Contrapunk – Real-time counterpoint harmony from guitar input

In plain words

Contrapunk is a macOS audio tool that generates real-time counterpoint harmonies from guitar, MIDI, or keyboard input. It analyzes incoming audio and creates harmony voices that follow classical counterpoint rules, allowing users to select the key, voice-leading style, and which harmony part they want to play. The software is designed for musicians who want to improvise or compose with automatic harmonic accompaniment based on their input.

written from the facts on this page · September 2026

From the sources

Real-time MIDI harmony and arrangement generator for desktop, browser, VST3, CLAP, and Logic. Play MIDI or guitar and generate counterpoint live.

let harmony = Engine.new(Palestrina); fn detect_pitch (buf) -> Note const MAX_VOICES: usize = 4; voice_leading. reject_parallels () struct GuitarInput &#123; onset &#125; engine. harmonize (note, scale) fn detect_pitch( buf: &[f32] ) -> Option<Note> let voices = counterpoint:: generate(line, mode); if interval == Fifth && motion == Parallel { reject() } #[inline(always)] fn onset( frame: &Frame ) -> bool block_size: 128 sample_rate: 48_000 latency_ms: 7.2 // Palestrina // counterpoint // rules.rs HARMONY AND COUNTERPOINT Generate and route additional MIDI voices while you play. Works with MIDI keyboards and monophonic guitar input. A live Logic session using generated harmony, canon,…from contrapunk.com

In the maker’s words, at launch

Hi HN, I built Contrapunk because I wanted to play guitar and hear counterpoint harmonies generated in real-time. It takes audio from your guitar, MIDI player or your computer keyboard and generates harmony voices that follow counterpoint rules to generate harmonies. You can choose the key you would like to…

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