Multiphonics
Fingering or blowing techniques that make an instrument produce more than one note at once.
What it means
Multiphonics are playing techniques by which a normally single-line instrument produces several notes at once. They occur above all on woodwind instruments such as flute, clarinet, oboe, bassoon and saxophone. Special fingerings, a modified air stream and an adapted lip and tongue position are combined so that two or more frequencies vibrate at the same time.
On brass instruments a similar effect arises when one plays and sings or hums into the instrument at the same time.
Musical use
In new music multiphonics have been investigated systematically since the 1960s. The composer and flautist Bruno Bartolozzi described them in his book New Sounds for Woodwind (1967) and thereby made them usable for composers. They often sound rough, glassy or floating and are used for effects of tone color.
Multiphonics should be distinguished from the double stop of string players, in which two strings are bowed separately, and from harmonics, which produce single overtones.
Performance practice
Practise multiphonics with a fingering chart and work very precisely on air control and embouchure. Small changes can alter the sound or make the instrument collapse into a single note; take time for an even, calm response.