Even balance weight or even something else, that's thequestion.

[Richard Brekne]

"David C. Stanwood" wrote:

> >David Love wrote:
> >>
> >> Anybody experimenting or setting up pianos with a graduated and
> >> increasing balance weight or, better yet, with uniform inertia?
> >>
> >> David Love
>

I would be very interested indeed in hearing how one would achieve uniform inertia
in the action while at the same time being able to vary hammer mass from bass to
treble. I suppose you had somthing in mind ?


> >John Hartman Wrote:
>
> >David,
>
> >As far as I know no one has created the tools or methods to calibrate an
> >even gradation of inertia in an action. I think it would be difficult to
> >use key leads to balance the action statically and dynamically at the
> >same time.
>

Isnt "balance"  rather <<by definition >> a static measurement ? Would you be so
kind as to expound a bit on what a "dynamic balance" is exactly ?...


> David Stanwood writes :

> We found that even when Strike Weights are smoothed and the keys balanced
> to a smooth Balance Weight, there are still significant note to note
> variations in the front weights.   These inconsistencies were eliminated
> with Equation Balancing using calculated Front Weight curves (US Pat
> 7877872).  This results in Front Weights that fit a smooth curve and
> pianists report that the pianos feel even better.

As well it must as in the end this (the Balance Equation) describes a device which
combines three levers (the action) with a clear definition of both the mechanical
advantages and the weight components involved neccessary to make the whole thing
very predictiable.  No matter how one goes about achieving this predictability
however, its interesting to note that imposing these smooth Strike Weight and
Front Weight specifications result in less then equally smooth Balance Weights
unless there is near absolute perfection in each and every point that affects the
total action ratio for each key. A nice diagnostic tool if its used for that, but
if such variance in total action ratio (however its taken) are left unimproved,
then that uneveness is reflected by an uneven BW curve.


> We find that this addresses the dynamic quality sufficiently enough using
> practical static
> weight methods...

I would have to agree, tho I would certainly entertain any arguementation why a
greater degree of resolution would be neccessary.


>
>
> Here is a picture of a "Tower Pattern" as we call it:
>
> http://www.stanwoodpiano.com/Pa100088web.jpg
>
> I can hear some saying to themselves "that looks like a lot of lead".  The
> example given is a Kawaii with a 5.3 strike weight ratio and 1/4 high zone
> hammer weights with 44.5mm blow and 10mm dip.  The Front Weights are under
> my published "ceiling".  We know from experience that such setups play,
> feel, and sound great...
>

Might be usefull for some to understand that this translates to a somewhat higher
<< total action ratio >>as taken by some more traditional conventions. Assuming 2
mm for dip, we are in the ballpark of a 5.6 (slightly under)  Action Ratio here.
Not so very unusual at all really. A bit on the heavy and short side to be sure,
but nothing radical here. It should suprise no one that this configuration should
function quite well.

Cheers

RicB

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