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The last few builds I've done, I started toying around with getting closer to actually voicing the plates. The last one was chladni tuned and I really enjoy the tone right off the bench. It has a distinct, full, warm, yet balanced and projective tone.

Trouble with that build was it had asymmetrical (traditionaly lower legs) bracing which made closing the ring on chladni tests a real bear.
So, I came up with this; inspired by Alan Carruth's bracing from his video on free plate tuning. I tried to avoid 90 degree corners, sharp points where tone could get lost, strengthen up the area around the sound hole with the tucked A frame and I let all of the braces into the X. I really believe that will help the most as the entire bracing scheme can move together.

That said, has anyone else tried a double-X-A-Frame-splayed-finger bracing pattern? If so, what did you note in terms of tone?

The braces look monstrous in the photo, but they are just 1/4" braces, 1/2" tall or shorter and are fresh from the go-bar deck so things are still quite messy. I've since tapered the ends and cleaned things up. I won't let the X braces or the fingers into the linings. They will be feathered into the soundboard 1/2" - 1" out from the linings.


Thanks in advance for any advice anyone might be able to lend,

Dave

I beleive Gibson used a doulbe X at one time, but probly not with the A around the sound hole.

[quote="Dave Livermore"] ..... Trouble with that build was it had asymmetrical (traditionaly lower legs) bracing which made closing the ring on chladni tests a real bear.


Dave

Imagine a line joining the points where the lower X-brace arms intersect the edge of the top. Any bracing below that line will tend to open the ring+ near the finger braces. If the bracing is to the right of center, the ring+ will open on the left side. With a typical Martin style bracing pattern, the lower ends of both tone bars extend below the line on the bass side and usually cause the ring+ to open on the treble side. The lower brace is especially influential. If you taper the lower end of that brace off, the ring+ will close a lot easier. Leaving a scallop peak on the lower end of the lower brace will cause serious problems with the ring+.

On my guitars, I solved all this by running the tone bars horizontally, straight across the grain. One is behind the bridge plate and the other connects the lower ends of the X braces. Yes, my bracing looks a lot like the Larrivee pattern.

The double X has the potential to open the ring+ on both sides unless you you taper off the lower ends of the braces significantly. Otherwise I think it is a good pattern. Al Carruth has built some great sounding guitars with it.

Mark

Thanks for the info and reassurance Mark.

Todd had me thinking I had just built a Hummer of a top and that it was doomed. However, upon some thoughtful reflection I came to the conclusion that Gibson built a ton of crummy sounding traditionally braced guitars too. So that comparison is moot. I'd prefer to believe that I can make one sound similar to a Carruth rather than a Gibson.

Dave

There are crummy and awesome sounding examples of nearly every bracing scheme out there. I think the particular bracing pattern itself is largely irrelevant as far as a tone producer. Even that Kasha/Schneider design eventually produced some decent sounding guitars, although Richard Schneider reportedly abandoned the system in his later years and went back to a more traditional design.

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Old growth, shmold growth!

You may still want to tuck the upper x ends into the linings along with the UTB for stuctual integrity...

At the A.S.I.A symposium last week there were several guitar tops that had been replaced. One was a Gibson double X. The Gibson double X braces were almost as tall and as thick as the upper transverse brace. They were huge! After looking at this top, I've come to the conclusion that you can't draw any conclusions on the merits of the double X by looking at Gibson's

If you tune your plates at all you should have no problem. Al's guitars are very responsive with a wide spectrum and balanced tone. They had a kind of kinship with Mark Blanchard's guitars even though he uses a different bracing pattern. I think closing up the ring+ is the key to that sound.

I have a guitar on the bench now that is almost the same bracing pattern as Al's Closing up the ring+ mode was pretty easy and I did it several times as I lowered the ring+ frequency.

Dave;
If you need a bit more reassurance... A few years ago, I re-topped an early 60's Gibson Gospel that had a similar bracing pattern to yours. The top was cracked in several places, but sounded surprisingly good.
Once I pulled the top, I was amazed the thing had any tone at all. The bridge plate was 1/4" hardwood ply & filled the entire space between the two sets of X braces. All of the braces were massively thick (and high) &, other than a taper towards the sides, no attempt had been made to reduce the mass. (They were roughly rounded on the top.)
Once removed, the top had all the tap tone of a knotty pine 2 X 4.

I believe the actual bracing pattern is a very small part of it. It's the overall stiffness, weight and resonance of the plate, as well as a bunch of other stuff that comes into play. You can do things that totally change the voice of a guitar without moving a single brace. I'm sure there's builders who can make a double X pattern sound great. I'm also sure there's builders who can make.....any pattern sound bad.

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I actually found out about the Gibson disaster at Sylvan Wells' talk at ASIA...the room wasn't very receptive to the idea. I asked if he'd tried it because that's what was on my first acoustic (built while studying with Al Carruth) and the thing's a cannon, but it's pretty clear that Gibson's failures have ranged much further than smaller luthiers' successes

Judging by the one I built, as well as the ones of Al's I played and heard of, the pattern has much merit if used properly. I like it because of the symmetry, which is an aid if you're using a 'guide' to tune like the Chladni pattern, or if you have a really good intuition for how the stiffness is affected by your carving.

As others have said, a good luthier can make most bracing patterns sound good and Gibson has succeeded at making all kinds of things not work throughout their history.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

+1

Other than the sound, I'd be concerned about poking a bridge pin through a brace or two - unless you're planning a pinless bridge.

There's nothing inherently wrong with a double X.

As to how it sounds, the answer is that in your hands, it is very likely to sound like a Livermore.

How is tone supposed to get lost in a sharp point? I'm not at all sure what that means.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Lot of highest grade classical guitar braces have knife edged tops...

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Build log

Thanks for all the responses. Howard especially. Best answer I've heard so far.
I was hoping someone could say that it needs to be tweaked one way or another to enhance bass/treble/mid response or that it has a more/less balanced sound than the traditional counterpart.
However, I'm assured that as long as I follow the rest of the rules and techniques that I use, it should be just fine.

As for Alexandru's question, I can't remember where I heard that. But I definitely heard it someplace.
Avoid sharp corners and ends where the sound waves could potentially cancel out each other or something like that.
As a result, I've always sanded corners down and tried to avoid 90 degree brace meetings.

Surely if I do all of those things, this guitar will turn out sounding like one of my guitars.

Dave

Dave, I have a 0 size that is waiting for the nitro to cure with a bracing pattern close to what you are doing. My lower x intersection was a little lower and only one finger brace per side, since it is a 0 size. I won't know how it sounds for a couple more weeks, but the ring + mode was easy to close and keep closed, with a nice rounded shape, as I lowered the frequency.

Chuck

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their is a David Taylor build thread on th AGF where he uses a vary similar bracing pattern.

Brent

My 1976 Mossman 12-string has a double-X bracing system and it sounds wonderful.

This one is nearing completion and has a sister with trad bracing so will let you know

To my eye your X is set kind of far back (toward the tail), and your lower face braces are crowding it. But all kinds of things turn out to work well.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard,
The X is exactly where the Antes plan puts it. The rest of the braces have been traveling for a few years now.

Good news is, I spent some time voicing this thing yesterday. It rings like a gong!

Does anyone have a range where the ring+ mode should be? I down just under 250hz right now and am worried I could be making it a little weak. The X is still .5" tall (at the X) and tapers from there to the lower bout. Upper X legs will be tucked in the lining.


Dave

I don't think that is a sufficient reason for putting it there.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

But Howard, that's the way Martin does it. So it must be good!

Regardless, I got the pattern to close up and it rings like a gong. Here's where it all ended up.

I look forward to hearing about how that sounds when it's done.

why angle the finger braces (as in your original pic)? Though relatively new I would tend to trust the lower brace method of Martin guitars and leave it at that. Why re-invent the wheel? Just a thought.

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.