What matters most ?

[Bill Ballard]

At 2:08 PM +0200 8/23/03, Richard Brekne wrote:
>Whats is more important to the <<heaviness>> of the action, the inertia
>of the hammer and top action, or that of the key.

I'd vote for inertia in the top action. From a design standpoint, and 
a mechanical one. First, someone setting up the action has far less 
control over it than key inertia. To elaborate, what determines top 
action inertia is SW and the ratio of hammer shanks and wippens. Once 
those parts have been selected, there is a limited extent to which 
top action inertia can be adjusted. (As for as SW, maybe if your 
lucky, .75g downwards. KR, which I'd call bearing directly on top 
action inertia and not on key inertia, provides more of a means of 
adjustment but at great extra effort.) The only reason to adjust key 
inertia would be in meeting the requirements of top action inertia. 
So from a design standpoint, I'd say that top action inertia is the 
one to pay attention to. Key inertia is the tail on the dog which 
wags when its's happy with the weight of the rest of the dog.

Mechanically, I'd also vote top action inertia. The top action is the 
driven portion of the system and the key is the driver. If the driven 
portion is lighter than the driver, there is the good chance in some 
circumstances that he top action will "fly away" from the key. (Have 
you ever had a pianist talk about "fly-away" hammers?) On the way up 
the top action inertia needs to be greater than the key. Otherwise 
coupling (and as a result, control) will be weakened. In effect, the 
driven needs to act like a brake on the driver.

>Or if there exists a
>kind of border condition where one becomes more important then the other
>and vice versa.... what is that condition ?

You mean like Steven Birkett's soft and hard zones? There would be 
two ways to determine this. 1.) happen to be Steven Birkett, with all 
his years of physics, math and the analysis of mechanical systems. of 
2.) do a massive survey of pianists under the controlled experimental 
circumstances proposed by David Anderson. Mind you, the existence of 
such a cross-over zone/point is only speculation at this point, and 
the variables which would cause that cross-over are as yet unproposed.

At 4:32 PM -0700 6/14/03, David Andersen wrote:
>Let's have a test with 10 fabulous piano players from different genres playing
>the same piano, but really PLAYING it, for as long as it took them to know the
>spielart, over a 48-hour period where the tuning, voicing, and regulation can
>be kept consistent to a very high standard.

Bill Ballard RPT
NH Chapter, P.T.G.

"We mustn't underestimate our power of teamwork."
     ...........Bob Davis RPT, pianotech '97
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