Assisted Music:

Generative Composition Tools for OS X

In my work as an intermedia artist, I have checked out an awful lot of software - and I always keep my eye opened for the unusual… of course!  Since the data is beginning to pile up, I thought some of you might benefit from my compulsive search for tools to help me transcend my limitations.

Being limited to a headmouse and 3 button/switches has forced me to explore (or rather, encouraged my natural interest in) alternatives to traditional music composition. By far my greatest handicap of course, is that I never mastered music notation - I'm illiterate!  So I'm on the lookout for a solution to the deceptively simple problem of having lost a wooden box with wires stretched across it - the apex of personal expression in my opinion. A hard act to follow.

The experience of making music as an exercise of pure determination and will. Entering midi heroically one note at a time is a pleasure I would not deprive any one of, but - it being 2010 - we have the benefits of alien technology to consider.

These are the chainsaws and flamethrowers of sound composition; robot looms that automatically weave intricate morphing sound by the yard, sophisticated automatic control of subtleties once considered the exclusive expressive realm of humans. However, this is all still just coming together... many of these programs only address one aspect or another of the dilemma - they are the musical equivalent of automatic transmissions - you just drive. Of course if you want to perform a high-speed four-wheel drift, it's not going to cut it, you will have to switch to manual. To get where you are going - sometimes you will have to get out and walk. Stitching together your creation can have a disturbingly Frankenstein-esque component, but oh, when one of them opens their eyes!

Luckily, media has a rich heritage of collage and appropriation - which is very liberating to someone trapped alone in their vibratory - I trust you follow me…

I won't go into a lot of detail here... for one thing, things are definitely picking up speed, generative composition and twisted little stand alone apps have become something of a moving target, not to mention the bewildering jungle of plug-ins and virtual instruments which really do multiply exponentially. 

i've kept a record of the more interesting apps i've crossed paths with

These apps were wiggling in the google alert "net" I set out every day.

I didn't know exactly how bizarre this selection of software was until I started to try categorizing them. Generally, I've let the developers speak for themselves by simply passing along some product blurb.

So, rather than an article or review, what we have here is a listing of OSx programs that would be useful to anyone making media in special circumstances. I have attempted here and there to indicate vague little recipes of how one might use these beasts.

So here's my report:

Generative Composition Tools

First you need to create some notes somehow. If playing a conventional keyboard is inconvenient you may want to explore alternate input systems. Once rare and exotic, alternate input systems have proliferated with new devices and frameworks popping up in ever increasing numbers. The Wii and iphone are legitimate musical instruments. Any data can be "sono-fied"  as the app “maestro frankenstein” illustrates,  so we have a spectrum of possibilities ranging from physically creating patterns, through capturing or repurposing data (much more satisfying than it sounds) all the way up to manipulating behaviors of complex rule sets.  I am concentrating on the more disembodied approaches here. Although the logical conclusion, direct mind control, will has\be dealt with later. 

As a sort of intermediate step in that direction you might want to consider hyper-instruments.

A groovy but misleading term, I guess the idea is that the instrument is granted responsibility for increasingly large portions of the composition, but this takes on an alarming aspect when you're actually envisioning one. Goals typically include - creation of synthetic harmony voices or chordal accompaniment, rhythmic mutation, interactive effect automation,etc… I fashioned a hyperinstrument of sorts when I created Gyre - and Brite Gray -the albums are primarily "played live" by controlling Noatikl  with custom scale sets in the µ-midi controller, and then feeding the results to Absynth and String Studio. The video production is another story!


The flexible design can play sequences and automation data in any direction or speed you desire. Innovative features like Audio -> MIDI pitch detection allow you to hum a melody or beat-box drum triggers. Most importantly, Nortron makes computer music fun. It's the perfect tool for sparking new ideas and exploring territory you never dreamed possible.



No musical ability required. Listen to a batch of critters, rate them and create a new generation based on your preferences. Breed them repeatedly, 'steering' your critters towards your desired destination. Or, start over with a fresh litter of random critters. Critters is not a loop-based composer. There are an infinite number of potential compositions (Well actually only 2 to the 10,000th). Create endless subtle (or not) mutations of your favorite critters. If you know what you like you can compose.


Noatikl is a generative (MIDI) music engine. Using various algorithms and rules it creates musical information in the form of MIDI notes, and can also generate and send MIDI controller information to generatively control settings of your favorite synths, FX units and samplers. Its interface is deceptively simple and uncluttered; yet Noatikl still lets you easily get remarkable results without needing to understand music theory or be a music scientist (although it helps)


What is Nodal?
Nodal is a generative software application for composing music.
It uses a novel method for the notation and playing of MIDI based music. This method is based around the concept of a user-defined graph. The graph consists of nodes (musical events) and edges (connections between events). You interactively define the graph, which is then traversed by any number of voices. These voices play the musical events as they encounter them on the graph. The time taken to travel from one node to another is based on the length of the edges that connect the nodes. Nodal allows you to create complex, changing sequences using just a few simple elements. Its unique visual representation shows a structural representation for generative systems that you can edit and interact with in real-time as the composition plays.


Tiction is a flexible, nodal music sequencer. It’s pretty simple: Each node represents an event, and a connection from one node to the next triggers the next event after a certain number of tics. Nodes send MIDI note messages and/or MIDI controller change messages when triggered. Connecting nodes in a circuit lets you start a repeating pattern when one of the nodes is triggered.  A node can change its pitch and controller values based on its position on the screen. When a node is triggered, it performs some physical action: either repelling or attracting other nearby nodes, or nudging itself in a random direction. The physical interaction between nodes allows you to construct complex, rhythmic melodies and effects without having to draw filter envelopes or touch a traditional sequencer.


Elysium is an interactive generative MIDI sequencer. Notable for it's distinctive hexagonal tone cluster keyboard layout, music is created by building up a “system” composed of layers, cells, tokens, and playheads that combined, when “played," to produce a sequence of notes.  Elysium is under active and enthusiastic development and shows definite tendencies towards being used to form a hyper-instrument.


Now that you have musical patterns being somehow generated - next you need to capture and manipulate your performance/data. In most cases this means a midi sequencer, although if you immediately commit to audio (a very refreshing approach) then you might edit your results in a Digital Audio Workstation. These are my personal favorites - but it is such a big topic! I really haven't determined which DAW is officially most "gimp-friendly" - although Ableton Live might be a good bet. 


logic audio

ableton live

Innovative Sequencers

In this context, i'm referring less to midi editors per se, and more to the twilight world of hybrid pattern production tools. Sort of musical drum machines with minds of their pwn.


FretPet is a unique guitar-oriented music sequencer, an educational tool for learning music theory, a controller for software and external synthesizers, a reference for all things relating to notes, chords, keys, and scales. And an indispensable assistant for creating coherent musical compositions with ease.

I love this thing more every day.


Breakage is an intelligent drum machine designed to make it easy and fun to play complex, live breakbeat performances. A step-sequencer pattern editor and previewer, database, sample browser, neural network, pattern morphs, statistics and probabilistic pattern generator give you the tools to work with breaks on a higher level than ever before.


Numerology is a modular music sequencing and audio plugin environment for Mac OS X. It takes the step sequencing and modulation metaphors established by the analog sequencers of the 70's, and implements them in a structured and highly interactive software environment designed for experimentation, improvisation and live performance. By using Numerology in conjunction with your choice of Audio Unit plugins and hardware synths, you can create an open compositional environment that is truly your own.

ValEVarion evolved103


Very organic and satisfying!


hypercyclic is an LFO-driven MIDI arpeggiator, gate effect and step sequencer for mangling MIDI input chords. Two tempo-synced LFOs can be used to modulate various parameters to create interesting rhythmic effects and chord variations. A unique feature is the possibility to modulate the sequencer step size itself, which is useful for creating glitchy stuttering effects. The sweetspot for hypercyclic is the narrow border between chaos and regularity. Or, in other words, how to induce a certain pleasant  randomness, yet forcing everything to align again on the bar or beat boundaries. The product is further complemented by a groove function for playing slightly off the beat. The groove parameters can also be modulated over time by the LFOs, adding to the rhythmic variation.


Once you are finally looking at your composition as an audio file you may not be able to resist the urge to twist it further. I am particularly guilty of excesses in this department. Although there is literally no end to the amount of funky audio manglers to be found on the net, I have restrained myself and offer here a couple that themselves feature strange generative qualities.


It is a live beat-slicer but instead of manipulating equal chunks of audio like most beatslicer do, it works on the notion of audio cuts whose length and number of repetition depends on the context and the cutting procedure. Cuts are organized in blocks which then form a phrase.


Automaton is a unique look at buffer effects, allowing you to experiment with artificial life within your DAW. With four separate effects (Stutter, Modulate, Bitcrush, and Replicate) driven by a cellular automata sequencer, Automaton is capable of adding subtle seemingly random fills and "humanizing" effects, but if you like, you can crank the sequencer up to eleven, and watch as your DAW becomes a petri dish while Automaton makes complete hay of the track you've inserted it to.

Software Instruments 

Finally - something that actually makes a noise. Again - there are huge swirling nebulas of software synths out there - you're on your own. There are no arguing matters of taste - but here are some of my current favorites.


Sonic Charge Synplant

Synplant is a software synthesizer with a genetic approach to sound creation. Instead of creating patches the conventional way by turning dials and knobs, Synplant lets you explore a world of organic sounds by planting seeds that grow into synth patches.

String Studio VS-1

String Studio VS-1 is a string modeling synthesizer plug-in that swaps the traditional oscillator, filter, and envelope pattern for real-life string instrument components. String Studio's pick, bow, hammer, finger, fret, damper, and soundboard let you control the materials, natural decay, grain, warmth, buzzes, harmonics, resonance, friction, tension, and component interaction that make up the sound of guitars, basses, clavinets, clavichords, pianos, and ethnic instruments.

Strum Acoustic Session

Also from AAS, deserves a mention because like its more metallic cousin Slayer, it skirts the hyperinstrument category, making its own decisions about rhythm,  chord voicings and picking patterns


Mr. Alias 2 may be the most utterly sick soft-synth on our planet. It  uses non-bandlimited oscillators which can be transposed near to and beyond the Nyquist frequency, causing most of their spectra to be aliased back into audible non-harmonic frequencies. The sound can then be further processed by a number of crude "effects."  The final sound is something like a brutal gang-fight between a group of delinquent shortwave radios and a posse of arcade games high on angel dust. A real eye-opener.

Odd Input Tools

If you don't play a traditional physical instrument, but you still want to affect the sounds in realtime - you're going to need some way of generating/modifying notes, to say nothing of the exhaustive list of parameters available for realtime automation via midi continuous controller info. The tools I'm presenting  here are "on-screen"  controllers  - specifically appropriate for headmouse users.


midimouse is a small, easy-to-use and very simple program. It sends MIDI-controller-messages (CC) by moving the mouse over its window. While moving the cursor (with or without mouseDown) over the X-/Y-axis, each axis sends a CC, so you might send values within up to 4 configurable Controllers.

So, what’s it for if you’ve never heard of CC’s?
You can make music with it! Just connect it as a MIDI-Controller (input) to your hardware-synthesizers or software-programs and you can control the effects by moving your mouse - on a small screensize or even on full screen. If midimouse is in “click-through” mode, you can even still reach the underlying controls!


ReMIDI is a tool that enhances a keyboard performance to by automatically changing notes into chords and chords into arpeggios or strums.

µ MIDI Controller

Use your computer keyboard & mouse or Wacom tablet to create a musical performance!

Control both your software & hardware MIDI devices.

Have complete control of your MIDI parameters.

Use our convenient tools for

entering chords, notes and

scales to tailor your performance

for each of your songs.

Always In Key

What is Always In Key?

Always In Key is a small utility app that allows a user to select a musical key and restrict the MIDI output to only notes contained in that key.

Why would I want to do that?

Well, for any number of reasons really. Let's say that you are ad-libbing a lead on your synth (and you know the key in which you are playing), you can simply route your MIDI into this app and jam away without fear of playing any wrong notes. (fear? ... wrong?... notes?)  



HighC uses only the simplest GUI techniques: draw notes, envelopes and wave shapes; move and resize sounds; copy and paste to create effects; group sounds into rhythms or patterns; repeat your groupings to create a harmonic line; link your sounds to one another to create modulations... Its simple, it's powerful!

(Sort of like Metasynth, but without destroying your brain. )

Argeïphontes Lyre

A set of audio, video and text filters

for the Macintosh. OSX (10.5+)

from iconoclast and geek-hero Akira Rabelais

AudioFinder 4.9.7

AudioFinder is an audio asset management system, and music production hub. AudioFinder gathers all the most useful tools in one quick and intuitive application, enabling you to be more creative by handling all the time consuming tasks that slow down your music production.

AudioFinder can build a catalog of every sound on your system, save it, and search it instantly to find the sounds you need when you need them. Use AudioFinder to create custom sets for sound categories and specific projects, with fast file browsing to audition, analyze, process, convert, and move or copy the samples in your library.

AudioFinder can visualize sounds instantly with the waveform overview and preview them at any pitch via MIDI or the built in keyboard, all in real-time. Sounds can even be previewed through your favorite AudioUnits. Speaking of Plug-Ins, AudioFinder features an advanced Plug-In manager and slew of other studio necessities that will make your workflow flow. Necessities like audio editing with built-in beat detection and tools for fast trimming, fading, slicing and dicing your sounds. You can even convert your audio sample CDs into individual files with just a few clicks of the mouse.

AudioFinder invented the genre of sound browsers, by being the first dedicated sound browser on any platform. With a long history of innovation, AudioFinder has consistently broke new ground and with free updates you can expect to always get more value added.

Built 100% for Mac OS X using CoreAudio, AudioFinder is PPC and Intel Native.

Kapling 1.0

Not quite a sequencer and yet not quite a software instrument - Kapling is a simple little standalone physical modeling synthesizer application for Mac OS X built with Max/MSP 5. It is based on the Karplus-Strong algorithm. Kapling uses this method to attempt the emulation of resonant bodies, like a string being plucked, or melodic percussion instrument being struck. Eight independent voices are triggered by a 32-step sequencer, with a variety of parameters set up to help you sculpt new timbres in realtime. Kapling also features a tempo-synced stereo delay and recording to disk. In simpler terms, Kapling can help you make twangy, boingy, klonky tones. If you could mate a banjo with a tabla - Kapling would be their baby!

WireTap Pro

Record Anything

Using WireTap Studio, you can record the discrete audio output of any application, as well as all system audio, or record audio input from any microphone, line-in, or audio input hardware.

If you can hear it, WireTap Studio can record it. Heh. A required feature of any pirate rig.


Seal-Show in a box: if you have a butt-load of audio lying around and you just want to go for it? Kenaxis' random load, modulation kookyness is extremely satisfying. It can't be bargained with. It can't be reasoned with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you are dead.


•Powerful Tools: 6 loop players each with a 12 band parametric EQ, granular synthesis, FFT phase vocoder, random file players, analog synthesis, pitch modulation, convolution, 30 second delay with automated filters, and VST support

•Intuitive Interface: clear, compact display of all parameters at once: monitor and manipulate every aspect of your performance

•Complete Control: keyboard & mouse, OSC (Open Sound Control), MIDI, USB Joystick, Wacom Tablet, or use built-in random generators or oscillators

•Easy to Learn: built-in help system, comprehensive manual, and video tutorials

•All Sources: your audio library, live real-time captures, synthesized sounds

•Tested and Honed for: live looping, film scores, theatre, DJing, free improvisation, soundscaping, glitch, ambient, noise, electro-acoustic works, much more



A realtime modular composition and processing software for sound design and experimental music like glitch, IDM, electroacoustic, ambient...

Gleetchlab 3 is a modular software designed to process audio files and live sound sources in realtime.

Unlike many music softwares, gleetchlab does not use a "timeline", instead you can process and record sound as it plays and quickly store every  parameter into ten easy-to-recall temporary presets.

You can manipulate samples with random loop points, alternate speed and direction of playing without limits, pencil-edit waveforms and use the internal DSPs such as convolution, feedback generator, granular re-synthesis, waveshaping distortion, spectral filtering, wow simulation, dynamic reverberation and your own VST plugins.

Also you can record  and re-record endlessly each processed sound into the 6 stereo loopers or manipulate  sources coming from your soundcard and last but not least, use a quadriphonic surround mixer/recorder.


Archibald is a virtual drummer who adds improvisational touches to your drum patterns. As you build your rhythm in the step-sequencer, you assign Archibald a margin of interpretation from 0 to 100%. This margin allows for a more realistic sound, based upon the simple fact that no drummer plays two consecutive eighth notes with exactly the same tone and attack. Archibald may be a "machine," but his interpretations may surprise you. The sampler engine which accompanies the step-sequencer uses 44.1 kHz resolution and an impressive set of realistic sounds.

The second sequencer, driving the first, allows the user to program sequences based on several bars. From Version 2.1 onward, Archibald may interface with your sequencer via Rewire technology, allowing you to mix the 12 individual outputs from within your favourite sequencing software. You may also export your work as audio. Or use Archibald to drive any MIDI device.


Oscillating Rhythms is a generative tool designed to help you explore rhythmic space. Leveraging the power of periodic functions, Oscillating Rhythms provides users with high level control over low-level detail. Up to four tracks can be layered providing users with a rich pattern generation tool, from straight 8ths through to the most complex polyrhythms. Oscillating Rhythms is an AudioUnit host, so load up your favorite drum sampler and away you go. From the simple to the sublime, Oscillating Rhythms is sure to spark your creativity – just don't forget to record your performance!

Really Miscellaneous

this is really important stuff, that just falls through the cracks in the context of this report. I wouldn't feel right if i didn't mention these while i had the chance.. . Studio Artist alone deserves it's own discussion as an enabling interface for gimpfolk. it's power is unfathomable.


rgGamma is an application to control your screen's gamma. It allows you to set the gamma to red, green or a custom color and to control the screen brightness. If you have multiple monitors rgGamma will set all of them at the same time. It can be used for night vision control with any application.

Studio Artist™ 4

Studio Artist 3.5 includes over 4000 paint presets plus hundreds of factory effects all completely editable. Apply any effect on a still image or video. Instantly create paintings, vector art, effect processed images or keyframe animations. Add warping, morphing, texture synthesis and much more. Anything that you can do with a still image can be applied automatically to a video source creating stunning one-of-a-kind effects.

USB Overdrive X

The USB Overdrive is a device driver for Mac OS X that handles any USB mouse / trackball / joystick / gamepad / media keyboard and any Bluetooth mouse from any manufacturer and lets you configure them either globally or on a per-application, per-device basis.

It works in Mac OS X 10.4 (Tiger), 10.5 (Leopard) and 10.6 (Snow Leopard) in both 32-bit and 64-bit modes.It reads all kinds of wheels, buttons, switches and controls and assigns them to useful actions like clicking, typing, scrolling, launching, opening documents and so forth. The USB Overdrive can easily handle several USB devices at once and can assign different settings to each one.

I've mentioned this utility before - but it bears repeating; whatever it is that you have to work with, be it a thumb, a toe, flppers or beak - this is the force-multiplier!

In Conclusion...

These programs really cheered me up! The ability to express one’s selves is certainly one of MY main prerequisites for a meaningful existence. 

Again, a blanket thankyou to the hard-working truth-weavers and iteration scrutineers who created these oddities out of thin air.

Please do be careful with these potent softwares, their potential for misuse is incalculable. See you again...