set letoff to get acceptable aftertouch?

[Richard Brekne]

Hi Dean

Most places I've run into make a clear distinction between grand 
aftertouch and vertical jack escapement.  Grand aftertouch is a 
different thing, tho to be sure it also involves the jack escaping from 
under the knuckle to a similar degree. That said there are some clear 
and significant differences which I am sure you already know when it 
comes down to it. Vertical pianos have nothing that is correspondent to 
drop in a grand. Nor do that have that little rise afterwards the 
Japanese like to refer to as Hataraki when the key is further depressed 
past drop.  Indeed the whole grand aftertouch is quite a bit more then 
simple escapement of the jack from under the knuckle.

Vertical pianos simply have escapement and catch. In some cases one can 
regulate a vertical so that the sensation of aftertouch seems a bit 
similar to the grands.. but most often you don't really get all that 
close.  There is no built in <<bump>> at letoff/drop.  It has to be 
simulated by letoff/catch and that relies a bit on a few related factors 
like the friction interface between the jack top and the leather of the 
knuckle, the effective weight of the hammer falling back onto the catch, 
return spring strength, and the like.

Even the critical element of jack escapement itself is a bit different 
in the grand.  If you dont escape at 1 + mm then you end up experiencing 
some degree of blocking. Bobbling alone due to lack of jack escapement 
in the grand is fairly rare IMB.

Cheers
RicB


    Ric,

    I don't think I've ever remembered hearing that jack escapement on a
    vertical is not aftertouch. I'm curious as to why? Seems like in
    both cases
    we are talking about jack movement after clearing the knuckle.

    Dean