Official Luthiers Forum!

Lately I've been drawn to the sound of a nylon string archtop. Until I heard a certain album that featured one I never really gave them much thought. I've tried to look around on the net for info, and so far (as much as I can tell), they are made almost exactly like traditional Spruce top archtops. The only differences I can tell by looking at pictures are; they have a glued on bridge like a flat top acoustic, they have a single round/oval sound hole like a flat top, the top is not very arched (couldn't tell from the pics but doesn't look very arched at all), and the headstock is like a traditional nylon guitar.

So I wanted to ask you guys... has anyone here built one? Right now I'm studying traditional archtop construction but down the line I would love to try and make one of these. Do you think I need to be an expert on flat top construction to make one? It seems like it's a 90% archtop beast. I also assume it is parallel braced. One particular example had a nice arched maple back (just like an archtop) and through the sound hole I could see there were no acoustic style braces. What do you guys think? The headstock seems like the biggest challenge.

I'd be interested to see what you've dug up so far. What is supposed to be different about what you've found relative to a regular nylon string guitar?

If the arching isn't much and the bridge is glued on, sounds like a regular nylon string guitar so far.

You've got me curious.

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Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

Douglas, being that I am a nut for the different guitar, your idea is both compelling and one I've been thinking about.
I have one very similar to your description drawn up, with an arched top and back, strung up in super high tension nylon and equipped with a fixed bridge and tail piece, scale length of 24" (or so) and tuned up to "G".
I was thinking of a shallower body, about 3" and amplified with off set sound holes beside the fret board and slotted head. the resulting tone would be bright, yet have a bit more bass tone than my 18" 12 string.
Let me know what you come up with for your design, I'd love to see it.

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Nehemiah Covey
www.coveysacoustics.com

Hey Nehemiah

It wasn't my post starting the thread! Though I am interested in the idea.

I do have a project in the planning stages. I'd be starting on it but have a few others in line ahead of it. Its based upon a Fleta body, but with double cutaways, kind of like a ES335, Selmer style D hole and headstock. It may sound like an odd combination, but I've made a plywood cutout to live with the idea, and I really like it. I'll try and get a picture after the weekend.

Do you have photos of yours? Comments on the results?

_________________
Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

I've built three, but the last one, finished up about a year ago, was by far the most successful. I'm looking forward to making another, to make certain that the last one wasn't a fluke. All three of these were true archtops, with a floating bridge and strings hooked to a tailpiece. I used round soundholes, and X bracing on all of the tops, and there is no bracing on the carved, arched backs.

The first one was built on my 12-fret 000 platform, with a spruce top and Padauk B&S. I'm not going to carve another arched plate of quartered padauk; you can't flex it across the grain AT ALL without it cracking. I used a lot of CA on that one. It's LOUD, which is what I wanted, but it's far too 'edgy' for a classical guitar. I thought maybe that was due to the low damping of the padauk, so I made the next one of redwood and walnut. The results were much the same, if somewhat better. Still too 'sharp' though.

I finally decided that the problem was with the arch height. The first two had archings around 22-24mm high, so I used a 15mm arch (bottom of plate to top of arch) on this one. The top is European spruce, iirc, and the B&S are mahogany, on a Small Jumbo platform. I would not say that this guitar sounds exactly like a 'normal' classical guitar, but it has a sound that is useful for the standard repertiore. Most important, the owner really likes it, where I had to give the first two away.

It seems to me that, as usual, there's a balancing act here. The lower you make the top arch, the 'rounder' the sound is likely to be. However, if you make the arch low then you need to make the top thicker to withstand the downbearing of the bridge, and that's going to cost you power. Of course, a tall arch is stiffer, which makes it harder for the bridge to move it, so you lose some of the benefit of making the top thinner. Chosing a low density piece of wood for the top helps in the weight department, and careful shaping of the arch and graduations is important.

I also think the last one would have been better with a heavier back, so the next one will have a nice curly maple B&S, with another Englemann top.

BTW, if you're looking for a sort of 'halfway house', try making one with an arched back and a normal flat top. Arching makes maple act more like rosewood in some ways, so you should be able to get the sound, make something 'different', and learn about making arched plates at the same time.