What even are musical keys?
No-nonsense guides to understanding keys, chords, and other stuff
Why I Made These Theory Pages
Maybe you’re like me, and maybe not, but keys can frustrate beginner players and more experienced (but theory-avoidant) players alike. I always bristled a bit when bandmates would talk ask me, “What key is this in?”, about a song that I’d written myself, but just by ear. Sometimes I could guess correctly, but I was always guessing. I’ve followed my ears for 30 years, and now I’m writing these resource pages to teach myself new tricks I wished I’d figured out long ago.
If you’re already aware of what a key is, jump to:
Keys are just organised sets of notes
In major and minor-key music, a key is simply a collection (scale) of seven notes arranged so that the first note feels like “home”; its chords are just stacked notes from that scale.
The home note is called the tonic.
All the other notes in the key can feel stable/unstable, tense, or resolved in relation to the tonic.
For most of what we do in major and minor keys, you can just think of a “key” as a 7-note scale that’s centred on a tonic, and the chords you can build from it.
Major vs minor is about how “home” is built
Major and minor are not opposites; they’re just constructed differently. The notes in the home chord for major and minor keys follow distinct but predictable patterns because of their scales.
In major scales, the 3rd note is 4 semitones (half-steps) up from home; in minor scales it’s just 3 semitones up. The distance between notes is called an interval, and the interval between the tonic and the 3rd note of the diatonic scale is called a “third”. Wacky naming, eh? This one small change creates a palpable shift in mood:
Major keys often sound brighter to a lot of ears because the tonic (or “home”) chord is built on note intervals that resonate well with one another.
Minor keys often sound darker because the tonic (home) chord contains intervals where notes are closer together, creating more tension than the equivalent major key.
But… Context matters, tempo matters, and plenty of songs break these stereotypes wide open..