Adjusting wippen assist springs

[Richard Brekne]

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"David C. Stanwood" wrote:

>
> I and many of my associates have been using support springs in various
> applications for many years and the force variations through the stroke
> have never been an issue.  This can be seen by the fact that the motion of
> the hammer when measuring up/down wt is of a similar character as with or
> without the spring hooked up.
>

Thats right... its never been an issue. It has yet to be closely looked into at
all.  I dont see that the behaviour of the hammer when measureing UW / DW with
and without springs bears on this. In both cases there is no real force variation
so what are you measureing ??... balance weight with or without springs is still
static measurement.

Sarah had a good point about this, and I know a few folks who are actually trying
to quantify the real differences that simply have to be there. Seems to me like a
logical next step to take with all this. For years people were leading keys
without taking regard to some of the consequences your ideas first began to
address... this is the same kind of thing... Course then on the flip side of
that... there are still a lot of folks who totally disregard your balancing
proceedures citing simply that the need for them have "never been an issue".

>
> What's the average StrikeWt Ratio?  An important question! 5.7 is good for
> 3/4Med SW, 5.5 for TopMed SW.
>
> 6.0 won't do very well dynamically speaking unless the SW level is closer
> to 1/2 med.
>

This is a very interesting. The most favorite piano at our conservatory for
practicing is an August Forster. It has a 6.2 ratio, with Top medium hammers on
it, and very strong assist springs, now replaced by very strong assist magnets
functioning between the key and whippen. Everything about this action should be
<<wrong>>, yet both before I replaced the assist springs with my magnet scheme,
and after the comments remain the same... it is heavy in a <<good> way. We have
several different instruments and action configurations for them to choose
from... but they like this.

I just scratch my head then.... who says (without further ado) that such and such
a ratio will not do well dynamically with such and such a SW level... and for
that matter who says 30 grams of assist leverage is (again without further ado) a
bad thing.


>

The thing I like the most about Stanwoods stuff, is that it gives us a set of
parameters that allows us to very consciously employ several different clearly
defined action configurations. I dont think we've actually gotten so far as to
establishing which one works best and for what reason. Seems to me that we are
still fumbling around with some pretty basic stuff... like <<really heavy top
actions cause friction problems...>> and the like.  As far as I know Davids
database of information is the only one of its kind, and none can say just how
subjectively that data is being interpreted. Stephens work seems to be the only
serious attempt so far at a more scientific quantification of many of the
dynamics that we dont yet understand. So all in all I'd say David supplied us all
with a set of tools we can use to start answering some of these questions... but
that its still a ways to go before those answers are really on the table.

Cheers
RicB

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


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