Aftertouch Question???

[Roger Jolly]

Susan Kline wrote:
Hi Susan,
         I've just measured a couple of grands for my own curiosity,
keys #2 and #3.
The ratio of 1.97 from the capstan centre to the balance pin centre and
then to the key tip for the natural. And 1.94 for the sharp, the
measurement taken to the front of the playing surface. The ratio is so
close due to the off set of the fulcrum points. The amount of lift at
the capstan for the amount of key travel is not quite the same, but not
enough to be a major concern.
 Now to add another wrinkle! The above measurement was on a 5'8" grand.
If you move up to a concert grand these ratios become tighter, hence the
lower differential at the key tips and along the playing surface of the
key. I have found on some concert grands that there is a noticeable
difference in dip and after touch, bass to treble, due to the ratio
changing because of the amount of action taper, and how accurately the
capstans and action stack have been installed.
 Hope this sheds some light
Roger.
> I don't understand this.
> 
> If everything else is equal, and >>keydip is the same<<, then, picturing
> the key as if it were a teeter-totter, wouldn't the sharp, moving the same
> distance at the front as the natural, but closer to the fulcrum, move the
> capstan higher?
> 
> That is to say, the back part of the lever being equal, the front part
> being shorter would travel a greater number of degrees of arc in order to
> cover the same distance as the natural? But the rear part of the lever
> being equal, the greater arc would lift the capstan further?
> 
> Please send enlightenment to this little patch of Oregon woods ....
> (thankee Klinely ...)
> 
> Susan
> Susan Kline