Music has vertical harmonic structures and horizontal moving lines. Scales are horizontal patterns of single semitone and 2 semitone intervals. Arpeggiations are moving sequences of chord notes found in all types of music.
A 2 octave arpeggio in C major is played as C,E,G,C,E,G,C going foreword and backward (up and down.) A harp piece often consists of arpeggiated chords, often played in dense rising and falling note sequences. Students learning to play musical instruments are required to practice scales and arpeggios to master scale patterns and to develop performance agility.
Professional electronic keyboards and sequencing software often include arpeggiators and other pattern generators that allow composers to generate arpeggiations with little effort. The most creative uses of note patterns explore polyphonies that exceed the capabilities of live performance both in speed and complexity.
Using midi composition tools, complex rhythms and polyphonies can be woven into a dense fabric of sounds. One path to new music involves combing variable arpeggiations with other patterns in evolving compositions that I like to describe as journeys of discovery. The problem facing a 21st century composer using digital tools is not lack of intellectual challenges and novel ideas but it is to discover pleasing sound experiences that avoid becoming noise.
EMU Proteus Arpeggiators
The EMU Proteus 2500 includes sophisticated programming options that allows a player to trigger complex, multi-track sequenced data from a keyboard. The EMU arpeggiations include up, down, up/down, forward assign, backward assign forward/backward and random patterns. You can also create unique patterns to control pitch sequences. You determine the tempo by choosing note values from a whole note to a 32nd note.
Additional variables are count and extension that control how often the arpeggio plays with each key press, with the option of transposing the repeating sequences. A recycle parameter resets the sequence to the beginning when the duration value has been reached. A latch function turns on and maintains the arpgeggiations until another key is pressed. The note range can be set to a user-defined section of the keyboard. It is possible to cascade arpeggiations so one arpeggiators controls and second, controls a third. I sometimes create performances using the keyboard to control several arpeggiators that can operate in sequence, overlap, and cascade.