I was taking in account the change in roller position, that is what I called higher moment of inertia on the hammer (lighter heads but roller near to the center pin vs. actual 17 mm setup) while I don't have the maths for , for instance differences of weight in the hammer vs. different placement of the roller relation. What is interesting in the way this affair is being made clearer (?) actually is that we used to discuss action weight in terms of static balancing more or less whatever method of balancing we choose, while if we begin to think about kinetic energy and angular motion, there we are more in what is perceived by a (deaf) pianist. It is unfortunate to us but the biggest parameter, not in balancing, but in toutchweigh, seem well to be finally the capacity to precisely accelerate or eventually restrain the hammer motion. The ideal action may give the pianist the sensation the hammers are at the tip of its fingers (transparence), hence the danger of any assisted method. And because the pianist is able to use different methods for tone production, the catapult analogy is not the only one that play a role. I believe that the pianist, because he have so much power to deliver to the key if he wish, may be faced with some sort of predictable brake, and that he use that braking as a security element. Then this internal resistance may that should be overridden easily if need arise should certainly be related . A pianist knows how much arms/shoulder weight is to be used to override the action weight (or moment of inertia), so the acceleration given by the finger is a smaller effort produced. Pianists that use their muscular force for each note have not a very good tone nor real speed generally. So the match between their own body mass and the mass of the parts they have to move is certainly an important notion. Talking about the way the leads placement influence the transmission of kinetic energy it is just a gut feeling but I see the key as being in a "resonant" mode whatever stiffness it have . Let's look at these videos ( promised to me for January) and see how the hammer strings hit and the key bottoming synchronize. By the way, I guess that the percussion point concept apply the same to the key when hitting the punching, more mass, probably more energy (?) delivered on the other side (again, in certain playing modes only). Up to some point, the defects of the instrument are appropriate in the end ( A very conservative point I admit !) But in the end all of that belong to the matrix - or whatever we call it ;>( Greetings, and best of courage for your future studies. Isaac > > To be clear : Steinway "accelerated action" : lower > moment of inertia > > on the key, higher moment of inertia of the hammer vs. actual setup > > lower moment of inertia of the hammer and higher at the key. > > Changing the moment of inertia for one part has no effect > on the moment > of inertia for another. That is to say.. that if you releaded an > accelerated action so that it had less lead weight but placed out > front... you would indeed change the moment of inertia for > the key, but > you not the moment of inertia of the hammer. To change the moment of > inertia for the hammer you need to move some of IT's mass > around. That should be clear. > > > > > Is not the more mass near the fulcrum lessening the > energy transmitted > > by the key ? > > Why would you think that ? > > What you CAN say, and seems to fit best what you say your experience > is... is that a Higher inertia key will offer more help in > moving the > key as long as you are playing softly. But as soon as you > approach 9.8 > m/s^2 acceleration rate then it becomes heavier. > > Then there is the use of this word energy. Obviously if we > are talking > phsysics things we all need to get to the point where we > are useing the > correct physics terms. Energy is not clear enough.. you > have different > kinds of energy.. and they all have their formulas. So > which one are you > talking about... and what is the math to back up your claim > > > > > I will try to get a hand from a friend in that affair ! > > > > Till next time . > > > > Best > > > > ------------------------------------ > > 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 : Richard Brekne [mailto:Richard.Brekne@grieg.uib.no] > > > Envoye : dimanche 21 decembre 2003 02:29 > > > A : oleg-i@noos.fr > > > Objet : Re: Touch Weight > > > > > > > > > > > > > > > Isaac sur Noos wrote: > > > > > > > > Ric sorry to be unclear, I mean the key with the less > moment of > > > > inertia, or the first one in your list. > > > > > > > > > > I was afraid of that. > > > > > > You are aware of course that under no circumstances will a > > > two keys with > > > differeing moments of inertia, all other things being > > > equal, will the > > > key with higher inertia be physically able to respond at > > > any velocity or > > > accelleration quicker or faster then the key with lower inertia. > > > > > > That being said... of course top action weight (or > inertia if you > > > translate weight to mass correctly) must be appropriate to the > > > counterbalance (whether seen in terms of inertia or > weight) and the > > > effective overall action ratio. Stanwoods simple balance > > > weight based > > > equation supplies us the tools to do accomplish this > much.... albiet > > > rather subjectively arrived at. > > > > > > I dont think you will be able to show under any > > > circumstances tho, that > > > a key with higher inertia will respond quicker, or have a larger > > > possibility for accelleration then a key with lower > > > inertia... all other > > > things being equal between the two keys and their respective top > > > actions.... tho it would be interesting to see you attempt > > > to do so :) > > > > > > > > > Cheers > > > > > > RicB > > > > > > > it is fairly possible that the moment of inertia of the > > > key only may > > > > be matched with the moment of inertia of the rest of > the action to > > > > have a consistent action. I really have felt a > "separated key". > > > > > > > > May be for instance a higher BW should have solve that > > > aspect, but I > > > > begin to wonder if we should not weight also the key mass > > > out of the > > > > balance function, and introduce it in the equation to > have some > > > > limits. > > > > > > > > It is amazing but in the end comprehensible that all > extra mass is > > > > perceived in a way or another, as what the pianist is > > > aiming for is a > > > > fine perception of the hammer (like you when you tune I > > > presume) in > > > > it's way to the strings, the directness and coherence of > > > the different > > > > acceleration elements is very important. > > > > > > > > In the end there may be some match between the hammer > mass and the > > > > mass of the other elements implicated. > > > > > > > > Please to read you. > > > > > > > > Best Regards. > > > > > > > > Isaac > > > > > > > > ------------------------------------ > > > > 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 : Richard Brekne [mailto:Richard.Brekne@grieg.uib.no] > > > > > Envoye : dimanche 21 decembre 2003 01:42 > > > > > A : oleg-i@noos.fr > > > > > Objet : Re: Touch Weight > > > > > > > > > > > > > > > > > > > > > > > > > Isaac sur Noos wrote: > > > > > > > > > > > > Ric, yes I mean the first statement, more lead in the key > > > > > makes the > > > > > > beginning of the stroke "fuzzy, or sluggish" , then with > > > > > acceleration, > > > > > > the key is having less control (it moves on it's > own preferred > > > > > > velocity) I feel that like assisted turning in cars, > > > > > comfortable, but > > > > > > less direct. > > > > > > > > > > > > > > > > > > > > > > > > > > > Hmm...again you are just as unclear. You do know what > > > FW is yes ? > > > > > > > > > > Given two keys with identical front weights which will > > > display this > > > > > lessening of possible accelerations you cited > > > > > > > > > > 1. A key with more mass concentrated towards the middle > > > of the key > > > > > or > > > > > 2 A key with less mass out front. > > > > > > > > > > Remember.. both have identical FW's... which means the > > > > > moment of inertia > > > > > is less for the first key. > > > > > > > > > > > > > > > Just want to make sure I understand you correctly. > > > > > > > > > > Cheers > > > > > RicB > > > > > > > > > > > > > > > -- > > > > > Richard Brekne > > > > > RPT, N.P.T.F. > > > > > UiB, Bergen, Norway > > > > > mailto:rbrekne@broadpark.no > > > > > http://home.broadpark.no/~rbrekne/ricmain.html > > > > > http://www.hf.uib.no/grieg/personer/cv_RB.html > > > > > > > > > > > -- > > > Richard Brekne > > > RPT, N.P.T.F. > > > UiB, Bergen, Norway > > > mailto:rbrekne@broadpark.no > > > http://home.broadpark.no/~rbrekne/ricmain.html > > > http://www.hf.uib.no/grieg/personer/cv_RB.html > > > > > -- > Richard Brekne > RPT, N.P.T.F. > UiB, Bergen, Norway > mailto:rbrekne@broadpark.no > http://home.broadpark.no/~rbrekne/ricmain.html > http://www.hf.uib.no/grieg/personer/cv_RB.html >
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