Arpeggiator

An arpeggiator is a feature available on some hardware synthesizers and virtual instruments. It allows the player to automatically step through a sequence of notes based on the player's input, thus creating an arpeggio.

Typically an arpeggiator will have several controls which allow the player to manipulate the order and speed in which the notes are played. Some arpeggiators allow the pattern to be sustained even if the player no longer holds down the keys; in this way an arpeggiated pattern may be built up over time by pressing several keys one after the other. Typically an arpeggiator will allow the user to step through the notes upwards, downwards, or in a random order. More advanced arpeggiators might allow the user to step through a complex sequence of notes, or play several arpeggios at once.

Arpeggiators grew from dedicated hardware sequencers of the late 1960s and 1970s, such as the 16-step ARP Sequencer, and the sequencers of modular synthesizers. They were commonly fitted to keyboard instruments throughout the late 1970s and early 1980s, notable examples of which include the Roland Jupiter 8, Oberheim OB-Xa, Roland SH-101, Roland Juno-6, Sequential Circuits Six-Trak, and Korg Polysix. Arpeggiators fell out of favour during the 1980s and early 1990s, and were absent from the most popular synthesizers of the period, such as the Yamaha DX-7, Casio CZ-101, Roland D-50, and Korg M1. The resurgence of interest in analog synthesisers during the 1990s, and the use of rapid-fire arpeggios in several popular dance hits, brought with it a resurgence of interest in arpeggiators, and most popular synthesizers manufactured since the mid 1990s include such a device.

Arpeggiators are also common features of modern-day software synthesizers, where they are typically synchronised with the tempo of the hosting application.