Phosphor

A spectrogram-based audio synthesis tool for macOS. Paint images that become sound.

Phosphor lets you draw directly on a spectrogram canvas -- the X-axis is time, the Y-axis is frequency, and brightness controls volume. Import any image and hear what it sounds like, or paint spectral sounds from scratch using a variety of tools and timbres.

Inspired by MetaSynth by U&I Software.

Features

• Paint sounds: Brush, eraser, line, and harmonic brush tools
• Timbre palette: Paint with different tonal colours (saw, square, warm)
• Image import: Drop any image onto the canvas and hear it
• Audio import: Load audio files for spectral editing
• Piano roll overlay: See note lines while you paint
• Beat grid and snap: Rhythmic alignment tools
• Undo/redo: Up to 30 levels with intelligent memory management
• Project files: Save and load your work in .phosphor format
• Export: Render to WAV or export as PNG

Download

Download the latest release from the Releases page.

System requirements: macOS 12 (Monterey) or later. Apple Silicon and Intel supported.

Getting Started

See the Getting Started Guide for a walkthrough of Phosphor's features and keyboard shortcuts.

Building from Source

Prerequisites

• macOS 12+
• Xcode Command Line Tools (xcode-select --install)
• CMake 3.15+ (brew install cmake)
• libsndfile (brew install libsndfile)

Build

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --target PhosphorGUI -j$(sysctl -n hw.logicalcpu)

The app bundle will be at build/PhosphorGUI_artefacts/Release/Phosphor.app.

Run Tests

cmake --build build --target phosphor_tests -j$(sysctl -n hw.logicalcpu)
./build/phosphor_tests

Feedback and Community

• Report a bug: GitHub Issues
• Suggest a feature: GitHub Discussions
• Discord: Join the community
• Website: roexaudio.com

License

Phosphor is freeware. See LICENSES/ for third-party attribution.

Author

RoEx -- roexaudio.com