Three symbols, fifteen positions, and why violists read a different clef
A clef is the curly symbol at the start of a staff that tells you which note sits on which line. Modern music uses just three shapes, the G, F and C clefs, but slide them up and down the five lines and you get a surprising family, ten of which composers have actually used.
The word comes from the French for key. Each clef pins one reference note to a line, and every other line and space follows from it. The G-clef fixes the G above middle C, the F-clef the F below it, and the C-clef middle C itself. That creates a tidy symmetry: the G and F clefs mark notes a fifth above and a fifth below the C-clef's anchor.
Why bother with several? Different clefs let every instrument and voice sit comfortably on the staff without a forest of extra ledger lines. High parts use the G-clef, middle parts the C-clef and low parts the F-clef. Put each of the three clefs on each of five lines and you get fifteen combinations. Six duplicate others, leaving nine distinct clefs, and adding a rare C-clef on the top line brings the historical total to ten.
Today only four are in regular use. The treble clef, a G-clef on the second line, is usually the first one students learn and covers violin, flute, trumpet, guitar, saxophones and most voices. The bass clef, which puts the F symbol on line four, handles cello, tuba, timpani and low voices. The alto clef, with middle C on the middle line, survives mainly for the viola, while the tenor clef serves the high notes of cellos, bassoons and trombones. Even low saxophones read treble clef, because instrument families tend to share a clef whatever their sounding pitch.
The retired clefs have stories of their own. A G-clef on the bottom line, the French violin clef, served violin and flute music in France during the seventeenth and eighteenth centuries. The sub-bass clef, an F-clef on the top line, turns up in low parts by Ockeghem and Schütz and in Bach's Musical Offering, and the mezzo-soprano clef appeared in operatic roles by Monteverdi.
Source: Clef
