Tetrachord Construction Kit — Build Any Scale From Two Four-Note Groups
Pick two tetrachords, build a scale, rotate through its modes with ◀ ▶, and harmonize in thirds, triads, or tetrads — hundreds of chords from two building blocks.
A tetrachord is just four notes in a row. Stack two of them and you've built a scale — this tool lets you build it, hear it, and harmonize it.
- Pick a bottom and top tetrachord to build a scale from two four-note groups.
- Use the ◀ ▶ buttons to step through the modes of your scale.
- Toggle 3rds triads tetrads to stack the harmony on each degree.
What is a tetrachord?
A tetrachord is a group of four notes — usually written as three intervals between them. The major tetrachord (whole-whole-half) is the first four notes of a major scale. The minor tetrachord (whole-half-whole) is the first four of a natural minor scale. There are only a handful of common tetrachord patterns, and every scale you’ll ever play is built from two of them stacked.
Why this matters
Once you can name a few tetrachord patterns, you can construct almost any scale without memorizing it. Dorian? Two minor tetrachords. Melodic minor? Minor on the bottom, major on top. Harmonic minor? Minor on the bottom, harmonic on top. Every “exotic” scale is just an unfamiliar pairing.
Read more
- Tetrachords — Learn 4 Patterns, Build Every Scale and Mode — the theory behind how tetrachord combinations work
- Modes Without the Mystique — the Musician Basics chapter that walks through every mode
- Your First Chords — start here if “tetrachord” is a new word
Learn it live
The Musician Basics & Ear Training class covers tetrachords, modes, and scale construction as a live cohort on Discord. Small groups, direct feedback, weekly sessions.
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