#1
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Short Scale Bridge and Bracing
I'm considering a 23" scale 00 or 000 (Martin) guitar. They have said it is possible but before speaking further on it I wanted to get some thoughts on what this entails vs. standard scale.
So I know it will change bridge placement. The headstock comes in ~1" and the bridge moves up the same. The bracing then will move up along with the bridge? Is this similar to the amount the X bracing moves up in Golden Era bracing? That seems to increase bass response so that would be an improvement in my mind. However, the bridge placement itself would be further up on the lower bout... What impact would that have? Also in terms of 00 vs. 000. The smaller guitar (.5" shorter body length) I imagine starts with slightly lower bridge position in comparison to the larger guitar. So, the bridge placement wouldn't be as far forward then? Is there a bridge placement that simply becomes too far shifted forward. For instance... On a 0000 guitar I imagine the bridge would way to close to soundhole. And it gets better as guitar gets smaller. Anyway, any help is greatly appreciated. Thanks! |
#2
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Of course you can do it, and it should work at least reasonably well.
However, I doubt that you will get much increase in bass response from moving the X-braces, because moving the bridge up places it at a narrower part of the body. There are three X-brace placements that Martin has used on dreadnoughts. The original (forward) position (~1" from the soundhole), the low X (~1 7/8" from the soundhole) and the modern position (~ 1 1/2" from the soundhole). So there is a 7/8" difference between the extremes. In other words, a 1" movement of the bridge should be workable in terms of the bracing layout. IMHO, the most important factor for X-brace location is the relationship between the X-braces and the bridge. The forward position has the X-braces intersecting the bottom corners of the bridge. That is what I would shoot for. Quote:
Quote:
Another thing to consider is how many frets the neck has. If you are willing to go from a 14-fret neck to a 13-fret neck, that will move the bridge down about 0.66". In that case, shortening the scale by 2" would only move the bridge up on the body about 0.3". |
#3
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Quote:
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---- Ned Milburn NSDCC Master Artisan Dartmouth, Nova Scotia |
#4
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Gibson made 13-fret guitars in the early-1930's, based on the L-00 body size. Santa Cruz has reproduced them with their H13 series.
http://www.santacruzguitar.com/instruments/h13-model/ I built a 14 3/4 fret ('almost' 15 fret) dreadnought a few years ago. By moving both the braces and the soundhole up 1/2", the result was a guitar that IMHO sounded just as good as any 14-fret, forward-X braced dread I have made. The player was accustomed to playing Gallagher cutaways, but he said that 1/2" was all he really needed. |
#5
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From what I can see, there's nothing magical about putting the bridge in the middle of the lower bout. Somogyi points out that shifting the bridge up from there can put it halfway between the tailblock and the upper transverse brace, which are the only logical structural/acoustic limits to the soundboard. And have you ever seen a banjo with the bridge in the center of the top?
IF the soundboard was uniformly flexible, and IF there was no bracing, then the maximum amplitude of vibration for the fundamental mode of the top would occur in the center. I'm pretty sure that's why they don't put banjo bridges there: the bridge would move so much you'd get a 'wolf' note at the resonant pitch of the top. But we're not talking about banjos here. We use bracing to stiffen up the top and make it work the way we want. You can move the location of the maximum amplitude of the top a fair amount by the way you do the bracing. It's not omnicompetant; a bridge 2" from the tailblock is going to be working under some limitations, but then again, heard any lutes lately? It does seem to me that the 23" scale should not pose too many problems. I made one steel string with 20" scale and a 14-fret neck (with 12 it would have looked like Thor's hammer...) and it worked fine. The tone was good, and the main issues had to do with intonation with such slack strings. Remember, the short scale reduces the tension a bit, and allows you to go thinner with the top, which helps make up for the reduced power. |
#6
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Guitar police
Seems to me (opinion, worth what you pay for it) that a builder can locate his neck/body intersection at any fret position that suits him. I don't think there's any wrong or right position to do it, or in-between frets for that matter. Whatever the builder wants is perfectly all right. There's no 'guitar police' who will write him a summons for not following some rigid convention somebody thinks is an iron rule. Builder is building for himself. Enjoy and experiment. That's why we roll our own.
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