Inertia

[Ron Nossaman]

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>But at what degree of mass difference does it become possible for a 
>performer to
>feel the difference, or for the jack to reset faster?

I don't know. It will depend on that particular pianist, that particular 
action, that particular key in that particular action, etc. Some people 
will notice things I can't detect, and others don't seem to notice anything 
at any level.


>If the mass differences required exceed the differences we can produce by 
>changing
>the configuration of key leads, then we are wasting time and money 
>plugging holes
>and moving leads.

Quite possibly.


>If not, then we should be looking for the best lead placement for high
>performance.

While taking into account everything else we know that affects action 
efficiency.


>Jim Ellis and Jon Hartman have shown us some calculations that seem to 
>indicate
>that these adjustments don't matter very much.  My clumsy mathematics seem to
>agree with them, but I don't consider my math skills very advanced or certain.
>
>Therefore, I'm interested in your calculations and opinion on this, since 
>you have
>experience, math skills, and an inquiring mind!

My math skills aren't any better than yours, and I don't have methods of 
calculating inertial effects that are any better than those presented. I'm 
just trying to point out that key leading is compensation for static 
balance concerns originating elsewhere in the action, and that most of the 
perceived inertia problems probably aren't going to be solved by looking at 
the key. I see key leading as the last step to compensate for the changes 
in hammer weight from bass to treble, not as a place to start. I wouldn't 
expect to see much improvement in an existing action with inertia problems 
come from removing lighter weights from the fronts of the keys and 
installing heavier ones toward the center.

Ron N

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