Inertia

madelyn mrykalo madvinmryk@yahoo.com
Mon, 29 Dec 2003 19:58:59 -0800 (PST)



I would like to address the notion that changing
moment of inertia of the key is not really going to
accomplish much because the hammer is what really
affects m.o.i..  For some reason, the key does have a
noticeable effect.  Let me give an example.  A
customer came into a friend of mine's store, and liked
a certain piano except for the touch.  It was too
light.  But he did like another piano's touch.  After
much consideration, we decided to measure the moi of
the key (since that was easier to measure and change
if need be).  Using the formula (in grams and inches)
and considering only the leads, we found differences
such as 1700 for the lighter one at key #3 and the
heavier one at 2400.  The differences varied, but they
were generally at least 500 in the bass and mid range
of the piano.  Without changing front weight, we
increased the moi of the lighter piano to match the
one the customer did like.  The customer noticed the
difference, and bought the piano.   

--- Alan McCoy <amccoy@mail.ewu.edu> wrote:
> This has been an interesting thread. 

> 
> Ed Sutton is really trying to steer us in a more
> fruitful direction when he
> says:
> 
> But what we are trying to do here (I think?), is try
> to make piano actions
> better for the pianists.
> Since there are so many kinds of pianists, there
> might be many ways to make
> pianos better, of more adapted to various players
> and ways of playing.
> 
> And in particular, we were concerned with the
> placement of key leads.  For a
> long time many of us have followed the rule of thumb
> that it was better to
> produce a given front weight by placing a large
> quantity of lead close to
> the balance rail than by placing a smaller quantity
> close to the front, that
> this makes the action "feel better" and repeat
> faster, at least in the bass
> octaves.
> 
> If this is true, then it is worth going to a lot of
> trouble to do it, if
> not, it is a waste of time.
> 
> FWIW,
> 
> Alan
> 
> ____________________________________________
> Alan McCoy, RPT
> Eastern Washington University
> 509-359-4627
> amccoy@mail.ewu.edu 
> 
> 
> 
> 


=====
Vince Mrykalo
University of Utah

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