The viola is larger and its strings are tuned a fifth lower than the violin. Since the 18th century it has acted as the middle or alto voice of the violin family. The strings are usually tuned to C3, G3, D4 and A4. Standard viola size is measured by the length of the body, ranging from 39 cm to 41-42.5 cm or more. Body size plays a key role in the instrument’s tone and player’s control.