Wondering if you're familiar with Atwater/Donnelly???Recently went to a couple of their concerts....traditional mountain (Appalachian) music. Will look for their website address when I get home from work. Old favorites of mine, with voices in the ranges you described, are Jean and Lee Schilling from Cosby, Tennessee. "Folk and/or Traditional songs.." sums up our entire history...any way to be more specific in what you're interested in????