Steingraeber factory pictures, bridge agraffes & adjustable vertical hitchpins

[Ron Nossaman]

> Isn't it so that these agraffes favor the vertical plane oscillation of 
> the strings, keeping the force vectors acting from string to bridge (and 
> soundboard) and other way round in the direction that makes the transfer 
> of the acoustic wave the most efficient ?  So, in a way, the driving 
> force, being something close to average vertical to the board it is 
> driving, will drive it better, which will have the same effect as if the 
> board was more free, no ?

So goes the marketing claim. A couple of people, Carl Myer 
among them, were intending to set up a strobe to see how valid 
the claim is that the string excursion is kept vertical by the 
agraffe. So far, no one has come up with supporting evidence - 
only conjecture.


> I would expect that the designer adapting such agraffes on a traditional 
> piano would have to tweak the impedance matching between strings and 
> board assembly, 

I don't see why.


>I mean not only because of the extra mass of the 
> agraffes on the bridge, 

Which will automatically increase sustain.


>but also because of that more efficient transfer 
> of the wave.

Which still remains conjecture. Consider too, that a primarily 
vertical excursion would efficiently dump the string energy 
into the board at a high rate, shortening sustain rather than 
improving it, and the only thing that would counteract that 
would be the increased mass from the agraffe. So the benefit 
would still be the mass, rather than any tendency toward 
vertical string excursion.

Ron N