setting let-off

[A440A]

Greetings all, 
     Setting the let off by how far the screw turns is, IMHO, capable of rough
regulation at best.  Unless all let-off buttons are perfectly level, a
"quarter turn" is going to mean different things on different buttons.  
     Also, setting let off just below the maximum string excursion zone is a
good method in the bass and middle of the piano, where hammer mass stores
enough energy to obviate the miniscule differences that may arise between
notes.  However,  when the excursion zone shrinks on the higher strings, and
the hammer size is smaller, setting the let-off to just miss will not always
leave the most sensitive action. 
    Tolerances must be widened for a piano that does not see constant
attention, but for the maximum performance on a stage set-up, let-off from
C-52 on up needs to be set by feel.  That is how it is going to be judged by
the artist, so it behooves the technicians to develop  a sense of let-off at
least as sensitive as the performers' they are likely to encounter.  
    The goal is to make escapement as even and transparent as possible, giving
maximum control.  I do this in the piano by first setting the let-off too high
and then turning it down as I play the key at ppp.  As the escapement point
moves down to string height, you will feel the  hammer  begin to let off with
a slight double note.  You have to be moving the key slow enough so that the
hammer rebounds onto the top of the jack.  Some have described it as a
"jackhammer" feel.  If you play a note slowly as you lower the let-off, you
will pass through this area.  With a little practise, you can begin to feel
this on extremely soft blows. 
     You want to be able to make the note slightly stutter on the softest note
you can play and then, turn the let-off button down until the stutter
disappears.  There is a narrow range between the "trace blocking" and having
sufficient let-off, but there is one magical point in that range that makes,
as one artist described it, "it feel like the note is just sitting on the end
of the key". 
     You don't want a piano like this going out on the road, ( though Ronnie
Milsap does), but for your home stage, it can do wonders. Also,  once the feel
is well established, it is easy to maintain. 
Regards, 
Ed Foote