The VIOLA (not the Violin) is a 4 stringed instrument that is bowed or played with varying techniques. It is slightly larger than a violin and has a lower and deeper sound. Since the 18th century it has been the middle or alto voice of the violin family, between the violin (which is tuned a perfect fifth above) and the cello (which is tuned an Octave below).The strings from low to high are generally tuned to open C, G, D, and A. Violists will use the Alto clef when reading sheet music.