Grant Muller

GOLSequencer, HarmonicTable, and MidiReference on GitHub

With just a little trepidation I have checked in the code for all of my free software goodies into GitHub. I was getting several requests to provide access to the source for several of my old projects, so rather than emailing code around on a case by case basis, I have simply checked everything in to GitHub for posterity. Who knows, maybe someone will jump in there and fix all the bugs.

I have written some other tools for my personal use that I will likely check in there as well, so check back if you’re interested in that kind of thing.




RWMidi, GMS, and GOL Sequencer: Adventures in Social Coding

Many moons ago, I created a little tool called the GOL Sequencer Bank. You can read more about it here, and here. In order to create the tool, I used RWMidi, a Java/Processing library created by Manuel Odendahl of Ruin&Wesen. While creating the sequencer bank, I discovered that the RWMidi library had no support for MIDI Sync messages, preventing me from syncing the sequencer with a master, like Ableton Live. This simply would not do.

In the past, I would have looked for another library, but given that I had the source readily available, and had already written a ton of code interfacing to RWMidi, I decided it would be a better use of my time to modify the RWMidi library to support sync messages. You can read more about that here. The changes were minimal, and I learned a lot in the process about MIDI, Java, and the art of modifying open source.

Not too long after that word got out that I had made this change to the RWMidi library, and I started getting one-off requests to send my modified library to folks for their own use. For instance, John Keston over at AudioCookbook built his GMS synth using my modified library.

A short time after that, Mr. Keston approached me with what I thought at the time was a strange requirement: modify the library to support greater than 24PPQ for recognizing 64th and 128th note resolutions. In plain English, John wanted the GMS to support 64 and 128 notes using plain-jane MIDI clock. I thought it couldn’t be done, but loved the challenge, and modified the RWMidi library accordingly. It was a doozy.

These modifications to the RWMidi library have only been available as a custom change to the GMS and the GOL Sequencer Bank, but now, through the power of GitHub and social coding, I can make these changes available to anyone who wants them. I have forked the RWMidi library on Github, incorporated the changes there, and issued a pull request to Manuel to include them in the main source.

You can check out the source here.

I have also built a jar file and included it as a download on GitHub. You can get it here.

Having finally discovered the beauty of social coding, I plan on eventually uploading the source of both the HarmonicTable and the GOL Seqeuencer. I’ve had requests in the past to make changes to the synth that I just don’t have time for, this way people in the know can simply fork the source, make their own changes, and ask me to pull them into the main body of work.

As more and more regular Janes and Joes become savvy programmers (i.e. our children), I expect we’ll see the power of social coding change the way we think about how software is made in general…

Harmonic Table 0.5: Midi Input & Lit Keys

While I thought the GOL Sequencer Bank would get the bulk of my attention this Winter, it turns out I’m getting far more requests to update to the Harmonic Table controller. Among them were Midi Input capabilities, buttons lighting up, and some bug fixes here and there. All that completed, I give you Harmonic Table 0.5. Here is the breakdown:

Midi Input – This feature allows you to accept midi note on and off events and display them as key presses on the main screen. I see this as a learning tool that allows a user to easily see the relationships between notes. Note: At this time it is difficult to keep up with a rapid number of midi input messages. If you’re using this as a learning tool, it is recommended that you reduce the tempo of your sequencer so you can see these relationships without missing any notes.

Midi Thru – This is just another aspect of midi input. When this is turned on any messages appearing on the midi input will be mirrored to the midi output you have selected

You can download it here: HarmonicTable 0.5

Lighting up buttons and accepting midi input introduced a few performance related bugs, but nothing that should keep anyone from using the tool. I’ll have this cleaned up in a future release.

The main target in the next release is touch screen support. I’m getting a lot of great info offline from a few people who are interested in testing this for me, so look for that very soon.

HarmonicTable 0.3

Bit slow these days with work and other stuff to get around to some of the changes I’m been meaning to make to these projects, but here is a quick 0.3 stab. I had more changes planned for this release, along with some stuff for playing back patterns and keyboard playback support, but for now I only had time to make a few changes:

  • Chord Mode – Chord mode allows the user to hold down a key on the keyboard and play a chord when a note is clicked. The chord map is on the release page.
  • Chord Lock – By default when playing a chord by pressing a key, the chord only sounds while the key is held down. In chord lock mode you need only press the key of the chord you want to play, and any note you click after that will play that chord
  • Various Performance Fixes – Nothing special here, moved some stuff around and improved map loops to speed the whole thing up a bit

That should cover it, you can download it here.

Processing HarmonicTable 02

Mac users pointed out some problems with 01, so I fixed the following:

  • When dragging notes, the note would only sound once until the mouse was released.
  • The software would not start up automatically on many Macs unless the java version was set to 6
  • Unreported: Notes would only sustain as long as the mouse button was held. May be seen as a feature, see below for fix.

I fixed the dragging problem, and recompiled the software in Java 5 so that it will work in either 5 or 6, so Mac users should be able to start up without issue. I added a Release Notes toggle button on the setup screen, so you can sustain notes after the mouse is released. If you want notes to sustain only as long as the mouse is held, you can turn this Release Notes on.


There are two tabs at the top, one for the main table screen, and one for setup. The basic setup options at this time are midi ports, starting note values, and a toggle for releasing notes.

This was built using the Processing libraries, along with the ControlP5 library and Ruin & Wesen’s rwmidi library for midi functionality.

This is an executable jar, meaning if you have java installed on your machine (version 5 or above), you should be able to double-click it and you’re off and running. I have only tested this on Windows and Linux, some testing has been completed in Mac, but more needs to be done, so any Mac users out there send me your feedback.

Harmonic Table 02

If you have any questions or comments, leave them in the section below.

Processing HarmonicTable 01

UPDATE: This is no longer the latest version, I fixed some bugs for Mac users and reposted. To get the latest version click here.

Since I don’t have a touchscreen to test this with, I’m releasing the 01 version with mouse functionality, along with a few GUI functions to change the midi out port and the starting note number. At some point I’ll get a tablet and add the touchscreen functionality, or if someone has a tablet I can pass the source code on and they can test/implement that functionality.


There are two tabs at the top, one for the main table screen, and one for setup. The basic setup options at this time are midi ports and starting note values.

This was built using the Processing libraries, along with the ControlP5 library and Ruin & Wesen’s rwmidi library for midi functionality.

This is an executable jar, meaning if you have java installed on your machine (version 6), you should be able to double-click it and you’re off and running. I have only tested this on Windows and Linux, so if there are any Mac users out there, please let me know if there are any problems.

Download HarmonicTable 01

If you have any questions or comments, leave them in the section below.

Processing HarmonicTable: Part 2

Since the last post I’ve had to make far more changes than I expected. If you looked at the previous examples, there was using a loop to create the hex buttons, making translations to relative to other translations on the screen. In the process I completely lost track of the absolute position of the button, which basically made it impossible to detect the location of the mouse on the screen in order to tell which button I was pressing. As a result I had to create a separate class to represent the Hex Button, and store the absolute starting point of each hex button and the length of one side. This is all the information I needed to create and detect a hexagon anywhere on the screen. From there I just created an array of these buttons in the setup() block, and drew them all over the screen:

hexButtons = new ArrayList</p>
<p>for (int j=2; j &lt;20; j++){
for (int i=0; i&lt;12; i++){
hexButtons.add(new HexButton(this, space+(i<em>xOffset), parseInt(height-(j</em>b)), length,    noteNumber));
<p>for (int i=0; i&lt;12; i++){
hexButtons.add(new HexButton(this, space+parseInt(a+c)+(i<em>xOffset), parseInt(height-(j</em>b)), length, noteNumber));

As you can see I’m still making relative translations to locations on the screen, but I’m storing them in the class to be accessed later. This way I can still change the proportions and space variable at the top and not have to change a bit of code anywhere else to resize and reposition items. This greatly simplifies my draw() block:

public void draw(){
for (int i = 0; i &lt; hexButtons.size(); i++){
HexButton button = (HexButton) hexButtons.get(i);

Now detecting the position of the mouse is simple:

public void mousePressed(){
for (int i = 0; i &lt; hexButtons.size(); i++){
HexButton button = (HexButton) hexButtons.get(i);
if (mouseX >= button.startX+a &amp;amp;amp;&amp;amp;amp; mouseX &lt;= button.startX+a+c &amp;amp;amp;&amp;amp;amp; mouseY >= button.startY &amp;amp;amp;&amp;amp;amp; mouseY &lt;= button.startY+(2*b)){
midiOutput.sendNoteOn(0, button.thisNoteNumber, 100);

Notice I only bother performing this function when the mouse it pressed, this saves me some cycle since I have no intention of sending a midi note on unless the mouse is pressed (or dragged, which is using the same function as above). Also notice the activeNotes array. I’m storing notes that have already been pressed, so that I don’t retrigger a note unless the mouse is pressed again, which is necessary for mouse drags. After the mouse is released, I just send a note off to all notes in the acttiveNotes array.

I also revised the array to create the rows of notes across the screen. Previously it was hard coded, but with the following bit of code:

public void resetNoteNumber(int rowNumber){
if (rowNumber == 0){
noteNumber = noteNameMap.get(startingNote);
previousNote = noteNumber;
} else if (rowNumber % 2 == 0){
noteNumber = previousNote + 3;
previousNote = noteNumber;
} else {
noteNumber = previousNote + 4;
previousNote = noteNumber;

I can just change the starting note field in the class to be whatever I want, and it will always move up by rows in 5ths and 3rds. So I can make my starting note A2 instead of C2, and everything lines up without a hitch and without any code changes:


I tested it out with some seriously 80’s sounding FM pad, dragging across intervals, drawing random chord shapes in honeycomb patterns, etc. Here is a short output:

Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.

As usual here are the updated files:

HarmonicTable HexButton NoteReference

Its a lot of fun, even though I can only play it with the mouse. Last step is to get a touch screen. Anyone want to donate one?

Processing HarmonicTable: Part 1

Earlier this year while reading Harmonic Experience by W. A. Mathieu, I was introduced to the concept of lattices to represent tones, chords and keys. These lattices can be used to represent the basics of music composition in a visual way that makes more sense than standard scales on staffs. Here is an example:


The lattice is effectively several staffs of music stacked on top of each other, so that the note can be displayed horizontally and vertically. Starting from any note in the lattice, moving horizontally (diagonally right or left), jumps by a 5th (for example C to G, or G to D). Moving vertically jumps by thirds (C to E, or G to B). Since nearly all music is the construction of 5ths in 3rds, this system makes it easy to create patterns visually for chords, cadences, scales etc, that will always look the same no matter where you start on the lattice. In the example above, you can see that Major chords are always point up triangles, Minor chords are the opposite, point down. Until recently this system didn’t translate directly to an instrument. Any chord on a keyboard will have similar but different fingerings and patterns depending on the starting note, so one still has to memorize a ton of different patterns for one scale, chord, or modulation.

A few weeks into reading Harmonic Experience, providence saw fit to lead me to the C-Thru AXiS controller. The AXiS is a Harmonic Table based midi controller that creates a table much like the lattice in Harmonic Experience, separating notes not in semi-tones like a keyboad, but by 5ths and 3rds (and of course many other inter-relationships based on this). Here is the layout of the AXiS: natural_keyboard If you look the relationships between the keys become clear. They are reversed from Mathieu’s lattice, 3rds are horizontal (diagonally), and 5ths are always straight up. To play a Major triad on the AXiS, just play that triangle pattern using starting at any key. C Major will have the same pattern as Bb Major, etc. There are of course drawbacks to this system (playing inversions, etc), but for the most part it accomplishes the goal of simplifying the muscle memory aspects of playing music so the user can concentrate on composition and performance. you learn the pattern for a scale, chord or mode only once, then you may modulate it anywhere without the need to retrain your fingers.

The problem with AXiS is the price tag. Its around $1700 for one from what I can tell, which is a pretty steep entrance fee for a device I may not be able to get used to. They are in the process of creating a cheaper smaller version, but I want to try it now. The solution was to build one in processing. I’ve only just started, but combining the midi reference classes I’ve been working on along with (eventually) a touch screen, I think I should be able to pull something off that works well enough for me to test this thing out. I started by looking for ways to draw regular hexagons, and came across this site. With a some basic trigonometry and a lot of cut-and-try with the vertex functions, I came up with this function:
int length=30;
float a = length/2;
float b = sin(radians(60))*length;
float c = length;
public void drawHex(){
This will construct a regular hexagon based on the length of one side. After that I used a series of translation matrices to draw them all over the screen: public void draw(){ rowNumber=0; setNoteNumber(rowNumber); for (int j=2; j<20; j++){ pushMatrix(); translate(0+space, (height-(j*(b+space/2)+1))); drawHex(getNextNote()); for (int i=1; i <12; i++){ translate(space+(2*a)+(2*c), 0); drawHex(getNextNote()); } popMatrix(); j++; rowNumber++; setNoteNumber(rowNumber); pushMatrix(); translate(a+c+1.5f*space, (height-(j*(b+space/2)))); drawHex(getNextNote()); for (int i=1; i <12; i++){ translate(space+(2*a)+(2*c), 0); drawHex(getNextNote()); } popMatrix(); rowNumber++; setNoteNumber(rowNumber); } } [/sourcecode] I predefined the number of horizontal hexagons to 12 for each row, this means that STRAIGHT horizontally across a row I will have a perfect chromatic scale. The number of vertical keys I simply copied from the AXiS.After predefining the number of columns and rows, it meant that I could construct the size of the screen based on the length of one side of the hexagon. I also included a variable that allows me to declare an amount of fixed space in between the keys (in case my fingers are too big for the key's surface). One variable, named length, can be changed to create a bigger surface with larger keys. After implementing some simple code to write the note name into the key as well, I was finished with the layout. Here is a snapshot of it directly out of processing: Virtual Harmonic Table Its of course much bigger. With the key surface complete now all I have to do is map the key locations to the midi note they’re associated with, and use some on press functions to trigger them. After that I just need to get access to a touch screen, anyone want to donate one? Here is the preliminary code to draw the hexagons, as well as the code required to map midi notes: HarmonicTable NoteReference In Part 2 I’ll have have midi functionality implemented and some testing done. In Part 3 I’ll have it implemented with a touchscreen, most likely a laptop, at that point I’ll make the rest of the code available.