Scallop Fretboard Sound effects

I’m now aware they are not called arches but scallops. Thanks you Strumelia

Ken:

Please forgive my ignorance for the use of the term (fret bar) and not (fretboard) and the location of (discussions)I posted my questions in on this forum. As I indicated I’m a new to the forum/dulcimer and I’m still fumbling my way around.

Speaking of fretboards it brings up another question that you might be able to expand on due to your expertise. Many of the newer dulcimers I’ve seen (via the Internet) I have notice two or three even more (arches)  and again (forgive me for the lack of a better or the correct term) being made under the the fretboard, is this an aesthetics thing or is it to enhance sound quality or perhaps a combination of both? No doubt hollowing out this style of fretboard would greatly reduce the gluing surface on the sound board, but will it or should enhance sound? I think it would.  Again your thoughts or others input would be again appreciated. 

Im sure this again will be posted in other discussions but I just don’t know how to move it elsewhere, sorry