Bridge Vibration... was Wapin Revisited

[John Delacour]

At 4:16 pm +0200 15/8/06, Ric Brekne wrote:

>JD copies and writes:
>>So much for "movement" of the bridge :-)


>AH  but it DOES move !  Dr. Birkett and I looked long and hard with 
>some decent resolution and a couple of inlayed markers to confirm 
>that.  Just how much it moves... and to what degree it is in sync 
>with the string pulse tho was less clear.
>
>I supposed that perhaps the two vibrating planes of the soundboard 
>and stringset might somehow trap (at least to some degree) the 
>bridge inbetween. That may sound very strange to some... and indeed 
>might not be the case... but it seemed fairly clear that the 
>vibration of the bridge we could observe was not in synch with the 
>period of the string pulse.

I must say that having seen all the videos, the only one that showed 
me anything that was interesting was the comparison of the touch 
baizes/felts.

Some of the vibration of the bridge is "in synch" with the string and 
lots of it is not.  To expect the bridge to vibrate up and down 
following the up and down pressure at the end of the string is 
against all reason and science. Vibration and translation are two 
different animals.

JD