A clef is a musical sign placed at the beginning of a stave, by which the absolute pitch of notes is determined. There are a number of different clefs, but only four are used in modern music: the treble clef, the bass clef, the the alto clef, and the tenor clef. Of these, the treble clef is by far the most common, followed by the bass clef, mainly because the latter appears on the grand stave, used in piano music, etc.

 

Treble clef

The treble clef is the clef most commonly encountered in music (Figure 1). It is used for relatively high notes and is also called the G-clef because it curls around the line – the second line from the bottom of the stave – that represents the note G (specifically, G4, equivalent to 392 Hz in scientific pitch notation). The stave with this kind of clef is known as the treble stave.

 

Instruments that use the treble clef include the guitar, violin, flute, oboe, all clarinets and saxophones, horn, and trumpet. The treble clef appears on the upper stave of the grand stave used for the piano and all other keyboard instruments, as well as the harp. In singing, the treble clef is used for the soprano, mezzo-soprano, alto, and tenor voices, although the tenor voice sounds an octave lower, and is often written using the so-called octave clef or double-treble clef.

 

Bass clef

The bass clef or F-clef, used to indicate relatively low notes, is placed so that the dot at the end of its curl sits on the fourth line – indicating an F (F3) – of the stave (Figure 2). In this case, the corresponding stave is called the bass stave.

 

The bass clef is used, among others. for the cello, double bass, bass guitar, bassoon, trombone, tuba, and timpani. It is also used for the lowest notes of the horn, and for the baritone and bass voices. Tenor voice is notated in bass clef when the tenor and bass are written on the same stave. The bass clef is the bottom clef in the grand stave.

 

Other clefs

Both the alto clef and the tenor clef (Figures 3 and 4) belong to the family of C-clefs. The symbol for all the C-clefs is the same; all that differs is the line of the stave on which it is positioned. In the case of the alto clef, the line indicated to be the C (specifically, C4) is the third line of the stave. Pitch-wise, this positions the alto stave a fifth below the treble (G) clef and a fifth above the bass (F) clef.

 

In the case of the tenor clef, the C falls on the fourth line. This clef is used for the upper ranges of the bassoon, cello, double bass, and trombone (which all use the bass clef in their lower and middle ranges, and in their extreme high ranges, the treble clef as well). Formerly, it was used by the tenor part in vocal music but its use has been largely supplanted either with an octave version of the treble clef when written alone or the bass clef when combined on one stave with the bass part. The double bass sounds an octave lower than the written pitch.

 

Middle C represented using five different clefs

In Figure 5 one note, middle C, represented in five different ways. The soprano clef is found in old German choral music. The alto clef, formerly used for the alto voice and certain instruments, is still in use for the viola. The tenor clef was formerly used for the tenor voice and is still in use for the higher notes of the cello, tenor trombone, and some others.