George, Let me first say how much appreciation I have for your contributions to this list. Invaluable. And certainly your experience is far greater than mine. However, I would disagree with your assessment. Of course I understand that removing leads adds downweight. I addressed that. I would disagree however, with the assessment that inertia only comes into play until.......[acceleration of gravity]. An object at rest tends to remain at rest. The heavier the key, regardless of DW/UW the more effort required to start the key moving. Make a key entirely out of lead and balance it out at 50g DW. Take a standard key and balance at 55g DW. It is very clear that the inertia of the lead key will make the instrument unplayable. Inertia comes into play immediately, and a high inertia key will be less responsive and more difficult to play, even with a lower DW. Yes? Or am I missing a few cells.......... William R. Monroe On Wed, Jan 6, 2010 at 12:21 AM, George F Emerson <pianoguru at cox.net> wrote: > William Monroe wrote: > > I'd also want to take a look at the leading and see if I couldn't remove > a lead from each key, thereby reducing inertia. > > The very purpose of adding lead weights to the front of grand piano keys is > to reduce DW and the effort required of the pianist to depress the key. > Removing leads can only be counterproductive, increasing the DW. The > pianist would have to apply even more force to the key to make up for the > assistance that the lead weight would have provided ... that is, unless you > are removing the furthest forward lead weight and adding more weight closer > to the balance rail. Removing the lead weight nearest the front of the key > and adding twice that weight at half the distance from the balance rail > would maintain the same DW with less inertia. > > Actually, inertia doesn't even come into play until the center of gravity > of the added weight achieves the acceleration of gravity, 9.8mss. If the > added weight is at the very front of the key, which is not even possible by > traditional means, it would achieve the acceleration of gravity at a volume > level of about *mf.* With traditional lead weights, you are not likely to > find a lead weight closer than 60mm from the front of the key. That being > the case, you could probably play a strong *forte *before the added weight > gets to the acceleration of gravity and a point at which inertia is actually > working against you. > > In this case, it would be useful to know the playing habits of the > pianist. If he/she plays church hymns at moderate volume levels, I wouldn't > worry about inertia. If he/she plays Rachmaninoff ... well, that's another > matter. > > Frank Emerson > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100106/98f3b58a/attachment.htm>
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