[CAUT] Black on Black... (Jack alignment)

[Fred Sturm]

On 8/9/07 6:31 PM, "Tim Coates" <tcoates1 at sio.midco.net> wrote:

> Fred, 
> 
> I would be interested in knowing if you experience the same issues I think
> Chris Soliday eluded to:  the jack back versus the jack forward affects speed.
> I agree that .5mm is a great deal of discrepancy and should not be there.  I
> deal with a number of Van Cliburn finalists and students from TCU (yes here in
> the Dakotas).  One of their obsessions is speed of repetition.   I see how
> what you are doing can be used with my methods.
> 
> I am always trying to tweak the performance instruments in my care and I find
> jacks to be critical to the condition of the piano.
> 
> Thanks, 
> 
> Tim Coates 
Hi Tim,
    I don't think jack alignment (within normal parameters) affects
repetition. It doesn't matter whether it gets back in contact with the stop
(ie, its regulation button felt contacts that metal upright) or not during
that fast repetition action, just that it gets under enough at the right
moment to stay there and not cheat out during the next stroke. What matters,
I think, is the stop felt at the end of the rep window, and the amount of
aftertouch. Felt being closer, and aftertouch less, means faster repetition.
    Looking at those high speed videos, what strikes me is the bouncing of
the jack against the knuckle, often several times and long bounces during
very fast repetition. Repetition will fail if the jack happens to be in one
of its bounces at the wrong time. So I figure the less bouncing, the better
the repetition. You'll get less bouncing if your stop felt is closer in, and
if you aren't pushing the jack as far away from the knuckle with the key.
You push the jack farther with the key if you have more aftertouch.
    These aren't the only factors. Obviously rep spring strength, friction,
etc come into play. But my sense is that aligning your jacks outward won't
improve repetition speed. It will make the feel of letoff smoother and less
noticeable, which will affect the touch, and there may well be many fine
pianists who prefer that feel.
Regards,
Fred Sturm
University of New Mexico