Stephane C wrote: > >>When hitting the string, we could consider............ > >>Let us call this third very point the optimal quasi tangential > >>point of intersection between hammer arc and quasi perpendiculat to > >>largest portion of string plane when at approximately 1/2 of it's largest > >>deflection from rest position at loudest power playing > >>(OQTPIBHAQPLPSPA1/2LDRPLPP). > > > >You leave me speechless. > > > >Phil Ford > >I think I understand what St�phane is trying to say. Imagine the piano >hammer is a bowling ball, and you drop it on a trampoline (get >some other sports in here besides baseball). There is a point where >the ball first touches (his first contact), and a point where the ball >is stopped before reversing direction (maximum excursion - hammer >compressed and string deflected). > >Halfway in between these two points is where the hammer should >be perpendicular to the string, since that is the vertical "center" >of the impact. This makes the average hammer to string angle >be 90 degrees. Actually I was just kidding. I think I understood what he was saying. His acronym took my breath away. If you believe that the hammer should contact at 90 degrees to the string, then I think it probably makes just as much sense, if not more so, to have that be at half excursion than at contact. Of course this means that you will have to have a rake that varies from the bass end to the treble end, since the string excursion is going to get less as you go up the scale. >But do you optimize for hard blows or soft... Nobody plays softly any more. Might as well optimize for a hard blow. >and what happens if the floor's not level? > >-Mark Turn the piano so the keys are running downhill. That will make them easier to push down, right? One thing that nobody raised in this discussion was anything about the jack / knuckle contact point and its relation to the 'magic line'. Most action manufacturers seem to set up their actions so that the contact point is on the line between wippen center and hammer center at letoff. We may say that letoff occurs at a certain point. However, the process of letoff is really happening over some portion of the key stroke, from the time the jack tender first contacts the letoff button until the jack escapes. During this time the jack is rotating about its own center and the contact point is moving slightly. I wonder if, with a conventional action arrangement, having the shank go slightly beyond parallel is doing something beneficial to help the jack escape more easily or transfer a little more power to the hammer. Any thoughts about that? Phil Ford
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