Key acceleration

[rhohf@eagle.idcnet.com]

Thank you for your comments, Don (Mannino).  Here are some replies:

>Your message made it sound like a wide "acceleration >envelope" is a good
thing -
>is this how you feel?

My intent was to not venture an opinion for the time being.  In real life
action work, my goal is to give my customers what they want, not what I think
they should want.  This means understanding the full range of possibilities,
and then producing results that are intentional. If the customer leaves it up
to me (which happens often enough),  I pull out the stops and opt for maximum
performance.

>A wide envelope would mean the the piano would be easy to
>control during soft playing,

I disagree with this but will need to lay more groundwork before dealing with
this issue.

>This is why I have always been puzzled
>by people who feel that uprights should have more leads in >the keys in order
to
>create more mass and make it feel better.

Yes, this is paradoxical.In my experience upright leads are almost always in
the back half of the key.  This is a very different case than the discussion
of front-weighting in my post.  When the lead is in the back of the key, there
is no ambiguity in the effect of gravity since gravity and inertia always act
in the same direction during playing.  According to my model, adding leads in
back do not change the size of the "acceleration envelope" but only raise the
envelope up the effort scale.  Leads in back cause other problems which I
don't feel are relevant to (fine) grand actions.

>Expressed in your terms, it is my opinion that a smaller >"acceleration
Envelope"
>would be the goal, with the position of the "envelope" placed >as low on the
>effort scale as possible.

I would say that the size of the "acceleration envleope" and its position in
the "effort scale" are related to the extent that setting one determines the
other (all other things remaining the same).

>I'd suggest that a better name might be "effort envelope," and >it could be a
>useful and interesting way to describe one aspect of the >"touch" of an
action.
>Not only the size of the envelope but the location on an >effort scale should
be
>expressed.

Yes, this is very important, thank you for clarifying it. I have defined
"acceleration envelope" as the range of >key< accelerations necessary to run a
given piano through its full dynamic range (other definitions are certainly
welcome), independent of the pianist.  However, I did not mean to totally
exclude the  pianist from the picture.  How about "force envelope" rather than
"effort envelope" since we all know pianists who apply a great deal of
"effort" with little net effect.  Let me suggest this for a  definition of
"force envelope":  the full range of hand (arm, back, full-body, whatever)
motions which a given pianist is capable of applying to a piano key.

I believe that understanding the relationship of these two "envelopes" is
essential to successful action work.  Naturally, every pianist has a different
force envelope, and if the acceleration envelope is not contained within the
force envelope, you've got big problems.  When you consider how different are
the force envelopes of different pianists it becomes obvious why there is so
little agreement on how actions should be made.  I would also stick my neck
out to say that a technician who does not play the piano well enough to
evaluate the response of a piano first-hand must depend upon second-hand
information, and usually ends up shooting in the dark.

Bob Hohf