Official Luthiers Forum!

I've had a few discussions with Dave White, he always says he doesn't like ball shaped guitars and this has got me thinking as I never really understood why. I haven't used radius dishes as I couldn't afford to get them shipped to the UK and I haven't the equipment to make them, but now I'm wondering if they can actually harm tone.

My reasoning goes like this and please feel free to correct me if I'm missing something. When wood is flexed across the grain it's quite weak and needs bracing and I imagine that's why ladder bracing was once popular as it looks obvious, yet along the grain it's quite stiff and needs less bracing. A radius dish though actually applies a uniform type of bracing across and along the grain not taking this into account.

Now I don't know if this is such a small amount of stiffening that in the final bracing that it's negligible, but it's certainly something to think about isn't it?

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Formerly JJH

I learn more from my mistakes than my successes

Well John, that's a bit of a blanket statement that is sure to rattle a few cages, I'm sure.

I've played many guitars with radiused tops and they sounded absolutely fantastic. Structurally, a dome is stronger than a plane, so this is the reason for arching tops. You can make the top thinner and still maintain the same stiffness with less mass. Less mass equals more movement (up until you reach a point of diminishing return).

Now, I know of some very high-end builders who don't arch their tops. Olson comes to mind. I've never played one personally, but their reputation is legendary. What gives?

I think the key in building a tone monster is finding that minute edge where you can balance responsiveness, projection and tonality, all the while providing enough structural integrity to stay implosion and foster longevity...

Whether you arch your top or not is purely arbitrary, I'm certain. You have to find what works for you, what techniques and architectural thoughts appeal to your guitar building worldview and then you have to practice. Practice makes perfect, but I'm certain that if you ask any builder on this board, they all have different perceptions of perfection, but they probably all have this thought - The next one will be better...

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

I have played an Olson, and a Hoffman. They were wonderful instruments. Is radius building necessary, no. Then why do it?

Basically folks love the sound, more piano-like say some. But the main reason for doming is to help the guitar remain structurally sound in wet and dry conditions all must endure for longevity. Domed structures resist the bellying behind the bridge and sinking in of the soundhole found on many, not all, vintage guitars.

We're just trying to build a better instrument that will stand the test of time. Stradivari built archtop fiddles. I wonder if the few guitars he built were flattops? Just a comical aside to your question.

Go ahead and build 'em flat, you may be one of those people 400 years from now that is held up as an example of those who didn't go with the flow. We'll all respect you for it too, that is, if you build some great instruments.

I built one flat, the rest are all domed. Can you borrow the use of a router and a bandsaw and have you any glue and a couple screws. You can easily build some dishes for guitars with no shipping. Lots of info out there. Cheers to you, Bruce

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http://www.dickeyguitars.com

Was it plywood or MDF?

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Aoibeann

Why would a domed top made in a radius dish sound any different than a top with the same dome made without a radius dish?

It seems like this question is really about the differences between flat tops and domed tops.

They do sound different.... but "Better" or "Worse" is not the right description.

So far, I have built both, and like the sound of both of them.

I feel like there are trade offs with domed and true flat tops... and you can use those to help build the best guitar for a specific playing style.

Good luck

John

Heres an interesting topic between among others John Arnold and Willi Henkes on the subject. The comparison with H&D flt vs arch is interesting too...

http://theunofficialmartinguitarforum.y ... 802?page=1

To get this back on track. John starts off mentioning discussions with Dave White, commenting that he doesn't like ball shaped guitars (those built in a radius dish). The dish gives you a dome shape, it's arched in all directions. Dave builds with a strong arch, usually 10' radius, but it's only across the grain, not lengthwise, giving you an arched/cylindrical top as opposed to a domed top.

So the question is not dome v. flattop, but dome v. cylindrical top.
What do you think?

Joe

My opinion is a "domed" top is stronger. It's also more resistant to humidity problems. Properly built it allows for lighter bracing, and a thinner top with the same strength. In the end there's more than one way to build a great guitar. Build 'em the way you like 'em.

Added: I didn't read the UMGF thread, but I'm pretty sure all of H&D's tops are arched. The rims are left flat on the "Traditional" models.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Howard Klepper,where are you when you are need? Howard and others use an arch rather then a dome. Think this may be the way to go given the reaction of wood due to changes in RH.

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A person who has never made a mistake has never made anything!!!

I just checked in, late as usual. I've been out in the shop building. I have only one commission, so I figure I'd better go ahead and do it.

I don't know what you are all talking about, but I'm against it.

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https://www.facebook.com/profile.php?id=100008907949110

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Bill Hodge


One does not simply, own enough guitars!

isn't the idea to use the "dome" to produce an arc which is stronger than the same thickness when flat? The dish allows a thinner back and top. I guess that doesn't automatically trasnslate into better tone or volume.

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Greg
http://garibaldiinstruments.com/

Great topic!

Since we are discussing the affect of radius on tone, I would sure love comments on the following quote from Mario that I read in an archived MIMF post:

As for the amount of the dome, this is another place where you can manipulate the tone of the instrument. Tighter radius in the back will produce a deeper bottom end, while flatter will brighten the instrument; opposite for the top.

That is an interesting statement. What do you think creates this effect? Does the tighter radius produce a more reflective back instead of responsive?

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Formerly known as Adaboy.......

Mario saying this does not make it so.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Mario saying this does not make it so.


Joe

Make two sister instruments;
sister cuts of wood ;same thickness tops -etc.
Same weight pieces.
One with the top & back with a radius(done in a dish) and the other flat.
Use modular templates with the radius you want to arch the plates.


Then choose which one you like.

Then you'll get a better idea of how you want to make your guitars.

Mike

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Mike Collins

What Mike siad, except I think you;d need to make ten or so each way to be reasonaby sure. It's hard to make 'identical' guitars even when you match everything as closely as you can.

As a New England builder, I dome the tops for self-protection. Flat tops tend to crack more in the dry winter air, and I hate having to fix my guitars. I'm willing to accept the possiblity of some minor degradation in the sound for that peace of mind. I don't have lots of folks lining up telling me how bad my guitars sound, in any case. I'm not going to say it's all fiction, but I'd need more that one person's say-so, even Mario's, to believe it.

I can see the argument if you're talking about using an egg-shaped dome rather than a spherical one. The logic being that elongating the arch in the direction of the string pull provides better resistance to it. Maybe..

Bri

That's not really a fair comparison. I've done "identical" guitars, or as "identical" as I can make them to test some other stuff, but I believe the domed top can be lighter than the flat top. If the strength is the same, with the lighter top, the tone might even be the same. Alot of this stuff is too complex for my simple mind anyway. If the desired result is a great sounding guitar that doesn't self destruct, I believe there's more than one way to do it. I perfer to "keep my head down" and concentrate on building the way that works for me.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

What Al says about resistance to cracking is important. A domed top can shrink a little more without failing, and that's a big plus for survivability.

The 'arches are stronger' argument doesn't work here, though; relative to string pull forces the arch is 'upside down'. It's easy for something to get out of an eggshell

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

We can't let this discussion go to far without considering building an arched top.......then gluing it to a flat rim (don't radius the rim with the dish). This pre-stesses the top I assume.......and I've heard this is how Martin builds their guitars.

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Formerly known as Adaboy.......

Woodrow;
That post was meant to stimulate John to do some experimental builds to find what works for him-like you stated.
Did you keep stats. on all thicknesses and such ?
How did you sister guitars come out?

Mike

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Mike Collins

Ever see a Karate kicker kick an arched piece of wood?
NO -it's much stronger than the flat piece.

Mc

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Mike Collins

I never saw one kick a 3mm piece, either!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Stronger in the same way are arched bridge is stronger than a flat one.

The question is how does that affect the tonal properties. Afterall, we aren't kicking our guitars, we are making music with them.

My ear is not and will probably never be refined enough to tell the difference tonally between different grades and types of wood, and I agree with the higher grade tops looking boring (especially englemann). Many consumers are trained to look for this 'plainness' or consistency in their tops. Esthetically, I personally like a little color variance in my tops. Of course if I were selling guitars, I'd probably be more inclined towards 'boring' I guess.

I recently bought a couple of red spruce tops from John Arnold that were considered "B" or "A" grade. They are stiffer than either of the master grade sitka or englemann tops I recently braced. The only thing 'wrong' with them are some light color streaks running parallel to the grain across both boughts. To quote John, "It will make a find sounding guitar"... and I'll add that I think it'll make a nice looking one too!

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Jim Hansen