Violin bridges (was The Soundboard according to McFerrin)

[Phillip L Ford]

On Fri, 4 Jan 2002 21:29:19   
 John Delacour wrote:
>At 10:42 AM +0100 1/4/02, Richard Brekne wrote:
>
>There follow just a few definitions and URIs.  Just one point, to 
>link to Robin's Chickering saga:  The incisions in a fiddle bridge 
>are there not purely for decoration but to lengthen the path of the 
>sound on its way through the bridge from certain strings.  The apron 
>of a bridge is designed so that the sound will enter the soundboard 
>at a more responsive point.

Actually I think that a violin bridge is more illustrative of Ron's position
than your own.  If the violin top is being activated by compression
waves then what difference would it make what the bridge looked like?
It could just be a solid piece.  The bow is moving the string side to side.
The top needs to move up and down to move the air so that we can hear
the violin.  So violin makers have cleverly devised a bridge and soundpost
system to convert the side to side motion of the string to up and down
motion of the top.  The bridge is rocking about the one foot that is over
the soundpost which is causing the other foot to move up and down.
Apparently violin makers seem to feel that some physical movement
of the top needs to take place as a result of the string movement.  I
believe the cuts or incisions are not there to 'lengthen the path of the
sound' (I'm not sure what the purpose of that would be anyway) but to
cause the flexibility (or impedance if you like) of the bridge to be more
or less the same for the four strings, since two of them are directly over
the feet and the other two are over an unsupported section of the bridge.

Phil F

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Phillip Ford
Piano Service & Restoration
1777 Yosemite Ave - 215
San Francisco, CA  94124