Key Leads and Inertia

[John Hartman]

Richard Brekne wrote:

> I dont think we are talking absolutes here John. The question as to 
> whether players benifit from any momentum is more a matter of whether or 
> not the amount of acelleration after the initial movement requires 
> enough force in itself to be significant. If not, then it is surely that 
> initial acelleration and ensueing momentum that is the reason. If the 
> degree of key acelleration after say the first mm of key travel is very 
> high, and continues to be very high then perhaps this is important. On 
> the other hand, if the finger gets the key moving within say 90 % of its 
> end speed right off the bat... then it is perhaps much less important.


Excuse me if am not understanding what you have written. You keep 
talking about momentum and I don't see much in the way of momentum 
taking place in the action. Things are accelerating and decelerating 
they are not just smoothy coasting along with constant speed. You are 
now bringing impulse into the discussion. Yes I do see that there is 
impulse taking place in the action with the key hitting the front 
punchings or the hammer hitting the string. And yes a player can strike 
the key with a short impulse in such a way that he does not apply force 
through the key dip. This can accelerate the action just the same as a 
force applied steadily through to dip. I would think that it would take 
the same amount of force either way.

Maybe I have this wrong but it seams like you are saying above that 
there is a difference in the end result between accelerating the key by 
a steady force or applying an impulsive force. That this impulsive force 
could be less (in force) and still give the key and action the same 
acceleration? The impulse (initial acceleration) causes the key and 
action to travel with momentum. And this is somehow a work around for 
high inertia?

I think your momentum still has to pay the price of acceleration first. 
So I don't thing players benefit from momentum however they play the key.

John Hartman RPT

John Hartman Pianos
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Rebuilding Steinway and Mason & Hamlin
Grand Pianos Since 1979

Piano Technicians Journal
Journal Illustrator/Contributing Editor
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