Portamento is a musical term currently used to mean pitch bending or sliding, and in 16th century polyphonic writing refers to a type of musical ornamentation.

Pitch bending

In current usage, portamento is making a continuous "slide" up or down in frequency from a previous note, rather than a discrete change from one note to the next. This is most commonly encountered on string instruments, such as the guitar or violin, which can produce a continuous range of frequencies rather than being limited to the chromatic or diatonic scale, and impossible on a fixed-pitch instrument like the piano. The trombone also produces quite effective portamento (referred to as a "smear"), as would any instrument with a slide, such as the slide whistle. Other wind instruments have a very limited capability to produce this effect, and can portamento through only as wide a pitch range as can be affected by embouchure alone, which is often not more than a step. A glissando is a similar effect which moves in discrete steps; for example, dragging a finger over the keys of the piano.

In MIDI sequencing, portamento is a channel message that creates a sliding effect by smoothly changing pitch from the last note played to the pitch of the currently playing note.

Portamento often appears as a parameter on synthesizers, where it controls the speed at which an oscillator moves to a new pitch. Often this parameter is called glide. Synth lines with lots of portamento defined West Coast G funk of the mid 1990s, and continue to be a distinctive part of electronic music today.

Ornamentation

In 16th century style, portamento is an anticipation figure, occurring on the off-beat of strong beats in the music (beats 1 and 3). The portamento resolves stepwise, almost always downward. It may occur either once or multiple times in succession.

In multi-voice polyphony, the portamento figure is normally consonant. This embellishment is frequently found ornamenting suspensions, though almost never at the final cadence.

Citations

• Gauldin, Robert (1985). A Practical Approach to Sixteenth-Century Counterpoint. Long Grove, IL: Waveland Press