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:

• 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.

Envelope:

• 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.

Distortion:

• 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.

New in v38-1

Oatmeal now has unison. At present this affects only the two oscillators; filters and noise remain singular (although the filters are duplicated if necessary for stereo output). Still, it's a nice addition for doing silly things with relative oscillator phase and so forth.