How It Works

ChordSine is a chord waveform visualizer for seeing the shape of music, designed like an instrument rather than a graph. Consonance and dissonance are not only things you hear; they are visible properties of the resulting waveform. When you hold a few notes, ChordSine shows each sine-wave component or their sum as separate view modes. The instrument marks where the pattern repeats, because the repeat is what turns the shape into something you can read.

Consonant intervals are built from simple frequency ratios. A perfect fifth is close to 3:2, an octave is 2:1, a major triad stacks ratios that line up quickly. Because the parts line up, the combined wave repeats cleanly over a short period, so it draws as a smooth, regularly repeating shape.

Dissonant intervals are built from complex ratios. A tritone is near 45:32, so its parts almost never line up. The combined wave takes a long time to repeat, or never quite closes, so it draws as a long, restless, jagged shape. That difference between a short clean period and a long unsettled one is the whole point: you can see the tension you have always been able to hear.

Change the waveform from sine to sawtooth, square, or triangle and the visual texture changes too. These are oscillator waveforms, not full instrument timbres: a compact way to compare a pure wave with richer wave shapes.

Sinescope shows a single moment, the chord you are holding, as a waveform. Sineprint asks the same question of an entire piece. Play a song on the keyboard or upload a MIDI file and ChordSine winds the whole performance into one still image called a Sineprint. Time spirals from the center outward, so the opening sits at the middle and the final chord closes the outer edge.

The same consonance you can see in a Sinescope waveform becomes color. At each moment ChordSine measures how cleanly the sounding notes line up, the ratio idea behind the smooth triad and the jagged tritone, and paints the spiral with it: consonant passages read cool and green, dissonant ones warm and amber. A calm, mostly consonant piece draws a mostly cool ring, while a restless, chromatic one flickers warm.

Loudness shapes the line itself. Louder, denser moments push the spiral into wider ripples; quiet passages draw it thin and smooth. So a single Sineprint carries both the harmony and the dynamics of a performance in one readable shape, the same idea of seeing what you hear, stretched across a whole song.

To look inside the picture, select Inspect beneath the Sineprint. Choose a point on the spiral, then move or resize the section below it. The waveform shows the notes sounding at that moment and explains why they read as smooth or rough.

A Sineprint is deterministic: the same notes always draw the same image, so it reads as a kind of fingerprint of a performance. Two takes of the same piece render as recognizably the same shape, and a different piece looks unmistakably different. Everything is computed in your browser, and nothing you play or upload is sent to a server.

ChordSine belongs to a broader field of music visualization. A notable earlier work is Martin Wattenberg's Shape of Song (2001).

• Martin Wattenberg, Shape of Song (2001). Arc diagrams that reveal repeated sequences in music. ChordSine explores a different question: how notes combine as waveforms in real time.