Definition
The modulation matrix is the table that connects sources (envelopes, LFOs, velocity, aftertouch, mod wheel, note number, random, sequencer) to destinations (pitch, cutoff, resonance, volume, pan, wavetable position, pulse width, effect parameters) with a positive or negative amount. In modular synths the connection is made with cables; in synths with a matrix (the 1985 Oberheim Matrix-12 is a historic example, emulated as Matrix-12 V in V Collection 9) with numbered slots. In modern synths (Serum, Vital, Pigments) you drag the source onto the parameter.
Elements of a slot
- Source: what modulates.
- Destination: what gets modulated.
- Amount (depth) and polarity: unipolar (0 → +) or bipolar (− ↔ +).
- Via / amount modulator: a second source scales the amount (e.g. the mod wheel controls how much LFO reaches the pitch: vibrato only kicks in when you raise the wheel).
- Curve: linear, exponential, stepped (quantized).
Sources and what they give
| Source | Character | Example |
|---|---|---|
| Envelope | movement tied to the note | “talking” filter attack |
| LFO | cyclic movement | vibrato, wobble, pan |
| Tempo-synced LFO | rhythmic movement | gate, wobble at 1/8 |
| Velocity | touch dynamics | brighter when you play harder |
| Key tracking | register | darker lead in the low register |
| Mod wheel / aftertouch | real-time expression | vibrato, filter opening |
| Random / S&H | unpredictability | small pitch and cutoff variations |
| MPE (slide, pressure) | per-note expression | independent pitch and timbre |
Macros
A macro is a control that moves several destinations together with different amounts and curves: for example “Energy”, which opens the filter (+40%), increases distortion (+30%), widens the stereo image (+20%) and raises the reverb (+10%). Macros are essential for performance and automation: a single automation clip replaces five.
Design principles
- Hierarchy: one or two main movements, the others subtle. Too many identical movements = chaos.
- Different timescales: slow LFOs (0.1–0.5 Hz) for “breathing”, tempo-synced ones for rhythm, envelopes for articulation.
- Cross-modulation: an LFO that modulates the rate of another LFO creates non-repeating movements.
- Modulate the effects: reverb mix tied to the envelope (tails that open up at the end of the note), drive that follows velocity.
- Human control: always assign the mod wheel and velocity to something meaningful.
Concrete examples
- Breathing pad: LFO 1 (0.08 Hz) → cutoff +15%; LFO 2 (0.13 Hz) → wavetable position +10%; velocity → attack (harder = shorter attack); mod wheel → chorus mix.
- Expressive lead: mod wheel → vibrato amount (LFO 5.5 Hz, ±20 cents) with a 300 ms delay; aftertouch → cutoff +25%; velocity → drive.
- Dubstep bass: “Growl” macro → LFO rate (from 1/4 to 1/16), wavetable position, formants, distortion.
In FL Studio
- In the stock synths: Sytrus (full modulation matrix and articulators for each operator), Harmor (envelopes for almost every parameter), 3x Osc (modulation via the channel: Envelope/LFO on volume, cutoff, resonance, pitch).
- Fruity Envelope Controller (envelopes and LFOs that can drive any parameter), Fruity Peak Controller (follows the volume of a track), Fruity Formula Controller (modulation with formulas) and above all Patcher, which lets you build macros: one control that drives several parameters with different curves.
- Multilink to controllers (menu option): links a hardware control to several parameters.
Example in A minor
Synthwave track at 100 BPM: pad on Am – F – C – G with a “Chorus” macro automated from 0 to 100% over 4 bars of pre-chorus: cutoff +35%, resonance +10%, stereo width +25%, reverb send +15%, level of a second oscillator an octave above +40%. A single automation clip builds the swell.
Common mistakes
- Modulating everything at the same speed: a “nauseating” sound.
- Excessive amounts on pitch: unwanted detuning.
- Forgetting polarity: a bipolar source that drops below zero closes the filter halfway through the cycle.
Exercise
- Take a static preset and add exactly three modulations (one slow, one tempo-synced, one expressive). Compare before and after.
- Create a macro with 4 destinations and use it as the only automation for an 8-bar build.
Related topics
“Envelopes, LFOs and modulation”, “Pad design”, “Lead design”, “Mix automation”, “Vector synthesis”.