Coypu — Setup & Installation

Load Coypu into a Pharo image, choose a sound engine, and make sure the two are talking to each other before you write a single pattern.

1. What Coypu is, and is not

Coypu is a package of classes and methods for Pharo designed for live-coding music. It was originally built as a controller for SymbolicSound Kyma over OSC, and today drives any OSC-capable application, MIDI hardware, or the Phausto DSP engine running inside the same image.

Its string-oriented syntax owes a debt to TidalCycles, and the name is a tribute to Kyma's Capytalk dialect — the coypu being a rodent closely related to the capybara.

Coypu makes no sound It is a sequencer, not a synthesiser. It decides when and what; something else turns that into audio. Setting up that something else is most of this page.

2. Requirements

Requirement	Detail
Pharo	11, 12 or 13. Examples here target 13 unless noted
Platform	macOS, Windows or Linux
A sound engine	At least one of the backends in §4

Download Pharo from pharo.org/download. The Pharo Launcher is the easiest way to manage images. If you would rather not assemble anything, the Launcher also offers a Pharo Music image with Coypu and Phausto already installed — see the Phausto install notes.

3. Installing Coypu

3.1 Via Metacello

Open a Playground (Cmd-O W, or Cmd-P in some images), paste this, select it all and evaluate with Cmd-D / Ctrl-D:

Metacello new
  baseline: 'Coypu';
  repository: 'github://lucretiomsp/coypu:master';
  load.

The branch is master Coypu is on master, while Phausto is on main. It is an easy mix-up and Metacello's error when you get it wrong is not especially clear.

3.2 What comes with it

Coypu's baseline declares two external dependencies, so both arrive automatically:

Package	Source	Why
OSC	`github://Ducasse/OSC/src`	Open Sound Control messaging — how Coypu talks to SuperDirt, Kyma and Pure Data
Phausto	`github://lucretiomsp/phausto:main/src`	The in-image DSP engine, including `EcoPhausto` and `TurboPhausto`

Phausto arrives, but its native libraries do not Metacello installs Phausto's Pharo code. The compiled FAUST libraries are a separate platform-specific download that must sit in a librariesBundle folder next to your .image file. Until that is in place, Phausto loads but makes no sound — see Phausto § Installation.

MIDI is not included. For MIDI in and out you also need Pharo-Sound — see §4.3.

4. Choosing a sound engine

Coypu routes everything through a Performer. Choosing a backend means choosing a Performer subclass and handing it to the Performance:

p := Performance uniqueInstance.
p performer: PerformerSuperDirt new.

Performer	Sends to	Needs
PerformerPhausto	A Phausto DSP in this image	Phausto's native libraries
PerformerSuperDirt	SuperDirt, over OSC	SuperCollider + SuperDirt running
PerformerMIDI	External MIDI hardware	Pharo-Sound (PortMidi)
PerformerKyma	A Kyma Paca(rana), over OSC	Kyma hardware on the network
PerformerLocal	Any local OSC listener	Something listening on the port

Setting the performer clears the Performance performer: calls muteAll before and after switching, so every running pattern is removed. Choose your backend first, then build your patterns.

4.1 Phausto — in the image

The shortest path to sound, because nothing external has to be running. Phausto compiles a DSP inside Pharo and Coypu drives it directly.

TurboPhausto start.
tp := TurboPhausto new.

p := Performance uniqueInstance.
p performer: PerformerPhausto new.
p activeDSP: tp.

EcoPhausto is the lighter rack if the full one is slow to compile on your machine. Both are documented in Phausto § TurboPhausto.

A Phausto performance needs an active DSP PerformerPhausto raises “There must be an active DSP for this performance” if activeDSP: was never set. See §6.

4.2 SuperDirt / SuperCollider

The richest sample library, and the backend most live coders already have. Install SuperCollider, then SuperDirt, and start SuperDirt before you play anything:

"in SuperCollider, not Pharo"
SuperDirt.start;

"then in Pharo"
p := Performance uniqueInstance.
p performer: PerformerSuperDirt new.

Coypu sends OSC to 127.0.0.1 on port 57120, the port sclang listens on, using the /dirt/play message. Instrument names become SuperDirt sample folder names, so #bd, #sn and #cp work out of the box.

4.3 MIDI hardware

Install Pharo-Sound, which wraps PortMidi over uFFI:

Metacello new
  baseline: 'PharoSound';
  repository: 'github://pharo-contributions/pharo-sound:main';
  load.

No /src on this one Pharo-Sound still uses the older Monticello package layout rather than Tonel, so its repository path has no /src suffix — unlike Coypu's and Phausto's.

Then set the MIDI performer and give it an output device. PerformerMIDI holds its sender on the class side:

p performer: PerformerMIDI new.
PerformerMIDI midiOut: aMidiSender.

Each Sequencer carries a midiChannel, so route patterns to channels with midiCh:to:. Coypu also emits MIDI clock and a start message, which means hardware sequencers and arpeggiators will follow your tempo.

4.4 Kyma

The backend Coypu was originally written for. Coypu resolves the Paca(rana) by its Bonjour name — something like beslime-51.local — and sends OSC to port 8000, addressing Kyma's Virtual Control Surface:

p performer: PerformerKyma new.

Instrument names map to VCS labels: a Sequencer at #bass drives /vcs/bassGate/1 and /vcs/bassNote/1. Coypu also sends the tempo to a BPM label.

4.5 Any other OSC application

PerformerLocal targets a generic OSC listener on localhost — Pure Data, Max/MSP, ChucK, a browser, anything. Each triggered step sends a gate and a note message built from the instrument name:

p performer: PerformerLocal new.

A Sequencer at #bass produces /bassNote and /bassGate, the gate going to 1, waiting the note's duration, then returning to 0. See Phausto & MIDI for the message formats.

5. Verify the install

Smallest possible test. Evaluate line by line:

p := Performance uniqueInstance.
p performer: PerformerSuperDirt new.   "or whichever backend you set up"
p freq: 120 bpm.

16 downbeats to: #bd.

p play.
p stop.

Four evenly spaced hits and then silence means Coypu, the Performer and the engine are all connected. If the code runs cleanly but you hear nothing, the problem is between the Performer and the engine rather than in Coypu — work through §6.

You can also confirm the package loaded without making any sound at all:

Rhythm list size.        "how many named rhythms are available"
Performance uniqueInstance. "the singleton; should not error"

6. Where to go next

Document	What it covers
First Sounds	The Performance, the transport, and your first working pattern.
Rhythms: Basics	Every way to build a rhythm and route it to an instrument.
Rhythm Library	All 31 named rhythms, with verified step patterns.
Phausto & MIDI	Backend specifics in depth.

7. Troubleshooting

Metacello cannot find the baseline

Check the branch: Coypu is master, not main. See §3.1.

Coypu loaded but there is no sound at all

No Performer has been set, so nothing is being sent anywhere. p performer: … — §4.

“There must be an active DSP for this performance”

You are on PerformerPhausto without an activeDSP:. Start a rack and assign it — §4.1.

Phausto loaded but every note is silent

The native libraries are missing. They are a separate download and must sit beside your image file — §3.2.

SuperDirt makes no sound although SuperCollider is running

SuperDirt.start must have been evaluated, not just sclang booted. Check the SuperCollider post window for the line saying SuperDirt is listening on 57120.

My patterns disappeared when I changed backend

Expected: performer: mutes everything on the way in and out. Set the backend first — §4.

Kyma does not respond

The Paca(rana) is resolved by Bonjour name. Confirm the machine is reachable at its beslime-NN.local address and that the VCS labels match your instrument names — §4.4.