Chapter 1 - First beeps

First beep in SuperCollider

Most of the synths you are used to calling in Sonic Pi are implemented in Super Collider.

This tutorial is to enable you to write your own synths and for you, or other people, to use them in Sonic Pi.

Obviously if you can write Super Collider code you could just program Super Collider without Sonic Pi. And this manual will help you learn some, but not all, of how to do just that.

Like Sonic Pi this manual has an overriding design principle - to get from nothing to make a noise as quickly as possible.

With Sonic Pi that’s just:

use_synth :beep
play 69

With Super Collider it is nearly as fast.

Lets have a go.

To start with you need to tell the SuperCollider App to start the server engine.

This can be done with the menu item: Server -> Boot Server

You then need to check the log window to see if there are error messages. Sometimes you will need to edit audio settings on your machine to get SuperCollider to work.

The Super Collider version of use_synth :beep; play 69 is:

{SinOsc.ar(440, 0, 0.2)}.play;

Copy the snippet into the coding window on SuperCollider. Place the cursor in the code line and press [SHIFT][ENTER] and you will hear an A4 note (the Stuttgart pitch for standard tuning).

This will play forever.

To stop it you press [COMMAND][.] (the command key and the full stop at the same time.

One of the key differences between Super Collider and Sonic Pi is that Sonic Pi is sound-based (play this sound for this time period) and Super Collider is state-based - get this synthesiser into this state. By default sounds in Super Collider are of indefinite duration.

Lets break down that beep:

Its a function:

{ ... }

We are invoking the play method with the function:

{ ...}.play;

and the body of the function is a Sine Oscillator:

{SinOsc.ar(440, 0, 0.2)}.play;

SinOsc is an object, a sine wave oscillator.

ar is a method called on that object with the parameters 440, 0 and 0.2.

If we look up SinOsc in the documentation browser we will see that the object exposes two functions with the same signature:

SinOsc.ar(freq: 440.0, phase: 0.0, mul: 1.0, add: 0.0)
SinOsc.kr(freq: 440.0, phase: 0.0, mul: 1.0, add: 0.0)

We can see that the parameters in our invocation are:

In this instance the mul is effectively the volume, make it higher and the note will sound louder, lower it will be quieter.

Lets look again at the interface and the two methods ar and kr. The ar/kr pairing appears throughout SuperCollider so its important to understand what they mean.

For the moment we will stick to ar. Later on when we start building a proper synthesiser for Sonic Pi we will look again at the meaning of these.