Arpeggiator is one of the MIDI Effects found in Live. Arpeggiator works by taking MIDI input from either a held chord or held note and plays the notes or note back in a rhythmic pattern of your choosing. Often a player will trigger a chord on their MIDI device and when Arpeggiator is enabled the chord will be output as individual notes playing at a set frequency (an arpeggio) rather than being heard in unison (a chord).
Arpeggiator in Live is modelled off similar arpeggiators found on several classic hardware synthesizers, such as the Korg PolySix or Roland’s Jupiter 8. Some classic examples of arpeggiators in popular music are “Baba O’Riley” by The Who and “Hungry Like The Wolf” by Duran Duran.
Like its hardware relatives, Live’s Arpeggiator contains most of the important elements that characterize an ARP. The “Rate” knob controls the frequency notes are played back at and can be synced to the master tempo of your project in Live. The “Style” drop down menu determines what pattern the notes of the chord are played in. While the “Gate” knob dictates the length each note in the pattern is played for.
The video below demonstrates how the MIDI pattern output from Live’s Arpeggiator can be recorded as a new MIDI clip on a new MIDI track using Ableton’s In/Out routing. This technique is particularly powerful because it affords you more control over the timing and pitch of the notes in your arpeggios than Arpeggiator does. In addition it can be used to save CPU power, for example imagine you’ve automated the “Rate” and “Steps” knob on an Arpeggiator in your song. Record the MIDI output, copy and paste your synth onto the new MIDI track you recorded the ARPs output on and finally freeze or delete your old track with the automation on it. Less automation and fewer devices translate to lower CPU load and could free up valuable processing power.
Another simple and powerful way to add interesting variations and rhythms to your recorded MIDI pattern is to use the “Stretch Notes” function. “Stretch Notes” is analogous to Live's audio “Warping” but with MIDI. In order to stretch MIDI, first you need to select some notes in your MIDI pattern. Once your notes have been selected you will see “Stretch Markers” (think of these like “Warp Markers”) appear along the top of your MIDI clip flanking the notes you selected. If you use your mouse to click and drag a “Stretch Marker” you will notice all of the MIDI notes you have selected decrease (or increase) in length and in time without changing the relative distance between notes.
What is really cool about the “Stretch Notes” function is that the MIDI changes you make while stretching the notes can be recorded in real time onto a new MIDI track. Just like in the video above, simply use your In/Out view to route the MIDI output of the track you are stretching into your new MIDI track and record while you stretch. After recording, listen back to what you recorded. Some parts may be junk but there may also be gems hidden inside your performance. Sometimes the outcome can be really surprising and distinct from what you would program on your own. Copy out the MIDI notes you like and put them into clips for use in your song. This trick can work especially well for programming wonky beat beats and fills.