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I was wondering what effect does radiusing a soundboard have on the sound quality of a guitar?  My thinking is that introducing a radius will increase the strength of the soundboard allowing for it to be built lighter and resonate more freely.(please correct that thinking if i'm way out there)  Having only built a few guitars, they have all been flat topped.  I am begining to toss around the idea of using a radiused top, but is the extra effort really rewarded through better sound and are the differences that noticable?

Thanks for any help,

Nate

Are you using completely flat top with flat sides? (I think I heard somewhere saying Kevin Ryan builds flat top, flat sides guitars. True?)

According to the Huss and Dalton folks, having dome top with domed sides brings out more mids, while dome top with flat sides brings out more bass. I am not sure what happens when you have flat top and sides?

 

I know James Olson builds flat tops. There are only a handfull of guys out there doing so.
I think the potential would be to lose a bit of bass with a domed top. That is because by doming it, you are essencially making it stiffer. But you also won't have it completely cave in in a short period of time.

I've always been told to build "light and stiff". Doming a top is one way of achieving this.

Kevin does indeed build flat topped guitars. He said it hasn't caused him problems after ~400 instruments, so I think he's sold on it. Kevin and Jim Olson have been friends for a long time, so there's probably some cross-pollination of ideas there.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Do you know if builders like Olson dome/radius the back at all?

Olson does 15 foot radius dome for the back. It sounds like he is keeping the top flat however, based on what Paul and Bob said.

So Olson and Kevin Ryan has flat top/side guitars. How do they sound different from others? Olson sounds very even to me, with not ton of bass but with sparkley treble, and it doesn't have that sort of nasally mids that alot of Martin OM/000 copies seems to have. I never played Kevin's guitar before. Do they sound smiliar to Olson than let say Martin OM/000?

The late Arthur Overholtzer made arched top & back guitars from 1965 to 1969, then apparently made all flat top and back guitars. One of them won a prize - according to his book. Of course he was very controversial in his time. He advocated joining tops & backs without any clamps at all. He said that the drying glue would pull the plates tightly together. (Who does that now??)

Ray

I have it directly from Kevin Ryan himself that the reason he builds tops with no radius is - and I'm paraphrasing, but closely - if you build your guitars just like everyone else, you can probably expect it to sound just like everyone else's. He also said he believes that introducing an artificial arch into a top limits the ability of the top to move freely, which reduces sound.

I plan on building only for myself, and my guitars will stay properly humidified at all times...so I don't fear the implosion that so many people worry about. If I were building commercially, a radius might make perfect sense...but then, most people who are making the significant purchase of an Olson, or Ryan, are probably somewhat well versed in guitar knowledge and know how to properly humidify a guitar. Of course, I could be wrong.

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Eagles may soar, but weasels don't get sucked into jet engines.

Structural stability under changes in humidity is not the only reason to put an arch in a top - check out guitars made by the Larson brothers, Stefan Sobell and others. If you want a top that moves really freely then find the floppiest one you can. An arched top doesn't I think reduce sound - think of a tightened drum skin - but it certainly gives a different sound.

I would guess that a guitar built with a flat top will arch to some degree under string tension and over time - certainly the photo's I've seen of a number of old Martin's built this way show arching.

Kevin and Jim make some great guitars, but so do other builders that arch. That's the great thing about guitar makers - there is more than enough room for all sorts of methods used by builders to produce great instruments.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010