Oscillators
Oscillators are the sound sources in any synthesizer—they generate the raw waveforms that filters and effects shape.
VCO (Voltage-Controlled Oscillator)
The primary sound source for subtractive synthesis.
let vco = patch.add("vco", Vco::new(44100.0));Inputs
| Port | Signal | Range | Description |
|---|---|---|---|
voct | V/Oct | ±10V | Pitch (0V = C4) |
fm | Bipolar CV | ±5V | Frequency modulation |
pw | Unipolar CV | 0-10V | Pulse width (5V = 50%) |
sync | Gate | 0/5V | Hard sync reset |
Outputs
| Port | Signal | Description |
|---|---|---|
sin | Audio | Sine wave |
tri | Audio | Triangle wave |
saw | Audio | Sawtooth wave |
sqr | Audio | Square/pulse wave |
Waveform Mathematics
Sine: $$y(t) = A \sin(2\pi f t)$$
Sawtooth (BLIT): $$y(t) = 2 \left( \frac{t}{T} - \lfloor \frac{t}{T} + 0.5 \rfloor \right)$$
Triangle: $$y(t) = 2 \left| 2 \left( \frac{t}{T} - \lfloor \frac{t}{T} + 0.5 \rfloor \right) \right| - 1$$
Square/Pulse: $$y(t) = \text{sign}(\sin(2\pi f t) - \cos(\pi \cdot \text{PW}))$$
Usage Example
// Basic VCO with external pitch
patch.connect(pitch_cv.out("out"), vco.in_("voct"))?;
// FM synthesis
patch.connect(modulator.out("sin"), vco.in_("fm"))?;
// PWM (pulse width modulation)
patch.connect(lfo.out("tri"), vco.in_("pw"))?;LFO (Low-Frequency Oscillator)
Sub-audio oscillator for modulation.
let lfo = patch.add("lfo", Lfo::new(44100.0));Inputs
| Port | Signal | Range | Description |
|---|---|---|---|
rate | Unipolar CV | 0-10V | Frequency (0.01-30 Hz) |
depth | Unipolar CV | 0-10V | Output amplitude |
reset | Trigger | 0/5V | Phase reset |
Outputs
| Port | Signal | Description |
|---|---|---|
sin | Bipolar CV | Sine wave (±5V) |
tri | Bipolar CV | Triangle wave |
saw | Bipolar CV | Sawtooth wave |
sqr | Bipolar CV | Square wave |
sin_uni | Unipolar CV | Unipolar sine (0-10V) |
Rate Mapping
Default rate curve: $$f = 0.01 \cdot e^{(\text{CV}/10) \cdot \ln(3000)}$$
| CV | Frequency |
|---|---|
| 0V | 0.01 Hz |
| 5V | ~1 Hz |
| 10V | 30 Hz |
Noise Generator
White and pink noise sources.
let noise = patch.add("noise", NoiseGenerator::new());Outputs
| Port | Signal | Description |
|---|---|---|
white_left | Audio | White noise (left) |
white_right | Audio | White noise (right) |
pink_left | Audio | Pink noise (left) |
pink_right | Audio | Pink noise (right) |
Noise Spectra
White noise: Equal energy per frequency (flat spectrum)
$$S(f) = \text{constant}$$
Pink noise: Equal energy per octave (-3dB/octave)
$$S(f) \propto \frac{1}{f}$$
Pink noise is generated using the Voss-McCartney algorithm.
AnalogVco
VCO with analog imperfections for authentic vintage sound.
use quiver::analog::AnalogVco;
let vco = patch.add("vco", AnalogVco::new(44100.0));Additional Features
- V/Oct tracking errors
- Component tolerance variation
- High-frequency rolloff
- Soft saturation
See Analog Modeling for details.
Common Patterns
Detuned Oscillators
let vco1 = patch.add("vco1", Vco::new(sr));
let vco2 = patch.add("vco2", Vco::new(sr));
// Slight detune for thickness
let detune = patch.add("detune", Offset::new(0.01)); // ~12 cents
patch.connect(pitch.out("out"), vco1.in_("voct"))?;
patch.connect(pitch.out("out"), vco2.in_("voct"))?;
patch.connect(detune.out("out"), vco2.in_("voct"))?; // Adds to pitchHard Sync
// Slave syncs to master
patch.connect(master.out("sqr"), slave.in_("sync"))?;
// Modulate slave pitch for classic sync sweep
patch.connect(lfo.out("sin"), slave.in_("voct"))?;FM Synthesis
// Carrier:Modulator = 1:1 for harmonic FM
patch.connect(modulator.out("sin"), carrier.in_("fm"))?;
// Control FM depth with envelope
patch.connect(env.out("env"), fm_vca.in_("cv"))?;
patch.connect(fm_vca.out("out"), carrier.in_("fm"))?;