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Are there any good reasons to using an X brace for the back? This is the alternate bracing scheme for the OLF SJ.



I can see how it might be stiffer, and change how the back might react to changes in RH. Thanks!

Alex


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It looks cool!

Thank you for such a thoughtful and indepth response, Danny! Ya, I think so too!

Alexx

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"Indecision is the key to flexibility" .... Bumper sticker

It would certainly be robust!

The neck block looks undersized to me. Is that typical of the SJ?

Regards, Michael

X-braced backs can vibrate in a different way then ladder braced ones. They can thus sound a bit different. Better? Maybe. That's a value judgement.

I'm planning something different for the neck block, Michael, so it will be larger.



Unfortunately, being my first build, I don't have anything to compare with, Alan. If nothing else, it might look more interesting looking through the sound hole. The back will be quilted maple BTW.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

X braced backs could help prevent the back from subdividing into out of phase modes of vibration. I have two in the works with backs like that. I don't expect earth shattering effects though.

Would you retain the lower bout spar brace as drawn?
I know that my ukuleles are a different animal but it looks over-braced to me.

Bob

I thought the same thing, Bob, but because my experience is zero, I'm open to suggestions.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

I've used X braces on the backs of a few jumbo. My thought being that this would tighten up the back and keep the guitar from getting too "boomy". It seemed to work, but as others have stated I'm not sure it made a huge difference. I've only used this method a few times when the customer was specific about not wanting the guitar to be "boomy". I usually ladder brace my jumbos with good results.

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If this is your first build, I would stick to convention. Jumping into extremes in the beginning is more confusing than helpful.

Very true, Haans. From a woodworking point of view, the X brace pattern would be enjoyable to do, but it would be a roll of the dice, sound wise.
If this build is reasonably successful, #'s 2 and 3 will be gifts, and made from sister sets. That might be a chance to alter the bracing, and see how the sound is affected, if at all. I'm learning that there are very few things in guitar building that are definitive. And that is good thing!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Trust me Alex, after dozens of X braces, they become boring too...
After your first instrument, you may be able to draw some conclusions. Taking small steps one at a time is the way to go from there unless you are quite dissatisfied with your first. Wild swings and multiple changes are for "wiping the slate clean" and starting over.

on the guitars that i build that are not "traditional" i go with a double x brace of mahogany. for me it makes for a back that is extremely even in it's tap tone through out and seems to strengthen the center of the "diaphragm" if you follow benade's theory on how the guitar's top and back act as "drum heads". with the edges of the plate properly detailed in terms of making an active back, for me i like the results. having said that through, all attempts at making an active back and having it act as an "energy flywheel" are null and void once the player quenches the plate with their body.

i have a pet theory that the early makers of guitars chose a row boat for a back bracing scheme, and a barn door for the top bracing scheme.

Guess Oscar Schmidt & Co. just went for the row boat...

[quote="arie
on the guitars that i build that are not "traditional" i go with a double x brace of mahogany. for me it makes for a back that is extremely even in it's tap tone through out and seems to strengthen the center of the "diaphragm" if you follow benade's theory on how the guitar's top and back act as "drum heads". with the edges of the plate properly detailed in terms of making an active back, for me i like the results. having said that through, all attempts at making an active back and having it act as an "energy flywheel" are null and void once the player quenches the plate with their body.

.[/quote]

I really dislike the drum head analogy
For starters, drum head vibration is a lot more complex than most people realize
Secondly, we do not have, on a guitar, an extremely flexible membrane under tension.

On the historical point... The X bracing is a fairly modern design in guitar building. Until very late 19th C., most tops used some derivation of ladder bracing (including those of Stauffer, who trained CF Martin). I agree with Haans, I would choose a plan to start with, and stick to it for several builds; maybe make tiny adjustments one at a time. Let your builds evolve slowly until you fine your voice. On my first build, I went with the Hauser plans (I build classicals) with decent results, then on my second, I had a radical concept for a hybrid fan/lattice brace. That guitar came out pretty terrible. I plan to go back to that concept at some point now that I've gotten pretty comfortable with things that I already know work (hauser, Torres, etc), but when I built that second one, my skills just weren't there yet.