What's all this I hear about Inertia ?

[Richard Brekne]

Hi Fenton.

Grin... you make a great case for Bob Hohfs approach to the whole 
issue.  Still, both are simply tools these two different minds use to 
help illustrate for us, and themselves a bit more of what actually is 
going on... provide perhaps more justification for why the <<bubble>> 
test works as well as it does.  Heck even Stanwood has a tool for 
arriving at this... he simply got his gang to average as many pianos as 
he could possibly measure... taking the mean area as a kind of 
expression of player preference.  Given some 10000 instruments or 
more... his averages fall into the field of statistical science and as 
such he has pretty solid backing for his claim.

In the end tho... as you say... it comes down to feel.  Unless you are 
out of the norm... say like a Horowitz or something... then your 
educated feel should be a pretty good measure.

Cheers
RicB

         > Agreed as far as it goes, tho you do change the key inertia
        quite a bit...
         > which several have offered opinion on. The only two formal
        studies I know
         > about the affect of key ratio are Dr. Stephen Birketts
        treatise on the
         > matter ( http://www.pianostemmer.no/files/key_balance.pdf )
        and Bob Hohfs
         > empirical experiments that bark up the exact same tree about
        half way up
         > and echo Stephens results quite nearly exactly. The effect of
        key inertia
         > / key mass on dynamic touch is quite interesting. The math in
        Birketts
         > paper requires a bit of study unless you are adept... but
        with a bit of
         > work most who have dug through their high school pre calculus
        and physics
         > stuff should be able to make sense of it easy enough.
         >
         > Cheers
         > RicB


    I don't think formulas will give me much here. A while back Nick G.
    talked about tire shops spinning a mounted tire to balance it, it
    just works better than the old static bubble.The best test for
    inertia in the key is to play the piano making note of what feels
    right. If you play a lot of pianos and take a peek at the leading I
    think you can gain an understanding of what that lead feels like.
    Too little lead has a weird fell as well. Just my opinion at the
    present time.
    Fenton