macmanmatty:
Interesting test. I'll note that in anything of this sort 'all else equal' gets to be a real consideration. You've used a variety of instruments from different manufacturers, and no doubt the design philosophies did as much, or more, to determine the outcome as the body sizes or materials. The real test would be to pit high end production or, even better, luthier built, instruments of different sizes, but otherwise similar in materials and construction, against each other.
rdmiller wrote:
"I'm a builder. I'm working on # 12 currently. Volume has everything to do with cavity size."
I'm a builder. I'm working on guitar #134 currently, with a few hundred stringed instruments of other types thrown in. I wish it were that simple...
Violins are loud because they're bowed. The bow, in effect, 'plucks' the string once for every cycle of vibration, replenishing whatever energy was lost since the last time.
Nobody can move a pick that fast. Given the limited horsepower in a plucked string the problem guitar makers have is getting any sort of volume out. One result of that is that the guitar is (believe it or not) one of the more efficient musical instruments. Violin makers have the opposite problem, in some respects: how to control all the power the bow can put in. A fiddle that was as efficient as a guitar would suffer from so many 'wolf' notes as to be unplayable.