Octave + fifth
Early partials overlap often. The ear readily groups them around a common fundamental.
Harmony · Exhibit
Three notes,
one sound.
Stack two thirds and the ear hears one object with a mood. Build the chord, then retune until the mood shifts.
Build the chord
Major
Partials 4, 5 and 6 already sit inside one octave, and together they make the first major triad the series offers.
Choose a structure, tap its numbered voices, then use the centre control to hear them together. Listen for separate pitches to fuse into one chord, and change the spacing or play them one by one to expose the parts again. Each voice is a ratio above the same root; altering one relationship changes the chord’s colour, shape, and pull.
Why chords fuse
Consonance
comes by degree.
Chords whose tones share many partials fold into one sound.
Two partials close together make the loudness fluctuate. Below about 20 fluctuations a second you hear beating, and above that the sound turns rough.
In the bass the rough zone runs about three semitones, a span musicians call a minor third. Up high it narrows to one, a minor second. Timbre and long listening habits move those limits too.
The voicings on this page use pure ratios, one historically important model. Equal steps and other systems are cultural choices about how to divide the octave.
Add a third
The fifth sets the frame. Raise or lower the third by a semitone and the whole chord changes mood.
Add dissonance
One tone rubs its neighbour and wants to step down. Let it, and the chord has changed under you. Musicians call that lean a suspension.
The exhibits have no set order.
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