Steingraeber factory pictures, bridge agraffes & adjustable vertical hitchpins

[Stéphane Collin]

> Someone mentioned something about a presumed vertical vibrational mode 
> enhancement being automatically something that would simply pump more 
> string energy directly into the soundboard and actually decreasing 
> sustain.  I would say that was rather premature stated.... tho I would be 
> delighted to see any science that backs that idea up.

Bizarre.  This seems so obvious to me :  the board is driven by the string 
(via the bridge).  If the string vibrates in a mode that is normal 
(perpendicular) to the board, then all of its energy contributes to make the 
board vibrate in a way that will in the end favor the acoustic pressure wave 
that we hear.  If the string (partly)  vibrates in a plane that is parallel 
to the board surface, that energy will result in bridge twisting and board 
compressions that will transfer only a tiny bit of energy into acoustic 
pressure wave that we can hear.  Now, in the case that the string vibrates 
in the vertical plane, thus, I think, transferring it's energy efficiently 
to the board, this doesn't always mean (or am I wrong) that the sustain 
would dininish, like in the case that the impedance of the board is too 
close to the impedance of the string.  In this case, impedances respectively 
are the same, it is just the vector of the forces acting that is more close 
to the shape that maximizes the transfer of energy (vertical in this case).

Best regards.

Stéphane Collin