[pianotech] Best way to change touch on Yamaha Grand

[V T]

Hi Ed,

You are describing a high power effect, a saturated action. At that point,
things have gone quite non-linear. I was addressing the needs of a client
with arthritis playing a small piano.

Now, we can broaden the discussion to something like a concert grand with
flexing keys and compliant punchings, etc., that is being pounded as hard
as possible. If there is significant compliance, then, yes, much of the
the force would be used to accelerate the key lead, compress the punching
on the balance rail and bend the key in the vicinity of the fulcrum point.
 

Vladan

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"   I think I disagree with this. Inertia's effect is most profound at the momemt that movement begins.  I submit that the inertia felt first, and most acutely, is from the mass of the keystick.  The compliance in the action is such that the key is moving well before the hammer. In some power-saturated actions, the key will actually touch the pad before the hammer is half-way to the string. The resistance to movement created by the key is instantaneous, that due to the hammer, not so much.  
  This can be demonstrated with an action that has excessive lead in the keys. Even with a light hammer, the inertial resistance is felt increasing at FF, regardless of DW.

 

Ed Foote RPT"