Melodic Dictation: Deciding What to Notate When the Tune Modulates
In a melodic dictation exercise, the instructor plays a eight-measure melody twice. The key signature given is one sharp (G major or E minor). The student transcribes the first four measures in G major with no accidentals. In measures 5–8, the student hears F natural and C natural and writes them as accidentals, labeling the passage "borrowed from G minor." A classmate hears the same passage and insists the melody has modulated to C major, pointing out that the F naturals function as lowered sevenths and the phrase ends on C. The instructor asks the class to adjudicate using the played melody's cadence and the behavior of the leading tone. The melody's final two notes, as played, are B then C, and the last chord implied is C major.
1. Using the cadential evidence, decide whether the passage is best analyzed as a modulation to C major or as modal mixture in G major.
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The decisive evidence is the cadence and the leading tone. The melody's last two notes are B → C, and the implied final chord is C major. In C major, B is the leading tone (scale degree 7) resolving up by semitone to the tonic C - the defining melodic gesture of an authentic cadence in C. If the passage were modal mixture in G major (borrowed iv or borrowed ♭VII), the F♮ and C♮ would appear as coloristic alterations, but the phrase would still cadence on G or a G-based chord. It does not; it cadences on C.
Therefore the passage is best analyzed as a modulation to C major, likely via a pivot. The F♮ is the subdominant of C (scale degree 4), and the B♮ is the leading tone of C. The absence of F♯ in measures 5–8 is consistent with C major (where F is natural). The student's "borrowed from G minor" label is weaker because G minor borrowing would typically produce B♭ and E♭, not the F♮–B♮–C cadential figure observed. The classmate is correct on the cadential evidence, though the analysis should specify the pivot chord (e.g., G major's I = C major's V, or a ii–V–I into C).
2. The student protests that the key signature never changed. Explain why the key signature alone does not determine the analysis, and state what additional evidence would confirm a modulation.
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A key signature is a notational convenience, not an analysis. Modulations are heard and analyzed from harmonic function and cadential behavior, not from the signature. A passage can modulate without a signature change (accidentals carry the new key), and a signature can persist through tonicizations. The signature of one sharp is consistent with both G major and E minor and does not by itself rule out a tonicization of C.
Additional confirming evidence for a modulation to C major:
- Cadence type and target: a PAC or IAC on C, with the leading tone B resolving to C in an outer voice.
- Pivot chord analysis: identify a chord common to both keys (e.g., G major = V of C; A minor = vi of C = ii of G; E minor = iii of C = vi of G) at the point where the F♮ first appears.
- Sustained use of the new leading tone: B♮ functioning as leading tone to C over several measures, not just as a passing tone.
- Absence of the old leading tone: F♯ disappearing after the pivot, consistent with leaving G major.
- Phrase structure: the modulation typically coincides with a phrase boundary; if the F♮ appears mid-phrase and the phrase still cadences on G, a tonicization or mixture reading is more defensible.
A single accidental is not enough; the analyst should weigh cadence, pivot, and sustained leading-tone behavior together.