A 3-band DJ isolator audio plugin inspired by Electronique & Spectacle (E&S) and TEIL3 B&.
- 3-band isolation with crossover points at 250 Hz and 3140 Hz
- LR4 crossover (Linkwitz-Riley 4th order, 24 dB/oct) for clean band separation
- Per-band gain from full kill (-100 dB) to boost (+12 dB)
- Configurable boost limiter (0 dB, +6 dB, +12 dB)
- Click-free transitions via EMA gain smoothing (5ms time constant)
- Zero latency (pure IIR, sample-by-sample processing)
- Formats: Standalone, VST3, AU
You can map this plugin to a MIDI controller with 3 knobs. We created a custom controller with Jérôme Barbé. It is based on Arduino UNO R4 and I'm planning to open source the code. Stay tuned!
Requires CMake 3.22+, Ninja, and a C++20 compiler.
# Debug build
cmake --preset default
cmake --build build
# Release build
cmake --preset release
cmake --build release-build
# Run tests
cd build && ctest# Install release plugins to ~/Library/Audio/Plug-Ins/
./scripts/install-plugins.sh --release| Parameter | Range | Default | Description |
|---|---|---|---|
| Low | -100 to +12 dB | 0 dB | Low band gain (< 250 Hz) |
| Mid | -100 to +12 dB | 0 dB | Mid band gain (250 Hz - 3140 Hz) |
| High | -100 to +12 dB | 0 dB | High band gain (> 3140 Hz) |
| Boost | 0 / +6 / +12 dB | 0 dB | Maximum boost level |
Input -> LR4(250Hz) -> LP -> Low band -> gain -> ╲
-> HP -> LR4(3140Hz) -> LP -> Mid band -> gain -> sum -> Output
-> HP -> High band -> gain -> ╱
Uses JUCE's LinkwitzRileyFilter (TPT structure) which guarantees LP + HP = allpass (flat magnitude response).