Modal Cadence Options

Question

I understand that when playing in a mode, the cadences are quite different from tonal cadences. For example, in the Phrygian mode a cadence would be IV - iii (or II - i if we're renumbering the chords).

Q: What are all of the cadence options for all of the major modes?

Answer 1

Our three major modes are Ionian, Lydian, and Mixolydian. The Roman numerals for these are:

Ionian
I  ii  iii  IV  V  vi  vii°

Lydian
I  II  iii ♯iv° V  vi  vii

Mixolydian
I  ii  iii° IV  v  vi ♭VII

You'll notice that both Ionian and Lydian have a major V chord, meaning that the standard cadence of V–I is possible in these two major modes. (Whether it's the most common, I can't answer.) Perhaps due to Mixolydian's minor v chord, the ♭VII is often substituted as a dominant, resulting in a ♭VII–I cadence.

If we generalize it to all modes, it seems that the hierarchy of cadential harmony goes something like:

1. V where possible (Ionian, Lydian)
2. ♭II where possible (Phrygian) (maybe there's something to be said about tritone substitutions here?)
3. ♭VII where possible (Dorian, Mixolydian, Aeolian, sometimes Phrygian)

The only mode missing here is Locrian, which many (myself included) don't even consider an adequate mode based on the diminished tonic triad.

Answer 2

The seven modes we all know are Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Modal cadences are quite different from tonal cadences. Modal cadences don't tend to set up a resolution to the tonic chord like how tonal cadences (V-I, IV-I) would do, but rather to show the character of the mode.

The characteristic tones are ^4 in Ionian, ^6 in Dorian, ^2 in Phrygian, ^4 in Lydian, ^7 in Mixolydian, ^6 in Aeolian, and ^5 in Locrian.

The diatonic chords of each mode are: (boldened chords are the characteristic chords.)

• Ionian: [I] [ii] [iii] [IV] [V] [vi] [vii^o] [I]

• Dorian: [i] [ii] [III] [IV] [v] [vi^o] [VII] [i]

• Phrygian: [i] [II] [III] [iv] [v^o] [VI] [vii] [i]

• Lydian: [I] [II] [iii] [iv^o] [V] [vi] [vii] [I]

• Mixolydian: [I] [ii] [iii^o] [IV] [v] [vi] [VII] [I]

• Aeolian: [i] [ii^o] [III] [iv] [v] [VI] [VII] [i]

• Locrian: [i^o] [II] [iii] [iv] [V] [VI] [vii] [i^o]

If we want to write a modal cadence, we would want to:

• Avoid use of tritone

• Avoid use of leading tone in first chord

• Keep the character of the mode

• Avoid cadences like V-I, IV-I, V-i, iv-i, or even rarer v-i

So, in Ionian you would use ii⁶-I or ii⁶₅-I, in Dorian ii⁶-i or ii⁶₅-i, in Phrygian II-i or vii⁶-i, in Lydian II⁶-I, in Mixolydian VII-I, in Aeolian VI-i, and in Locrian iii⁶-i^(no5).

Notice how all modes have the characteristic tone in the first chord of their cadences. Also notice how all modes but Dorian (which has it on the tenor) have it on the bass of the chord. For more information, go to Cadences for Modes.