In my graduate school career, I had the opportunity with our evolutionary complexity lab to study creating music using neural networks and interactive genetic algorithms. It’s fun to study these two topics together since I enjoy crafting code and music. If you enjoy this too, you might enjoy Music maker, a library I created to explore generating music with code. Sonic Pi by Sam Aaron, a popular tool to teach music theory and Ruby code, inspired me to build this tool. My team from InspiredToEducate.NET enjoyed teaching a coding workshop on music using Sonic Pi. We, however, encountered a challenge of installing Sonic-Pi on a lab of computers. The workshop targets 5th-grade to 8th-grade students who have good typing skills. It would be cool if something like Sonic-Pi supported features like Blockly coding too.

In terms of musical motivations, I wanted to provide features like the following:

• Like Sonic-Pi, the tool should make it easy to generate chords and scales.
• I want it to feel simple like Sonic-Pi. I, however, don’t think I’ve achieved this yet.
• I wanted the tool to have a concept of players who can generate music over a chord progression. I believe it would be cool to grow an ecosystem of players for various time signatures and musical types.
  I wanted to support the MIDI file format for output making it possible to blend music from this tool in sequencers broadly available on the market. This also enables us to print out sheet music using the MIDI files.
• Building drum patterns can be tedious at times, I wanted to create a way to express rhythm simply.
• We desired to have a browser-based interface that a teacher could install on a Raspberry Pi or some other computer. This was a key idea from one of my teachers.  I’m focusing on building a tool that works on a local area network.  (not the broad internet)
• From a coding perspective, we need to build a tool that could interface with Blockly coding someday. JavaScript became a logical choice. I’ve wanted to explore a project the used TypeScript, NodeJS and Express too. I especially enjoyed using TypeScript for enums, classes, abstract classes, etc.

Here’s a sample MIDI file for your enjoyment:  jazz midi test

I do want to give a shout out to David Ingram of Google for putting together jsmidgen. David’s library handled all the low-level concerns for generating MIDI files, adding tracks, and notes. Please keep in mind that MIDI is a music protocol and file format that focuses on the idea of turning notes and off like switches over time. Make sure to check out his work. It’s great NodeJS library.

Here’s a quick tour of the API. It’s a work in progress.

Where do I get the code?

https://github.com/michaelprosario/music_maker

• run app.js to load the browser application.   Once the application is running, you should find it running on http://localhost:3000 .
• Make sure to check out the demo type scripts and music_maker.ts for sample code.

JSMIDGen reference

To learn more JSMIDGEN,
please visit https://github.com/dingram/jsmidgen

Hello world

var fs = require('fs');
var Midi = require('jsmidgen');
var Util = require('jsmidgen').Util;
import mm = require('./MusicMaker')

var beat=25;
var file = new Midi.File();

// Build a track
var track = new Midi.Track();
track.setTempo(80);
file.addTrack(track);

// Play a scale
var scale = mm.MakeScale("c4", mm.ScaleType.MajorPentatonic,2)

for(var i=0; i<scale.length; i++){
    track.addNote(0,scale[i],beat*2);
}

// Write a MIDI file
fs.writeFileSync('test.mid', file.toBytes(), 'binary');

Creating a new file and track

var file = new Midi.File();
var track = new Midi.Track();
track.setTempo(80);
file.addTrack(track);

// Play cool music here ...

Play three notes

track.addNote(0, mm.GetNoteNumber("c4"), beat);
track.addNote(0, mm.GetNoteNumber("d4"), beat);
track.addNote(0, mm.GetNoteNumber("e4"), beat);

Saving file to MIDI

fs.writeFileSync('test.mid', file.toBytes(), 'binary');

Playing a scale

var scale = mm.MakeScale("c4", mm.ScaleType.MajorPentatonic,2)

for(var i=0; i<scale.length; i++){
    track.addNote(0,scale[i],beat*2);
}

Playing drum patterns

var DrumNotes = mm.DrumNotes;
var addRhythmPattern = mm.AddRhythmPattern;
addRhythmPattern(track, "x-x-|x-x-|xxx-|x-xx",DrumNotes.ClosedHighHat);

Setup chord progression

var chordList = new Array();
chordList.push(new mm.ChordChange(mm.MakeChord("e4", mm.ChordType.Minor),4));
chordList.push(new mm.ChordChange(mm.MakeChord("c4", mm.ChordType.Major),4));
chordList.push(new mm.ChordChange(mm.MakeChord("d4", mm.ChordType.Major),4));
chordList.push(new mm.ChordChange(mm.MakeChord("c4", mm.ChordType.Major),4));

Play random notes from chord progression

var p = new mm.RandomPlayer
p.PlayFromChordChanges(track, chordList, 0);

Play root of chord every measure

var p = new mm.SimplePlayer
p.PlayFromChordChanges(track, chordList, 0);

Tour of chord players

var chordList = new Array();

// setup chord progression
chordList.push(new mm.ChordChange(mm.MakeChord("e4", mm.ChordType.Minor),4));
chordList.push(new mm.ChordChange(mm.MakeChord("c4", mm.ChordType.Major),4));
chordList.push(new mm.ChordChange(mm.MakeChord("d4", mm.ChordType.Major),4));
chordList.push(new mm.ChordChange(mm.MakeChord("c4", mm.ChordType.Major),4));

var chordPlayer = new mm.SimplePlayer
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.Arpeggio1
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.RandomPlayer
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.BassPLayer1
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.BassPLayer2
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.BassPLayer3
chordPlayer.PlayFromChordChanges(track, chordList, 0);

chordPlayer = new mm.OffBeatPlayer
chordPlayer.PlayFromChordChanges(track, chordList, 0);

If you write music using Music Maker, got ideas for features, or you’d like to contribute to the project, drop me a line in the comments or contact me through GitHub!  Hope you have a great one!