Diatom
A monophonic FM synthesizer with a sub oscillator, modulation envelope, amplitude envelope, glide and warble controls.
Overview
Diatom is a monophonic dual oscillator synth that combines an FM voice with a filtered sub oscillator. The FM section provides classic bell and electric piano tones, as well as bleeps and bloops. The sub oscillator anchors the output to the fundamental pitch.
FM Section
The FM section creates its main tone by using one oscillator to modulate the frequency of another. FM controls how strongly that modulation acts, while Ratio changes the relationship between the two frequencies. Lower Ratio values create glitchy bleeps and higher values produce richer, ringing or metallic colors. Setting the Ratio control to rounded values produces more harmonic resonances between the two FM oscillators.
The FM Envelope is used to control the curve of the FM amount over time. It applies the FM amount contour separately from Amp Envelope’s volume contour. A quick rise and fall in the FM Envelope can create a bright strike followed by a smoother body. A longer attack ramps the extra harmonics, creating rich swells.
The Sub Oscillator
The sub oscillator provides a separate lower layer that provides a steady foundation underneath the more complex FM tone. Lower Sub Cutoff to soften its upper harmonics without having to soften the main FM voice.
Warble & Glide
The Warble section adds a vibrato effect to both the FM and sub oscillators. Depth controls its extent and Rate its speed. The Glide dial applies portamento, creating a smooth transition from one note to the next and affects only the FM section.
Properties
| Property | Value |
|---|---|
| Default polyphony | 1 |
| Maximum polyphony | 1 |
| Tonal scale support | Yes |
| Velocity support | Yes |
| Sustain support | Yes |
| Voice allocation | First note priority |
Controls
| Control | Description | Default | Minimum | Maximum | Units | Options |
|---|---|---|---|---|---|---|
| FM Level | Sets the main FM oscillator level. | 1 | -64 | 8 | dB | |
| FM | Sets the FM modulation depth. | 20 | 0 | 30 | amount | |
| Ratio | Sets the frequency ratio between carrier and modulator. | 16 | 0 | 16 | ratio | |
| FM Envelope Attack | Sets how long FM modulation takes to rise. | 0.001 | 0 | 2 | seconds | |
| FM Envelope Decay | Sets how long FM modulation takes to fall to sustain. | 0.2 | 0 | 5 | seconds | |
| FM Envelope Sustain | Sets the sustain of the FM modulation. | 0.5 | 0 | 1 | Gain | |
| FM Envelope Release | Sets how long FM modulation takes to fade after release. | 2 | 0 | 5 | seconds | |
| Sub Level | Sets the sub oscillator level. | 0.5 | -64 | 8 | dB | |
| Sub Cutoff | Sets the sub oscillator filter cutoff. | 20000 | 20 | 20000 | Hz | |
| Sub Res | Emphasizes frequencies around the sub filter cutoff. | 0 | 0 | 24 | Q | |
| Sub Octave | Chooses the sub oscillator octave division. | 1 | 1 | 2 | octave | I, II |
| Sub Shape | Chooses the sub oscillator waveform. | sine | sine, square, sawtooth, triangle | |||
| Warble Depth | Sets vibrato depth. | 0 | 0 | 1 | amount | |
| Warble Rate | Sets vibrato speed. | 8 | 0.01 | 16 | Hz | |
| Glide | Sets the portamento time between notes. | 0 | 0 | 1 | seconds | |
| Amp Envelope Attack | Sets how long the note takes to reach full volume. | 0.001 | 0 | 2 | seconds | |
| Amp Envelope Decay | Sets how long the volume takes to fall to sustain. | 0.2 | 0 | 5 | seconds | |
| Amp Envelope Sustain | Sets the held volume level. | 0.5 | 0 | 1 | Gain | |
| Amp Envelope Release | Sets how long the note fades after release. | 2 | 0 | 5 | seconds |