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View Full Version : Forward-shifted X brace vs. Standard X brace


vintageom
10-10-2009, 03:14 PM
I've have played and owned both X brace scenarios, and found that the forward shifting lets the bass resonate more and allows the top to move more freely, to me at least. But also, to me, I find that the crispness gets compromised to a small degree. I overcome this compromise with perhaps an Adirondack top, just to get back the extra "stiffness" so that it does not sound muddy when driven hard. Just my personal impressions. You perhaps disagree.

Now for the question and perhaps a builder would be a great resource for an answer. If Martin, for example, in the "pre-war" years used forward shifted X bracing, why would they have migrated to braces positioned rearward only to later market pre-war forward shifted bracing? What are the pros and cons of each type of bracing patterns, both structurally and long term durability. Is one better than the other? And secondly, perspectives on the resulting tone to your ears?

Thanks everyone.

mellowman
10-10-2009, 03:33 PM
I agree with your perceptions on the differences between forward shifted and standard bracing. I happen to really like the tone of a dread with forward shifted x bracing, mahogany back & sides, and adi top and I think others do as well judging from the popularity of Martin's D18-GE and Authentic.

JoeCharter
10-10-2009, 03:43 PM
Back in the days, people were using larger strings and the braces were moved down to make the guitar stronger.

Nowadays people use lighter strings and forward-shifted braces have regained their place in the sun.

Brackett Instruments
10-10-2009, 03:56 PM
(I've read more than I've seen)

From what I've seen and read Martin stopped using scalloped braces, and added a "popsicle" brace for better durability sometime around or during WWII. I've heard all kinds of stories about the rearward shifting of the braces, including that something happend to their template, or jig, and the braces got moved by accident. Maybe John Arnold will read this. I'm sure he can tell us the correct reasons.

66strummer
10-10-2009, 04:50 PM
In playing both kinds (bracing) in some of my dreads, I tend to agree with the OP on the "bass crispness" factor of forward vs standard. Is the Martin D-18GE forward shifted bracing? Didn't realize that. One more reason for their popularity.

mellowman
10-10-2009, 06:00 PM
Yes, the D18-GE is has forward shifted braces. I got one a few years ago and really like it.

66strummer
10-10-2009, 08:32 PM
Yes, the D18-GE is has forward shifted braces. I got one a few years ago and really like it.


Golden Era was no doubt a giveaway that I somehow missed :D. OK, back to our regularly scheduled topic ;).

815C
10-11-2009, 06:48 AM
I've got one (forward shifted bracing, adi top, mahogany back & sides) and one feature I've found with it is that it has more volume and cuts through/projects more than my non-forward shifted guitars. I don't know if that is a result of the placement of braces, or some other factor in the guitar's design, but it is an obvious difference - I've had several folks comment upon this feature.

rmyAddison
10-11-2009, 07:24 AM
A lot of the different Martin models exist mostly because of the bracing. The Difference between the D-28 (standard bracing), HD-28 (scalloped braces) and HD-28V (forward shifted scalloped braces) is pruimarily the bracing and they all sound different. When you get to the GE's and Authentics those forward shifted scalloped braces are also of a more vintage shape.

I agree that forward shifted scalloped braces add some bass and responsiveness, the negatives in some instances can be some loss of balance or clarity. Probably just as influential on the small body models is the size of the braces, 5/16" versus 1/4". To me 5/16" braces on OM/000's can be the culprit for the dreaded "boxy" sound, while 1/4" braced OM's can be almost as powerful as dreads. I know Martin geeks who prefer OM/000's and their criteria for purchases is that the braces be 1/4", now that I've had my OM-45for a while I agree.

All the above are choices rather than right/wrong or Martin and others wouldn't have the variety. As far as structural integrity, etc. hopefully the builders will chime in.......

korby
10-11-2009, 07:35 AM
I noticed with the forward-shifted X braced guitars I have you have to play over the soundhole or it looses volume and sounds twangy .

Doubleneck
10-11-2009, 08:07 AM
I noticed that my 1967 Gibson J-45 has forward bracing and your description matches the sound of a Gibson. Are these J-45 forward braced? I look at mine and there is no way that the X could be any closer to the sound hole. I never really hear this in describing Gibson guitars.
Steve

Tim McKnight
10-11-2009, 08:16 AM
When the X is shifted forward, towards the sound hole, the tone is changed ... BUT ... more importantly the entire bracing structure is changed. Forward shifting allows the bridge area to be less stiff which allows the bridge to move a greater distance for the same amount of string energy input. There is a fine line to walk between too stiff and too floppy and finding that structural mean is the difficulty.

Some may make claims that the new guitars are built exactly the same as the pre-war guitars ... BUT ... upon closer examination, that is ... NOT ... the case. They may use the same bracing footprint ... BUT ... they are making changes elsewhere to cover their warranty in case the owner uses heavier strings than they should. There are lots of subtle ways to stiffen the bridge including: thicker bridge plates, taller braces, less scalloping, thicker and taller bridges, thicker tops, etc... So what may initially ... LOOK ... the same on quick reading of the specs ... closer examination of the two structures reveal VAST differences that are not apparent immediately to the unsuspecting.

SpruceTop
10-11-2009, 08:16 AM
I noticed that my 1967 Gibson J-45 has forward bracing and your description matches the sound of a Gibson. Are these J-45 forward braced? I look at mine and there is no way that the X could be any closer to the sound hole. I never really hear this in describing Gibson guitars.
Steve

My recently-sold 2007 Gibson J-45 Honeyburst Koa Custom had forward-shifted, scalloped braces and sounded very loud, full and resonant. I don't know if J-45s have always had forward-shifted braces since their introduction in 1942.

Regards,

SpruceTop

SlopeD
10-11-2009, 10:37 AM
When the X is shifted forward, towards the sound hole, the tone is changed ... BUT ... more importantly the entire bracing structure is changed. Forward shifting allows the bridge area to be less stiff which allows the bridge to move a greater distance for the same amount of string energy input. There is a fine line to walk between too stiff and too floppy and finding that structural mean is the difficulty.

Some may make claims that the new guitars are built exactly the same as the pre-war guitars ... BUT ... upon closer examination, that is ... NOT ... the case. They may use the same bracing footprint ... BUT ... they are making changes elsewhere to cover their warranty in case the owner uses heavier strings than they should. There are lots of subtle ways to stiffen the bridge including: thicker bridge plates, taller braces, less scalloping, thicker and taller bridges, thicker tops, etc... So what may initially ... LOOK ... the same on quick reading of the specs ... closer examination of the two structures reveal VAST differences that are not apparent immediately to the unsuspecting.

Very insightful and interesting.

Glennwillow
10-11-2009, 12:05 PM
.. So what may initially ... LOOK ... the same on quick reading of the specs ... closer examination of the two structures reveal VAST differences that are not apparent immediately to the unsuspecting.
Yes, this is great stuff!

- Glenn

66strummer
10-11-2009, 12:39 PM
Some may make claims that the new guitars are built exactly the same as the pre-war guitars ... BUT ... upon closer examination, that is ... NOT ... the case. They may use the same bracing footprint ... BUT ... they are making changes elsewhere to cover their warranty in case the owner uses heavier strings than they should. There are lots of subtle ways to stiffen the bridge including: thicker bridge plates, taller braces, less scalloping, thicker and taller bridges, thicker tops, etc... So what may initially ... LOOK ... the same on quick reading of the specs ... closer examination of the two structures reveal VAST differences that are not apparent immediately to the unsuspecting.



Do you think this is the case with all or most of the modern day companies that offer forward braced models covered under a lifetime warranty? There are 3 or 4 import brands I know of that come to mind when I think of this, Blueridge being the top one. What's interesting is that 2 of the brands I tried out did not have the tone I was expecting, as they seemed way overbraced. I wonder if Blueridge has altered it's bracing at all since offering a lifetime warranty on the latest models. I'll guess that the original 1 year warranty they offered had to do with forward bracing and speculation on problems developing later because of it. Is a modern made forward braced Martin built "stiffer" or don't you know offhand?

Bruce Sexauer
10-11-2009, 03:53 PM
It is surprising that the are not called backward shifted braces v. Standard braces as the shift was made in that direction in the late 30's, I believe. I have always done my braces in what is currently called called the "forward shifted" way as it seems so obviously correct to me. I've yet to see the reason to change.

brian a.
10-11-2009, 04:15 PM
According to Walter Carter in The Martin Book page 39: Most players stayed with steel-string guitars, and by the mid-1930's, in order to get more volume, they had begun using heavier-gauge strings, which took their toll on guitar tops. So Martin made several structural changes to counteract the problem, the first of which was to move the bracing.... On the smaller guitars the move took place by 1935; on the dreadnoughts it occured in 1939 or '40.... the top bracing on Martins had always been 'scalloped' ... According to the notes of factory foreman John Deichmann, this practice was halted in 1944 with guitar #89926.

page 105: 1935 X-brace moved away from soundhole toward bridge on 000 and smaller models. 1939 X-brace moved away from soundhole toward bridge on dreadnought models. 1944 Braces no longer scalloped.

Brackett Instruments
10-11-2009, 04:17 PM
There's a bunch more going on with the X braces, even if you don't consider the rest of the braces. "Forward shifted" is just a term, and really shouldn't mean alot unless you're dealing with specific Martins. It is a term used alot, but not really accurately. Gibson J-45's have a different angle(wider than Martins) on the "X", as well as a shorter scale. Gibson Advanced Jumbos have an angle wider than J-45's, but a longer scale. What's really changing, with "forward shifted" braces is the location where the "X" crosses under the wings of the bridge. Moving the intersection of the "X" forward, or back changes this, but so does the angle, and scale length.

stringjunky
10-11-2009, 04:42 PM
The construction of my guitar's top is apparently based on Prewar Martins using a thinner than usual top (apparently) which is, centrally, 2.5mm tapering thinner outwards towards the edges. The structural rigidity is maintained by heavier, rounded scalloped braces...I can't use strings heavier than 12's or they will pull it to bits! It sounds as powerful as any dreadnought I've heard but with more balance befitting its body type of 000.

The logic is that the thinner top creates a more responsive guitar and the heavier bracing carries the sustain. Is the thinner top /heavier bracing approach common amongst US luthiers? Is this the 'authentic' Prewar Martin approach?

SpruceTop
10-11-2009, 05:11 PM
There's a bunch more going on with the X braces, even if you don't consider the rest of the braces. "Forward shifted" is just a term, and really shouldn't mean alot unless you're dealing with specific Martins. It is a term used alot, but not really accurately. Gibson J-45's have a different angle(wider than Martins) on the "X", as well as a shorter scale. Gibson Advanced Jumbos have an angle wider than J-45's, but a longer scale. What's really changing, with "forward shifted" braces is the location where the "X" crosses under the wings of the bridge. Moving the intersection of the "X" forward, or back changes this, but so does the angle, and scale length.

Hi Woody B & All,

Another guitar-construction variation that can throw an observer's visual cues off is the introduction of larger soundholes on some dreadnoughts. Generally, a dreadnought soundhole is about 4" in diameter but guitars like Huss & Dalton's DS and D-RH/DM models, Larrivee's D-50/D-60 Traditional models, and Martin's D-28CW Clarence White model, have enlarged soundholes: 4-3/8" for the H&D guitars and maybe about the same for the Larrivee's, and 4-9/16" for the Martin Clarence White (also Santa Cruz's Tony Rice models have this diameter). This gives the impression that the braces are forward-shifted because the enlarged soundhole diameter is closer to the legs of the X-bracing as they pass the soundhole's diameter. The H&D, Martin and Santa Cruz guitars actually feature forward-shifted braces with the Larrivee D-50/D-60 models a maybe but the enlarged soundhole diameter can make the forward-shifted bracing feature seem even more so.

Regards,

SpruceTop

Doubleneck
10-12-2009, 05:07 PM
Tim insight certainly true of my old J-45. Larger bridgeplate for that adjustable bridge. No schallop bracing either, though very thin by modern standards.
Steve

John Arnold
10-12-2009, 05:53 PM
Gibsons have always been forward braced, with a wider X-angle than most Martins. The wider X-angle facilitates the higher bridge due to the shorter Gibson scale.
page 105: 1935 X-brace moved away from soundhole toward bridge on 000 and smaller models. 1939 X-brace moved away from soundhole toward bridge on dreadnought models. 1944 Braces no longer scalloped.
I will insert a correction here. The braces on the 000's were moved the same time as the dreadnoughts (late 1938).
Like Bruce, I have always used the forward pattern when doing a Martin-inspired design, and I have had no problem getting the sound I want. There is a lot more to it than just brace location. Sure enough, if the top thickness, bridgeplate size and thickness, and brace shape are all exactly the same, the forward pattern will produce more bass. But that is not the way things were done in the Golden Age. When Martin shifted the bracing, they altered the scalloping and the top thickness. Shortly after that (mid-1939), they also added a popsicle brace, made the #1 cross brace 60% thicker, and made the neck block 1/4" thinner. Add the narrower neck to the equation, too. These are significant changes, to the point that they probably have as much or more to do with the result than the brace location.

KMClark
10-12-2009, 07:26 PM
Never thought about it but i have 3 different brace placings. the Same template but 3 designated places for the body fret . X closer to the soundhole for what will be considered tight wood and farther back for softer woods. {cedar} Only thing to change are the cantilevers.

Tend to change it for tone also so the rules above don`t apply in those cases..

Howard Klepper
10-13-2009, 01:14 AM
Never thought about it but i have 3 different brace placings. the Same template but 3 designated places for the body fret . X closer to the soundhole for what will be considered tight wood and farther back for softer woods. {cedar} Only thing to change are the cantilevers.

Tend to change it for tone also so the rules above don`t apply in those cases..

Isn't the "body fret" always placed where the neck meets the body? Or is there something else you call the "body fret?" And what parts are you calling the "cantilevers?"

KMClark
10-13-2009, 07:04 AM
Yes the 14th fret or the edge of the neck attachment point , the scale is always the same. If its a 12 fret to body or Baritone its a different template. Tone bars and transverse bracing, sorry about that.