Key Leads and Inertia

[Richard Brekne]

John Hartman wrote:.

> It seams like we are hell bent on calibrating static balance and action leverage
> with out putting it into proper
> perspective. Placing a tiny piece of lead it a key to achieve a balance
> of 38g instead of 39g or making sure that all of the knuckles are in a
> line to achieve a particular leverage seems overly picky and unnecessary
> considering the magnitude of issues left unattended. These static
> particulars are only relevant if the piano is played very softly. Once
> the action gets up to speed (accelerated) inertia and compliance become
> far more important.

While I certainly agree that there are other important issues relating to action
dynamics that static balancing and assuring a consistant leverage do not asdress,
I dont think it advisable to underestimate the value of these. Certainly any
obtainable degree of dynamic balance does not include obvious and significant
static imbalances.  As such, I cannot aggree that  the static balance as
prescribed by the equation based method can be said to only be relevant to piano
play at very soft levels. Further, we cannot simply disreagard the effect of
consistancy across the keyboard such balancing results in.


> In order to improve action efficiency I have been installing stiffening
> top plates on actions with longer keys. I have done this on several
> Steinway model Bs with good success. This seems to extend the dynamic
> range while using a relatively soft light hammer (lighter hammers are
> more efficient because they have lower inertia and bend the shank less).

The discussion about heavy vs light hammers has gone on forever. Over the years
there have been put forward several diifferent reasonings for why light hammers
can be made create the exact same sound as heavier hammers. The only problem is
that they dont. Heavy hammers sound different then light hammers and no amount of
juggling numbers or physics equations is going to change that.

> John Hartman RPT

The issue of compliance is an interesting one to be sure, tho I am not sure how
directly connected it is to the topic matter of key leads and inertia. Certainly
whatever benifit that can be had from assuring appropriate stiffness in keys does
not detract from the positive benifits to be had from assuring even and consistant
static balance.



>
> Stephen Birkett wrote
>
>
> Balancing inertial properties across a keyboard is not much more
> difficult to accomplish than static balancing using touchweights. You
> have two independent parameters to adjust in the key instead of
> one...the only practical limitation is that you cannot use
> pre-defined lead weights and simply stick them in the key where the
> desired balance is obtained. You have to be able to adjust both the
> mass of the lead and its location separately.

Stephen ...

This sounds fairly compatible with the quantity known as FW .... or what ?

Thanks muchly for your insights.

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html