SuperCollider Granular Example

Henrik von Coler — Sun, 02 May 2021 10:40:00 GMT

The TGrains UGen is an easy to use granular synth. It uses a Hanning window for each grain and offers control over position, pitch and length of the grains. The help files offer multiple examples for using this unit generator. The following example uses a simple pulse train for triggering grains.

Reading Channels

A single channel is loaded to a buffer from a sample for this granular example. The duration in seconds can be queried from the buffer object, once loaded.

~buffer = Buffer.readChannel(s,"/some/wavefile.wav",channels:0);

~buffer.duration;

The Granular Node

The granular node uses an Impulse UGen to create a trigger signal for the TGrains UGen. This node has several arguments to control the granular process:

The density defines how often a grain is triggered per second.
Every grain can be pitch shifted by a value (1 = default rate).
The grain duration is specified in seconds.
The grain center is defined in seconds.
A gain parameter can be used for amplification.
buffer specifies the index of the buffer to be used.

Once the node has been created with a nil buffer, the buffer index of the previously loaded sample can be passed. Depending on the nature of the sample, this can already result in something audible:

~grains =
{
    |
    density = 1,
    pitch   = 1,
    dur     = 0.1,
    center  = 0,
    gain    = 1,
    buffer  = nil
    |

    var trigger = Impulse.kr(density);

    Out.ar(0,   gain * TGrains.ar(1, trigger, buffer, pitch, center, dur));

}.play();


~grains.set(\buffer,~buffer.bufnum);

Manual Parameter Setting

As with any node, the arguments of the granular process can be set, manually. Since the center is specified in seconds, the buffer duration is useful at this point.

~grains.set(\center,0.2);
~grains.set(\density,100);
~grains.set(\dur,0.2);
~grains.set(\pitch,0.8);

Exercise

Playing Samples in SuperCollider

Henrik von Coler — Sun, 02 May 2021 10:40:00 GMT

The Buffer class manages samples in SuperCollider. There are many ways to use samples, based on these buffers. The following example loads a WAV file (find it in the download) and creates a looping node. When running, the playback speed can be changed:

s.boot;

// get and enter the absolute path to a sample
~sample_path = "/some/directory/sala_formanten.wav";

~buffer  = Buffer.read(s,~sample_path);

(
~sampler = {

      |rate= 0.1|

      var out = LoopBuf.ar(1,~buffer.bufnum, BufRateScale.kr(~buffer.bufnum) * rate, 1, 0,0,~buffer.numFrames);

      Out.ar(0, out);

}.play;

)

// set the play rate manually
~sampler.set(\rate,-0.1);

RingBuffer (Posts about _sound_synthesis:sampling-practical)

SuperCollider Granular Example

Reading Channels

The Granular Node

Manual Parameter Setting

Exercise

Playing Samples in SuperCollider

Exercise