JUCE-based VST3 audio effect that splits a stereo input into 7 frequency bands using Linkwitz-Riley crossover filters.
Each band is output as a separate stereo channel, enabling multiband processing workflows in a DAW.
- 7-band Linkwitz-Riley crossover with 48 dB/octave slopes
- Draggable crossover frequency bar — click and drag dividers on a logarithmic frequency axis
- Draggable amplify/attenuator bar — click and drag horizontal line in each band to amplify/attenuate it's output
- Editable frequency text boxes — double-click to type a value in Hz, kHz, or musical note names (e.g.
C#3,E#1,Ab4) - Preset system — save, load, rename, and delete presets; navigate with prev/next buttons
- Full DAW automation — crossover frequencies are exposed as automatable parameters
- State save/restore — all settings are persisted with the DAW session
Prerequisite: The plugin requires the Microsoft Visual C++ 2015–2022 Redistributable (x64) to be installed on the host machine. Download: vc_redist.x64.exe — already present if Visual Studio 2019 or 2022 is installed.
This repo is set up for CMake presets.
Recommended (PowerShell):
.\scripts\build.ps1 # Build Release configuration
.\scripts\build.ps1 -Clean # Clean build
.\scripts\build.ps1 -Config Debug # Build Debug configurationThe build script automatically locates cmake.exe in Visual Studio installations.
Manual CMake:
- Configure:
cmake --preset vs2026-x64 - Build Debug:
cmake --build --preset debug - Build Release:
cmake --build --preset release
See docs/LINUX_BUILD.md for detailed instructions.
Quick start:
sudo bash scripts/install-linux-deps.sh # Install dependencies
cmake --preset linux-release # Configure
cmake --build --preset linux-build # BuildThe target built by the presets is phu-splitter_VST3.
The plugin uses Linkwitz-Riley crossover filters to split the incoming stereo audio into 7 frequency bands:
| Band | Range | Colour |
|---|---|---|
| Sub bass | < 80 Hz | Dark red |
| Bass | 80 – 250 Hz | Burnt orange |
| Low-mid | 250 – 500 Hz | Yellow |
| Mid | 500 – 2000 Hz | Forest green |
| Upper-mid | 2000 – 6000 Hz | Steel blue |
| Presence | 6000 – 12000 Hz | Indigo |
| Brilliance | > 12000 Hz | Purple |
Each band is output to a separate stereo bus, allowing independent processing in your DAW.
| Split | Frequency |
|---|---|
| Sub bass / Bass | 80 Hz |
| Bass / Low-mid | 250 Hz |
| Low-mid / Mid | 500 Hz |
| Mid / Upper-mid | 2000 Hz |
| Upper-mid / Presence | 6000 Hz |
| Presence / Brilliance | 12000 Hz |
All crossover frequencies are adjustable via the UI or DAW automation.
Crossover frequencies can be entered as musical note names using equal-temperament tuning (A4 = 440 Hz):
A4→ 440 HzC#3→ 138.59 HzE#1→ 43.65 Hz (enharmonic of F1)Db3→ 138.59 Hz (enharmonic of C#3)
Sharps (#, ##), flats (b, bb), and octaves 0–9 are supported.
Presets are stored as XML files in %APPDATA%/PhuSplitter/Presets/.
- Init — built-in default preset (cannot be deleted or overwritten)
- Save / Save As — save current crossover frequencies to a named preset
- Delete / Rename — manage saved presets from the dropdown menu
- Prev / Next — step through presets sequentially
For a detailed code map see CONTRIBUTING.md.