Arpeggiator

What Is an Arpeggio?

According to musical theory, an arpeggio is a broken chord in which the notes that compose the chord are played or sung in rising or descending order. An arpeggio can also span more than one octave. Even though the notes of an arpeggio are not played or sung simultaneously, listeners hear the sequence of notes as forming a chord.  

Arp Instruments in Synths

Most synthesizers today have arpeggiators. In essence, an arpeggiator is a very basic real-time sequencer. It takes a chord as an input and turns it into an arpeggio. Since they originated in the early days of hardware synthesizers, their simplicity and immediacy have captured the attention of musicians.

Arpeggiator History

The history of arpeggiators began with dedicated hardware synthesizers in the late 1960s and 1970s. Later on, they became an inevitable part of some of the famous analog synthesizers like Roland Jupiter 8, Oberheim OB-Xa, Roland SH-101, Roland Juno-6, Sequential Circuits Six-Trak, and Korg Polysix to mention a few. The period of the late 1980s and the beginning of the 1990s brought an absence of arpeggiator features among top-selling synthesizers. Yamaha DX-7, Casio CZ-101, Roland D-50, and Korg M1 didn't have this feature. However, the remarkable comeback in the interest of analog synthesizers happened in the 1990s. This is because some dance music hits incorporated arpeggiator sequences, again bringing interest to arpeggiators. Consequently, most popular synthesizers manufactured since the mid-1990s include such a device.  

Chord Progressions

Music is typically based on progressions of chords. However, this may not be so obvious. This means that the players may not simultaneously play the chords' notes. For example, you can imagine a guitarist playing finger-style and using intricate plucks to create a far more complex pattern. Often, this is still based on simple chord shapes. An arpeggiator takes advantage of this fact and provides synth players with an easy way to play complex synth parts via simple chords. Switching on an arpeggiator tells the synth to 'listen' to synth players' notes. Then, it creates a pattern (an arpeggio, typically) using these notes, played at a set master tempo. The player only needs to hold the notes. Or, if the arpeggiator has a 'latch' function activated, just hit the chord once, and the pattern will continue to play until another note or chord is hit.  

Modern Arpeggiators

At its simplest state, an arpeggiator will cycle through the notes played, either up or down in pitch, playing each note to a specified length. Modern arpeggiators, however, have far more options. Typically, even a modestly equipped arpeggiator can switch between 'up,' 'down,' and 'up and down' modes, with a random mode usually thrown in for good measure. These, with the ability to change tempo and note length, represent a surprisingly creative set of tools in their own right. More sophisticated designs allow users to specify more complex pre-programmed patterns or even program their own. Some arpeggiators allow for polyphonic patterns. This means that the chords are tempo-synchronized. Often, synth players can set octave ranges. This means that notes held will leap up or down to higher or lower octaves according to the notes held and specified pattern. Workstation-style synths often have immensely complex arpeggiators. They allow the user to program multiple layers of sounds with differing patterns; consequently, users can create very complex, evolving, layered sounds.  

Additional Resources & Source Texts

• Arpeggiator