Modulation to E Minor: Pivot Chord or Chromatic Turn?
A Level 3 composition student has a 32-bar song in G major (key signature F♯). Bars 1–16 use G–Em–C–D. In bars 17–24 the melody introduces D♯ in bar 22 as a lower neighbour to E, and C♮ in bar 23. The student harmonises bars 21–24 as Am–D7–G–Em and then wants to pivot to E minor at bar 25 using Am as a common chord: ii in G, iv in E minor. The draft melody in bar 22 is E–D♯–E over a D7 chord (D–F♯–A–C), and bar 23 is C♮–B–A over Am. The student cannot hear a convincing arrival in E minor and asks whether the pivot is legal. The song is for voice and piano, tempo 96 bpm, and the bridge must last exactly 8 bars.
1. Diagnose the harmonic problem in bars 21–24. Explain why the proposed Am pivot at bar 25 does not convincingly establish E minor, referring to the melody notes and chord functions.
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The problem is not that Am is an illegal pivot; it is that the harmony before it has already closed the door to E minor. D7 is V7 of G: it contains F♯ and D natural, and it pulls to G. The melody’s D♯ in bar 22 is the leading tone of E minor, but over D7 it clashes directly with D natural and is not supported by the chord. The C♮ in bar 23 over Am is consistent with E minor (iv) but also with G major (ii), so Am is an ambiguous pivot at best. When the music reaches Em at bar 25, the ear has been told “G major” by D7 and hears Em as vi, not as a new tonic. To make a pivot convincing, the new key needs its own dominant - B7 (D♯–F♯–A–B) - before the arrival, and the melody’s D♯ should be supported by that dominant or by G♯dim7.
2. Propose a revised progression for bars 21–24 that supports the given melody notes (D♯ in bar 22, C♮ in bar 23) and prepares E minor at bar 25. Give chord symbols and Roman numerals in both keys, and justify each choice.
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Revised bars 21–24: bar 21 G (I in G) or Em (vi); bar 22 B7 (V7/vi in G, V7 in E minor) supports D♯; bar 23 Am (ii in G, iv in E minor) supports C♮; bar 24 B7 (V7/vi, V7) or F♯7 (V7/V in E minor) prepares the cadence; bar 25 Em (vi in G, i in E minor). If the melody’s E in bar 22 must be a chord tone, use B7sus4–B7 or treat E as an appoggiatura to D♯. The Roman numerals show the double function: B7 is the pivot by function, not Am. Justification: B7 introduces the leading tone D♯ and confirms E minor’s dominant; Am preserves the C♮ and provides a subdominant; the final B7 makes the arrival at bar 25 a cadence rather than a colour change.
3. Discuss how the key signature, accidentals and enharmonic spelling should be handled in the score after bar 25. Include one risk of not changing the key signature and one risk of changing it.
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Because E minor shares G major’s key signature (one sharp), no new key signature is needed at bar 25. Write D♯ as an accidental every time it appears, and do not respell it as E♭: it is the leading tone and its spelling shows its function. C♮ is already natural in the key signature, but if the piece uses E harmonic minor, the D♯ will be the only raised note; do not add a key signature for harmonic minor. Risk of not changing: the score may look like it is still in G, so the performer must read the accidentals carefully. Risk of changing: adding an unnecessary signature or changing to a different minor key signature would confuse the singer and pianist and could cancel the G-major accidentals incorrectly. If the bridge later returns to G major, natural signs may be needed to cancel D♯.