Recurve question

[John Bertotti]

So as I understand it the top plate acts kind of like a speaker and the carving process helps decide the way it reacts and its stiffness overall while tone bars refine the stiffness and the plate is determining how modes react. My question is why is the recurve on the outside? Don’t get me wrong I do like it but I think a smoothly arched top would look cool also so why isn’t it left smooth and all the carving hidden on the inside?

I hope it isn't too obvious a question but I learn best from crazy questions then trying things anyway, drove my dad who was very process-oriented, absolutely nuts.

[HoGo]

So as I understand it the top plate acts kind of like a speaker and the carving process helps decide the way it reacts and its stiffness overall while tone bars refine the stiffness and the plate is determining how modes react. My question is why is the recurve on the outside? Don’t get me wrong I do like it but I think a smoothly arched top would look cool also so why isn’t it left smooth and all the carving hidden on the inside?

I hope it isn't too obvious a question but I learn best from crazy questions then trying things anyway, drove my dad who was very process-oriented, absolutely nuts.

Generally simple arch is much stiffer than "recurved" arch od similar thicknesses. I've seen mandolins with such arching and the sound was thin and less resonant than "normal". Violin arching is close to this (most of the channeling is outside of active part of plates) but they are driven by bow and work differently.

[John Bertotti]

Ah! That, oddly enough makes perfect sense to me when I think about it! Thanks, in this case, you saved me a costly time-consuming mistake!

[sunburst]

The top doesn't really act very much like a speaker cone. A speaker cone is made to be very stiff overall with a very flexible edge to help it to move as a unit. The mandolin top (and back) move in all possible normal modes of motion, only one of which somewhat resembles the movement of a speaker cone. (Of course, speaker cones aren't perfect and they do tend to move in their own normal modes of motion to some extent despite the design and engineering attempts to make them move in only one mode.)

As for the recurve, I've seen and heard mandolns made with no recurve and they sounded good. Stromberg guitars were made (at least some of them) with little to no recurve and they were and are considered some of the most powerful jazz guitars ever made.
The recurve is mostly for looks.