In music theory, the concept of the “family of chords” refers to a group of chords that are derived from a common scale or key. The chords in a family are built using the notes of a particular scale, and they share a harmonic relationship with each other. Understanding the family of chords helps in creating chord progressions and harmonizing melodies.
The most common family of chords is the diatonic chords derived from the major scale. In a major key, the diatonic chords are built on each degree of the scale using a combination of major and minor triads. The diatonic chords in a major key are as follows:
Major (I)-
Root, Major Third, Perfect Fifth
Minor (ii)-
Root, Minor Third, Perfect Fifth
Minor (iii)
Root, Minor Third, Perfect Fifth
Major (IV)-
Root, Major Third, Perfect Fifth
Major (V)
Root, Major Third, Perfect Fifth
Minor (vi)
Root, Minor Third, Perfect Fifth
Diminished (vii°)
Root, Minor Third, Diminished Fifth
The Roman numerals in parentheses represent the scale degrees on which each chord is built. The uppercase Roman numerals indicate major chords, while lowercase Roman numerals indicate minor chords. The “vii°” symbol represents a diminished triad.
By using the diatonic chords of a major scale, musicians can create chord progressions that follow the tonality and character of the key. Additionally, variations and extensions can be added to these chords to create more complex and colorful harmonies.
It’s important to note that other scales, such as the natural minor scale or modes like the Dorian or Mixolydian, also have their own families of chords. These chords may differ from the diatonic chords derived from the major scale but still follow the same concept of building chords from the scale’s notes.
Understanding the family of chords and their relationships is a fundamental aspect of music theory and composition, allowing musicians to create harmonically coherent and interesting musical arrangements.