Heisenberg

Essentials

Heisenberg is a four-operator phase-modulation synthesizer (PM), offering FM-like tones through flexible sound design capabilities.

• Flexible modulation matrix for complex routing

• Assignable envelopes for dynamic control

• Multiple LFOs for modulation

• Multimode filter for tone shaping

Ideal for digital pianos, bells, basses, and experimental textures.

Global Controls

Mode	Play mode: Polyphone: Multiple notes can play simultaneously Legato: New notes retrigger envelopes only when previous note is released Monophone: Only one note plays at a time
Unisono	Amount of unison voices per note (1-4). Values > 1 create multiple voices for fatter, wider sounds
Detune	Tuning of unison voices in semitones (0-1 semitones). Creates detuning between voices when unisono > 1
Spread	Stereo width of unison voices (-100 to 100%). 0 = centered, positive = spread right, negative = spread left
Glide	Portamento time between notes (0-5000 ms). In Mono/Legato mode, notes glide if they overlap; in Polyphone mode, notes glide if they don’t overlap
Tune	Global pitch adjustment in semitones (-12 to +12 semitones)
Velocity	Global velocity sensitivity multiplier (0-100%). Controls how much note velocity affects loudness
Volume	Overall output level (0-1, equivalent to -∞ to 0 dB)
Active	Enable/disable the device (). When disabled, the synthesizer is silent
Detune Mode	Controls how operator detune is displayed: Semitone (1) or Ratio (2) mode (1-2). This affects the display only, not the audio behavior
Micro-tuning	Optional micro-tuning reference. Links to a micro-tuning device for alternative tuning systems

Operator (A–D)

Each operator can act as either a carrier (sound generator) or a modulator (affecting another operator’s sound). Every operator has individually controllable parameters.

Wave	Choose waveform from 49 selectable waves like sine, square, sawtooth, triangle, etc.
Semitone/Ratio	Coarse pitch adjustment. Can be displayed as semitones (0-64) or frequency ratio, depending on operator detune mode setting
Offset	Fine pitch adjustment in Hz (-9999.99 to 9999.99 Hz)
Pitch	Enables the pitch envelope for this operator

The waveform significantly affects the character of modulation. Sine waves produce clean, harmonic sounds, while complex waves introduce richer overtones.

Phase Modulation

At the heart of the interface is the modulation matrix, where you define which operator modulates which.

Instead of altering pitch, PM changes a signal’s phase over time. When the phase of a carrier is modulated by another operator (the modulator), new harmonics are created, making the sound more complex or animated.

Unlike subtractive synthesis (which removes harmonics via filters), phase modulation adds harmonics through modulation. This results in metallic, bell-like, or digital textures that are difficult to achieve with analog-style filtering.

The matrix works like a grid:

• Rows = Carriers (operators producing the final sound)

• Columns = Modulators (operators modifying other operators)

Each cell in the matrix holds a value (e.g., 0.5 or 1.0) that determines how much one operator modulates another.

Example

• In row A, column B, the value is “0.7”: This means B modulates A with a depth of 0.7

You can combine them freely:

• A modulator can affect multiple carriers

• A carrier can be affected by multiple modulators

• Chained or circular modulations are possible: e.g., C -> B -> A or even A -> B -> C -> A (feedback)

Visual Analogy

• Think of each operator as a light source

• Modulation is like placing colored filters in front of that light

• The more filters (i.e., modulators) in the chain, the more colorful, complex, or unpredictable the result becomes

Mix

Pan (left knob)	Stereo placement (-100 to 100). -100 = fully left, 0 = centered, 100 = fully right
Volume (right knob)	Audio output level of the operator (0-1, equivalent to -∞ to 0 dB). Only affects audible output, not modulation

These only affect the audible output, not modulation.

Default Behavior

• When loading a new patch, only Operator A has Volume > 0 (audible)

• Operators B, C, and D are muted (Volume = 0) by default and typically serve as modulators

Amplitude Modulation

Rows	Operators A–D and Filter Mod
Columns	Mod sources (Main ENV, ENV2, ENV3, LFO1, LFO2, Velocity)
Function	Controls how strongly each source modulates an operator’s amplitude or the filter cutoff
Filter Mod	Bottom row controls how modulation sources affect the filter

Envelopes

Main ENV	Standard ADSR envelope. Always applied to overall gain, but can also be assigned to individual operators via the amplitude modulation matrix
ENV2 & ENV3	Freely assignable ADSR envelopes. Can be routed to operator amplitude, filter cutoff, or other destinations via the amplitude modulation matrix
Pitch Envelope	Dedicated pitch envelope. Can be enabled per operator to modulate pitch over time
Loop	All envelopes can loop for rhythmic or evolving modulation patterns

LFO

Waveforms	Selectable waveforms including sine, square, saw, triangle, parabola, etc.
Rate	LFO speed. When free-running: 0.01-500 Hz ( normalized). When synced: quantized to bar time durations from 1/256 to 4/1 bars
Sync	Free-running or synced to host tempo. When synced, rate is quantized to one of 30 tempo-based values
Destinations	Can modulate pitch, amplitude, filter cutoff, etc. via the amplitude modulation matrix

Filter

Type	Multimode filter type (continuous: -1 = Low-pass, ~0 = Shelf, 1 = High-pass)
Slope	Filter order/slope: 12 dB , 24 dB, 36 dB, or 48 dB per octave
Cutoff	Filter cutoff frequency (33-22500 Hz)
Resonance	Filter resonance/Q factor (0.707 to 60). Higher values create more emphasis at the cutoff frequency
Keytracking	Adapts cutoff frequency to keyboard pitch (modulation depth: -1 to 1)
Envelope Modulation	Main ENV, ENV2, and ENV3 can modulate filter cutoff (modulation depth: -1 to 1 for each)
LFO Modulation	LFO1 and LFO2 can modulate filter cutoff (modulation depth: -1 to 1 for each)
Velocity Modulation	Note velocity can modulate filter cutoff (modulation depth: -1 to 1)

Step-by-step Modulation Setup

Set up your first phase modulation patch step by step.

1. Make sure Operator A is audible (Volume > 0).

2. Enter a value in the matrix, e.g., B -> A = 0.5.

3. Listen to how A’s tone changes.

4. Add another layer: C -> B = 0.8 -> now you get indirect modulation from C to A.

Note: Only the values in this matrix control modulation depth. The Volume sliders do not affect modulation.

Use Cases

Digital E-Piano	A = sine (carrier), long release; B = square (modulates A); ENV2 = velocity-sensitive amplitude
Synth Kick	A = sine, pitch envelope active with steep drop; Short amplitude envelope
Bell Tone	A = sine (carrier); B = square (modulator), high ratio; ENV3 modulates filter cutoff slightly

Practical Tips

Practical Tips

• Mod depth controls harmonic complexity; start low and increase gradually.

• Use ENV loop for rhythmic modulation; sync LFOs to host tempo when needed.

• Keep only one operator audible at first; add modulators step by step.

• Keytrack the filter for playable patches; combine with velocity in the mod matrix.