I. Fundamentals
Triads
Chelsey Hamm
Key Takeaways
- A triad is a three-note chord whose notes can be arranged in thirds. A triad can always be “stacked” so that its notes are either on all lines or all spaces.
- When a triad is stacked in its most compact form in thirds, the lowest note is called the root, the middle note is called the third, and the highest note is called the fifth.
- There are four qualities of triad. A major triad's third is major and its fifth is perfect, while a minor triad's third is minor and its fifth is perfect. A diminished triad's third is minor and its fifth is diminished, while an augmented triad's third is major and its fifth is augmented.
- In chord symbols, major triads are represented with capital letters that correspond to the triad’s root. Minor triads have a lowercase “mi” after the letter, diminished triads have a superscript circle (o), and augmented triads have a plus sign (+). You may see other abbreviations in other contexts (a more exhaustive list is given in the Chord Symbols chapter).
- Within major and minor keys, triads have particular qualities that correspond to scale degree. These are the same in every major and minor key, which makes memorizing them useful.
- Triads are identified by their root, quality, and inversion.
Triads
The three notes of a triad can always be arranged in thirds. melodically and harmonically. The first triad is on three adjacent spaces, while the second triad is on three adjacent lines. A triad can always be “stacked” so that its notes are either on all lines or all spaces. When a triad is stacked in its most compact form (measures 2 and 4 of ), it looks like a snowperson (see ). Just as a snowperson consists of a bottom, middle, and head, a triad consists of lowest, middle, and upper notes.
shows two triads, each written both
Colloquially, when a triad is stacked in this fashion, we might call this “snowperson form,” but the official term is root position; this is explored more in the chapter titled Inversion and Figured Bass. As shows, the lowest note of a triad is called the root, the middle note is called the third (a generic third above the root), and the highest note is called the fifth (a generic fifth above the root).
Triadic Qualities and Listening to Triads
There are four qualities of triad—major, minor, diminished, and augmented—which are determined by the quality of the intervals from the root to the third and the root to the fifth. These qualities are labeled in
: triad qualities are shown above the staff, the quality of the fifth to the root is given in red to the left of the triad, and the quality of the third is given in blue to the right of the triad. Augmented triads are shown last because the other three types are more common in most classical and popular music.Note that triads are named for certain important intervals they contain:
- Major and minor triads are named for the quality of their third. (Both have perfect fifths.)
- Diminished and augmented tr