Chapter 12 - Key Relationships

Mode Mixture

• Mode mixture - Harmonic technique of combining chords from a major key and the parallel minor, or mixing the parallel major and minor modes using the b3, b6 and b7 from the parallel natural minor.
• To analyze and notate chords in a major key whose quality has been altered by mode mixture:
  • Adjust the Roman numeral to uppercase or lowercase to reflect the change in the third of the chord.
  • If the root of the chord is altered, add a b or # before the Roman numeral to show that the chord is built on an altered pitch.
  • If the chord has been altered to be augmented, add the + sign; if the chord has been altered to be diminished, add the diminished (°) sign.
  • As a general rule, since these mixture chords are derived from lowered scale degrees, resolve the chromatic alterations down.

Mixture Chords in Minor

• Picardy third - One of the most common uses of mode mixture when in minor is the practice of ending a piece with an authentic cadence using a major tonic. The major tonic is borrowed from the parallel for a more "authentic-sounding" ending.
  • The third of the chord is raised to make it major.

Modulation

• Modulation - The process of moving from one tonal center to another, with or without changing the key signature.
  • Usually occurs to closely related keys because they have common chords between them.
  • Occurs within a phrase by using a chord common to both the old and new key or by changing tonal centers directly as a new phrase or section begins.
• Tonicization - When we have a region of a new key or experience a temporary sense of a new tonic by the occurrence of one or two non-diatonic chords.
• The difference between modulation and tonicization is the occurrence of a convincing cadence and significant time in the new key.
• Common modulations:
  • From major to relative minor (the submediant) is one of the most common ones.
  • Modulation to the dominant
  • Modulation to the subdominant
  • Modulation from major to parallel minor