Contrapunk
Real-time counterpoint harmony from guitar input
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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 improvise/play in and the voice leading style and which part of the harmony you would like to play as, as well.macOS DMG: https://github.com/contrapunk-audio/contrapunk/releases/tag/...Source: https://github.com/contrapunk-audio/contrapunk (do open any issues if you have any)Would love feedback on the DSP approach and the harmony algorithms. I am also looking at training a ML model for better realtime guitar to midi detection. I believe that will take some time.
HN · launched Apr 5, 2026 · 118 upvotes (top 9%) · 2 views
Niche: software synthesizers and midi tools · 119 launches, 5 in the last 7 days ▼ -64% · Explore this niche →
Category and tags
- Media & entertainment
- Content generation
- Prosumer
- Not AI
- Hobby / open-source project
Visit website ↗ Source listing ↗
More like this: all 119 launches in software synthesizers and midi tools →
Could you build this?
No Low-latency polyphonic pitch detection from raw guitar audio combined with formal algorithmic counterpoint voice-leading engines in real time requires specialized DSP and music theory expertise.
What it would actually take: Real-time guitar-to-MIDI requires advanced audio digital signal processing (DSP) like YIN, pYIN, or deep learning monophonic/polyphonic pitch tracking implemented with near-zero latency in C++/Rust or WebAudio Worklets. In addition, generating species counterpoint in real time requires algorithmic music composition engines that enforce strict voice-leading rules on the fly without introducing perceptible latency.
Discussion
20 comments analyzed.
Competitors mentioned: Jam Origin's Midi Guitar, ChordMini, Scale builder (langy-yua.net/skala), SonoBus
Concerns raised: Guitar to MIDI detection not real-time, Polyphonic guitar to MIDI recognition unsolved, Bach mode harmonies don't match traditional voicings, Extra setup steps needed for SonoBus integration (IAC buses, BlackHole routing)
Feature requests: Native SonoBus integration via AOO protocol, Real-time guitar to MIDI detection, Polyphonic chord recognition from guitar, Video demo for users without guitar/MIDI instruments, More scale options beyond Bach mode
Competitors
Other products that read as similar to this one : 345 launches clear the similarity bar, closest 8 shown.
Attention rank: #34 of 346 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 158 days after the earliest competitor.
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- Ableton Live MCP · hn · 2026-05-03 · 123 upvotes · similarity 0.47
- still.synth · ph · 2026-11-07 · 1 upvotes · similarity 0.46
- Harmony Lab · ph · 2026-10-08 · 3 upvotes · similarity 0.46
- FlexChords · ph · 2026-10-04 · 67 upvotes · similarity 0.45
- Browser based sythesizer, drum machine and squencer · hn · 2026-05-15 · 22 upvotes · similarity 0.45
- Wario Synth · hn · 2026-01-01 · 72 upvotes · similarity 0.44
- FlexChords · hn · 2026-10-20 · 13 upvotes · similarity 0.44
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