Lesson 23 - Diatonic Modulation
Part I - Introduction to modulation
When we say modulation in music, what is meant is shifting tons; areas within a piece. Most often two closely related keys (C Major and F Major for example) will share chords. In this example, the ii chord in C Major is the same exact chord as the vi chord in F Major. when analyzing a modulation, one needs to analyze the chords as they are in BOTH keys.
When analyzing a piece that modulates, we use this bracket:
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it tells us when one tonal center has ended and the new one has begun. The Roman numeral analysis, as you can see for this example looks like this:
I V I ii6 I V vi vi ii |
| vi ii6 V I When analyzing a piece that modulates, we use this bracket:
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it tells us when one tonal center has ended and the new one has begun. The Roman numeral analysis, as you can see for this example looks like this:
I V I ii6 I V vi vi ii |
The final analysis loos like this:
C Major: I V I ii6 I V vi vi ii |
F Major: | vi ii6 V I
C Major: I V I ii6 I V vi vi ii |
F Major: | vi ii6 V I
Part II - Closely related keys
Closely related keys are keys that share the same key signature (C Major and a minor) and keys that are one accidental apart (C Major(0 sharps) and G Major (One sharp))
Relative keys
C Major
Relative keys
C Major
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A minor
closely related keys
1 flat 0 sharps or flats 1 sharp
F Major-----------C Major-----------G Major
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D minor A minor E minor
Using another Key as an example, we can see all of the closely related keys to B flat Major
3 flats 2 flats 1 flat
Eb Major------------Bb Major-------------F Major
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C minor Gminor D minor
All of these keys would be easy to modulate between using only one or two pivot chords.
pivot chord- a chord that serves as a link between two keys or tonal centers.
In the example, the pivot chord is the d minor chord.
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A minor
closely related keys
1 flat 0 sharps or flats 1 sharp
F Major-----------C Major-----------G Major
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D minor A minor E minor
Using another Key as an example, we can see all of the closely related keys to B flat Major
3 flats 2 flats 1 flat
Eb Major------------Bb Major-------------F Major
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C minor Gminor D minor
All of these keys would be easy to modulate between using only one or two pivot chords.
pivot chord- a chord that serves as a link between two keys or tonal centers.
In the example, the pivot chord is the d minor chord.
Part III - Diatonic Modulation
As you can see the d minor chord can be analyzed as the vi in F Major, as well as the ii in C Major.
Notice the presence of the B flat after the modulation. That is a sure sign that the modulation has occurred.
Being that E Major and A Major are only one step away from each other on the circle of fifths, they share many chords. Here, the modulation takes place over three chords.
Fig.1 Diatonic Modulation from C Major to F Major
Listen:
Fig.2 Diatonic Modulation from E Major to A Major
Listen:
Part IV - Establishing a Key
The best way to establish a new key is to write the progression - ii V7 I (or i) - in the new key. That progression by far is the best way to establish the new tonal center
Part V - Part Writing Diatonic Modulations.
The most difficult aspect to part writing diatonic modulations is determining the point of modulation. Then one can figure out the best ay to voice chords through the modulation.
