How It Works
Why a major triad looks smooth and a tritone looks jagged
This page shows how to see the shape of music. 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.
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.
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, shaped by its overtones and envelope. A flute and a violin on the same note sound different because their timbres differ. ChordSine's current waveform control is simpler than that: it switches oscillator wave shapes.
- Partial
- A single sine component of a tone. A pure sine is one partial; richer waveforms contain multiple partials stacked above the fundamental, and their agreement or clash is what your eye and ear pick up.
Lineage and influences
ChordSine fits into a music-visualization tradition. The direct public reference point is Martin Wattenberg's Shape of Song.
- 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.
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.