When enthusiasm for a piano rises in the concert pianist, it is a wonderful thing. Their spirit soars, their talents fully manifest, the music ascends, and the listener gets emotional.
What can stir this response? Consistency note-to-note, a well-integrated tuning, and responsive repetition are a rather boring group of contributors, but very important. They elicit confidence. And confidence taps all knowledge, feeling, and sensibility directly, without instruction from little voices in the head, without reference to who is listening or what they might think. Scales, memorization, and all forms of effort are transcended.
The mechanics of a grand action are brilliant, a series of levers that reaches inside the piano while converting finger force into a hammer force that can play strings with musical expression. Such a feat has many complicated details, but observed individually, they are logical, pragmatic – mechanical. Geometry is the design engine for this collaboration. And its leverages both transfer these forces and transform the distances they travel. Each finger’s mechanical advantage (2 kilograms to play a 10-or-less gram hammer) is divided by 5 in a tradeoff multiplying finger travel distance by 5 into a hammer travel distance that accomplishes fff. Or ppp.