Bernt Damm wrote:

> This is an interesting topic.  The point is that yes, the balance point
> and travel can be the same for short keys and long keys but there is
> another important difference between the 2 that is significant.  It is
> the actual mass of the key.  The longer the key, the heavier it is.
> This means that more energy has to be applied to get it moving with the
> same speed of a lighter key.  It also means that when it hits the end
> stop, it has more energy to transmit to the next component.  This does
> indeed change the characteristics of the touch.
>

I tried to compute the effects using standard physics.  Results:

* The resulting force difference is on the order of 0.2 Newtons (the
computation is easy -- I'll leave it as an "exercise").  I do not know
whether this is much or little.

* The key has to move about 1 cm at the end; in the same time, the
hammer has to move at least 5 cm.  Very roughly, the mass of the hammer
might be equal to the additional mass by adding 15 cm (6") to a key.
So whatever the effect is, it is about 20% of the force necessary to
get the whole system moving.  (I'm guessing the distances and masses
from a vacation - so I might be far off ...).

What does that mean?

Harald M. Mueller
Grafing b. Muenchen - Germany
http://www.haraldmmueller.de/

 [ I hope to have some articles about the physics of the piano
 [ action at the MMD Tech site.  John Rhodes and Johan Liljencrants
 [ are helping me with this effort.  -- Robbie