The fingering system of the flute family is largely determined by the harmonic series. The instrument overblows to the octave, and for most notes the fingerings for the low and middle registers are the same, with the player making slight alterations to the air speed and angle to determine which octave is sounded. Keeping the fingerings the same, it is possible to overblow further through the harmonic series, meaning that standard fingerings will produce pitches which can also be reached by other fingerings. The effect of using a harmonic fingering instead of a standard fingering is usually a more hollow sound, and a different composition of harmonics within the sound. On the alto flute, the pitch of the fundamental can be detected in the tone of harmonics, so care must be taken to ensure this resides within the context of the sound required. There is also some alteration of pitch, in line with the natural intonation of the harmonics, although this can be controlled by the player.
On the alto flute, high harmonics are more difficult to control than on the C flute, and the lower down the note is in the harmonic series, the easier and more reliable it is to produce. The majority of the alto flute’s notes in the upper registers are available as harmonics, but the higher the pitch the less dynamic control the player has, and extremely high notes are only generally available at fortissimo dynamics with greatly increased air sound in the note. Intonation of these high-pitched notes is also extremely difficult to control and care must be used if composing using this effect.
Harmonic series from b
The same note is played here using different harmonic fingerings to demonstrate different balance of fundamentals in the sound and subtle changes of pitch.
Harmonic alternate fingerings
Notation of harmonics
Harmonics are notated with circles above the noteheads. Fingerings can be provided as diamond noteheads below the sounding pitches. Note that harmonics are only available on all members of the flute family from b' upwards.