Basic Action Design/Performance Question

[John Delacour]

At 08:57 24/09/01 -0400, Farrell wrote:

>Does this make any sense? Perhaps I am asking "besides material quality,
>design, manufacturing, etc. (and the piano it is installed in), is there
>anything else (magical?) about an action that makes one superior to another
>one?

I would say there are two key words to the answer to this question: a) geometry and b) friction.  Geometry alone would affect the touch of a piano but it will inevitably also affect friction.  A very long book remains to be written on the subject of the piano action, and it would be long enough even if only the Erard-Herz action were considered.  Hansing, Pfeiffer et al. deal seriously with essential aspects of the question but leave many aspects untreated besides practically neglecting the dynamic behaviour of the action.  Nevertheless I would say that Pfeiffer is essential reading.  I myself began years ago with Hansing.

The friction (and weight, tending to friction) inherent in the design of the EH action and aggravated by the increase in hammer weight after 1850, is considerable and can be reduced only to a certain point.  The only significant improvement in the geometry of the intermediate lever was made by Herrburger of Paris about 1900 and was adopted by very few makers.  Steinway, of course, was not changing, and Bechstein and Broadwood (significant commercial forces at the time) eventually switched to a less radical Herrburger "improvement" which had a very large following until recently. This so-called Schwander lever retains the basic geometric layout of the EH action, addressing only the problem of spring adjustment, which had and has been addressed in other ways on the basis of the EH design (most effectively, in my opinion, by Ibach/Isermann using a "piece of string").

Del expresses a preference for firmer contact surfaces than are common, and there is some rationale for this, though it would need to be carefully defined.  Any preference for hornbeam v. maple would also need to be justified and I'd be interested to hear this, since it's a question I've often wondered about to no good end.  So far as the intermediate lever is concerned, I've seen no evidence that either wood is better than the other and prefer hornbeam only for its cleaner and smoother texture.  The shank is another matter altogether.

Reduced to essentials, the action consists of nothing but points, each of which consists of contacting surfaces.  It is the positioning of these points and the management of the coefficient of friction of the contacting surfaces that is critical in the production of a good touch, and it in these two respects that makers and/or grand finishers can vary wildly and produce a wide range of results from components that are fundamentally very similar.  You might think that the Steinway tubular action frame restricts the finisher's geometrical excursions, but anyone who has fitted a new Kluge keyboard to an existing action has been made painfully aware of the amount of geometry that lies outside that frame.

JD