VOOG

Virtual Analog Synthesizer — a Moog-style polyphonic synthesizer built in Python with a tkinter GUI inspired by the Subsequent 37.

┌─────────────────────────────────────────────────────────────────┐
│  VOOG   VIRTUAL ANALOG SYNTHESIZER                              │
├─────────────────────────────────────────────────────────────────┤
│  OSC 1        OSC 2        OSC 3        NOISE                   │
│  (Oct)(Semi)  (Oct)(Semi)  (Oct)(Semi)  (Lvl)                   │
│  (Det)(Lvl)   (Det)(Lvl)   (Det)(Lvl)                           │
├─────────────────────────────────────────────────────────────────┤
│  FILTER       FILTER ENV   AMP ENV      LFO                     │
│  (Cut)(Res)   (A)(D)       (A)(D)       (Rate)(Depth)           │
│  (Env)(Key)   (S)(R)       (S)(R)                               │
├─────────────────────────────────────────────────────────────────┤
│  ┌─┬█┬─┬█┬─┬─┬█┬─┬█┬─┬█┬─┬─┬█┬─┬█┬─┬─┬█┬─┬█┬─┬█┬─┐         │    │
│  │ │█│ │█│ │ │█│ │█│ │█│ │ │█│ │█│ │ │█│ │█│ │█│ │         │    │
│  └─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┴─┘         │    │
└─────────────────────────────────────────────────────────────────┘

Features

• 3 oscillators with sine, saw, square, and triangle waveforms
• Moog ladder filter (24dB/oct) with resonance and envelope modulation
• Dual ADSR envelopes for amplitude and filter
• LFO with 4 waveforms and 3 modulation destinations (filter, pitch, amp)
• Glide/portamento with off, always, and legato modes
• Noise generator (white/pink)
• 4 multitimbral channels, 8-voice polyphony each
• 19 built-in presets from deep sub basses to screaming leads
• Rotary knob GUI with Subsequent 37-inspired dark theme
• Virtual keyboard — mouse click/drag + QWERTY PC keyboard input
• MIDI input support (optional, graceful fallback)
• Patch save/load system (~/.synth_patches/)

Installation

Requires Python 3.13+ with tkinter.

# Clone
git clone https://github.com/gpasquero/voog.git
cd voog

# Create virtual environment
python3.13 -m venv .venv
source .venv/bin/activate

# Install dependencies
pip install numpy sounddevice

# Optional: MIDI support
pip install mido python-rtmidi

# macOS only: install tkinter if needed
brew install python-tk@3.13

Usage

GUI mode

source .venv/bin/activate
python -m synth --gui

CLI REPL mode

python -m synth

Command-line options

--gui          Launch graphical interface
--patch NAME   Load a preset by name (e.g. "Bass Voog")
--midi-port P  Connect to a specific MIDI port
--no-midi      Start without MIDI input
--list-midi    List available MIDI ports and exit

Playing notes

QWERTY keyboard mapping

 W E   T Y U   O P        ← black keys (sharps)
A S D F G H J K L          ← white keys
C D E F G A B C D

Hold a key to sustain — key repeat is filtered so notes don't re-trigger.

Mouse

Click and drag on the virtual keyboard. Drag across keys to glide between notes.

MIDI

Connect any MIDI controller. MIDI CC messages are mapped to synth parameters (cutoff, resonance, envelopes, LFO, etc.).

Rotary knobs

All synth parameters use rotary knob controls:

• Drag vertically on any knob to change its value (up = increase)
• Scroll wheel for fine adjustment
• The amber arc shows the current value position

Presets

Preset	Description
Init	Default starting patch
Bass Voog	Fat detuned saw bass with filter envelope
Lead Saw	Aggressive dual-saw lead with legato glide
Pad Strings	Warm evolving pad with slow filter LFO
Sub Thunder	Deep sub bass with square wave foundation
Acid Squelch	High-resonance filter sweep, 303-style
Funky Pluck	Snappy percussive hit, fast decay
Screaming Lead	Bright resonant lead with vibrato and glide
Warm Brass	Square/saw mix with medium attack
Dark Drone	Detuned low saws with slow LFO sweep
Perc Hit	Noise burst with ultra-short envelope
Vintage Keys	Triangle/square electric piano tone
Wobble Bass	LFO-driven filter modulation
Trance Lead	Wide-detuned triple saw with pitch vibrato
Fat Unison	Three saws spread ±25 cents
Reso Sweep	Near self-oscillating filter with long decay
Fifth Stab	Power fifth interval, short punch
Glass Bell	Sine harmonics with long crystalline release
Noise Sweep	Filtered noise with resonant LFO, sci-fi

Architecture

synth/
├── dsp/            # Signal processing modules
│   ├── oscillator  # Wavetable synthesis (sine, saw, square, triangle)
│   ├── filter      # Moog ladder filter (24dB/oct, Huovilainen model)
│   ├── envelope    # ADSR envelope generator
│   ├── lfo         # Low-frequency oscillator
│   ├── glide       # Pitch portamento
│   └── noise       # White/pink noise generator
├── engine/         # Audio engine
│   ├── audio_engine  # Master engine, sounddevice output, MIDI routing
│   ├── channel       # Multitimbral channel (patch + voice allocator)
│   ├── voice         # Single voice (oscillators + filter + envelopes)
│   └── voice_allocator  # Polyphonic allocation with voice stealing
├── gui/            # Graphical interface
│   └── app         # tkinter GUI with rotary knobs and virtual keyboard
├── midi/           # MIDI support
│   ├── midi_input  # MIDI port listener (mido/rtmidi)
│   ├── midi_router # Message routing
│   └── cc_map      # CC-to-parameter mapping
├── patch/          # Patch system
│   ├── patch       # Patch data structure
│   ├── patch_manager  # Save/load to disk
│   └── default_patches  # 19 built-in presets
└── cli/            # Command-line interface
    └── repl        # Interactive REPL

License

MIT