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Inertia calculator ? Yet sold ?

All the words in the world, all the formulas, etc. cannot compare to actually playing an instrument on which this has been done. If you can locate one near you, or if you can find a PTG chapter near you to tell you about a piano that has been done, go for it. I was shocked, amazed and highly covetous once I played one. Go for it!

Which one are you referring to? Stanwood or Rhodes?

I would lean towards the Rhodes analysis, having attended seminars by both. John Rhodes and Darrel Fandrich are measuring not just the weight, but that actual inertia of the parts; how much energy is required to get them moving. A far more important factor in determining the feel of action performance than the 'leverage/mass' equations used by the Stanwood Method.

The Rhodes approach allows you to predict the 'feel' of the keys with some real precision. The Stanwood will provide an extremely even action (...all the weights/leverage are steamlined), but sometimes the end result is 'heavier' than the numbers you'd expect...because it does not compute the inertia of the parts. See? Rhodes measures the energy required to get things moving, while Stanwood is calculating mass/leverage.

I completely agree here, regarding Stanwood actions tending to the heavy side, or more precisely they seem to generally have more inertia built into them. That feel, though dead nuts even, steered me away from the Stanwood approach in all my action work, and I approach it rather from the optimized geometry side and hammer weight control side of things.

To be sure though, both of these protocols offer techs something that they have craved for years, that is the ability to quantify what the devil was going on in a problem action, or an action that was not satisfying the pianist.

One of my fears regarding the Rhodes/Fandrich is that the thing that bugs me about the Stanwood approach could happen to the Rhodes. That is, by defining a touch range as "Touch to die for", in the hands of techs in the field, the data will be used to tailor the action to some predicted ideal rather than helping a individual discover the touch that turns them on subjectively and individually.

Though the Stanwood in theory helps a competent tech achieve whatever touch they and their client have determined they want to shoot for, despite this fact, all of the Stanwood actions I've played were shooting at a particular feel, as Jeff said which ended up being on the heavy side. So the adjustability of at least the Stanwood seems to be undermined in practice. This could easily happen to the Rhodes/Fandrich.

Also ,to the OP, keep in mind tonal and belly issues often masquerade as action issues. Pianos which are not tonally responsive are quite often perceived as having action problems. However, amazingly the "action" issues go away when the belly/tone regulation side of the equation has been dealt with. So make sure your tech looks at the tonal part of the experience and addresses it before assuming action redesign is in order. I have played Stanwood actions, on old worn out bellys. The tonal experience was completely uncontrollable despite the action modifications...this because the tonal problem was ignored and assumed to be exclusively action related.

Jim Ialeggio

The Rhodes/Fandrich is a better -- but still interim -- approach to touch design issues. Stanwood's patent -- and the assumptions that follow from it -- have been demonstrated to be scientifically invalid and in actual practice unable to provide accurate diagnosis nor reliable prediction of action "feel".

That's a pretty damning assessment, Keith. I've spoken to a few people who have played or own a Stanwood modified action and all are extremely satisfied with it. They say it improved the evenness and performance of their action no end. I don't think they were concerned about how the theory was expressed in any document or the completeness of the details, but rather the fact that their action had been adjusted for great evenness of response and that it was adjusted to suit their preferred weight. In the end, isn't that what counts?

Also, shouldn't you provide evidence of all this demonstration of invalidity, since you've stated it so forcefully? At least direct us toward a scientific breakdown of the failing you speak of. (ie. link to site or journal). Or your own explanation. Otherwise you really haven't actually said anything and what you've said is borderline slanderous.

Pianists sense a piano's response as a result of what they are getting, aurally, for the effort required. A brilliant 58 gram action feels lighter than a dull 50 gram action. I don't think either of the two approaches deals with that.
Regards,

>>The Rhodes/Fandrich is a better -- but still interim -- approach to touch design issues. Stanwood's patent -- and the assumptions that follow from it -- have been demonstrated to be scientifically invalid and in actual practice unable to provide accurate diagnosis nor reliable prediction of action "feel". <<

Greetings,
It seems someone (too many quotes, I don't know who said the above). doesn't totally understand what "feel" is. The feel of a piano is as dependent on the sound as the physical effort involved in pressing the key, ie. I can totally change the feel of a piano with voicing needles or lacquer;. This is because the "feel" is dependent on what the brain senses of the relationship between effort and result. Does the Rhodes/Fandrich approach measure the spectra? Does it measure the alteration of the sound with increasing force? Does it measure the tonal range of the hammer? If not, it isn't dealing with "feel", but rather the effort aspect, and that is only half of what determines "feel".

Pianists sense a piano's response as a result of what they are getting, aurally, for the effort required. A brilliant 58 gram action feels lighter than a dull 50 gram action. I don't think either of the two approaches deals with that.
Regards,