How to Build Chords - Triads and Sevenths
Chords are the architecture of music. While a melody is like a line, a chord is like a building—it has depth and structure. In western music, most chords are built using a system called tertian harmony, which is just a fancy way of saying we stack notes in intervals of "thirds."
The Foundation: The Triad
A triad is a three-note chord. To build one, you start with a Root note, skip a note in the scale to get the Third, and skip another note to get the Fifth.
- Major Triad: Root + Major 3rd + Perfect 5th (Formula: 1 - 3 - 5)
- Minor Triad: Root + Minor 3rd + Perfect 5th (Formula: 1 - b3 - 5)
- Diminished Triad: Root + Minor 3rd + Diminished 5th (Formula: 1 - b3 - b5)
- Augmented Triad: Root + Major 3rd + Augmented 5th (Formula: 1 - 3 - #5)
Visualizing Tone Spacing
Think of it like steps. A Major 3rd is 4 half-steps (semitones). A Minor 3rd is 3 half-steps. By combining these different "sizes" of thirds, you create the different qualities of chords.
Adding Color: Seventh Chords
If you add one more "third" on top of a triad, you get a Seventh Chord. These are the backbone of Jazz, Soul, and complex Pop music.
Common Seventh Chords:
- Major 7th (maj7): Major triad + Major 7th. Sound: Dreamy, lush.
- Dominant 7th (7): Major triad + Minor 7th. Sound: Bluesy, wants to resolve.
- Minor 7th (m7): Minor triad + Minor 7th. Sound: Mellow, sophisticated.
- Minor 7th Flat 5 (m7b5): Diminished triad + Minor 7th. Sound: Dark, tense.
Practical Exercise
Pick a scale, like G Major. Try building a triad on every single note of the scale. You'll find that the chords naturally come out as Major, Minor, and Diminished in a specific pattern: I - ii - iii - IV - V - vi - vii°. This is the key to understanding chord progressions!