---------------------- multipart/alternative attachment Dear Richard, I'm so glad this makes you itchy. Seems to me that there is a=20 differential between (gravitational acceleration of the key and lead) and the acceleration greater than gravity provided by the guy on the=20 end of the keystick, I think most practiced pianists can handily create=20= the necessary pressure whether by finger, paw, forearm, or upper torso=20= assist. BUT/AND isn't the only factor that affects loud/soft or tone quality (once the piano is prepared) the VELOCITY OF THE HAMMER=20= when it strikes the string? (I'm assuming the hammer and shank are free=20= and clear of the mass and inertia of the remainder of the action at the=20= moment of strike.) So the pianists challenge is to modulate whatever=20 mass/ inertia/balance characteristics are presented in a given action.=20= Speaking as a pianist I prefer an action balance closest to consistent throughout its range as my first desire. But I =20= don't necessarily want the entire action to have to bow to the=20 inertia/balance characteristics found at the extreme registers of the=20 instrument. In my experience I can play well on a variety of actions=20 which have different characteristics of 'balance feel'. The biggest=20 issues are either frictional OR sudden inconsistencies at what I'll=20 call 'break points' (someone else made mention of the potential for=20 very different characteristics in adjacent keys). Please don't shoot me. I'm only the piano player. (not to mention that=20= it made sense to me at the time) Best, Rich Olmsted On Friday, April 25, 2003, at 11:42 AM, Richard Brekne wrote: > =A0 > > Farrell wrote: > > Comments below:=A0Terry Farrell=A0> 1. Isnt this question about lead = in=20 > the key really about its total mass, and > > if you first were going to conceptually <<de-couple>> the lead mass=20= > and > > dangle it on a string, wouldnt you have to do that for the wood mass=20= > as wellWell yes, but...... John is trying to demonstrate what the=20 > addition of lead to a key makes. The key with no lead with have=20 > certain inertia characteristics. The key with the lead will have=20 > different inertia characteristics. Comparing the force required to=20 > push the key down slowly (less than the acceleration due to gravity)=20= > with no lead and with the lead will reveal that less finger force is=20= > required when you have lead in the front portion of the key. Comparing=20= > no lead and lead when applying a forte blow (much greater acceleration=20= > than that due to gravity), it will require more force applied to the=20= > key with the lead to accelerate the key at the same rate as with no=20 > lead. Decoupling the lead in the diagram is simply to help visualize=20= > this phenomena. > > > Er,,,, grin.. All this is well and fine, and I dont think doesnt=20 > understand that more mass means more force to accelerate it. Thats the=20= > same with or without gravity. And seems to me we are forgetting whats=20= > on the other side of the keystick in this. Something about this image=20= > bothers me, and me thinks I have a bit of an itch behind my left ear=20= > coming up :) > > Answer me this then.... a see-saw with 5 grams of mass 1 meter from=20 > the fulcrum on each side, and another with 500 grams of mass 1 meter=20= > on each side of the fulcrum. Same scenerio.... less then 980/sec^2=20 > acceleration and then greater then that. While I'm pondering that on=20= > my evening walk... I am sure ya'll will ponsk out an answer for me :) > =A0 > > =A0 > > 2. How fast is the approximate fastest we could expect the key to be > > accelerated by human fingers in the first place ?=A0Lift the front = of=20 > the key up. Drop it. That is the acceleration due to gravity. A forte=20= > blow is many times (est.) the acceleration rate due to gravity. > > > I dont think that answers what I asked. > =A0 > > > 3. Exceeding 980/sec^2 just means you are not getting any more=20 > <<help>> as > > it were from the force that is gravity. But this isnt the same as=20 > saying > > that doing so somehow creates an increase in resistance to > > acceleration....yes ?? Its not like gravity has a kind of reverse=20 > gear > > affect here.=A0No, gravity does not change, it is an acceleration=20 > force that is consistent. The pianist is the one that is applying an=20= > additional acceleration force. If the finger force is less than that=20= > of gravity, adding lead to the key will decrease the amount of force=20= > required to push the key down at some acceleration rate less than that=20= > of gravity. If the finger force is greater than that of gravity,=20 > adding lead to the key will increase the amount of force required to=20= > push the key down at some acceleration rate greater than that of=20 > gravity. > > > Yes... something about this definantly bothers me..... grin... what=20 > else is new eh ?=A0 Well, I am off for a walk. Perhaps my mind will = see=20 > more clearly later on. > > Cheers > > RicB > > -- > Richard Brekne > RPT, N.P.T.F. > UiB, Bergen, Norway > mailto:rbrekne@broadpark.no > http://home.broadpark.no/~rbrekne/ricmain.html > =A0 > ---------------------- multipart/alternative attachment A non-text attachment was scrubbed... Name: not available Type: text/enriched Size: 5172 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/3f/6c/16/0a/attachment.bin ---------------------- multipart/alternative attachment--
This PTG archive page provided courtesy of Moy Piano Service, LLC