Minor chord

Chords that are constructed of consecutive (or "stacked") thirds are called tertian.

A unique particularity of the minor chord is that this is the only chord of three notes in which the three notes have one harmonic – hearable and with a not too high row – in common (more or less exactly, depending on the tuning system used).

This is the sixth harmonic of the root of the chord, the fifth of the middle note, and the fourth of the high note: Demonstration: In just intonation, a minor chord is often (but not exclusively) tuned in the frequency ratio 10:12:15 (playⓘ).

[6] In 12-TET, or twelve-tone equal temperament (now the most common tuning system in the West), a minor chord has 3 semitones between the root and third, 4 between the third and fifth, and 7 between the root and fifth.

[8][full citation needed] In the 16th through 18th centuries, prior to 12-TET, the minor third in meantone temperament was 310 cents Playⓘ and much rougher than the 300 cent ET minor third.

A minor triad has a minor third (m3) on the bottom, a major third (M3) on top, and a perfect fifth (P5) between the outer notes.
An illustration of the harmonic series as musical notation. The numbers above the harmonic indicate the number of cents it deviates from equal temperament . Red notes are sharp. Blue notes are flat.