted without leads (actually I believe the system is now mixed leads/magnets). Because he was obliged to go with the key all along (no way to throw the key and wait for it to rebound) He calls that inertia of a key (absence of inertia in that case) and say it is necessary (to have some) for really fast playing. Best Regards. Isaac OLEG ------------------------------------ Isaac OLEG accordeur - reparateur - concert oleg-i@noos.fr 19 rue Jules Ferry 94400 VITRY sur SEINE tel: 033 01 47 18 06 98 fax: 33 01 47 18 06 90 mobile: 033 06 60 42 58 77 ------------------------------------ > -----Message d'origine----- > De : caut-bounces@ptg.org [mailto:caut-bounces@ptg.org]De > la part de Ed > Sutton > Envoyé : mardi 30 décembre 2003 15:05 > À : College and University Technicians > Objet : Re: Inertia > > > John Hartman wrote: > > > > I figured the MOI for the three action parts of a typical > note. The > > hammer was 8 gms and there were three leads in the key. > The front arm of > > the key was 25cm and action leverage was 5.3/1 with a BW > of 35gms. Here > > are the number for the MOI as adjusted for reflected MOI: > > > > Key MOI = 10,307 gmcm^2 > > Wippen MOI = 3149 gmcm*2 > > Hammer and shank MOI = 165,528 gmcm*2 > > > > There may be many virtues for keeping leads out of the > keys but I can't > > see how it makes very much difference to the perceived > weight of the > > action. > > Similarly, using Jim Ellis' simple velocity formulas, I > calculated that with a 12 > gm hammer head, and 48 gms of lead (more than any of us are > likely to use!), with > the leads magically compressed at 1/2 distance of the key > from the balance pin, > the force to move the leads would be 1/25 of the force to > move the hammer head > (all other factors omitted). If the leads were magically > compressed to be at 1/4 > of the key length from the balance rail, the force to move > the leads would be > 1/100 of the force to move the hammer. > > These are simplified and exaggerated results because > 1) All other parts weight are omitted > 2) The front weight is excessive > 3) It would not be possible to compress the leads to a > single point, so that > in practice one could not make such a significant change in > the location of the > leads. > > This leads to the question of whether a pianist could > discern a difference in the > order of 1/100th, 1/50th, 1/25th of the total force needed > to move the system and > make a sound of a given intensity. And how might we test > this empirically? > > One of the claims of the Magnetic Balanced Action is that > the key lead inertia is > removed from the system. This is certainly true, but is it > significant for > performance? A blind comparison between two Fazioli pianos > with identical > downweights, one with key leads, one with MBA would be the > way to test this. (A > performer friend who has played the MBA is convinced he can > feel the "lack of > inertia." However, I have felt a similar ease and > sensitivity in a standard > Fazioli, so I am not yet convinced what he feels is the > result of removing the key > leads.) > > Or might it be possible to install a few MBA keys in a > standard weighted piano, > adjust them to correct downweight, and see if the performer > can detect them, and > how? > > Again I suspect that the difference would be in speed of repetition. > > So, Jim, we're looking forward to your experiments in jack > reset time! > > Ed Sutton > > > > > > _______________________________________________ > caut list info: https://www.moypiano.com/resources/#archives
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