The strings on the bass violin are tuned in the reverse order of the violin. They are E, A, D, G, with the E and octave below the low E on the guitar. They are tuned in fourths. Otherwise the distance between the notes would be too long to reach. They use the bass cleft but the notes are played an octave lower. Even then ledger lines are required. Sometimes there is a fifth string used on a classical bass violin. It is tuned even lower depending on the music.