Random: turn pitch variation into a repeatable arrangement

Learn the distance before introducing probability

Start with a predictable version of the effect. The first original MIDI melody plays through Random and then Synth, with Mode Alt, Choices 3, Interval 2 and Sign Add. Chance is set to 100%, although Alt mode does not use that control. Follow the input and output pitches beside the real clip rather than treating the device as a mysterious melody generator.

The offsets cycle through +2, +4 and +6 semitones. The first three input notes, 60, 62 and 64, therefore become 62, 66 and 70; the next note begins the offset cycle again. Alt changes every note in this phrase. It does not alternate between processed and unprocessed notes, nor does it necessarily alternate upward and downward.

Choices counts offsets; Interval sets their size

Keep Choices at 3 and reduce Interval from 2 to 1. The offsets become +1, +2 and +3, giving less register movement but different harmonic implications. Now set Choices to 1. Every Alt event gets the single selected interval. A triggered choice starts at one interval, not zero: Choices 2 with Interval 12 means one or two octaves, not unison or one octave.

Add moves upward and Sub moves downward. Bi chooses the sign per note, so even Alt with Bi is not a simple up/down pendulum. Try Sub on the first example, keeping the instrument level comfortable. If the line falls into an indistinct register, reduce Interval or Choices. Changing the direction of a large leap does not make it less large.

This transform keeps the source velocities and note-on times. It does not add echoes or arpeggiate the melody. At the MIDI pitch limits, results are clamped to 0–127; extreme settings can collapse several intended pitches onto the same boundary. The modest settings here avoid that problem and leave enough space between notes to hear the pitch decisions clearly.

Let an octave move change the register, not the pitch class

The second original phrase is a broken chord. It starts in Random mode with Chance 60%, Choices 2, Interval 12 and Sign Bi. Notes selected for processing move one or two octaves in either direction; others remain at their input pitches. Octave offsets preserve pitch class, though a large register change can still make a melodic line feel disconnected.

Compare Chance at 30% and 80%. Inspect which note events change, then listen for whether the original contour remains recognizable. A percentage is a per-note selection rule, not a guarantee that exactly that fraction of eight notes moves. If the result sounds scattered, first reduce Choices to 1; then reduce Chance if too many notes still leave their original register.

Repeatable does not mean every clip shares the same pattern

Random mode derives its decisions from stable note-occurrence identities. Replaying the same unchanged teaching phrase with the same controls gives the same result. Reset restores authored settings across the entire chain; it is not a new random seed. Different note identities or occurrences elsewhere in a project can produce different decisions. Alt instead assigns its steps in time order, with pitch ordering notes that start together.

Bypass only Random to hear the source played by the same Synth. Decide whether the revised register creates a useful answer or distracts from the phrase. For non-octave intervals, this device does not know the song’s key; Scale is a separate next step when you want pitch changes constrained to a chosen note collection. These examples teach scheduled notes, not live MIDI hardware processing or importing a new performance.