Random Chords

If you randomly pick 2 or 3 notes from a scale or mode, you’ll end up creating random chords. They won’t necessarily sound good, but since we will use JavaScript for this, we can generate a bunch of chord progressions and tweak something that we like from that bunch. We will use lodash for the random picking.

Write your own script

We will create a new file called random-chords.js and start by importing our dependencies.

const _ = require('lodash');
const scribble = require('scribbletune');

For the set of notes, we’ll start with the C major scale and a simple pattern:

const setOfNotes = scribble.scale('C3 major');
const pattern = 'x___'.repeat(4);

Now we need to get the count of x in this pattern so that we can generate that many random chords.

const count = pattern.replace(/[^x]/g, '').length;

Next, we’ll randomly pick 3 notes from our set for each x:

const notes = [];
for (let i = 0; i < count; i++) {
  notes.push(_.sampleSize([...setOfNotes], 3));
}

And that should be good enough to produce our MIDI file:

scribble.midi(
  scribble.clip({
    notes,
    pattern,
  })
);

Finally, execute this file in your terminal with Node.js:

node random-chords.js

Ready to roll

You can use any DAW to do the rest of the steps. I use Ableton Live and a bunch of fancy third-party VSTs, hence I created a group instrument combining Jupiter 8 V3 and Hive 2. On rendering the MIDI it sounded like this: