Inertia

[Ron Nossaman]

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>Similarly, using Jim Ellis' simple velocity formulas, I calculated that 
>with a 12
>gm hammer head, and 48 gms of lead (more than any of us are likely to 
>use!), with
>the leads magically compressed at 1/2 distance of the key from the balance 
>pin,
>the force to move the leads would be 1/25 of the force to move the hammer head
>(all other factors omitted).  If the leads were magically compressed to be 
>at 1/4
>of the key length from the balance rail, the force to move the leads would be
>1/100 of the force to move the hammer.

And since the leads are there to counterbalance the hammer weight (etc.), 
did you double the weight of the lead when you halved the length of the moment?


>One of the claims of the Magnetic Balanced Action is that the key lead 
>inertia is
>removed from the system.  This is certainly true, but is it significant for
>performance? A blind comparison between two Fazioli pianos with identical
>downweights, one with key leads, one with MBA would be the way to test this.

But identical down weights won't tell you a thing about inertia in the two 
actions, or any action for that matter. A slightly heavier hammer in the 
MBA could very well make it the higher inertia action even without a bit of 
lead in the keys.


>   (A
>performer friend who has played the MBA is convinced he can feel the "lack of
>inertia."  However, I have felt a similar ease and sensitivity in a standard
>Fazioli, so I am not yet convinced what he feels is the result of removing 
>the key
>leads.)

Exactly.


>Or might it be possible to install a few MBA keys in a standard weighted 
>piano,
>adjust them to correct downweight, and see if the performer can detect 
>them, and
>how?

This might be a more meaningful first test.


>Again I suspect that the difference would be in speed of repetition.

Probably, all else being equal, and depending on how much key lead is 
actually removed. It has to become noticeable in the power stroke too, at 
some threshold level.

Ron N

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