Classes | UGens > Generators > Granular

GrainFM : MultiOutUGen : UGen : AbstractFunction : Object

Granular synthesis with frequency modulated sine tones

Class Methods 1, trigger: 0, dur: 1, carfreq: 440, modfreq: 200, index: 1, pan: 0, envbufnum: -1, maxGrains: 512, mul: 1, add: 0)



the number of channels to output. If 1, mono is returned and pan is ignored.


a kr or ar trigger to start a new grain. If ar, grains after the start of the synth are sample accurate.


size of the grain (in seconds).


the carrier freq of the grain generators internal oscillator


the modulating freq of the grain generators internal oscillator


the index of modulation


determines where to pan the output.

  • If numChannels = 1, no panning is done.
  • If numChannels = 2, panning is similar to Pan2.
  • If numChannels > 2, pannins is the same as PanAz.

the buffer number containing a signal to use for the grain envelope. -1 uses a built-in Hann envelope.


the maximum number of overlapping grains that can be used at a given time. This value is set at the UGens init time and can't be modified. Defaults to 512. This can be set lower for more efficient use of memory.

WARNING: The above parameter is new (post SC 3.3.1) and has the potential to break code written <= 3.3.1. This parameter is BEFORE the mul slot, and you may need to update code to account for this difference.


All args except numChannels and trigger are polled at grain creation time.

Inherited class methods

Instance Methods

Inherited instance methods



var winenv;
// a custom envelope
winenv = Env([0, 1, 0], [0.5, 0.5], [8, -8]);
z = Buffer.sendCollection(s, winenv.discretize, 1);

SynthDef(\fm_grain_test, { |out, gate = 1, amp = 1, envbuf|
    var pan, env, freqdev;
    // use mouse x to control panning
    pan =, 1);
    // use WhiteNoise and mouse y to control deviation from center pitch
    freqdev =, 400));
    env =
        Env([0, 1, 0], [1, 1], \sin, 1),
        levelScale: amp,
        doneAction: Done.freeSelf);,,, 0.1, 440 + freqdev, 200,, 10),
            pan, envbuf) * env)


// use built-in env
x = Synth(\fm_grain_test, [\envbuf, -1])

// switch to the custom env
x.set(\envbuf, z)
x.set(\envbuf, -1);

x.set(\gate, 0);