Stand up bass/walking bass/double bass is the Bass of the viol family, and the only True Viol. There is not a Single Bass. Soozie, look for a vielle, viola d'bras (or some other spelling of the French "arm"), the low end of the viola is awfully close to baritone. I love the voice, so mellow and sweet, but have trouble playing in the right key--the one I learned the tune in on the violin and the one the rest of the band plays said tune in.....I can play a 5th below no problem, but that changes the key!!