Scribbletune can generate arpeggios from chords
You can set the order of the notes in the arpeggiator and the count of notes in it. Take a look at this example,
const scribble = require('scribbletune');
const c = scribble.clip({
notes: scribble.arp('CM FM CM GM'),
pattern: 'x'.repeat(32)
});
scribble.midi(c, 'arp.mid');
This will create a MIDI clip with the notes of the chord progression in an arpeggiated format where each note is a quarter note. You can change this by setting a property called subdiv
subdiv: '16n'
Now it plays a bit faster as we set the default duration of each note to sixteenth notes. By default the arp method uses 4 notes per arpeggio and it plays those notes from 0 to 3. But you can change that, as the arp method also accepts an object as it’s argument instead of a String.
const scribble = require('scribbletune');
// we can use scribbletune's getChordsByProgression method to get the chord progression i iv i iv i v i II
// from a C major scale on the fourth octave
const theChords = scribble.getChordsByProgression('C4 major', 'i iv i iv i v i II');
// This will return 'Cm Fm Cm Fm Cm Gm Cm DM'. Here 'm' stands for a minor chord and 'M' stands for a major chord.
const notesArr = scribble.arp({
chords: theChords, // you can even provide a string like 'Cm Fm Cm Fm Cm Gm Cm DM'
count: 3, // you can set any number from 2 to 8
// The default value of order is 0123 as count is 4 by default
// but here we set count to 3 hence we are only using the first 3 indices to set a order
order: '102' // Any number up to the `count`
// Here the `count` is 3, hence any combination of 0, 1 and 2
});
const c = scribble.clip({
notes: notesArr,
pattern: 'x-x_'.repeat(notesArr.length/2),
subdiv: '16n'
});
scribble.midi(c, 'arp.mid');
This will create a midi file called “arp.mid” at the same location as you run this script with node and it will arpeggiate the triads Cm, Fm, Cm, Fm, Cm, Gm, Cm and DM chords each with 3 notes in them ordered as 1 0 2. So if the first arpeggio (for Cm) was C4 D#4 G4 then the order of these notes would be 1 0 2, which is D#4 C4 G4
Here’s how it sounded when I imported the MIDI file it produced into Ableton Live
You can use this in the browser as well. Just make sure to pull in Tone.js first however!