multiphonics
A technique for producing multiple notes simultaneously on a wind instrument.
In Depth
Multiphonics is an extended technique for wind instruments that produces two or more pitches simultaneously from a single instrument. On woodwinds, this is achieved through special fingerings and embouchure adjustments that cause the air column to vibrate at multiple frequencies at once.
The resulting sound is complex, often rough and otherworldly — far from the clean, single-pitch tone these instruments normally produce. Multiphonics became an important tool in avant-garde and contemporary classical music from the mid-20th century onward. Composers like Luciano Berio and Helmut Lachenmann explored the technique extensively, and it has since entered the standard vocabulary of extended techniques.
A skilled saxophonist can produce up to four distinct pitches simultaneously through multiphonics — a feat that seems to violate the basic physics of a single-bore instrument.