Re: Music/sound and colour/vision
There is, actually, a very fundamental issue involved in trying to go too far with the analogies being drawn here. That is the question of bandwidth. Most musical notes are usually very "pure". They consist of a group of frequencies very close to one another. You could regard a single piano note as being of a single frequency. I imagine, though do not know, that a concert grand in perfect pitch produces very tightly grouped frequencies.
Such single frequencies allow certain things to happen - the most obvious is "beating". Here two close but dissimilar frequencies "beat" together to produce a difference frequency - old fashioned four engined aeroplanes do it all the time. In music these are the overtones and resonances referred to by llawerence.
Color, in everyday life, doesn't do this. The main reason is that no everyday color is "pure". Colors are usually very messy and broadband by nature. I can see this easily with my XRite. Almost all common paints cover the entire visible spectrum just happening to have a peak at red, or green or blue. Their combined color response is defined by absorption and scattering in which the fiendishly complicated Kubelka Munk laws rule.
In a more rarefied world color behaves in a very similar way to sound. Colored light does produce beats and resonances - just like sound. But in order to get there you need vary "pure" light sources. Normally these are laser sources and when I was a lad these were the only way to get there. Nowadays LEDs are pretty good and this accounts for the extraordinary color rendition of modern day TVs and computer screens. The average punter really has little idea just how good these machines are.
This free flowing mind game leads back to an observation on paint mixing. If absolutely "pure" pigments were available, just like absolutely "pure" electronic colors are available, then any color could be mixed from a very small number of inputs. Thus it is my belief that most amateur artists like myself can make any mix they wish from about a dozen colors. These colors should be as "pure" as possible and distributed as evenly as possible around the "elliptical triangle" of the CIELab diagram. Mid value colors like Burnt Sienna are completely redundant.
This is my POV. Clearly Gigalot will have a different one - which I totally respect. I am sure that we completely share the same sense of wonder as we contemplate the mysterious spread of an ultramarine wash across an Arches cold press. (Un)fortunately for me science underlies the whole process.