-Below, we see a simple melody (in A major) that walks straight down the scale from scale degree 1 (A) to scale degree 5 (E).

-Each note is repeated once before it moves down a step. This two note group, dropped and repeated, creates a pattern that is a MELODIC SEQUENCE.

-The note durations, rhythms and intervals remain the same with each downward progression.



-If we add another line that follows a repeatable pattern, we can create a harmonic sequence.

-Below, we have a bass line that starts on the root (A) and moves up a 4th (D) and down a fifth (G#) and so on.

-This pattern repeats in each measure.

-All these chords will be in ROOT POSITION.

-These two lines (bass and soprano) working together, in this fashion, creates a HARMONIC SEQUENCE.



-With these two voices, a harmony is implied. But if we fill in the middle voices to build diatonic chords (triads in this case) we will see that these chords make a harmonic sequence based on the descending cirlce of fifths: I - IV - viiº - iii - vi - ii - V - I



-A more concise version of this sequence would be: I - iii - vi - ii - V - I

1. The “descending 5ths” bass line usually features alternating descending 5ths and ascending 4ths, as just seen above.

2. In a full diatonic circle of 5ths sequence, one of the 5ths will be a diminished 5th (º). But it may appear as an augmented (+) 4th. In major, the º5 or the +4 interval will occur between scale degrees 4 and 7. In minor, it will occur between scale degrees 6 and 2.

3. One of the triads in a diatonic circle of 5th will be a diminished triad. This will be viiº in major and iiº in minor.

4. Voice leading between chord pairs should be preserved because the circle of 5ths sequence is a descending harmonic sequence on a two chord segment.

5. In a harmonic sequence, preserving voice leading patterns is more important than functionality regarding the scale degrees. In major, the viiº will be in root position and will proceed to the iii instead of I, thereby abandoning its' normal leading tone function. In minor, the iiº will appear in root position and the VII chord will be major on the b7, rather than a diminished chord on the leading tone.

-One good way to preserve good voice leading within these sequences is to alternate the intervals of 10 (compound 3rd) and 8 (octave) in the outer voices. In this way, we can avoid parallel octaves in the outer voices.

-Below, we have the same sequence but we will rearrange the voicings so the 3rd in the upper voice (soprano). This voice will also move up 1 and down 3 in each stage of the sequence. The lower voice (bass) will continue the pattern from our first example, only moving down a 5th and up a 4th (with the same notes resulting).

-The distance between the bass note (A) and the soprano note (C#) creates the compound interval of a 10th in the first chord (I).

-In the following chord the distance between the bass note (D) and the soprano note (D) creates an interval of an octave. This pattern repeats, resulting in a sequence.

-By keeping this pattern consistant we can avoid parallel octaves in the outer voices. Looking at the score, you can see the expanding and contracting of the distances between these lines.

-Another common technique in building circle of 5ths harmonic sequences involves alternating root position (5/3) triads with first inversion triads (6/3).

-Below, again we have the same progression. Only now we begin the the first chord (I) in ROOT position and the following chord (IV) first inversion, with the 3rd of that chord (F#) in the bass.

-Now we have a pattern that alternates the intervals of 10ths and 6ths, until the final cadence. You can also the how the intervals of these voices expand and contract, thereby avoiding parallel motion.

-Thus far, we’ve been discussing triads. When it comes to seventh chords, a good strategy for proper voice leading is to alternate complete (C) and incomplete (IN) chords. In this way, we can properly prepare and resolve all the sevenths involved.

-Below, with the exception of the first and last chords (I), we have all seventh chords. The first of these 7th chords (DM7) has all 4 chord members. The chord that follows (G#ø7) has only 3 chord members (with the 5th the chord omitted). So for example, the seventh of the previous chord (C#) now resolves down to B rather than up to D by leading tone motion. Again this is to ensure good voice leading while preserving the patterns within the sequence.