Bracing

Opsimath · Jan 10, 2017

I'm not sure if this is where this thread goes, but while contemplating the non-lefty left-handed unprofessionally-modified guitar discussed in the ebay section, I was curious about the differences in manufacture of a right handed versus left handed guitar where bracing is concerned. I went through Gardman's blog on guitar bracing and those Henkogram photos are terrific! All the guitars shown are right handed and I was wondering if a lefty would have reversed bracing? Anyone with a lefty Henkogram?

Not that it matters in any way if there is a difference or not - I'm just curious.

Thank you.

kakerlak · Jan 10, 2017

I'd think anything asymmetrical should be mirrored on a proper (factory) lefty.

chazmo · Jan 10, 2017

Cynthia, a true left-handed guitar would indeed have the soundboard bracing reversed. I don't know if Guild actually did that for any of its left-handed models, but from what I remember of the process of assembling the body of the guitar (which involved templating and vacuum-sealing the soundboards in New Hartford), I think it would be an easy matter to build them this way. You'd just flip the template over. I'm not sure if doing this would present any challenges for the kerfing (which has to be cut around braces) or the bridge plate. Probably not. I don't think you'd have to do anything different there.

I really wonder if any of us, though, could perceive a difference in tone. I.e., doing this is probably more trouble than it's worth. But, if I were really searching for the perfect lefty guitar, I would want it built that way.

gjmalcyon · Jan 10, 2017

<<deleted>>

Should know better than opine on something I have no knowledge of.....

<<sigh>>

bluesypicky · Jan 10, 2017

chazmo said:
I really wonder if any of us, though, could perceive a difference in tone.

Never had a chance to test this but I'd say you probably would feel a difference, particularly on the bass range.

chazmo · Jan 10, 2017

Probably true, Bluesy! I really have no idea.

There was one fellow I used to know on the AGF who had some custom, lefty 12-strings built by luthier Kevin Ryan (I think) that were absolutely spectacular. Kevin is a very detail-oriented guy who uses a lot of modern, interesting techniques in his builds, and I think he did reverse everything for these beauties. But, a guy like that would probably be one of the few people who could speak cogently about actual and perceived differences of a lefty/righty 12-string (specifically).

It's a very cool investigation, though!

adorshki · Jan 10, 2017

chazmo said:
Cynthia, a true left-handed guitar would indeed have the soundboard bracing reversed. I don't know if Guild actually did that for any of its left-handed models,

Yes they did, at least in Westerly, except for 12-ers, remember that came up a l-o-o-ng time ago .
Can't remember why 12-ers were exempt, or maybe it was that they didn't offer the option of building a lefty 12-er, not as a "regular order option" anyway..
Example: '86 price list on Westerly Guild Guitars:
"Left handed acoustic guitars- Avail. most models-Add 10% to List"
Primarily because the top at least had to be pretty much built as a one-off and the other "lefty" details required a lot more individual attention to that instrument.

chazmo said:
But, if I were really searching for the perfect lefty guitar, I would want it built that way.

Right. The bracing pattern's designed to deal with the unequal tension exerted on the top by the graduation of string tensions across the bridge.
So bass response would be affected if not patterned to deal with it correctly.

Opsimath · Jan 10, 2017

It's fascinating all the tiny details that go into making a good sounding instrument. On the surface they would seem to be not particularly complicated, but it's incredible all the things a good guitar builder and a good luthier have to know! I'm impressed!

walrus · Jan 10, 2017

On the other hand, a talented left-handed player would probably not worry about top or bottom, up or down, and just play the guitar strung upside down. Like, maybe, Jimi Hendrix...

https://www.youtube.com/watch?v=IPtv14q9ZDg

walrus

Christopher Cozad · Jan 10, 2017

The "bass side" of the soundboard is typically under more tension than the the "treble side". Those skinny little solid strands of steel, encased in a spiral wound metal sheath that comprise strings (3,)4,5 and 6 are stretched much tighter than the 1st and 2nd strings. The situation is compounded on a 12 string. In a conventional "X Brace" pattern, two so-called "tone bars" reinforce the leg of the "X" that extends under the bridge on the treble side. Guild 12 strings add a third "tone bar" parallel with the other two.

It is not the only way to brace a soundboard for a steel string guitar, but it is the most popular. The whole world doesn't fall apart if a person strings the guitar up in reverse. That guitar may or may not exhibit structural issues, over time. It won't sound horrible, but it will not sound optimal. Here's a photo showing the asymmetrical bracing, asymmetrical by design. (Remember, you are looking at the underside of the guitar top, so the treble is on the left side of the photo):

Opsimath · Jan 10, 2017

The pickguard is on the top, so this really is a right handed guitar strung upside down for a left handed player. Did he get it from that guy in the ebay thread who is meeting the need of rural lefties everywhere?

I'll bet Hendrix could tune that guitar without a Snark tuner, too. (I love my Snark.)

I think I need to go practice guitar some more. Maybe I'll even try to tune without a Snark and see what kind of mess I make of it. Whatever tuning I end up with, I will be thankful that my guitar is properly braced to withstand the rigorous demands (cough, cough) that I ask of it.

Opsimath · Jan 10, 2017

Christopher Cozad said:
The "treble side" of the soundboard is typically under significantly more tension than the the "bass side". Those skinny little solid strands of steel that comprise strings 1, 2 and 3 are stretched much tighter than the 4th, 5th and 6th strings. The situation is compounded on a 12 string. In a conventional "X Brace" pattern, two so-called "tone bars" reinforce the leg of the "X" that extends under the bridge on the treble side. Guild 12 strings add a third "tone bar" parallel with the other two.

It is not the only way to brace a soundboard for a steel string guitar, but it is the most popular. The whole world doesn't fall apart if a person strings the guitar up in reverse. That guitar may or may not exhibit structural issues, over time. It won't sound horrible, but it will not sound optimal. Here's a photo showing the asymmetrical bracing, asymmetrical by design. (Remember, you are looking at the underside of the guitar top, so the treble is on the left side of the photo):

Thank you! That is fascinating. And thank you for pointing out that this is the underside and treble is on the left. I'm not sure I would have thought to take that into consideration. Also I would have thought the bass strings would pull harder, just because they're bigger.

Again, my goodness but the things guitar experts know! I'm still impressed, and thank you for sharing.

Opsimath · Jan 10, 2017

Okay, I see the bridge plate. What is that around the sound hole? Is that what a rosette would sit on? I would have thought the wood would be all the same to the edge of the soundhole. What is that above the sound hole that is the same material as the bridge plate?

Sorry for the questions. I just like to know how things are made and why they work like they do. I think it's a sickness.

Edit: Just got back from Gardman's blog: Soundhole reinforcement and neck block extension? Why does a soundhole need reinforcing?

chazmo · Jan 10, 2017

Hey, Chris, I may be reading the D'Addario charts wrong, but I think you might have the tension thing backwards. I.e., I think it's the wound strings that have more tension than the unwound (i.e., bass side has more tension than treble side). What do you think?

AoxoA · Jan 10, 2017

Christopher Cozad said:

Interesting.

adorshki · Jan 10, 2017

Opsimath said:
Edit: Just got back from Gardman's blog: Soundhole reinforcement and neck block extension? Why does a soundhole need reinforcing?

Because the cut edge creates a break in the grain, and thus weakens the strength and stability of the top in that area, creating a big potential for warpage/damage.

AcornHouse · Jan 10, 2017

Opsimath said:
Okay, I see the bridge plate. What is that around the sound hole? Is that what a rosette would sit on? I would have thought the wood would be all the same to the edge of the soundhole. What is that above the sound hole that is the same material as the bridge plate?

Sorry for the questions. I just like to know how things are made and why they work like they do. I think it's a sickness.

Edit: Just got back from Gardman's blog: Soundhole reinforcement and neck block extension? Why does a soundhole need reinforcing?

The soundhole is the weak point of the guitar top. That's why the x-brace is necessary for steel strings; it needs to have the strongest structure near the weak spot. (That's why guitars with sound holes in the upper bout(s) can get away without x-braces, and have different bracing.) The soundhole reinforcement can be a ring, as in classical guitars, or short braces that help counteract any fractures from opening. Remember, that soundboards are usually only 1.5mm or so thick.

Btw, the simplest guitars to change from righty to lefty, would be Larrivees; they use a symmetrical bracing system, so only the bridge and nut would need to be changed.

AoxoA · Jan 10, 2017

walrus said:
On the other hand, a talented left-handed player would probably not worry about top or bottom, up or down, and just play the guitar strung upside down. Like, maybe, Jimi Hendrix...

https://www.youtube.com/watch?v=IPtv14q9ZDg

walrus

What is Hendrix doing with the headstock at about 3:03? Is he doing a quick micro tuning adjustment right there on the fly ... Legend.

Christopher Cozad · Jan 10, 2017

Opsimath said:
... What is that around the sound hole? Is that what a rosette would sit on? I would have thought the wood would be all the same to the edge of the soundhole...

It can be. Some builders use three small braces, set back just slightly from the edge of the soundhole, kind of forming a triangle around the soundhole. It is a weak area of very thin wood with a giant hole in it, and no reinforcement can lead to trouble. I like to really stiffen the area, so I use a hardwood ring.

Opsimath said:
... What is that above the sound hole that is the same material as the bridge plate?

That is the fingerboard patch. It is a recent innovation designed to mitigate the risk of those nasty soundboard cracks along the fingerboard, that travel all the way into the soundhole. Most acoustic guitars have a small strip of wood that runs across the upper bout. What you see is carbon fiber plate. It is super strong and super lightweight stuff.

adorshki · Jan 10, 2017

walrus said:
On the other hand, a talented left-handed player would probably not worry about top or bottom, up or down, and just play the guitar strung upside down. Like, maybe, Jimi Hendrix...

https://www.youtube.com/watch?v=IPtv14q9ZDg

walrus

Ah yes, Jimi's 12-string video.
Remember also there's a pic in Hans' book of a receipt from Manny's in New York for an F212-XL, "IIRC", but don't recall if it's spec'd as a "lefty".
I think all these years I've just been happy to know he owned a Guild.
FWIW, on his Strats, his tech Roger Mayer has said they did in fact adjust the saddles and put in a correct nut to get proper intonation.
And he did have some true leftys, like a Flying V:

Bracing

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