ABSTRACT
The major chord contains two essential chord tones-a major 7th and a major 6th; two diatonic extensions-a major 9th and a major 13th; one chromatic extension-a ≥11th; and two pitch alterations-a ≤5th and a ≥5th. The minor chord admits four essential chord tones-a minor 7th, a major 6th, a major 7th, and a minor 6th; three diatonic extensionsa major 9th, a perfect 11th, and a major 13th; and two chromatic extensions-a ≤13th and a ≥11th. The minor 7(≤5) chord (also known as the half-diminished 7th) allows one essential chord tone-a minor 7th; two diatonic extensions-a major 9th and a perfect 11th; and one chromatic extension-a ≤13th. The diminished 7th chord uses two essential chord tones-a diminished 7th and a major 7th; and three extensions-a major 9th, a perfect 11th, and a ≤13th. The dominant 7th chord contains one essential chord tone —a minor 7th; two diatonic extensions-a major 9th and a major 13th; four chromatic extensions-a ≤9th, a ≥9th, a ≥11th, and a ≤13th; and two pitch alterations-a ≤5th and a
≥5th. The suspended dominant chord includes one essential chord tone-a minor 7th; two diatonic extensions-a major 9th and a major 13th; three chromatic extensions-a ≤9th, a ≥9th, and a ≤13th; and two pitch alterations-a ≤5th and a ≥5th. Figure 5.1 summarizes the distribution of essential chord tones, pitch alterations, and extensions in Maj7, min7, dom7, suspended dominant, min7(≤5), and diminished 7th chords.
