Major and minor triads
Stack two thirds into a major or minor triad, build it on any note and tell them apart by ear.
The triad
A triad is a chord of three notes stacked in thirds. The lowest note is the root, which gives the chord its name. Above it is the third, and above that the fifth (a fifth above the root).
A triad is easy to spot on the staff: three notes on neighbouring lines or in neighbouring spaces, like a snowman.
A triad on C: C, E, G, one by one and together
On the keyboard: every other white key
Practice: A triad in thirds
Major and minor
The thirds in a triad differ, and they decide its colour.
- "major triad": a major third below, a minor third above (4 + 3 semitones). It sounds bright.
- "minor triad": a minor third below, a major third above (3 + 4 semitones). It sounds darker.
The outer notes of both are a perfect fifth. Only the middle note, the third, changes.
A major triad on C: C, E, G
A minor triad on C: C, E♭, G
On the white keys, the major triads are on C, F and G, the minor ones on D, E and A. To build a major triad on any other note, count semitones: 4 up from the root for the third, 3 more for the fifth.
When you build a triad, first write the three notes as a snowman, so the letters are right. Then check the semitones and add the accidentals you need.