Guide: see the shape of music
Why a major triad looks smooth and a tritone looks jagged
Consonance and dissonance are not only things you hear. They are visible properties of the resulting waveform. When you hold a few notes, ChordSine adds their sine waves together and draws the sum. The shape of that sum is the shape of the sound.
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.
Switch the timbre from a pure sine to a richer waveform and the effect grows stronger. A pure sine has no overtones, so it understates the contrast; a harmonically rich tone adds partials that clash or agree, which makes consonance and dissonance more visceral on both the screen and the ear.
A short glossary
- Consonance
- How stable or restful a combination of notes sounds. In ChordSine it shows up as a wave that repeats cleanly over a short period.
- Dissonance
- How tense or unstable a combination sounds. It shows up as a wave whose period is long, irregular, or never quite closes.
- Period
- The length of one full repetition of the combined wave. A short period reads as smooth and settled; a long one reads as jagged and restless. ChordSine marks where the wave repeats.
- Timbre
- The character of a tone, set by which overtones it carries. A flute and a violin on the same note sound different because their timbres differ. ChordSine lets you switch between a pure sine and richer waveforms.
- Partial
- A single sine component of a tone. A pure sine is one partial; a rich timbre is many partials stacked above the fundamental, and their agreement or clash is what your eye and ear pick up.
Lineage and influences
ChordSine stands on decades of work that asked what music looks like. We name our predecessors directly, because it is correct and because the resemblance is a heritage, not a coincidence.
- Martin Wattenberg, Shape of Song (2001). Arc diagrams that reveal musical form through repeated sequences. The spirit of making music's hidden architecture visible is directly inherited.
- Stephen Malinowski, Music Animation Machine (1985 onward). Decades of piano-roll-as-art renderings that established watching music as its own medium.
- John Whitney, kinetic mathematical films and the Whitney Music Box. Harmonic ratios rendered as moving geometry, a conceptual ancestor of the geometry-of-harmony idea.
- Chrome Music Lab and 3Blue1Brown. The pedagogical lineage: instruments and explanations that teach by being explored, not lectured.
- Bret Victor, Explorable Explanations. The philosophical lineage for the instrument-not-a-course stance.
Try it
The fastest way to understand any of this is to play with it. Open Sinescope and hold a major triad, then a tritone, and watch the two shapes. The instrument teaches by being played.