Where do visible light (and color) sit on the electromagnetic spectrum?

see;

also;

The Electromagnetic Spectrum

Lucy’s Tuning Scale Development

COMING SOON:

Wavelengths and Frequencies; Understanding the Similarities and Differences Between Light and Sound

But right now,

Check out Fred Collopy’s RhythmicLight website;

http://rhythmiclight.com/archives/timeline.html

for a TIMELINE of the history of the use of Color and Music

and while you’re there, check out the Galleries section - very nice work.

Read about the early 20th century Russian composer Alexander Scriabin’s “Color-Hearing”

also known as synesthesia

A related movement in the music and art world of the early to mid 20th century; 

Gesamtkunstwerk (Whole-Art)

See also; Kandinsky

Goethe’s Experiments with Color