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What did the Gibson company leave undone in their ebony bridges?

Here's an experiment to show how Gibson could have improved on their solid ebony mandolin bridges.
Three very successful ebony bridges are pictured at the bottom of the page.



Here's a scan of three ebony bridges. At top is an old Gibson solid ebony bridge (the small hole in this bridge was for the fingerrest-mount).

At center and bottom are two new bridges, made to be very similar to the old one. Bridge #87, in the center, is made without separated bridge feet, just like the Gibson bridge. Bridge #86, at bottom, is made with the bridge separated.

(These bridges are all about 4" long, but all scans on this page have been reduced a little to save loading time.)

picture of three ebony bridges



Bridge #87, as an "all-foot" bridge: Midrange good, sustain fairly good, but bass somewhat muted. Treble is smooth but feels a bit unresponsive.

#86, the Two-footed bridge: Much more resonance and volume from the whole mandolin, compared to the "all-foot" bridge #87. Better clarity up high; a 'freer' feeling in playing.


Now I separated the foot of Bridge #87 into two parts, each about 1 3/8" long. With the feet separated it gave much more response, and was more fun to play. It had better sustain, richness, and volume, and better "chunk" chords, high and low.



picture of ebony bridges



At this point I had two bridges, substantially identical, as scanned in the picture above. Now to investigate the importance of central cutouts and wings in these bridges.

 





Wanting to test these features one at a time, I put wings in Bridge #86 and a central cutout in Bridge #87, as shown here, and tried them on the mandolin:



picture of mandolin bridges



#86 with wings only: Much more volume and richness in bass and treble. Considerably more sustain.

#87 with central cutout only: More bass response and slightly more volume and sustain. Slightly better feeling overall.

--So at this point with these two ebony bridges, the wings seem more important than the central cutout, but both give more sound.



Now I added the features each bridge was lacking: wings for #87, and a central cutout for #86. Now the two bridges were nearly alike again:

picture of ebony bridges



After playing both bridges, I can say that they not only look, but also sound very much alike.

Bridge #87 gained much richness and volume with its new wings. Bridge #86 gained a little volume, but while it did improve, it, like the other, was not transformed by the central cutout alone.



Both bridges now give a very satisfying response from the mandolin, with good volume, clarity, balance, and thunky "chunks" low and high. We can say, now, that we wish the Gibson company had made some improvements in their bridges over 80 years ago.

Gibson manufactured many thousands of mandolins with solid one-piece ebony bridges, which were fitted to the mandolin top all across the 4" length of the bridge. Here are some alterations, which would have been cheap and easy to do, which might have improved the sound of all those instruments:

1. Dividing the bridge foot, which was unbroken in early Gibson bridges, into two separated feet gives a big improvement in volume and clarity. A sad thing is how easy this would have been to do. The factory could have done this with about 10 seconds per bridge, on a belt or spindle sander.

2. Providing a central cutout improved these two bridges significantly. This, like the next step, would have taken only a minute or two in the factory, and would have been worth it in improving the sound of all those quality-made Gibson mandolins.

3. Providing small "wings" on these two bridges yielded a very impressive gain in volume and richness. This would not have taken much work, but would have been a very important step in improvement.


 

Three successful ebony bridges

picture of ebony bridges



1. The top bridge is Bridge 87 above, with two holes added to become a 6-hole winged bridge. The volume increased noticeably when I added the holes, though the tone was about unchanged.

2. Bridge 91, in the middle, is of persimmon, which is really American ebony. Aside from the variegated color (which, if the wood is fine-sanded to a glossy finish, is actually quite attractive), I could not tell any difference in sound between this bridge and an African ebony bridge of the same design.

3. Bridge 545, at the bottom, is a persimmon (American ebony) bridge made to the 11-hole design. This bridge's overall volume and richness were superior to all the previous ebony bridges I've made. I suggest that if you make an ebony bridge, use this 11-hole design,





Those who would like to provide additional response to their mandolins while preserving much of the traditional appearance might consider installing one-piece ebony bridges. For me, the ebony bridges do not quite equal the best maple bridges in the richness of the bass and treble response, in the sustain, or in the overall volume and sense of projection of the sound from the mandolin. However, ebony does deserve additional investigation and may suit some instruments better than the ones I have tried it on.

I encourage others to try ebony bridges (along with maple and other woods) and let me know of the results, so that I can post them on this site.


To email me: click here.

Red Henry.







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