>>Hi Ric, >> >>Just friendly discussion here, my friend... :-) >> >> No Problem... just wanted to keep us in focus and not wander from one murkey sumphole into another without first having a chance to change my boots and get some dry socks on. >>Isn't playing with friction a bit like driving a car with the emergency >>brake on? To me, it makes the car feel awkward, and I don't feel I get more >>control. I feel I have less of it. I have to press the gas pedal harder to >>go, and when I reach I reach this point, the car quickly lurches forward. I >>quickly notice how weird the car feels when it happens, and I'm quick to say >>"oops!" and release the brake. >> >> I think I'd rather compare it to how a car feels coasting (clutch in) vs just taking your foot off the gas pedal. Course the car is really a bad analogy to begin with because it has gears, built in manually operated brakes, engine compression, and a host of other functions that get used for different operating conditions. But too your example above... an emergency brake on would IMHO compare to the hammer shank not being able to complete even 1 complete swing of a swing test... even a partially engaged emergency brake comes down to less then 4 swings on the swing test. >>Experienced cooks know that sharp knives are safer than dull ones. Why? >>More control. The sharp knife slides through food with less effort (lower >>friction, if you will), and so energy is less likely to end up misdirected >>into one's finger. >> >> Another analogy that really has no use in this discussion... yes.. I mean.. you can actually choose to use the knife slowly regardless of friction. But flip it over... ms frictionless... because that knife is so sharp... you simply must use it more carefully because you dont have enough time to react to a slip in the wrong direction. The dull knife accident scenario has to do with being forced to use more force then you can controll,,, not causing you to watch your speed. Again... 4-7 swiings.... >>In fact friction slightly compresses the effective dynamic range available >>to the pianist. It takes more pressure to deliver a soft note, while the >>highest pressure available to the pianist is still the same. >> Which, however your physics figure this... ends up being the opposite as reported by users who advocate this. Besides... I take issue here... Less friction means a lower downweight and greater up weight. Ok... Balance weight stayes the same.. but it will accelerate more easily. So not only will it be more difficult to maintain just as slow a <<slow>> blow then with a little friction.. but the general control of key accelleration in general will reguire a more sensitive touch in order to meet the increased control demands. The maintainance of Balance weight as being unchanged just means you dont really even save any real effort for this cost.... At least not above medium play levels when inertia takes over as the determining <<weight>> factor. >> Of course >>friction can be compensated with leading in the keys, but only to an extent. >>Less range in available pressures means less control. This would be >>comparable to a wide letoff gap, which doesn't help control a bit. >> >> Not really... lead in keys will change both the Balance Weight, and the system intertia. >>Besides that, friction is an ugly beast in that it is not consistent with >>key velocity. When key velocity is zero, friction is at its highest. This >>friction level is called "static" friction. When the key moves, friction >>levels dramatically decrease. This is called "sliding" friction. Having >>(by necessity) a friction level that changes with movement is not a bonus to >>the controllability of a piano action. It's also what happens in the >>emergency brake example (see above). >> >> The fact that the relationship between friction and key velocity is probably roughly an exponential one does not infer inconsistancy in that relationship. Seems to me you've already shot yourself in the foot here. Above you mention it will requre more work to execute a soft blow... exactly because the lack of friction... and while there is not anything to gain on the fast end... seems to me like the only thing you've accomplished is to loose some degree of control. >>Perhaps the most extreme example of the consequences of changing friction >>are found in any auto repair shop, although they aren't so much a simple >>consequence "static" vs. "sliding" friction -- but same idea. When a >>mechanic strives to turn a nut with a wrench, he is prone to slip when the >>nut breaks free. Just look at his knuckles! That's not control. >> >> >> Depends again on the degree... you are going from one exteme to the other... infact describing a near frictionless scenario on the one hand,,, and comparing that to a heavy friction condition on the other hand... In terms of our swing test that would be going from 20 swings to 0.5. In none of your examples do you deal with the concept of optimum... except to try and argue that the optimum is the <<least possible>> using the consequences of <<most possible>> as your reasoning. Cant see that any of this washes really... but thats just me. >>Let's bring this closer to the piano. <grin> Put a Steinway D on its side >>on a skid. Put the skid in the middle of a parking lot. Now get several >>strong men to slide it around, to position it in some *exact* location you >>specify. Now put the piano on a dolly, and repeat the experiment. In what >>situation do the men have more control? This is nothing more than a >>question of friction. In the first situation, the men are prone to >>overshooting a position, due to the difference between static and sliding >>friction. When this differential is reduced (with a piano dolly), >>positioning is easier and (more to the point) more accurate. >> >> Again.. you are dealing with hypothetical extremes... go ask piano movers whether or not they think an appropriate amount of friction is an aid to them or not in moving a piano. Or better yet... imagine the 300 kilo piano on a frictionless skid sitting at a 45 degree angle on a set of stairs..... Friction works as a brake as well here. >>Finally, the control scenario that you paint with regard to a piano action >>incorporates active sensorimotor feedback. That is: Push the key, see >>whether it has traveled far enough, fast enough, correct the velocity >>accordingly, see if the correction is adequate, etc., etc., until the hammer >>reaches the string. Pianists don't play that way, except when the music is >>very slow and pp. There's simply not enough time to do it that way. >>Instead, they fire off finger movements and listen to what the piano gives >>back. Then they adjust the overall output of their motor program to >>compensate for anything that is not right. This is a process that is done >>over several notes, not within a single note. >> >> And by your own admission and definition... friction checks out as it were at higher levels of play, so its not a problem one way or the other there... it is at lower levels of play the control issue becomes more acute... and your frictionless world accomplishes only requiring the pianist to exert more control in order to determine any exact level of pianisimo play. >>These two different ways of carrying out movements involve very different >>neural machinery. The precisely controlled movement of a single key is >>mostly done through feedback loops involving the basal ganglia, which seem >>to coordinate the whole mess. The complex motor programs that can be >>adjusted as needed are a function of the cerebellum. To use your example, >>when someone throws a fast ball at you, you use a motor program in your >>cerebellum to hit it with the bat. If the ball is slow enough, then, maybe >>then, you'll have enough time to fine-tune your swing through active >>sensorimotor feedback involving your basal ganglia. Very different neural >>machinery. Does the sensorimotor feedback scenario give you better control? >>You bet. But you can't use it on a fast ball. It's just not that good. >>Neither can you use it on 99.9% of the passages played on a piano. >> >> >> Again.. we see a tendancy to pull exacting figures out of the hat and declare them to be fact. Where does this 99.9 % come from...? Me thinks you are far beyond the bounds of science here and just reaching for figures to fit into a predetermined conclusion. Secondly... you try and tell any batter that a pitch coming in at 80 miles an hour... a reasonble figure for curves and similiar pitches, is not much easier to hit solidly and in the intended direction then one coming in approaching 100 miles an hour.. which some fastballers can reach. The only assumption you must take for this analogy is that the batter knows what pitch is comming. Course the final arguement is simply that the more or less friction free hammer shank flange has been around for a long long time... and you know what... the majority of pianists apparently prefer a bit of friction... which is undoubtebly why the market has arrived at the defacto standard that it has. That doesnt mean that there is some degree of statistical variance to be expected. Do as you feel best to be sure... but I stick with friction levels that result from 5-7 swings. >>Peace, >>Sarah >> >> >> Cheers RicB
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