Bravo! David Love davidlovepianos@comcast.net -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Jon Page Sent: Sunday, May 08, 2005 8:14 PM To: pianotech-ptg.org Subject: CRESCENDO GRAND PUNCHINGS, after touch, etc... This conversation has touched on tangents and drifted off from there. By now, y'all are lookin' at the wrong end of the horse. Let's get back to the basic function of the cushioning material placed under the front of the key. Obviously to reduce noise created by wood impacting on wood and/or shimming material which defines the end of the keystroke. Let's compare what effect a firm punching and a soft punching has on touch and after touch: A firm punching will impart a solid landing to a pianists' finger much the same as a runner feels jogging on concrete or road surface. A soft punching will absorb some of the impact of the key and the pianist will feel a cushioned landing much the same as a runner feels less stress on joints by jogging on grass surfaces. A soft punching will have a variance in dip between fff and ppp. Being more compressional, dip will change relative to the degree of force exerted, ie: a hard blow will compress the felt more than a soft blow. A firm punching has less of a compression factor and will offer less variance in dip through the dynamic range. So that is the extent of a soft or firm punching will have in regards to after touch. After touch is a product of action geometry and regulation parameters/deviations. The amount of after touch in regards to the density of the front rail punching is relative to the force imparted since with each punching the after touch needs to be set for a soft blow (which would be the same dip) to insure the jack to clear the knuckle/roller. On a harder blow a soft punching will have a deeper dip than a firm punching and more after touch, but at that speed who can really notice. I'm not talking mushy soft here. I am eager to try these new punchings but I have never been asked to change out too soft punchings. I have had two professionals ask to keep their fingers from feeling like they're hitting concrete. Increasing after touch was not an option since one was a B which already had too high of an action ratio with long blow and short dip. The other also had a complaint of the key impact resounding through the floor to the room below. Newer, softer punching to replace the highly compacted, old, hard punchings solved both situations: fingers impacting on hard surface. Hard vs. Soft Landing: The key travels through 'x' distance. Irrelative of the point of jack escapement (amount of after touch) the key still impacts onto a surface. The density of that surface determines the impact felt in the finger. After touch relates to the degree of efficiency of the key stroke. Degree of after touch related to Hard or Soft Landing: Can't quite grasp that concept mechanically, it must be a perceptual thing. As I see the degree of after touch in relation to energy output: The longer period of time the jack imparts force on the knuckle/roller, the greater control the finger has over the energy output. An efficient action will have minimal after touch. Increase the after touch (maintaining dip) and decrease dynamic control. There are circumstances which might necessitate variations from specs and still maintain efficiency but for something which is operating optimally, variations decrease efficiency. So, in summation (whew), the inclusion of the degree of after touch only confounded the issue in regards to the density of front rail punchings. A firmer front rail punching will have a narrower gradient of key dip through the dynamic range than a soft punching (period). A firmer front rail punching may have an acceptable effect on tonal production but that is not within the scope of this posting. Best Regards to all you Mothers, Jon Page _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives
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