The group was called Plain Folk, and the guy's name is Ivan Stiles. You can hear him at festivals, and he is quite a respected authority on the autoharp. He wrote The True Hisory of the Autoharp, an article which corrected wrong assumption about the instrument's origin. I believe the woman was named Marcy, although Mercy might be right. I think she was, and possibly still is, Ivan's wife, but I haven't seen her name listed along with his recently.