Negative bearing

[Overs Pianos]

Greg and all,

Greg wrote;

>  . . . . Could one
>move the long bridge gradually in more toward the center of the 
>board toward the
>tenor end  as a replacement for (or compliment to) a gradual thinning of the
>board toward the same end of the long bridge?

Del's post pretty much answers your question. The trench we machine 
into the perimeter of the sound board panel around the bass is 
designed to achieve a similar outcome (there's an image of this board 
now on the opening page of our site, and a larger one linked to the 
small one).

>     If the previous is done would it then become impossible to have 
>the low end
>of the treble bridge and the bass bridge be roughly the same distance from the
>edge of the board?

I've written about this a couple of times on this list. This is a one 
of the conditions I try to satisfy when laying out a new instrument. 
However, the notes at the end of the long bridge will enjoy greater 
flexibility relative to those at the mid section of the bridge, since 
the bridge end will have bridge wood running away in one direction 
only, ie. towards to middle notes. Whereas, the notes towards the 
middle of the long bridge have bridge wood extending in both 
directions. This is one of the factors which can contribute to 'ducks 
disease' at the end of the long bridge.

>  I believe I understand that if they are not relatively the
>same distance from the edge of the board that an impedance imbalance problem
>will result.

Indeed it may. Now if only a great majority of the manufacturers out 
there were mindful of this, we might see a higher percentage of 
pianos with a satisfactory cross-over,

>I have an A.B. Chase I am delivering soon that has a low tenor
>"hockey stick" with all wound strings on it. BOOM, BOOM, BOOM go all the notes
>down there. Really quite unfortunate but it was here for refinishing. That
>portion of the bridge is curled inward toward the center of the board (where
>else would it go?) and is quite a bit farther in than the bass bridge.

This is the opposite to the way this problem usually presents itself. 
Usually the long bridge is closer to the rim and more rigidly held 
than the upper end of the bass bridge. This results in a 'skinny' 
tone crossing down to a boomy muddy bass. Either way its a disaster. 
Some of the most expensive pianos on the planet are outstanding 
examples of this phenomena.

>The
>transition is astounding! And not in a good way. Any thoughts? Or am I just
>stating what you guys have seen for years?

Welcome to the club Greg. Nothing will ever be the same for you again.

Ron O.
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Website:  http://www.overspianos.com.au
Email:        mailto:ron@overspianos.com.au
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