Ebony bridge caps

[Ron Nossaman]

> I don't recall the exact figures, but the weight difference between the 
> three is significant and without question a significant factor. 

Yup.


>I suspect it's a sort of backdoor mass loading effect without having to 
> screw things to the bottom of the board. Unfortunately, it's not quite 
> as easy to remove the bridge as it is the weights 8-).

Actually, building it into the bridge is the front door. Which 
is why I like the weights. Every piano I do is a one-off, and 
I'm not stuck with what I get if I don't hit an optimal 
balance on the first shot.


> For the MOE, heck if I know, but I did perform the mechanic's 
> stethoscope, non scientific, experiment and I am happy to report that 
> the ebony/maple/mahogany laminted bridge, without a doubt, has mo sound 
> than the others. 

Modulus Of Elasticity. Stiffness. Did you happen to do any 
bending comparison tests?

> I had a helper strike and place a tuning fork on one end while I 
> listened through the stethoscope at the other.  We made several passes 
> between the three, and then switched places.  The volume of the sound 
> between the three was very different.  The solid bridge sounded nice, 
> the maple/mahogany was much louder, and the maple/ebony/mahogany bridge 
> the loudest of the three.

A while back, I had a soundboard out of a piano and was 
playing with the tap tone of the belly rail, deciding where it 
best needed bracing. The lowest pitched "bonk" was around the 
end of the dampers. Surprise, killer octave country! I clamped 
a big F clamp on it in that area, not clamped to anything 
else, just pointing straight up, and tapped it again. That 
same area now had as high pitched a "tock" as the rim, just 
from the addition of mass. I hadn't changed the hardness or 
stiffness at all.


> Originally, knowing that obviously mo is better, I put an ebony cap on 
> the bottom of tenor treble bridge.  It's a great sound and looks really 
> cool, but when compared to the latest version of the 220, it's evident 
> that the board might, maybe, perhaps, possibly just might be restricted 
> just a tad.   

Now, for fun, Add some weights under the plain maple bridge in 
a few places and see if anything changes.
Ron N