glissandi

A glissando, plural glissandi, is a musical technique that produces a continuous slide in pitch from one note to another. The glide may move through many intermediate pitches and can be ascending or descending. It can be produced by various mechanisms, including sliding a finger along a string, sweeping a hand across keyboard keys, or using equivalent methods on wind or brass instruments, as well as by the human voice.

Notation and execution: In scores, glissando is usually indicated by the word glissando or the abbreviation gliss., connected to the starting and ending notes by a straight or wavy line. In keyboard music, a pianist may perform a rapid sweep across the keys. On string instruments, the performer slides the finger along the string while sustaining the note. On wind and brass instruments, the effect is produced through embouchure adjustments or, in some cases, by physically changing the instrument’s configuration.

Types and relation to portamento: Glissandi are often described as diatonic or chromatic. A diatonic glissando moves within a given scale, while a chromatic glissando spans the chromatic pitches between two endpoints. Portamento is a related concept that emphasizes a smooth connection between pitches; in practice, the two terms are sometimes used interchangeably, but glissando generally implies an audible glide between the notated notes.

History and usage: The technique has longstanding use in classical music, particularly by string players and vocalists, and has become common in jazz and popular genres as well. Glissandi can be explicitly notated, or improvised as expressive devices within a performance.