quote:

ORIGINAL:
Why not make a solera? Its not so hard to make one and you seem to be in to the woodworking, otherwise you would not have taken the top off in the first place. I made one in a couple of hours and used the book from Roy Courtnall for the plans.

quote:

personally i see the advantage of doming the top, but i don't think he needs to worry about it right now, esp when basic woodworking skills need to be considered.

quote:

You made a solera in a couple hours?

quote:

ORIGINAL: Ricardo
If I read it correct, only some of the guys that use Cedar tops a lot make a true "flat" top.

quote:

ORIGINAL: jshelton5040

quote:

ORIGINAL: Ricardo
If I read it correct, only some of the guys that use Cedar tops a lot make a true "flat" top.

All of the cedar top guitars we make and all I've examined have domed tops. I don't know why cedar would be any different from spruce regarding the advantage of using a solera. Ricardo is it true that you've never played a cedar top flamenco guitar? What about Ramirez or Gerundino?

quote:

Ricardo,

John Shelton is spot on with his description of how guitars are arched. As I'm sure you know, this is completely different than the strong arching one sees in a lot of American steel-stringed (usually f-holed) guitars.

Torres' guitars were arched as John S. describes, as were the guitars of his predecessors and contemporaries in Spain, but it is a subtle arch -- a few mm. Lay a straight-edge parallel to your bridge and it will be obvious. I have seen 19th century Andalucian gut-strung guitars in the Smithsonian collection (when I worked in their instrument restoration lab) that had 2 cm of arch.

EXCEPTION -- Manuel Ramirez started building nearly flat-topped guitars in the 60's. Segovia's guitar was one, and it was so widely copied that a trend toward flat tops started and arched tops almost disappeared in the "Madrid School" during that time, and they still tend to be flatter than the Granada school. These near-flat guitars were a departure from Jose Ramirez I guitars, which were arched like Torres'. Segovia's M. Ramirez had a cedar top, too, and I've heard it said that the reason M. Ramirez started making those flat tops was that cedar was too stiff to bend easily; luthiers: is this true in your experience? I have an arched cedar, and I don't think they are a particular rarity these days.
Dieter Hopf makes cedar tops and is renowned for his precise control of the arching, but his are designed to draw level under tension. His principle seems to be that the top should be just strong enough to resist deformation by string tension (no stronger) and free to vibrate in both directions.
Cedar tops were virtually unknown before M. Ramirez, but they got a reputation for loudness that made them popular with professionals who followed Segovia into the large concert halls. My personal experience tells me the loudness difference is overrated, if not fictional.

Of course nowadays, there are a lot of cedar-topped negras and classicals made, but cedar-topped blancas are a relative rarity, at least before the 80's.

I' be interested in the Foro luthiers' opinions, but I suspect the arch works like an architectural arch to stiffen the top and force it to vibrate as a "rigid" unit -- at least more so than a flat top would, which is structurally more free to bow inward and outward in response to string vibration. Thinning an arched top at the edges and arching it in the middle causes the whole top to (tend to) move as a unit since it CAN'T flex inward (much) any more than an architectural arch could, so it flexes more around the edges, while a flat top tends to "flap" both inward and outward. (Think of the whole arched top jumping up and down rather than flapping in and out). I'm exaggerating the difference, obviously, since cedar tops (reportedly) compensate by gaining stiffness from the material rather than from the arch design (so take words like "flap" and "rigid" as illustrative hyperbole) but I think this structural behavior may be responsible for the greater punch in arched-topped (mostly spruce) guitars. They can be thinner (Huber reports that flat cedar tops average 10% thicker than spruce) and yet still be stiff; less mass means they accelerate faster in response to bridge vibration. The arch architecture means they accelerate as a unit. Sounds like a recipe for punch to me.

Anyway, the Granada school generally stuck with the (Torres/Jose Ramirez I) arched design. Shifting bracing around can result in refinements (Mike Kasha, a physicist here at Florida State U., where I teach (not music), developed some pretty radical brace design innovations that really made his guitars loud, but the off-center hole looks too unconventional for my taste), but I will go out on a limb and say that the combined effect of the arch and the reduced mass on sound is major (compared with fan bracing arrangement).

Huber's book says that the Granada school arched top is much more sensitive to string selection (compared with flat cedar) because of this tendency to vibrate as a whole unit. I'm not quite sure I understand why that should be, but my guitars (all but one are arched spruce) do sound very different with different strings. The cedar one (Rafael Morales of Granada, 1972, also arched) doesn't seem to change much with different strings.

quote:



Remember I said "some of" meaning, well, J. Ramirez III I guess. Point being most guitars are not "flat", so why would you want to make a flat one??? I have owned Ramirez in the past, and played pedro de miguel and Gonzales guitars that are Cedar top flamencos, but at the time (meaning not long ago), I never was aware about the dome thing behind the bridge.