Modulation (music)

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Example of modulation from the tonic to the dominant as in vocal music.[1]  Play (help·info)
Key change example: C major to C minor.

In music, modulation is most commonly the act or process of changing from one key (tonic, or tonal center) to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest. Treatment of a chord as the tonic for less than a phrase is considered tonicization.

Modulation is the essential part of the art. Without it there is little music, for a piece derives its true beauty not from the large number of fixed modes which it embraces but rather from the subtle fabric of its modulation.
—Charles-Henri Blainville (1767), [1]

Requirements

The quasi-tonic is the tonic of the new key established by the modulation. The modulating dominant is the dominant of the quasi-tonic. The pivot chord is a predominant to the modulating dominant and a chord common to both the keys of the tonic and the quasi-tonic. For example, in a modulation to the dominant, ii/V-V/V-V could be a pivot chord, modulating dominant, and quasi-tonic.

Types

Common-chord modulation

Common-chord modulation in the opening of Chopin's Prelude in C minor.[3]  Play (help·info)

Common-chord modulation (also known as diatonic-pivot-chord modulation) moves from the original key to the destination key (usually a closely related key) by way of a chord both keys share. For example, G major and D major share 4 chords in common: G, Bm, D, Em. This can be easily determined by a chart similar to the one below, which compares chord qualities. The I chord in G Major—a G major chord—is also the IV chord in D major, so I in G major and IV in D major are aligned on the chart.

GMaj: I ii iii IV V vi vii°
DMaj: IV V vi vii° I ii iii

Any chord with the same root note and chord quality (major/minor/diminished) can be used as the "pivot chord." However, chords that are not generally found in the style of the piece (for example, major VII chords in a Bach-style chorale) are also not likely to be chosen as the pivot chord. The most common pivot chords are the predominant chords (ii and IV) in the new key. In analysis of a piece that uses this style of modulation, the common chord is labeled with its function in both the original and the destination keys, as it can be heard either way.

Enharmonic modulation

Modulation from D major to D♭ major in Schubert's op. 9, D. 365, mm. 17-24, using the German sixth, in the new key, that is enharmonic to the dominant seventh in the old key.[4]  Play (help·info)
Modulation from a minor to e♭ minor in Schubert's op.29, D. 804, I, mm.144-49, using viio7: g♯o7 = do7 (= bo7 = fo7)[2]  Play (help·info)

An enharmonic modulation takes place when one treats a chord as if it were spelled enharmonically as a functional chord in the destination key, and then proceeds in the destination key. There are two main types of enharmonic modulations: dominant seventh/augmented sixth, and (fully) diminished seventh -- by respelling the notes, any dominant seventh can be reinterpreted as a German or Italian sixth (depending on whether or not the fifth is present), and any diminished seventh chord can be respelled in multiple other ways to form other diminished seventh chords. By combining the diminished seventh with a dominant seventh and/or augmented sixth, changing only one pivot note at a time, it is possible to modulate quite smoothly from any key to any other in at most three chords, no matter how distant the starting and ending keys; however, the effect is easily overworked.

(Examples: C-E-G-B♭, a dominant 7th, becomes C-E-G-A♯, a German sixth. C♯-E-G-B♭, a C♯ diminished seventh, can also be spelled as E-G-B♭-D♭, an E diminished seventh, G-B♭-D♭-F♭, a G diminished seventh, and B♭-D♭-F♭-A, a B♭ diminished seventh. Combining the diminished 7th with the dominant 7th/aug.6th: starting again from C♯ diminished seventh, the progression C♯-E-G-B♭, C♯-E-G-A (dom.7th), D-F♯-A takes us to the key of D major; C♯-E-G-B♭, C-E-g-B♭ (dom.7th), C-F-A, to F major; but exactly the same progression enharmonically C♯-E-G-B♭, C-E-G-B♭(dom.7th)=C-E-G-A♯(aug.6th), B-D♯-F♯-B takes us somewhat unexpectedly to B major; C♯-E-G-B♭, C♯-E♭-G-B♭=D♭-E♭-G-B♭(dom.7th), C-E♭-A♭ to A♭ major; etc. )

In short, lowering any note of a diminished seventh chord a half tone leads to a dominant seventh chord, the lowered note being the root of the new chord. Raising any note of a diminished seventh chord a half tone leads to a half-diminished seventh chord, the root of which is a whole step above the raised note. This means that any diminished chord can be modulated to eight different chords by simply lowering or raising any of its notes.

This type of modulation is particularly common in Romantic music, in which chromaticism rose to prominence.

Common-tone modulation

Modulationn between relative keys, C minor and E♭ major, using a common-tone, G, in Schubert's Op. 163 (D. 956).[5]  Play (help·info)

Common-tone modulation uses a sustained or repeated pitch from the old key as a bridge between it and the new key. Usually, this pitch will be held alone before the music continues in the new key. For example, a held F from a section in B♭ major could be used to transition to F major. This is used, for example, in Schubert's Unfinished Symphony.

Starting from a major chord, for example G (G-B-D), there are twelve potential goals using a common-tone modulation: G minor, G♯ minor, B♭ major, B major, B minor, C major, C minor, D minor, D major, E♭ major, E major, E minor.[3] Thus common-tone modulations are convenient for modulation by diatonic or chromatic third.

Chromatic modulation

Chromatic modulation in Bach's Du grosser Schmerzensmann, BWV 300, m. 5-6[6] ( Play (help·info) with half cadence,  Play (help·info) with PAC) transitions from FM to dm through the inflection of C♮ to C♯ between the second and third chords. Note that there is no common chord.

A chromatic modulation is so named because it occurs at the point of a chromatic progression, one which involves the chromatic inflection of one or more notes whose letter name, thus, remains the same though altered through an accidental.[4] Chromatic modulations are often between keys which are not closely related.[4] A secondary dominant or other chromatically altered chord may be used to lead one voice chromatically up or down on the way to the new key. (In standard four-part chorale-style writing, this chromatic line will most often be in one voice.) For example, a chromatic modulation from C major to d minor:

CM: IV V/ii ii
Dm: i (...)

In this case, the IV chord in CM (F major) would be spelled F-A-C, the V/ii chord in CM (A major) spelled A-C♯-E, and the ii chord in CM (d minor), D-F-A. Thus the chromaticism, C-C♯-D, along the three chords; this could easily be partwritten so those notes all occurred in one voice. Despite the common chord (ii in CM or i in dm), this modulation is chromatic due to this inflection.

In the example pictured, a chromatic modulation from FM to dm:

FM: I V
dm: V i iv V

In this case, the V chord in FM (C major) would be spelled C-E-G, the V in dm (A major) would be spelled A-C♯-E. Thus the chromaticism, C-C♯-D, which is here split between voices but may often easily be part-written so that all three notes occur in one voice.

The combination of chromatic modulation with enharmonic modulation in late Romantic music led to extremely complex progressions in the music of such composers as César Franck, in which two or three key shifts may occur in the space of a single bar, each phrase ends in a key harmonically remote from its beginning, and great dramatic tension is built while all sense of underlying tonality is temporarily in abeyance. Good examples are to be found in the opening of his Symphony in D Minor, of which he himself said (see Wikiquote) "I dared much, but the next time, you will see, I will dare even more..."; and his Trois Chorals for organ, especially the first and third of these, indeed fulfill that promise.

Phrase modulation

Phrase modulation in Mozart's Sonata in A Major, K.331, III (Alla turca), mm.6-10.[7]  Play (help·info)

Phrase (also called direct, static, or abrupt) modulation is a modulation in which one phrase ends with a cadence in the original key, and begins the next phrase in the destination key without any transition material linking the two keys. This type of modulation is frequently done to a closely related key -- particularly the dominant or the relative major/minor key.

An unprepared modulation is a modulation "without any harmonic bridge", characteristic of impressionism.[5]

For example:

  A  E  A  F  Bb  F
A:I  V  I F:I IV  I

Sequential modulation

"A passage in a given key ending in a cadence might be followed by the same passage transposed (up or down) to another key," this being known as sequential modulation.[6] Although a sequence does not have to modulate, it is also possible to modulate by way of a sequence. A sequential modulation is also called rosalia. The sequential passage will begin in the home key, and may move either diatonically or chromatically. Harmonic function is generally disregarded in a sequence, or, at least, it is far less important than the sequential motion. For this reason, a sequence may end at a point that suggests a different tonality than the home key, and the composition may continue naturally in that key.

Chain modulation

Distant keys may be reached sequentially through closely related keys by chain modulation, for example C to G to D or C to C minor to E♭ major.[7] A common technique is the addition of the minor seventh after each tonic is reached, thus turning it into a dominant seventh chord:

D-->D7 G-->G7 C-->C7 F
I-->V7/I-->V7/I-->V7/I

Parallel key modulation

A parallel key modulation is a change of mode, but maintains the same tonal center. For example, one section of a composition may be in the key of E major and then modulate to E minor. This can be done directly or facilitated by the various modulation techniques described above. Depending on the length of the modulation and whether or not it returns to the original key, it may or may not be designated by a change of key signature.

Common modulations

Modulation to the dominant in Haydn's Symphony in C Major, No. 97 (reduction).  Play (help·info)
The circle of fifths drawn within the chromatic circle as a dodecagram[8]

The most common modulations are to closely related keys. V (dominant) is the most frequent goal and, in minor, III (relative key) is also a common goal.[8] Modulation to the dominant or the subdominant is relatively simple as they are adjacent steps on the circle of fifths. Modulations to the relative major or minor are also simple, as these keys share all pitches in common. Modulation to distantly related keys is often done smoothly through using chords in successive related keys, such as through the circle of fifths, the entirety of which may be used in either direction:

D - A - E - B/C♭ - F♯/G♭ - C♯/D♭ - G♯/A♭ - D♯/E♭ - A♯/B♭ - F - C - G - D

If a given key were in G Major, the following chart could be used:

         C -- G -- D

From G (which is the given key), a musician would go P5 (a perfect fifth) above G (which is D) and also P5 below G (which is C).

From this, the musician would go to G Major's relative minor which is E minor, and potentially to C Major and D Major's related minor as well... a musician who does not know the related minor for C and D Major may also go BELOW or ABOVE E minor.

         C -- G -- D
         ㅣ   ㅣ   ㅣ
         a    e    b

By using the relative minor keys one can find the specific key that the key can MODULATE into.

Many musicians use the circle of fifths to find these keys and make similar charts to help with the modulation.

For examples of the use of modulations in popular music, see List of songs with chromatic harmony

Significance

In certain classical music forms, a modulation can have structural significance. In sonata form, for example, a modulation separates the first subject from the second subject. Frequent changes of key characterize the development section of sonatas. Moving to the subdominant is a standard practice in the trio section of a march in a major key, while a minor march will typically move to the relative major.

Changes of key may also represent changes in mood. Moving from a lower key to a higher often indicates an increase in energy.

Change of key is not possible in the full chromatic or the twelve tone technique, as the modulatory space is completely filled; i.e., if every pitch is equal and ubiquitous there is nowhere else to go. Thus other differentiating methods are used, most importantly ordering and permutation. However, certain pitch formations may be used as a "tonic" or home area.

Other types

Though modulation generally refers to changes of key, any parameter may be modulated, particularly in music of the 20th and 21st century. Metric modulation (known also as tempo modulation) is the most common, while timbral modulation (gradual changes in tone color), and spatial modulation (changing the location from which sound occurs) are also used.

Modulation may also occur from a single tonality to a polytonality, often by beginning with a duplicated tonic chord and modulating the chords in contrary motion until the desired polytonality is reached.

See also

Further reading

References

  1. ↑ Forte, Allen (1979). Tonal Harmony in Concept & Practice, p.265. ISBN 0-03-020756-8.
  2. ↑ 2.0 2.1 2.2 Forte (1979), p.267.
  3. ↑ Kopp, David (2006). Chromatic Transformations in Nineteenth-Century Music, p.50. Cambridge University Press. ISBN 9780521028493. After Marx, Adolph Bernard. Theory and Practice (1837). Trans. Saroni.
  4. ↑ 4.0 4.1 Benward and Saker (2003). Music: In Theory and Practice, Vol. I, p.245. Seventh Edition. ISBN 978-0-07-294262-0.
  5. ↑ Reti, Rudolph (1978). Tonality, Atonality, Pantonality. Westport, CT: Greenwood Press. ISBN 0-313-20478-0.
  6. ↑ Heussenstamm, George (2011). Hal Leonard Harmony & Theory - Part 2: Chromatic. ISBN 9781476841212.
  7. ↑ Jones, George T. (1994). HarperCollins College Outline Music Theory, p.217. ISBN 0-06-467168-2.
  8. ↑ Forte (1979), p.269.

External links

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