This is exactly the point I made to begin with when I brought up the <<breaking function>> of friction. This is why (half of why anyways) we are looking at a trade-off (in the case of the hammer shank flange center) between firmness and friction. The firmer the better with regards to hammer contact, opposed to that is the need for a freely playing action... but the needed degree of freeness is limited by the need for some degree of resistance for the reasons you describe below. And, as you point out, that exact degree will vary from pianist to pianist dependant on just how much control they are able to exert on an action, and with general styles of playing. Further... it is no difficult task to assert that the huge amount of data on the subject shows clearly a preference for the kind of friction levels that have become the industry standard. Cheers RicB V T wrote: >Hello Friction Thread, > >Here is an additional view to get the conversation >heated up: > >The musician has roughly 10 mm of key travel to apply >the force to the key. The choice exists of where on >the key to push, and how to time the force. If we >plot a function of finger force vs. time, we will see >that the player controls his touch by modulating this >force during the travel of the key. There is a >feedback loop at work and the player integrates the >force to get the proper momentum into the hammer head. > He may start with a higher force to get the static >friction out of the way, but then he might lessen the >force in order to create a soft blow. > >The following assumes that the balance weight is kept >the same when comparing the low friction to a normal >friction action. > >All mechanical systems have a "damping ratio". This >is a ratio of stored to dissipated energy. Control >basically amounts to being able to impart just the >right amount of momentum to the hammer. A mechanism >with a low damping ratio (little friction) is harder >to control because a mass set into motion without >friction will continue to move freely. The player has >no means to slow the mass down if he initially presses >too hard on the key. His skills then consist of not >pressing too hard, or quickly backing off in case he >did press too hard. This is exactly what a >"frictionless" action requires - the ability to change >finger force in an incredibly short period of time. >Again, he has only 10mm of key travel during which he >can distribute the force. For best expressiveness, >the musician would probably like to have as much of >those 10 mm available to modulate the pressure without >feeling that he is moving the key stick through >molasses. If he doesn't have the physical ability to >reduce the force quickly, he will feel that the action >is "temperamental". > >The situation changes when very fast playing is >required. The requirement for a precisely controlled >dynamic level may give way to the need for speed. A >fast (low friction) action becomes advantageous. I >think that pianists who like to play fast pieces and >have phenomenal control over their touch may prefer an >action with very low friction. They have the ability >to put just the right amount of energy into the hammer >in the shortest amount of time, basically using the >initial stage of the key movement to send the hammer >on its way with the precise amount of momentum. Since >they did all the work in the initial stage of the key >movement, they are free to quickly move on to the next >note. > >Vladan > > > >_______________________________ >Do you Yahoo!? >Win 1 of 4,000 free domain names from Yahoo! Enter now. >http://promotions.yahoo.com/goldrush >_______________________________________________ >pianotech list info: https://www.moypiano.com/resources/#archives > > >
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