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I have 3 plans that show 3 different top bracing approaches. Is anyone familiar with the Cumpiano, O'Brien, and LMI classical guitar plans. What do the differences add?

The main difference is that O'Brien and LMI have a lower cross strut that is diagonal whereas Cumpianos is not. There are some minor differences around the sound hole as well.

Thanks,

Doug Ubele

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It's real easy to over-think this stuff at first, and worry about small differences. If you haven't made one before, or this is your first 'from scratch' after a couple of kits, I'd say just pick one pattern and go with it, and don't worry too much about those small differences. Each maker has a sound thay are going for, and their own ideas about where it comes from. They make changes based on their acoustic model until they get what they want. If you build carefully and use good materials you will probably end up with a pretty nice guitar no matter which pattern you use, although it's likely that it won't be a lot like the guitar it's based on. No two cooks make the dish come out the same. After a while you'll get ideas about what's making the sound and how those other patterns work, and then maybe you'll switch, but don't sweat it now.

I would tend to agree with what alan says. In addition, there are many many different patterens for bracing a classical guitar top. Most anything you pick will give adequate results.

If you're not really into classicals and just building it because, then just pick one (plan) that appeals to you and do your best. If you are into classicals then you could try to find samples of what different builders guitars sound like and after finding one that's pleasing, try to build a replica. Remember, however, like Alan said it may not end up sounding like the guitar it's based on.

That lower cross strut is used by some builders to shorten the vibrating area on the treble side of the guitar. This stiffens that area and, theoretically, (sp?) makes the instument's trebles better. Some would disagree. Torrez and Hauser used a pattern closer to that of Cumpiano's. Many other equally great guitars have been built with that angled cross strut.

Check out "Making Master Guitars" by Roy Courtnall. Lot's of good info on classicals there.

[QUOTE=dubell] I have 3 plans that show 3 different top bracing approaches. Is anyone familiar with the Cumpiano, O'Brien, and LMI classical guitar plans. What do the differences add?

The main difference is that O'Brien and LMI have a lower cross strut that is diagonal whereas Cumpianos is not. There are some minor differences around the sound hole as well.

Thanks,

Doug Ubele[/QUOTE]

Doug,

There are many things to take into consideration when bracing a classical guitar top; species of wood to be used, thickness and stiffness of the top, sound you are trying to achieve etc. In my classical guitar building DVD I show the LMI plans but you will notice that I brace the top using a FLeta design. I do this because the top I was using was cedar and the Fleta design lends itself well for this. When I build using a spruce top I use a design similar to the LMI plans with a few slight changes.
I suggest you pick a design and see what results you achieve. On your next guitar make some changes and see what the differences are. With time you will favor one type of design over another and then can refine that design.

Doug,

What Alan and Ronn said. My advice? Start out with THE plan that's the grandfather of all modern classical plans -- the 7-fan pattern by Torres. If you look at the plans by Hauser and Ramirez I and others, you'll see that they are all basically very close to the original Torres design. The bracing pattern that Cumpiano shows in his book and the one that Sloane shows in his book, Classic Guitar Construction, are essentially the same, and are both based on the Torres 7-fan pattern.

Sloane adds the diagonal cross struts, as did Hauser. So do I, when I'm building a guitar using this traditional pattern. I do so because I shape my braces in a dish, and I think the diagonal cross braces at the bottom help somewhat maintaining the soundboard's arch. The different treatments up around the soundhole will not affect the sound in any significant way. I don't install the reinforcement strips; instead, I install a "donut" around the soundhole.

One reason why the Torres plan is still so enduringly popular is because it works so well. Start out with a good selection of woods, install the 7-fan pattern, and chances are very high that you'll wind up with a very nice sounding instrument.

Best,

Michael

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