Tetrachords

What is a Tetrachord?

A Tetrachord is a specific series of four notes. The Major Tetrachord consists of the pattern: Whole Step, Whole Step, Half Step (W-W-H).

The Minor Tetrachord

While the Major Tetrachord is bright and stable, the Minor Tetrachord has a distinctively sadder or more serious quality. It is built with the pattern: Whole Step, Half Step, Whole Step (W-H-W).

Other Common Tetrachords

Beyond Major and Minor, two other tetrachords are essential for advanced theory:

Named after the Phrygian mode, this pattern starts immediately with a Half Step. It has a distinctive exotic, Spanish, or dark flavor.

Pattern: H - W - W

The brightest of all. It consists entirely of Whole Steps, creating a dreamy, floating quality that spans a "Tritone" (Augmented 4th).

Pattern: W - W - W

Building a Scale with Two Tetrachords

You can construct a full Major Scale by joining two Major Tetrachords together with a Whole Step in between.

Example: C Major

In C Major, the first tetrachord is C-D-E-F. The second is G-A-B-C. Separating them is the interval between F and G (a whole step).

Key Discovery

Every Major scale is built from two identical W-W-H tetrachords separated by a whole step. This modular thinking will transform how you understand scale construction and key relationships.