Synthesizer Guide: 3-Oscillator Subtractive Synth

Crayonbrain includes a three-oscillator subtractive-style synthesizer built into Compose. Each oscillator can be switched on or off and edited independently. When you play a note, all enabled oscillators sound together, each passing through its own filter and envelope before they are summed, limited, and sent to the mix.

This is the same general architecture used by classic hardware and software synths: from oscillator, to filter, to amplifier (envelope), and finally to the output, with an optional LFO (low-frequency oscillator) moving parameters over time. You do not need a separate app or plugin. Open Compose, switch to Keys, tap Synthesizer, or read the Compose guide for the full workflow.

A single oscillator can only produce one basic waveform at a time (sine, square, triangle, or saw). Stacking multiple oscillators together creates more harmonic complexity:

• Osc 1 might carry the main pitch with a bright saw or square wave
• Osc 2 might be detuned a bit up or down for a chorus-like widening effect
• Osc 3 might sit an octave lower with a soft sine for body

In Crayonbrain, tabs labeled Osc 1, Osc 2, and Osc 3 let you edit one layer at a time. A small indicator shows whether each oscillator is enabled. Only enabled oscillators contribute to the sound and to CPU load.

For each enabled oscillator, the path looks like this:

1. Oscillator: generates a periodic waveform at the note pitch (plus fine detune in cents).
2. Filter (optional): shapes brightness by removing or emphasizing frequencies. An LFO can wobble the filter cutoff when enabled.
3. Amplitude envelope (optional ADSR): controls how loud the note is over time: attack, decay, sustain, release.
4. Mix bus: enabled oscillators are combined, passed through headroom gain and a limiter, then routed into the Compose mixer and export path like other instruments.

Think of it as three mini-synths that share one note and one output. Disabling an oscillator removes it from the stack instantly.

Under the Waveform section for the active oscillator, choose a basic tone:

• Sine: pure and smooth, good for sub bass and soft pads
• Triangle: slightly richer than sine, still mellow
• Sawtooth: more aggressive and buzzy, common for leads
• Square: clarinet-like character, strong odd harmonics

Fine detune shifts pitch in cents (±100). Small detune values (3-15 cents) between oscillators create the “supersaw” thickness heard in trance and EDM. Large detune sounds out of tune, often used intentionally for experimental effects.

The Filter section sculpts the harmonic content after the raw oscillator.

• Lowpass: lets lows through and cancels highs. Lower cutoff = darker, muffled sound. Classic for warm bass and pads
• Highpass: removes lows, thin and airy
• Bandpass: cancels lows and highs, often described as creating a retro phone or radio like effect
• Notch: cuts a narrow band, used to make precise edits to the spectrum

Cutoff sets the filter frequency, and Resonance boosts frequencies near the cutoff. High resonance can whistle or self-oscillate on some settings, this could sound either good or bad, depending on how it was set up.

The Envelope section is an ADSR envelope: Attack, Decay, Sustain, Release. It controls how the volume changes from the moment the note is played until it ends.

• Attack: time to reach full level after note on. Short = plucky, long = soft fade-in (pads)
• Decay: time to fall from peak to sustain level
• Sustain: level while the note is held (silent hold/full level)
• Release: time for the sound to fade out

A visual curve in the UI shows the shape as you drag sliders. Plucks: fast attack, low sustain, medium release. Pads: slow attack, high sustain, long release. Bass: fast attack, medium sustain, short release.

When the envelope is disabled for an oscillator, a default amp shape is still applied by the engine so notes remain audible, enable the envelope when you want explicit sculpting.

An LFO (low-frequency oscillator) cycles slowly compared to an audio oscillator. It does not make pitched musical notes by itself, it modulates another parameter. In Crayonbrain, the LFO modulates filter cutoff on that oscillator's filter, so the cutoff rises and falls.

• Waveform: sine, square, triangle, or saw shapes the modulation contour (smooth vs stepped vs ramp)
• Rate: speed of the cycle in Hz
• Depth: how strongly the LFO pushes the cutoff (0-100%)

Tip: enable the filter on the same oscillator before expecting a strong LFO effect.

Key and Duration apply to how the synth patch behaves in isolation.

• Key: pitch when played as a standalone sample
• Duration: how long the note plays as a standalone sample

These of course can change when you write them into the composer as a melody. This workflow is a bit different than most music apps, it's done this way in order to be useable across different devices.

1. Go to Compose.
2. Switch the Drums / Keys toggle to Keys
3. Go to Synthesizer in the piano roll toolbar
4. Use Composer (back arrow) to return to the piano roll when finished

In synth view, the navbar displays a collapsible Visualizer that can sit above the panel. Check out the Visuals guide for more information about the synth visuals.

Open the preset drawer from the right side in synth view. Built-in categories include pads, plucks, leads, and basses.

• Apply: loads the preset
• Clear: resets toward a simple default.
• Save / Load preset: store your own patches when signed in

You can also pick a saved synth preset as an instrument on the piano roll alongside samples.