arpeggiators

An arpeggiator is a device or software feature that converts a chord sounded on a keyboard into a repeating sequence of its constituent notes. It outputs notes in a pattern rather than sustaining a static chord, and it typically syncs to a tempo or external clock. Arpeggiators appear as built-in functionality on many synthesizers, as standalone hardware units, and as MIDI-enabled effects within digital audio workstations.

Basic operation involves pressing one or more keys to form a chord; the arpeggiator then plays the chord notes in a loop according to configurable parameters. Common options set the order (ascending, descending, up-down, or random), the octave range, and the tempo expressed as a rate or subdivision. Additional controls include hold or latch (to sustain the pattern after keys are released), swing, velocity, and gate length. Some devices offer a chord mode that maps chord tones to the arpeggio sequence, or a legato mode that changes how notes connect.

Arpeggiators vary in capability from simple, fixed-pattern devices to advanced engines with polyphonic input, multiple simultaneous patterns, and per-step programmable notes. They can operate in hardware synths, groove boxes, and software plug-ins, including MIDI effects that can be inserted in a track. They are widely used to create rhythmic accompaniment, melodic figures, and evolving textures across genres such as electronic dance music, pop, techno, and film scoring.

Historically, arpeggiators evolved with early polyphonic synthesizers and MIDI-era instruments, becoming a standard feature on many hardware synths in the late 20th century and continuing in software form with modern digital audio workstations.