Chord Types
The Four Families
A short reading, then a 50-question self-test. Work at your own pace. The goal is not to get every question right — it is to find the ones you can't yet answer without thinking.
§ 1The Premise
Every chord in tonal music can be reduced to a formula applied to a major scale. Once you know the formula, you can build any chord in any key without memorization. Chords are not shapes to memorize — they are recipes you execute.
This is the shift to make. If you memorize twelve major chords, twelve minor chords, twelve diminished chords, and twelve augmented chords, that is forty-eight items. If you memorize four formulas and the major scale of each key, you can build all forty-eight on demand — plus every chord type you have not met yet.
§ 2The Reference
Every chord is built relative to a major scale. Number the scale degrees 1 through 7. The numbering is the same in every key.
The key signature tells you which notes are sharp or flat. The numbering does not change.
§ 3The Four Chord Types
Major 1 · 3 · 5
The default. Stable, resolved, the sound of "home."
Minor 1 · ♭3 · 5
Take a major chord. Lower the 3 by a half step. That is the only change.
Diminished 1 · ♭3 · ♭5
Take a minor chord. Now lower the 5 by a half step too. Both the 3 and the 5 are flat.
Diminished chords sound tense. They never feel like home — they always want to resolve somewhere else. There is one in the chorus of Read My Mind.
Augmented 1 · 3 · ♯5
Take a major chord. Raise the 5 by a half step. Rare in pop. Sounds suspended, ungrounded, slightly theatrical.
The Killers use one — exactly once — at the end of Indie Rock and Roll.
§ 4A Note on Spelling
A chord must be spelled correctly using the right letter names, even when two notes sound identical. F diminished is F, A♭, C♭ — not F, A♭, B — even though C♭ and B are the same key on the piano. Every chord uses every other letter: F, skip G, A, skip B, C. The 5th of an F-something chord must be a C of some kind.
Why spelling matters: It keeps the notation consistent with the key signature, and it tells other musicians what role the chord plays. C♭ and B sound the same; they are not the same note in music notation.
§ 5Summary Table
That is the entire framework. Memorize those four lines and you can build any of the four chord types in any of the twelve keys.
Test Bank50 Questions
Tap an answer to lock it in. You will see whether you were right or wrong immediately, with a one-line explanation. There is no time limit and no penalty for wrong answers — they are the most useful data point in the whole exercise.
If you find yourself guessing, that is a flag. Note the question number and bring it to the next lesson.