Key Leads and Inertia

[Sarah Fox]

Hi Phil,

> I don't understand by what you mean by jerk reduction.

First derivative of position is velocity (rate of change in position).
Second derivative of position is acceleration (rate of change in velocity).
Third derivative of position is jerk (rate of change in acceleration).
Etc...  but I don't know if the higher order derivatives have special names.

Smooth acceleration is desireable, as it minimizes stresses and weird
movements in the various components.  Acceleration is not smooth to the
extent that the higher derivatives, especially including jerk, are present.
Jerk(ing) occurs when a student driver lets off of the clutch too fast and
throws the instructor's head backwards and forwards, giving him/her an
"Excedrin headache."  Jerk reduction is when the weary instructor takes over
and starts the car into motion more smoothly.

> Hopefully adored by some and despised by others.  I think the piano world
> would be a more interesting place if there were more choices.  Everyone
> these days seems to be trying to build the same piano, including the
> actions.  Basically an Erard-Herz action, with some minor variations here
> and there.  Why do all pianos have to feel the same and respond in the
> same
> way?  It's educational to play on some older pianos or fortepianos to get
> an idea of how different an action can feel.  You might like it or you
> might not.

I agree completely!  Variety is the spice of life.  In fact when I write
(very amateurish) music, it tends to be very specific to the instrument.  I
once even wrote something that was inspired by a bobbling hammer in a wreck
of a piano abandoned in a basement during my college days.  I suppose if it
had to be performed on another piano, some sort of echo effect could be
imposed electronically. <grin>  (And now all you techs *KNOW* I'm off my
rocker!)

Peace,
Sarah