Just curious, but a lot of flattop guitars have scalloped bracing. Anybody know if it would benefit archtops, or if it's being done?
Brad
Brad
Bracing
- Thread starter Brad Little
- Start date
A quick google search of guitar bracing came up with a couple of interesting general resources on bracing patterns:
http://en.wikipedia.org/wiki/Guitar_bracing
http://www.esomogyi.com/principles.html
but do not answer your specific question. At least these are a starting point.
To generally address your Q, I would start with the thought that flattop bracing stiffens a rather thin top plate being loaded primarily in bending at the bridge resulting from the string pull. In general, bracing stiffens the plate against excessive deformation caused by string loads and prevents string-fret alignment issues. The out-of-plane plate deformation pattern would be an "S" curve in the top plate with the bridge at the center of the "S", and the string force also might cause other buckling wave patterns, as the plate is also in in-plane compression between the bridge and neck.
However, an archtop top plate is loaded primarily in out-of-plane compression (downward string force applied through the bridge), as well as in-plane compression between the neck termination and the tail piece attachment on the guitar's bottom [side] rib. The arched top plate is inherently stiff in out-of-plane compression when applied forces run counter to the arch, and the string force passes through top plate to the sides. Archtop top plates, I believe, are generally thicker than flattop top plates. If true, I would also believe that archtops would require relatively less bracing stiffness than flattops since the archtop plate is already quite stiff in compression.
It would be an interesting academic exercise to structurally model the deformations and resulting dynamic (acoustic) properties of varous bracing patterns, but I would think that luthiers have done just that by building and testing various bracing patterns for many years. I could find no readibly accessible references that define 'usual' archtop bracing patterns for comparison to flattops. I would think that a luthier who hit upon a successful bracing pattern for either type of guitar would either protect the information, or keep it to himself for competetive purposes. I would.
Hope this helps.
http://en.wikipedia.org/wiki/Guitar_bracing
http://www.esomogyi.com/principles.html
but do not answer your specific question. At least these are a starting point.
To generally address your Q, I would start with the thought that flattop bracing stiffens a rather thin top plate being loaded primarily in bending at the bridge resulting from the string pull. In general, bracing stiffens the plate against excessive deformation caused by string loads and prevents string-fret alignment issues. The out-of-plane plate deformation pattern would be an "S" curve in the top plate with the bridge at the center of the "S", and the string force also might cause other buckling wave patterns, as the plate is also in in-plane compression between the bridge and neck.
However, an archtop top plate is loaded primarily in out-of-plane compression (downward string force applied through the bridge), as well as in-plane compression between the neck termination and the tail piece attachment on the guitar's bottom [side] rib. The arched top plate is inherently stiff in out-of-plane compression when applied forces run counter to the arch, and the string force passes through top plate to the sides. Archtop top plates, I believe, are generally thicker than flattop top plates. If true, I would also believe that archtops would require relatively less bracing stiffness than flattops since the archtop plate is already quite stiff in compression.
It would be an interesting academic exercise to structurally model the deformations and resulting dynamic (acoustic) properties of varous bracing patterns, but I would think that luthiers have done just that by building and testing various bracing patterns for many years. I could find no readibly accessible references that define 'usual' archtop bracing patterns for comparison to flattops. I would think that a luthier who hit upon a successful bracing pattern for either type of guitar would either protect the information, or keep it to himself for competetive purposes. I would.
Hope this helps.