Killer Octave Question

[Ron Nossaman]

>I've done some playin' and some tinkin'. And I've decided that there is a 
>difference between a crowned bridge, but that the difference, in practical 
>terms, is negligent.
>
>If you cut a circle out of cardboard one foot in diameter, and then cut a 
>circle out of the middle of that, let's say eight inches in diameter, you 
>have a big flat donut. Set that donut on a basketball so that it sets like 
>a topless hat. Now also realize that you need about a foot of tangent 
>coming off the donut at some point (low tenor or long bridge). Now you can 
>see the argument for a crowned bridge. Or perhaps not really just a 
>crowned bridge, but a bridge that has a bottom bevel in the treble area 
>and a crown in the lower tenor.
>
>Now back to reality. Soundboards, even Fandrich soundboards, have a larger 
>crown radius than a basketball, and a bridge is only 32 or 35 mm wide. So 
>I do suppose that the ribbed soundboard panel and bridge itself will 
>conform quite readily to the very slightly mis-matched straight bridge and 
>curved soundboard panel. The tenor end will bend enough (what, maybe 1 mm) 
>and the treble section of the bridge can have a top whose plane is not 
>quite parallel to the plane of the bridge bottom/panel top interface. 
>Bottom line: any difference is close to or wholly within common 
>woodworking error and completely negated by the flexibility of the woods.
>
>That make sense?
>
>Terry Farrell


Yes it does. That's why I asked John Hartman, among other things, if he 
fitted his bridges to the soundboard like fitting a pinblock to a plate. 
Since just crowning the bridge still won't make it fit the soundboard 
absolutely exactly, while both crowned and flat bridges work as well, 
there's neither demonstrable benefit nor penalty either way.

Ron N