Gauldin lists tonicizations by strength:
- transient modulation
In Chapter 22, we’re concerned with modulations – particularly to the key of the Dominant (when starting in a major key), and to the relative minor when starting in minor.
To call something a true modulation, the passage typically needs to include a cadence, and last for at least one phrase.
Pivot or Common Chord Modulation
Primarily we’re talking about common chord, or pivot chord modulations. (ignoring for now sectional and chromatic modulations)
Modulations by pivot chord happen within a phrase, with the diatonic function of a chord within the original key also functioning as a diatonic chord in the new key. Note that pivot/common chords are diatonic in both the original and the new key.
Pivot chords typically appear as pre-dominants (vi, IV, and ii) in the new key, leading to a dominant in the new key. Usually the pivot chord is the chord immediately preceding the first instance of the new dominant.
Indicating Modulations with Roman Numerals
Be clear and neat when indicating modulations. The pivot chord will be labeled with a Roman numeral indicating its diatonic function in the original key, and immediately below it with a Roman numeral indicating its diatonic function in the new key. The new key will be indicated by Roman numeral enclosed in a box, followed by a colon (:). I also like to add a type of bracket/divider at pivot points that clearly shows the end of the original key and the beginning of the new key. Maintain the vertical positioning of Roman numerals as they apply to either the original key (nearest to the staff), or new key (one level lower).
Recognizing Modulations in Analysis
Modulations are easy to recognize by scanning the bass line, since the bass line usually supplies a more functional harmonic outline of the key area. Look for prominent leaps of a P4 up/P5 down at cadences, as well as cadential passages that could be interpreted as scale degrees 4 – 5 – 1. (M2 up, P4 up) These cadential sign-posts will usually indicate the tonic of the passage.
You can also look at the soprano for step-wise descents into cadences that could be interpreted as scale degrees 3 – 2 – 1. Remember that standard analytical reductions look for a 3 – 2 – 1 descent into cadences. Scale degree descents of 7 – 6 – 5 at cadences (in major) are strong indicators of modulation to the Dominant, as the leading tone would rarely not resolve in a prominent location near a cadence.
Modulations in minor can be a bit more subtle, as no chromatic alterations are necessary to modulate to the relative major. It can be most useful to look for the absence of the chromatic alterations necessary to indicate a minor key as a sign that you have modulated to the relative major. For example, if you are no longer raising scale degree 7 in the original minor key (for a leading tone), you may have modulated to the relative major, where that scale degree is now 5.
Relying on What You Know
Right now, our studies are focused on modulating to V in major, and to III (the relative major) in minor. These are the most common modulations in classical music, and almost exclusive in early classical. Understand that music is a set of common practices. Therefore, when you encounter a new piece or a new melody, first determine the initial key. If it is major, determine the key of the dominant and its associated important scale degrees (4 – 5 – 1 for bass lines; 3 – 2 – 1 for soprano lines). If the initial key is minor, do the same thing with the relative major.
In analyzing two-reprise forms (two repeated sections) typically found in minuets and trios, know that the typical tonal plan is usually:
- to have the first phrase cadence in the initial key.
- modulate to V or III (depending on major or minor) and cadence in the new key during the second phrase.
- either at the beginning of the second section, or shortly afterwards, the piece will modulate back to tonic, often with a prolonged dominant (2 – 3 measures of dominant in the original tonic key) to re-establish the original key.