In every musical key, there are special relationships between the notes. And all these relationships evolve around a central – and uber-powerful – tonic note. In the key of C, for example, the C note acts as the tonic … the tonal center of the key that presides over all the other pitches in its kingly domain.
No, really … the tonic note of a key truly is like the lord of the castle. It exerts a strong influence on the other notes, which act as its subservient subjects.
Taking this analogy a bit further, you can find all sorts of royal intrigue in a key. Some of the tonic king’s courtiers hold more sway than others – while others act as the king’s foes. The tritone, for example, is the tonic’s arch nemesis. It sounds highly dissonant when paired with the tonic … and therefore, rarely gets invited to the king’s parties.
But the tonic’s close relatives – the subdominant and dominant notes – are favored kin. So they are often seen cavorting with the royal king. In the key of C, for example, the subdominant (F) and dominant (G) even share the tonic’s “red blood” … so they sound very consonant when played with the tonic. In fact, you might even say they sound downright beautiful together.
The tonic is closely related to the subdominant and dominant because these notes are all neighbors in the circle of fifths. So the royal C note feels nice and snug when nestled between F and G.
But when the circle of fifths pattern is rearranged into the chromatic scale, the subdominant (4) and dominant (5) notes are moved to straddle the tonic king’s tritone (#4/b5). And that makes for some fascinating royal intrigue. As a result, all of these tonal friends and enemies in the chromatic scale are forced to be in close quarters … which heightens the musical drama.
But wait – it gets even better!
That’s because every note can have its day in the sun. That is, every note in music can serve as the king of its own key. And because the relationships between notes are symmetrical in each key, the connections between pitches are super rich and intriguing.
To see what I mean, check out this illustration of the chromatic scale – with lines connecting every tonic with its respective subdominants and dominants. The symmetry is astounding. And the multiple layers of tonal relationships are, frankly, mind-blowing.
Ahhh, the ever-compelling story of music theory. The ongoing battles for consonance and dissonance. The shifts in tonal power. The harmonic loyalties, and conflicting betrayals. It’s images like this that give meaning to the phrase, “Oh, what a tangled web we weave.”