SPECTRUM PRIMARY

Red, Green and Violet. White light in the middle.
Touch a sector to hear its note. Touch the white middle to hear all of them at once.

the visible spectrum spans one octave — violet vibrates at twice the frequency of deep red
the augmented triad divides the octave into three equal parts and belongs to no key,
as white belongs to no hue · all wavelengths = white light · all notes = white noise

THE SPIRAL

a wheel that climbs

Each turn of this spiral is one octave — five turns, C2 to B6, dark to icy.
Touch any cell to hear its true pitch.

chroma is the angle · register is the radius · every C on one ray
the flat wheel is this spiral’s shadow (Drobisch 1855, Shepard 1964)

SPIRAL OF FIFTHS

a wheel that cannot close

Twelve pure fifths from C2, each step 3:2.
The last step lands on B♯, just outside home. The gap is the comma.

each cell is a true 3:2 above the last · twelve of them climb seven octaves and overshoot
by 531441/524288 — about a quarter of a semitone · the spiral never comes home