Key Leads and Inertia

[Richard Brekne]

Bill Ballard wrote:

> At 4:17 PM +0200 6/14/03, Richard Brekne wrote:
> >But now that we are on the same
> >page about whether or not the choice of springs visa vi leads results in a
> >significant difference in how the action behaves, I'm sure its also
> >easy to see
> >that at least some portion of this is going to necessarilly fall
> >into a more or
> >less subjective category which will be hard to quantify in terms of
> >performance
> >shortcomings.
>
> I could think of some mechanical studies. At one point I wanted to
> find out if the hammer tail and the backchecks were ever in contact
> during deep and fast repetition. I mean, that's what this kind of
> repetition seems to ask for (among other things). So I fantasied an
> electrical circuit which would be completed by contact between these
> two parts, a brass mesh grid wrapped around the hammer tail and a
> single flattened wire running down the face of the backcheck. Anytime
> the two touch, an indicator bulb would come on. The same set-up could
> monitor decoupling between a capstan and a wippen heel cushion.
>
> To provide mechanized fast repetition, Bill Spurlock once mounted an
> eccentric wheel in the chuck of a 3/8" drill, attached it to a bench
> and set an action model in front of it. The action noise was very
> loud, he said, and the friction from the wheel melted a hole in the
> keytop. I would imagine a solenoid capable of delivering 1kg of
> force, with variable excursion, in continuous cycles of up to 15/sec.
> With knobs to set all of these. The mounting of this in relation to
> the key could include actuating the key, beginning at half stroke.
> (Not just fast but deep repetition, also.)
>
> >Some folks are just plain going to like the feel of lead driven
> >counterbalancing
> >compared to springs or magnets.
>
> As we heard of Don Mannino, and as we would expect of many
> generations of pianists raised on pianos with conventional levels of
> inertia.
>
> >Grin... we are going in circles me thinks....
>
> We've been going around in circles for a while. I just don't know
> who's Fred and who's Ginger. <g>
>
> >I dont believe there exists a desirable BW/FW combination that
> >cannot be accomplished without the use of assist springs. I also
> >dont believe there exists a desirable SW level that cannot
> >be comfortably counterbalanced with leads and an appropriate ratio.
>
> Yep, we can leave it at that, with user-defined values such as
> "desirable", "comfortable", and "appropriate". No problem.
>
> >In fact,  Stephen's slopes would seem to be telling us that the adjustment
> >of BW should be done from exactly a mass standpoint instead.
>
> What he has said so far is that using mass in the key sick to adjust
> BW should also comply with how that mass is also determining the
> key's moment of inertia. Which is to say that you pick one spot to
> make your mass adjustments (which determines the force on inertia to
> be encountered), and that you vary the size of that mass to determine
> the force of gravity to be encountered. But that's when what you're
> employing to adjust BW is mass, and not say another force, say
> magnetism or deformation of an elastic material.
>
> I think Stephen needs some more cookies.
>
> Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "Talking about music is like dancing about architecture"
>      ...........Steve Martin
>
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--
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