1812 · Sideman
A generative jazz trio that follows your tempo and key — and shows you the chord it's about to play a beat early, so you can play into the change.
Press Start — the trio grooves immediately. Then play a melody on your keyboard rows below and watch it follow you.
Your keyboard is the melody instrument (quantized to the current key, so it always fits):
Read the design notes
The one question: what if your rhythm section could read your playing a beat ahead — showing you the next chord before it lands, so you play into the change instead of chasing it?
The trio synthesizes a walking bass (chord tones + chromatic approach), rootless left-hand comping voicings (Bill Evans / Bud Powell), and a brush-drum swing groove, all on a look-ahead scheduler. It infers your tempo from note-onset spacing and biases the key from your pitch-class histogram (lock either if it feels jumpy).
The anticipation display is borrowed from ReaLJam (arXiv:2502.21267, 2025), whose key idea is that the agent commits to and shows its upcoming chords ahead of time. Here the accompaniment engine is rule-based, not ML — the anticipation idea implemented in a browser with Web Audio + Canvas2D.
input: keyboard-played (QWERTY) + Web MIDI · output: Canvas2D · technique: reactive/anticipatory generative accompaniment · vibe: jazz