Key Leads and Inertia

[Richard Brekne]

Bill Ballard wrote:

> At 8:27 AM +0200 6/12/03, Richard Brekne wrote:
> >In point of fact... the whole method provides an excellent tool for
> >finding an smoothing certain aspects of geometric issues commonly
> >overlooked.
>
> This was what i was referring to. In providing note-by-note SWRs (did
> I get that right?)...

<G>

> ..., the Stanwood systems offers the user so inclined
> to tune up the outliers. Yes, this is nothing more than a magnifying
> glass with which to pick nits.

A nice way of putting it Bill :)

> You're right: fine tuning SWRs is not necessary, once the SWR has on
> a more general level been matched to the SW. The job of reconciling
> the discrepancies between FW and BW is easily done by a helper
> spring.

I suppose a spring would be much easier for such corrections. My ow preference
(prejudice ??) tho is to not use them and to nitpick with knuckles and the like.
The SWR is still a reflection of the ratio looked at via all the other valid
perspectives. Adjusting a spring for example wont change the fact that something is
<<wrong>>... so any regulation irregularities caused by a single key error in ratio
will remain.

> I'd imagine that given the relatively small size of these
> discrepancies, this would be the helper spring's least controversial
> use.
>

Springs are always going to be controversial me thinks... have been since the
beggining of time.

> What did you have in mind as far as the behavior of action mass,
> beyond the relationship of the force applied to the key and the
> acceleration it produces in the hammer. Were you pointing in the
> direction of what a pianist might report (as opposed to what lab
> instruments might read)?

I kind of realized I worded that clumsily after I wrote it. Behaviour of the
mass.... yes... No I think lab instruments should be able to graph a very nice
visual representation of what the pianist feels... if only the instruments and
proceedures are sophisitated and thought through well enough. But what I was
directly refering to is more or less the curve of how the position of the center of
mass changes throughout the key stroke. Perhaps... this is one of those design
issues we are after. Is it just a smooth curved slope, or does is have a hump or
two in it along the way ?... and what's actually to prefer ? As I said in my last
reply to Stephens posts... I really am just guessing at that curve and its
significance at this point.. but it would seem to me, at least intuitively to be of
interest.

> >Tho in the end... both of these may very well
> >turn out to be a moot point. With the present action design, we are
> >not going to
> >get away from the present choices put in front of us regarding
> >choice of hammer
> >weight and counterbalancing schemes.
>
> Complementing these present choices are the generations of pianists
> who have trained on the conventional action, and who might not know
> how to handle an action with radically different inertia and friction
> could we come up with it.

Another good point by the Bill :)

> Bill Ballard RPT
> NH Chapter, P.T.G.

--
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