6.6 Melodic Sequences

TLDR

A melodic sequence is when a short melodic segment is stated, then immediately repeated at a higher or lower pitch level. The interval of transposition usually stays the same size across each repetition (for example, a sequence that moves up a third keeps moving up a third). On the AP Music Theory exam, your job is to recognize and apply this pattern in both performed and notated music.

A melodic sequence is a short segment restated at a higher or lower pitch level, and spotting one lets you parse a melody faster and see how the phrase is built. Because it often sits over a harmonic sequence, it leads straight into the next topic, 6.7.

Defining and Identifying a Melodic Sequence

• A melodic sequence is a melodic segment followed immediately by one or more transpositions of that same segment.
• The interval of transposition is usually held constant in size (for example, all repetitions move up a third).
• Sequences can be ascending or descending; the direction usually stays consistent.
• Diatonic (tonal) sequences stay in the key, so interval quality can shift between repetitions; chromatic sequences use accidentals to keep interval quality exact.
• A melodic sequence may occur with a corresponding harmonic sequence underneath it.
• To identify one, find the segment (pattern), then confirm the next statements are transpositions by the same interval.

Two Things to Track in Every Sequence

When you analyze a melodic sequence, focus on two features.

The pattern (segment). This is the original melodic idea being repeated. The pattern is defined by both its pitches and its rhythm, and those properties usually stay intact through the sequence. A pattern can be a motive, but it does not have to be. A motive is a thematic idea developed across a piece, while a sequence pattern may just repeat a few times and not return.

The interval of transposition. This is the interval each repetition is moved up or down. In typical sequences this interval is small, often a step (second) or a third, so the line stays smooth rather than jumping by large leaps. The size usually stays consistent across the whole sequence.

Diatonic vs. Chromatic Sequences

Diatonic (tonal) sequences stay inside the key. Because you only use notes of the scale, the quality of the transposition interval can change from one repetition to the next. For example, in F minor descending stepwise from F, you might first move down a Major 2nd to E♭, then down another Major 2nd to D♭, but later move down a minor 2nd to C♮. The size (a 2nd) stays the same, but the quality shifts to fit the key.

Chromatic sequences use accidentals to keep the interval quality exactly the same between repetitions. The composer essentially restates the same melody in a different key each time. Because of this, chromatic sequences are often associated with motion toward a new key.

One useful exception to the "same interval" rule happens when a melody outlines the tones of a chord. A pattern might move up a 4th, then up a 3rd, to arpeggiate a chord. In that case the intervals are not all identical, but the segment is still being moved through chord tones in an organized way.

How a Sequence Functions in a Phrase

Sequences tend to do one of two things in a passage.

Prolonging the tonic area. Repeating a pattern with notes drawn from the tonic key reinforces stability and keeps the music centered. These are usually diatonic, since accidentals would pull away from the tonic feel.

Signaling motion to another key. Because a sequence creates a sense of forward motion, it can carry a passage toward a new key. Sequences used this way are often chromatic, moving by steps or thirds (or following common harmonic patterns) until the target key arrives.

Spotting and Labeling Transposed Segments

MCQ: When a melody repeats, ask yourself: is this an exact transposition of the previous segment by a consistent interval? If yes, it is a sequence. Then decide:

• Is it ascending or descending?
• Is the interval of transposition a step or a third (most common)?
• Is it diatonic (stays in key, quality may shift) or chromatic (uses accidentals to keep quality exact)?

For aural questions, listen for the same contour and rhythm coming back at a new pitch level. For notated questions, mark off the first segment, then compare it to what follows note by note.

Score Analysis: Bracket the pattern, then bracket each repetition. Label the interval and direction (for example, "sequence descending by step"). Note whether a harmonic sequence supports the melodic one, since the two often appear together.

Sight-Singing: If you spot a sequence early, you can predict upcoming pitches instead of reading every note from scratch. Recognizing the pattern keeps you accurate and steady.

Common Trap: The pattern is defined by both pitch and rhythm. If the rhythm changes or the segment is not actually transposed by a consistent interval, it may be repetition or variation, not a true sequence.

Common Misconceptions

• Misconception: A sequence is just any repetition.
  Actually: A sequence is not just any repetition. True repetition restates a segment at the same pitch level. A sequence restates it at a new pitch level by transposition.
• Misconception: The interval quality has to be identical in a diatonic sequence.
  Actually: The interval quality does not have to be identical in a diatonic sequence. Only the size of the interval is usually held constant; staying in the key can change the quality (Major 2nd vs. minor 2nd, for example).
• Misconception: Sequences have to be motives.
  Actually: Sequences do not have to be motives. A sequence pattern can be a short idea that repeats a few times and never returns, while a motive is developed across a whole piece.
• Misconception: Chromatic means random accidentals.
  Actually: Chromatic does not mean random accidentals. In a chromatic sequence, the accidentals exist specifically to keep the interval quality exact between repetitions.
• Misconception: Melodic and harmonic sequences are the same.
  Actually: Melodic and harmonic sequences are related but not the same. A melodic sequence may occur with a corresponding harmonic sequence, but you should still confirm each one separately.

Practice Prompt

Find a passage in a piece you know and check it for sequences. For each repeated segment, identify the pattern, the interval and direction of transposition, and whether it is diatonic or chromatic. Then decide whether it seems to prolong the tonic area or push toward a new key. This is exactly the kind of thinking the exam rewards.

Related AP Music Theory Guides

• 6.7 Harmonic Sequences
• 6.2 Embellishing Tones: Writing Passing Tones and Neighbor Tones
• Unit 6 Review: Harmony and Voice Leading III (Embellishments, Motives, and Melodic Devices)
• 6.4 Embellishing Tones: Identifying and Writing Suspensions; Identifying Retardations
• 6.1 Embellishing Tones: Identifying Passing Tones and Neighbor Tones
• 6.3 Embellishing Tones: Identifying Anticipations, Escape Tones, Appoggiaturas, and Pedal Points