Perhaps because so many of the other aspects of classic/flamenco design are pretty much fixed, the aspect of how the top is braced has come under much scrutiny and debate. Certainly it’s a factor, but the expectation that as if by magic some similarity to a Torres will magically appear just because you put the top braces in the same places as he did is folly. When Torres arrived on the scene, the guitar still looked about like this:
This is a guitar in the style of Jose Pages of Cadiz circa 1810. Due to the small size and light stringing, many guitars had no bracing under the bridge, but using a thinner top with, usually, five braces fanned out to resist warping was also common. This shape and size was a holdover from the 5 course guitar whose lowest string was an A. As seems common on stringed instruments, the air cavity resonance of a box this dimension was four semitones up from the lowest note – in this case a C# above the low A. With the addition of the sixth course no adjustment for the increased lower range was made, thus the sixth string could sometimes feel a bit like an orphan.
Unsurprisingly, Torres’ larger plantilla produced a guitar whose air cavity resonance was exactly a fourth lower – G# on the E string – than the guitar of Sor and Giuliani. By giving support to the fundamental of the sixth string, a larger and more symphonic effect was produced, which, while revolutionary at the time, was what should have happened back when the 6th string was added. If we examine the bracing system he used, we can see that the perimeter of the ‘kite’ coincides with an approximation of where the sides were on the previous style. Inboard of that is the same 5 brace fan typical of early 19th century guitars.
If he had made the top flat, the amount of mass at a typical thickness of, say, 2.4mm would have been too heavy for the strings and playing style of the day, so he graduated it progressively from 2.5mm down to as little as 1.6 out past the kite. In order to give this larger panel more stability he arched it somewhat thus employing form stiffness to make up for the thinner construction. Not only was the air cavity capable of lower frequencies but the top also capable of generating them with its larger area and looser edge yet it still had the stiffness in the center to retain the upper register.
Merely making a flat top of uniform thickness and putting the braces in Torres’ locations will not have remotely the same effect. The perimeter will be stiff and inactive and the center weak and comparatively loose, thus rendering the tonal and dynamic range rather narrow. The outer kite would be redundant. This is a case in which arching, graduation and bracing are all interdependent in order to function optimally.
Another school of thought developed around a nine fan arrangement that seems to have originated in Valencia. Rather than retain the old dimensions via the kite, they went to a more radial fan and more radical doming which in my opinion produced a guitar with more power but perhaps less tonal diversity. This is an 1898 Saturnino Rojas which, while a Madrid maker, shows the typical design:
The center brace is slightly offset to accomodate a reinforcing strip under the center seam. The narrow fans are quite widely splayed and quite a bit of ‘real estate’ is unbraced near the perimeter. The arching is complex and about three times what you would see in a modern instrument. This is typical of the ‘guitarra de tablao’ and perhaps one of few surviving examples as they were working guitars not expected to last decades let alone a century. As you can see, it is quite experienced but still plays well, if a bit geriatrically. The center seam is still fine!
At the same time, the standard guitar was smaller and usually braced with five fans:
Typically these guitars would be pitched at a B flat while the larger style would go as low as F#. The one above is a reproduction and has the easy to play qualities of the originals. With less top to drive, a full sound is easy and, while it lacks the big bass boom of the larger guitars, it is perhaps more melodic and vocal up high.
As strings became better and players developed stronger techniques, the Torres model also, in some makers hands, lost its ‘closing bars’ and some of the graduation resulting in this simple seven fan arrangement. A usual feature of guitars by Domingo Esteso, it was used for both flamenco and classics and is still used by many makers today such as Manuel Reyes.
This has become my standard pattern, an adaptation of the ’50s style bracing of Marcelo Barbero which was widely imitated. By adding two smaller fans I find I can more precisely control the area not directly stiffened by the bridge. But in the final analysis it seems as though all these patterns retain the 5 fans under the bridge that dates from the time of Louis Panormo and Jose Pages with additions to accomodate the larger top.
One sees countless variations and experiments, some of which seem pointlessly complex. In the long run it is not so much the pattern but choosing one which is logical and known to work, suited to the purpose, and becoming good at maximizing its potential.