gRainbow is an open-source synthesizer designed for cross-platform use, focusing on innovative granular synthesis through pitch detection. Unlike traditional granular synths that often rely on short audio snippets, gRainbow works with longer, pitch-rich samples to create harmonics that align closely with MIDI input. This approach minimizes excessive timestretching and enhances the natural harmonic content, resulting in more musically accurate and pleasing textures.

This synthesizer supports full MIDI range and polyphonic voicing, making it suitable for complex musical arrangements. It employs a reliable pitch detection system powered by advanced machine learning technology, allowing up to 100 grains to play simultaneously. Users can customize a wide range of parameters such as grain envelope shape, rate, duration, pitch, pan, and position, with options to adjust these settings on a per-note or per-generator basis. Additional features include the ability to play grains in reverse, synchronize grain rates with the host BPM, and play reference tones to assist in precise pitch calibration.

gRainbow offers a robust internal modulation and mapping system, featuring amplitude envelopes, multiple modulators, LFOs, and macro controls to shape sound dynamically. Its preset management system simplifies workflow by bundling audio samples directly within presets for easy recall. This combination of advanced granular synthesis techniques and user-friendly customization makes gRainbow a powerful tool for musicians and sound designers seeking rich, harmonically complex sounds with intuitive control.