type of bracing used with oval hole archtops

[Greg Martin]

Im halfway complete with my first 17"er and got a request for another one--- yea !!
He wants an oval sound hole in the upper bout. Im wondering 3 things. does size of the oval hole change tone/volume, would you back the rossette with spruce, and would you use a x brace or something different. it would have a floating pickup too.

[Patrick Hanna]

Hi, Greg,
You've probably read Bob Benedetto's book on arch top construction. In it, he expresses his view that the field of oval hole arch tops is not yet well-explored, but the field is wide open to experimentation. He seems to me to have the view that this experimentation will be fruitful. His book was written in the 90s, so there has been a lot of experimentation since then. I'm sorry to say that I can't advise you about your particular questions. I hope someone with real experience building oval holes will chime in. I will be watching the thread with you--and with great interest. Arch tops fascinate me like no other guitar does. Frankly, I have the hunch that the general rule will apply: X-brace allows for a mellower tone. Parallel braces allow for a brighter, punchier tone. Both are good. Common intuition suggests to me that an X-brace allows more open room in the upper end for an oval hole.

Realize this, though: None of that is based on anything more than intuition. I sure hope someone else chimes in soon. Best of luck to you and please let us know how it comes out.

[Michael Lewis]

Steve Andersen has made and may still make archtops with oval hole in the upper bout. It adds a bit to the bass response of the box and helps fill in the lower range of overtones if the rest of the instrument is also agreeable. There is no ONE THING that will guarantee you a specific tonal result, it is THE WHOLE with all the parts working together.

The size of the hole does make a difference, smaller gives a lower resonant frequency of the air chamber, but too small chokes the sound.

You can make X or parallel bracing work, it sort of depends on what 'color' you are looking for in the tone.

[Dave Stewart]

All good advice.
FWIW I made one, using an X-brace (which you have to open up quite a bit to clear the oval) and a transverse brace. Bit beefy in hindsight, but it worked out well.

[Paco Jimenez]

Solomon uses three fingers kinda fan for his great Phidelity.

Old Gibsons had parallel (more an inverted Vee than actually parallel) before the X was introduced by the early '30s.

does size of the oval hole change tone/volume

Of course, like in any guitar. Smaller holes soud bassier, big holes sound brighter and more open. Don't go too big as a start. follow the classic sizings as a rule of thumb, perhaps a bit smaller. You can always enlarge it progressively by small steps each time until you find your sweet spot. You'll notice when the low end starts to be a bit short for your taste at a given point. Then bind it to make it a bit smaller matching your exact favorite size. If you check pre and post '28 Gibson L-4 guitars you'll find two common successful sizings for either a warmer or a bridgter response.

PS, Don't forget that the 14 frets shifted the soundhole noth. More clearance for an X.

[Greg Martin]

wonderful info on the L4 oval hole size Ill check it out .
I saw a guitar that used what he called a "K" bracing system for upper bout holes that seems to draw me in. If I were putting the hole in the middle then Id use a spread x brace for sure. I guess the key to anything untried is to be conservative, I guess my goal is to open the sound up for the player.

[Darrel Friesen]

I made and braced one the same as Dave has shown (although with considerably less skill It is a great sounding guitar and has been my main player for a few years. I used a K & K pickup on it as well and really like it. I also added an upper bout soundport. I bound the soundhole but wouldn't think a backing veneer would be required regardless. I used the Paint program in windows to make the oval template. Too easy.