Color Coding

Nothing on the wheel is colored for decoration. Every wedge, ribbon segment, and legend swatch in Music Wheel is derived from the same idea: distance matters more than direction. A minor third above the root and a minor third below it get the same color, because to the ear they're the same interval class - the wheel just cares which flavor of interval you're looking at, not which way it points.

The same rule carries over to inversions. Flip an interval over - a major 3rd becomes a minor 6th, for instance - and it's still the same interval class, so it keeps the same color; see interval inversions for why. The same goes for chords: triad inversions rearrange which note sits in the bass without changing which intervals are stacked, so a chord and every inversion of it land on the same color.

There are seven interval classes, 0 through 6, running from a unison up to a tritone. Anything past a tritone is really one of these seven counted the other way around the octave, so seven colors are all the palette ever needs.

A single note or a bare interval just wears its interval class's color directly. A chord is where it gets more interesting: with three or more notes there are several intervals stacked on top of each other, so the app blends their colors together rather than picking one and discarding the rest. That blend isn't a flat average, either - it leans on a couple of rules that keep the result readable instead of muddy.

First, the mixing happens in LCH color space rather than plain RGB, so hues combine the way they look like they should combine instead of sliding toward brown the way naive RGB averaging tends to. Second, not every interval in the chord gets an equal vote: the unstable ones - the minor second/major seventh and the tritone - are weighted more heavily, since they're usually what gives a chord its particular color to the ear in the first place. A plain major triad leans on its calmer, more evenly weighted intervals and comes out as a fairly settled blend; add a seventh or a sharp dissonance and the mix visibly shifts toward that interval's color.

This is why some qualities land close together and others stand apart: any two chords built from the same interval classes come out looking similar regardless of what they're called, while a single unstable interval buried in an otherwise calm chord can still pull its color noticeably off to one side.

The scale ribbon underneath the wheel uses the same palette for a different question - not “what interval is this from the root” but “how big is the step to the next note.” With step annotations on, each segment of the ribbon is colored by its own semitone distance, so the half steps and whole steps of a scale are visually distinct from each other, and a stretched step - the augmented second in harmonic minor, for instance - stands out by color as well as by width.

Wherever you see a legend panel - next to the wheel, under a chord preset, alongside a progression - it's reading colors back out of this same system, not inventing its own. That's deliberate: the swatch next to a chord's name is exactly the color that chord lights up on the wheel, so the legend can always be trusted as a direct key to what's on screen rather than an approximation of it.