Steingraeber factory pictures, bridge agraffes & adjustable -- some more thoughts.

[Ric Brekne]

Hi folks. 

Hope this isnt dead because its actually full of good stuff.  I think 
one of the main points with this mathematical model of Dr. Andersen is 
being missed in the rush to discount the whole thing.  I'm assuming the 
model he built was based on a piano string isolated from outside 
influences... such as a soundboard.  If this is so then the question 
about validity and how all this in turn fits into the piano, then things 
are not quite as straightforward as the discussion so far has required.

First there is the matter of whether or not <<a string>> will vibrate 
longer if kept virbrating in a vertical direction by the terminations as 
opposed to changing over to the horizontal mode. I'm assuming for the 
moment that its possible to actually control vibrational direction to 
some degree thus.  In order to find out whether the nett sustain of the 
string actually is longer for same input force one is going to have to 
isolate the string from all driven systems... like a soundboard.  i.e. 
maximize the impeadance in all directions at the terminations.   If a 
string in iself does then actually have longer sustain when forced to 
vibrate vertically --- or rather in the same direction as the input 
force (which is the actual heart of the matter me thinks) then we can 
move on to the next bit.

A few facts have been thrown into the mesh here already. Most notably 
the effect of mass on sustain and the fact that the soundboard is more 
easily driven up and down rather then sideways. This second used to 
assert that if the (installed) string did actually vibrate longer in the 
vertical direction then the board would just more readily suck up its 
energy and sustain would decrease... ie the opposite of the <<claim>>.

But if it was established in the first place that  a string in itself 
will indeed vibrate longer if its vibrational direction stays in the 
same direction as the input force... then suddenly we have an entirely 
puppy we are dealing with.  And this puppy, as it were, would have to be 
correctly designed into the rest of the piano.  One scenario I can 
imagine is that Stuart and his team KNEW that he would have to exploit 
this sustaining string correctly BECAUSE of the problem with soundboard 
impeadance.... and that the mass of the aggraffes could be used along 
with other soundboard design issues to create an appropriate impedance 
to a string vibrating thus.  Just a thought.

btw... this is why I thought it interesting to hear the Steingræaber in 
comparison.  No doubt Udo came up with some different combination of 
things and it would be real cool to know what those were and listen to 
the differences.

Cheers
RicB