The Physics of Sound as it Pertains to Dulcimers

I am new to this forum as well as new to dulcimers and making them. So this may be a topic already covered somewhere on this site. I am working on a design for my own dulcimer with (like many builders) looking to create as much volume as possible so as not to have it drowned out by louder instruments that may accompany my playing. I am already aware of some of the elements that makers employ to increase volume: false back/possum board, reducing the contact between the fret board and the sound board, separating the bridge from the sound board, etc. These may all be somewhat effective, but it got me thinking. Why are dulcimers quieter instruments compared with say mandolins which have smaller sound boxes? Is it the way a mandolin's bridge is mounted? Is it the tension of the strings or that a mando's strings are doubled? Does the arching of the back and soundboard create a sort of tension in the sound box that resonates better? And finally, can any of these be incorporated into a dulcimer without making the dulcimer not sound like a dulcimer? Will the sweet mellow tone be lost with the increase in volume? Any thoughts or observations, snide remarks, etc?