Optimizing repetition

[Bill Ballard]

Joel Rappaport <joelr@flash.net>On 4/16/97,  rote:
<<My point is that (Alicia) demands thatthe action repeat with the key
having to rise from "bottoming out" aslittle as possible.  And no, she is
going so fast, she does not requirethe damper to get back on the string
before the next blow.>>

There is a point which Yamaha has made in its grand regulaing classes,
which I haven't seen in this discussion yet. The jack is in no postion to
act on the knuckle again until the return of the key from the
"aftertouch"portion of its stroke, has passed the point where the jack
tender has broken contact with the LO button. As long as these two are
still touching, the jack fly will either be still out from under the
knuckle, or if returning under  it probably not far enough to avoid
skipping out at the next thrust. Yamaha's point was that the fatter the
aftertouch, the more of this part of the key's stroke will have to be
endured to reach the point where the jack is redy to repeat. If I
understand Joel's point about setting the jack a shade back of the
knuckle molding, that extra travel (which Jon Page pointed up) will
reduce the aftertouch.

Joel Rappaport <joelr@flash.net>On 4/16/97,  rote:
<<Then I adjusted the jack _substantially_ back, away from theplayer.
Pressed the key and, as Ed and Jon theorized, the jack wound upat the
same place, not as I thought, closer to the knuckle.  But I stillthink
this works, only now I have to figure out why. >>

There may be another factor at work here, having to do with how soon the
jack will achieve its minimum "toehold" under the knuckle, to avoid
skipping when asked to thrudt again at this extremely early stage of the
return cycle. This has to do with what that toehold is with the jack
button at the spoon, not when everyone is back at the rest position but
when the action is only 10% through the return. "In anticipation of
everyone running out to the garage to delveinto the mysteries of jack
movement," I should say that on my Yomama grand action model, a jack set
3mm back of the knuckle molding at rest will be 1mm further back under
than the jack whose back edge was set in line with the back side of  the
knuckle molding. But the properly set jack, at the 10% of return point
will still have it's back edge pointing at the center of the knuckle
"circle", which as far as I'm concerned is right where it needs to be.
(As long as we're talking round knuckles here.)

How to regulate for this. I used to believe that the hammer, rep lever,
and jack center pinning needed to be firm, fir, and free respectively.
With the first two tight, the butterfly's wings would have to be stronger
to move them, and the jack being quite free would be all the faster for
this extra beefing of the rep spring.  But that hasn't been the
consistent answer for me. Aparanetly it comes down to how close to drop
you can get the check, an accurate setting of a minimal .040" aftertouch,
and a tweaking of LO, drop and rep spring strength  to as close to the
dangerous side as you dare get.

I'm no pianist, and I don't have the four-finger roll. How I do check the
depth of repetition is, with my left index finger hanging down over
thedge of a neighboring key to provide a "depth stop" for the reutnr of
the nore being tested, and then run a dotted-eighth/sixteenth on the
note. (I'd love to do 4 sixteenths together, but I figure the interval
between the fourth and first sixteenth should tell me what I want to
know.) I push my depth stop down until the repetition skips. While this
kind of regulation is not rocket science, it is Le Mans formula one
engine tuning. It's a delicate balance which should be looked after
frequently.

SUPPORT YOUR SECOND AMENDMENT RIGHTS TO OWN AND USE ASSAULT WIPPENS. (and
to think that Danny Dover wanted to ban them.)

Bill Ballard RPT
NH Chapter

"We mustn't underestimate our power of teamwork."
 Bob Davis