<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Hi Jon,<DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>I'm going to disagree to some extent with what you write here, inserted below:<BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "></SPAN></SPAN></DIV><DIV><DIV>On Aug 11, 2007, at 11:42 PM, Jon Page wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">For optimal action performance, the jack should move through as short a distance as possible. This begins with key dip and action ratio and ends with ultimately, the rep</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">upstop and the jack pitch being sync'd such that the knuckle never/barely leaves the rep lever.</DIV></BLOCKQUOTE><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>I guess I agree that the jack should move as little as possible, but I would focus on the period of aftertouch, rather than the period while the jack top is scraping on the knuckle. That's where performance (repetition) is compromised. High speed video makes clear that the jack could get back under the knuckle in plenty of time if the darned knuckle would just get out of the way. It is amazing to see how many times the jack will bounce against the knuckle during very high speed repetition. I think the amplitude of those bounces is the major factor in how fast it can re-set (once the finger/key/wipp/rep has reversed course far enough).</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN> I am essentially in agreement that drop should be minimized. But not to nothing. There is a range where drop is disappearing altogether and the action can still function fine (with aftertouch in balance) that I believe "goes too far" from the point of view of touch.<BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">This places the jack at about half-core or forwards. A precarious point which is on the verge of failure but at that 'racer's edge'. All things considered, for a performance it</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">might, hopefully squeak by but in real life we can't live on the razor's edge and have to err on the side of sustainable performance.</DIV></BLOCKQUOTE><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>This is what several on this list consider to be optimal: as far forward as possible consistent with not failing (cheating out). I don't believe it is optimal. I don't think there is performance enhancement from this farthest possible forward position. From the performance point of view (actually getting the action through its cycle and re-setting to repeat), I believe the jack alignment is negotiable through a fairly broad range, without having _any_ effect on repetition (that is probably too absolute a statement, and I would love to see Stephen Birkett address the question through high speed videography). It will, however, have a very noticeable affect on touch.</DIV><DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>And this is where I have been trying to focus attention. Jack alignment can be used to "fine tune" touch, in the sense of regulating feedback to the finger of what is happening in the action. And that feedback is very important to the pianist. I believe that a better default position for the jack is the conservative, "what everybody says officially" standard of lined up with the core. Not because it makes it less likely to have a cheating jack, but because it "feels better" to the pianist. That said, I also believe that there is room for fudging, both back and forward, to address the taste of the pianist.<BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Regards,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Jon Page</DIV> </BLOCKQUOTE></DIV><BR></DIV><DIV><DIV>Regards,</DIV><DIV>Fred Sturm</DIV><DIV>University of New Mexico</DIV><DIV><A href="mailto:fssturm@unm.edu">fssturm@unm.edu</A></DIV><DIV><BR class="khtml-block-placeholder"></DIV></DIV><BR><DIV><BR class="khtml-block-placeholder"></DIV></BODY></HTML>