Official Luthiers Forum!

Hi,
I'm Ken. I've made about 8 violins and 2 violas. I made a cut down Stradivarius guitar (1/2 scale) for the grandsons that came out reasonably well. Gave it 5 strings, not double courses. I would have made it thinner for myself. But hey; they're kids.
I have a smallish (16") acoustic arch top started. I saw some online by Dan Koentopp, and of course decided to make one. Like it is easy.
I have no fear. That's better than saying no sense.

I have a blog where I've been documenting what I'm doing. https://kensarchtop.blogspot.com I have the back and belly roughed out, but still thick, especially around the edges where it is about 6 mm.

The first question is about bracing the belly. I thought about parallel braces, but I'm using some very cool, very curly redwood, and it doesn't seem to have a lot of cross grain stiffness. Would cross bracing be a better fit?

Do you get the back and belly somewhat close in tune with each other? Most of my violins are pretty close, but some, when I didn't use the "proper" maple and spruce have been a fourth or so apart, and they seemed to work. The flex was there, the wood just had a different voice. The belly right now taps at D4. Hard to tell, it has a higher sound that could be just one that my brain comes up with! I just use an online tone generator, and see where it matches. No fancy stuff. If I had a piano I'd use that. But I don't. The back is higher; maybe F#? It is still way too stiff. The belly is starting to flex some.

I don't go by tap tones. I just use them as a gage to know when I'd better stop making it thinner, and put it together and tune it from the outside.

I'll leave the questions at that for now. Don't want to be a bother.

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Why be normal?

Hi Ken,
You might try digging through the archives for answers to some of your questions. As to tuning the top and back, most suggest not having them close to the same pitch to avoid wolf notes. I haven't worked on arch tops so others may have better advice on bracing schemes.
Welcome to the OLF

Ken, that top is looking good. Can't add much to the discussion on tuning the top of an archtop, but welcome to the OLF and keep the questions coming. There are others here that have built archtops and when they see your post you are likely to get some feedback...

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Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

I did read an interesting post on what to do with your guitars on the first page. I get asked the same questions about the violins and violas I've made. I guess I could easily give them away. No one asks if they can have one. Or find someone willing to sell them for a very high commission! I don't play them! Guitars I can play a little. So they could build up. But one guy at work has already claimed the arch top I'm building. He was upset when I didn't make it left handed. Really?

I haven't come across a wolf note yet. I don't think so anyway. Don't really want one. It should be easy enough to keep them separated. Thanks.

I wonder if I could go in a shop, and play on a cross braced, and a parallel braced and see if there is any difference. On a laminated top would the difference be that noticeable? I like the more open, punchy sound of the parallel on YouTube videos. It might be good to do just to see how the neck/fingerboard looks over the belly, and how the neck fits on the ribs. That whole system looks so weird compared to violins, and it puzzles me some. The only thing I have at home is a classical, and it is a different animal.

Thanks Steve, I bought the redwood from Orcas Island Tonewood, on the guitar specials page. Bruce is a good guy.

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Why be normal?