Oatmeal is a two-oscillator subtractive synth.


Two oscillators:

  • Waveform: sine, sawtooth, pulse (square), triangle, user, and “user PWM”.
  • Amp: Amplitude of the oscillator.
  • Tpitch (aftertouch > pitch): The effect of note velocity and later pressure changes on the oscillator’s pitch.
  • Pulsewidth, PWM rate, PWM depth. These are ignored unless the waveform is “pulse” or “user PWM”, in which case they set the base pulsewidth and the modulation rate and depth.
  • Trans (transpose): Transposition of the second oscillator relative to the first (i.e. the voice’s pitch).
  • Detune: Constant frequency shift of the second oscillator.
  • Touch (aftertouch > osc amp): The effect of note velocity and pressure changes on both oscillators’ amplitude.

Noise (white or bandpassed):

  • Amp: Noise amplitude.
  • Touch: The effect of note velocity and pressure changes on the noise level.
  • Resonance: If this is 0, unfiltered white noise is generated. Higher values increase the resonance of the bandpass filter, making the output purer.
  • Transpose: Transposition of the filter’s center frequency relative to the note.


  • Filter type.
  • Double (filter doubling): If this is enabled, two copies of the filter are run in parallel. See the “split”, “mix”, and “speed ratio” parameters.
  • Cutoff: Cutoff or center frequency of the filter.
  • Track (keytracking): In octaves/octave: if it is 1, an increase in the voice’s pitch of one octave will cause the cutoff to increase by the same amount.
  • Reso (resonance): Resonance of the filter (if applicable).
  • Split: If doubling is on, the second filter’s cutoff frequency will be this much higher than the first’s.
  • Mix: If doubling is on, this changes the output amplitude ratio between the two filters.
  • Touch (aftertouch > cutoff): The effect of note velocity and pressure changes on both filters’ cutoff frequencies.
  • Mod (envelope modulation): Strength and direction of the filter envelope’s effect.
  • Velocity: Effect of note velocity on the envelope modulation depth, not on the filter cutoff itself.
  • Filter envelope: For details, see the envelope block below.
  • Speed ratio: If doubling is on, the second filter’s envelope will move at this rate relative to the first’s.


  • Attack: The time it takes for the level to reach 1.
  • Hold: After reaching 1, the level stays there for this long.
  • Decay 1: The time it takes for the level to reach the breakpoint; however, if the breakpoint is set to 1 (0 dB), this is skipped.
  • Breakpoint: The point reached after the first decay phase (see just above to see what happens if you set this to 0 dB); immediately followed by
  • Decay 2: The time taken for the level to change from the breakpoint to the sustain level.
  • Sustain: Sustain level.
  • Release: Release time.


  • Type: Hard clip, soft clip (tanh), sine (which can produce fm-like timbres or, failing that, horrible noise), or asymmetric.
  • Mode: This sets where the distortion is applied:
    Global: i.e. once, after summing all the voices.
    Per voice: after the filter.
    Per voice: before the filter.
    Double: i.e. per voice before the filter and then again after summing the voices.
  • Oversample: Oversamples the distortion to reduce aliasing.
  • Pregain.
  • Limit: The level at which the signal is clipped (or the amplitude of the sine).
  • Postgain: In double mode, this is not applied to the per-voice distortion.


  • Mode: Sine, Ramp, and FM are essentially the same thing with different LFO shapes. Irregular is a bit different: the delay times of the voices vary randomly within the given range.

Sources :

Fuzzpilz: http://bicycle-for-slugs.org/
KVR: http://www.kvraudio.com/product/oatmeal_by_fuzzpilz